Oxford University Press (OUP)Acta Medica Okayama2977-0548232026Truncation by death in the sufficient-cause frameworkuuag021ENBronner PGonçalvesFaculty of Health and Medical Sciences, University of SurreyEijiYamamotoOkayama University of ScienceEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityThe sufficient-cause framework has been used for decades to improve our understanding of both basic and complex causal concepts in epidemiology, such as mediation and interaction. Here, we make use of this framework to provide a description of truncation by death, in which the outcome of interest is undefined for individuals who die before the assessment time at the end of follow-up. We explain the noncausal nature of the crude estimand that compares outcomes by treatment levels conditional on observed survival by showing that it corresponds to a comparison of distinct risk-status types, which are defined based on their susceptibility to sufficient causes. Further, expressions for the crude estimand and for the survivor average causal effect (SACE)―a causal estimand defined under the principal stratification approach―are provided in terms of population-level joint frequencies of the background factors of sufficient causes. Finally, we also describe conditions, based on background factors of sufficient causes, under which the SACE is null. Our description of this problem, which studies truncation by death from a new perspective, might encourage further analyses of principal stratification-based estimands using sufficient causes.No potential conflict of interest relevant to this article was reported.Oxford University Press (OUP)Acta Medica Okayama0002-92622026Causal diagrams integrating counterfactuals and sufficient causeskwag046ENEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityEijiYamamotoOkayama University of ScienceNo potential conflict of interest relevant to this article was reported.MDPI AGActa Medica Okayama1718-77293262025Global Incidence Trend of Early-Onset Obesity-Related and Non-Obesity-Related Cancers324ENMiyuTerashimaOkayama University Medical SchoolKotaNakayamaOkayama University Medical SchoolSatokoUgaiDepartment of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA 02215, USAHwa-YoungLeeGraduate School of Public Health and Healthcare Management, The Catholic University of KoreaYutaTsukumoDepartment of Epidemiology, Harvard T.H. Chan School of Public HealthEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityHirokiMizunoDepartment of Epidemiology, Harvard T.H. Chan School of Public HealthMinkyoSongLaboratory of Epidemiology and Population Sciences, National Institute on Aging, National Institutes of HealthNaokoSasamotoPublic Health Sciences Division, Fred Hutchinson Cancer CenterIchiroKawachiDepartment of Social and Behavioral Sciences, Harvard T.H. Chan School of Public HealthTomotakaUgaiDepartment of Epidemiology, Harvard T.H. Chan School of Public HealthThe global rise in obesity prevalence and the incidence of early-onset cancer (diagnosed between 20 and 49 years of age) is a serious public health concern. We, therefore, evaluated the recent global trends in the incidence of early-onset obesity-related cancers and compared them to those of non-obesity-related cancers. We obtained age-standardized incidence rates of early-onset cancers diagnosed between 2000 and 2012 in 44 countries from the Cancer Incidence in Five Continents database. Using joinpoint regression models, we calculated the average annual percentage changes (AAPCs) and their corresponding 95% confidence intervals (95% CIs) for combined and individual categories of obesity-related cancers (11 and 9 cancer types in females and males, respectively) and non-obesity-related cancers (12 cancer types in both females and males). Differences in the AAPC were assessed by comparing 95% CIs, where nonoverlapping 95% CIs were considered statistically significantly different. We observed statistically significant positive AAPCs for early-onset obesity-related cancers in all available countries combined among females (global AAPC, 4.3%; 95% CI, 4.1–4.6%) and males (global AAPC, 1.4%; 95% CI, 1.2–1.7%). When analyzed by countries, we observed statistically significant positive AAPCs in 26 countries among females and 11 countries among males. AAPCs for early-onset obesity-related cancers were statistically significantly higher than those of non-obesity-related cancers in several regions, especially North America and Oceania. In conclusion, this study indicates that the incidence of early-onset obesity-related cancers exhibited a more pronounced increasing trend than non-obesity-related cancers among both sexes in many countries and regions.No potential conflict of interest relevant to this article was reported.Springer Science and Business Media LLCActa Medica Okayama1046-13104562026Adolescent screen use in the pre-internet era and subsequent health and well-being: an outcome-wide longitudinal study657ENPedro Antoniode la Rosa Fernández-PachecoYouth in Transition, Institute for Culture and Society, Universidad de NavarraRenaeWilkinsonHuman Flourishing Program, Institute for Quantitative Social Science, Harvard UniversityRichard G.CowdenHuman Flourishing Program, Institute for Quantitative Social Science, Harvard UniversityYingChenHuman Flourishing Program, Institute for Quantitative Social Science, Harvard UniversityBrendanCaseHuman Flourishing Program, Institute for Quantitative Social Science, Harvard UniversityEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityTyler J.VanderWeeleDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityThis study used data from the National Longitudinal Study of Adolescent to Adult Health (Add Health, N = 11,054) to assess whether increases in screen-based leisure during adolescence (Wave II, from 1996) predicted adult well-being (Wave IV, from 2008-09), adjusting for a wide range of covariates (Wave I, from 1995). Using an outcome-wide analytic approach, we examined associations between screen time and 38 adult outcomes, adjusting for prior screen time, values of most outcomes, and confounders. Most associations were null. Modest evidence was found for links between screen time (continuous) and reduced sense of control, illicit drug use, and allostatic load. High screen time (14 h/week) or more also showed weak associations with lower depression and preventive care use. Because the data predate widespread internet use, the findings help establish a baseline for the long-term effects of non-internet screen activities, which appeared to behave had limited impact on adult health and well-being.No potential conflict of interest relevant to this article was reported.BMJActa Medica Okayama0143-005X8022025Exposure-induced mediator–outcome confounders in causal mediation: implications and visualisation129130ENEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityTomohiroShinozakiInterfaculty Initiative in Information Studies, the University of TokyoEijiYamamotoOkayama University of ScienceNo potential conflict of interest relevant to this article was reported.Springer Science and Business Media LLCActa Medica Okayama2196-29951212025Natural Effects and Separable Effects: Insights into Mediation Analysis20ENEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityTomohiroShinozakiInterfaculty Initiative in Information Studies, the University of TokyoEijiYamamotoOkayama University of SciencePurpose of Review We compare natural effects and separable effects under nonparametric structural equation models with independent errors, highlighting their similarities and differences. By examining their required properties and sufficient conditions for identification, we aim to provide deeper insights into mediation analysis.<br>
Recent Findings If certain assumptions about confounding, positivity, and consistency are met, we can identify natural direct and indirect effects under nonparametric structural equation models with independent errors. However, these effects have been criticized because they rely on a specific cross-world quantity, and the so-called cross-world independence assumption cannot be empirically verified. Furthermore, interventions on the mediator may sometimes be challenging to even conceive. As an alternative approach, separable effects have recently been proposed and applied in mediation analysis, often under finest fully randomized causally interpretable structured tree graph models. These effects are defined without relying on any cross-world quantities and are claimed to be identifiable under assumptions that are testable in principle, thereby addressing some of the challenges associated with natural direct and indirect effects.<br>
Summary To conduct meaningful mediation analysis, it is crucial to clearly define the research question of interest, and the choice of methods should align with the nature of the question and the assumptions researchers are willing to make. Examining the underlying philosophical perspectives on causation and manipulation can provide valuable insights.No potential conflict of interest relevant to this article was reported.Japan Epidemiological AssociationActa Medica Okayama0917-50402025Effect modification and its impact on preventable and attributable fractions in the potential outcomes frameworkJE20250409ENBronner P.GonçalvesFaculty of Health and Medical Sciences, University of SurreyEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityBackground: Policy decisions should be guided by measures that capture the impact of exposures on outcomes and that explicitly account for present-day exposure distribution. Both the preventable and attributable fractions have been used for this purpose; however, exposure effects can vary across subpopulations, and when this occurs, appropriate interpretation of these measures should be facilitated by a discussion of the contributions of different subpopulations.<br>
Methods: We analyze preventable and attributable fractions in the presence of effect modification. In particular, we use potential outcomes to formally define these quantities and to clarify the weighting of different strata in the total population measures.<br>
Results: Our derivations show that stratum-specific preventable and attributable fractions are weighted in proportion to the relative frequencies of effect modifiers among individuals with the outcome of interest. We also demonstrate that these weights are valid for the related quantities, preventable and attributable proportions. Finally, we present an example that illustrates how effect modification affects interpretation of these measures.<br>
Conclusions: In sum, when effect modification is present, investigators should consider reporting these measures by the relevant population strata, and information that would allow quantification of their implicit weights in the total population estimate. Our study provides a formal justification for this approach.No potential conflict of interest relevant to this article was reported.Ovid Technologies (Wolters Kluwer Health)Acta Medica Okayama1044-39833662025Causal Approaches to Disease Progression Analyses732740ENBronner P.GonçalvesFaculty of Health and Medical Sciences, University of SurreyEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityEpidemiologic analyses that aim to quantify exposure effects on disease progression are not uncommon. Understanding the implications of these studies, however, is complicated, in part because different causal estimands could, at least in theory, be the target of such analyses. Here, to facilitate interpretation of these studies, we describe different settings in which causal questions related to disease progression can be asked, and consider possible estimands. For clarity, our discussion is structured around settings defined based on two factors: whether the disease occurrence is manipulable or not, and the type of outcome. We describe relevant causal structures and sets of response types, which consist of joint potential outcomes of disease occurrence and disease progression, and argue that settings where interventions to manipulate disease occurrence are not plausible are more common, and that, in this case, principal stratification might be an appropriate framework to conceptualize the analysis. Further, we suggest that the precise definition of the outcome of interest, in particular of what constitutes its permissible levels, might determine whether potential outcomes linked to disease progression are definable in different strata of the population. Our hope is that this paper will encourage additional methodological work on causal analysis of disease progression, as well as serve as a resource for future applied studies.No potential conflict of interest relevant to this article was reported.Ovid Technologies (Wolters Kluwer Health)Acta Medica Okayama1044-39833652025L or M1―Critical Challenges in Mediation Analysis686689ENEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityMethods for causal mediation analysis have developed dramatically over the past few decades.1–7 In the causal mediation literature, several causal quantities―or estimands―have been proposed, including natural direct and indirect effects, interventional direct and indirect effects, and separable direct and indirect effects. As another possible causal estimand, Chen and Lin8 proposed separable path-specific effects, which is an extension of the separable effects framework to cases that involve multiple ordered mediators. In this commentary, I briefly discuss the newly proposed method from a broader perspective on causal mediation analysis. For readers less familiar with common causal mediation approaches, please see related literature.1–3,9–11No potential conflict of interest relevant to this article was reported.Ovid Technologies (Wolters Kluwer Health)Acta Medica Okayama1044-39833632025Effect Modification in Settings with “Truncation by Death”374380ENBronner P.GonçalvesDepartment of Comparative Biomedical Sciences, Faculty of Health and Medical Sciences, University of SurreyEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityEpidemiologic studies recruiting individuals with higher-than-population-average mortality can be affected by “truncation by death,” whereby the outcome of interest (e.g., quality of life) is considered not to be defined for individuals who die before the end of follow-up. Here, we use the potential outcomes framework and principal stratification to derive conditions under which the survivor average causal effect, an estimand defined for the “always-survivors” stratum, is modified by a variable that represents a possible common cause of survival and the outcome of interest and by a variable that only affects survival. Further, we show that this principal effect can be expressed as a weighted average of this treatment effect for individuals with each level of these variables, and that these weights depend not only on the relative frequencies of the levels in the total population but also on the “always-survivors” principal stratum. We also discuss the implications of this work for the transportability of the survivor average causal effect.No potential conflict of interest relevant to this article was reported.Springer Science and Business Media LLCActa Medica Okayama0172-06432025Management Strategies for Truncus Arteriosus: A Comparative Analysis of Staged vs. Primary RepairENYasuyukiKobayashiDepartment of Cardiovascular Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences and Okayama University HospitalShunjiSanoDepartment of Pediatric Cardiac Surgery, Showa University Hospital ToyosuYutoNarumiyaDepartment of Cardiovascular Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences and Okayama University HospitalAyariKimuraDepartment of Cardiovascular Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences and Okayama University HospitalEtsujiSuzukiDepartment of Epidemiology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical SciencesShingoKasaharaDepartment of Cardiovascular Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences and Okayama University HospitalYasuhiroKotaniDepartment of Cardiovascular Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences and Okayama University HospitalWe reviewed the outcomes of truncus arteriosus repair (primary vs. staged repair incorporating bilateral pulmonary artery banding), focusing on survival, reintervention, and functional data. We analyzed 39 patients who underwent a first intervention for truncus arteriosus (staged, n = 19; primary, n = 20) between 1992 and 2022. The median follow-up period was 8.0 (2.2–13.2) years. Survival, freedom from reoperation, and freedom from catheter intervention were estimated using the Kaplan–Meier method. High-risk patients were defined as those with a weight ≤ 2.5 kg, ≥ moderate truncal valve regurgitation, interrupted aortic arch, or preoperative shock. In the staged group, patients with a median weight of 2.6 kg had a median intensive care unit stay of 5 days and no hospital mortality after bilateral pulmonary artery banding. At repair, the staged group had a larger conduit for the right ventricular outflow tract (14 vs. 12 mm; P = .008). Catheter intervention on the branch pulmonary artery was required in 67% of patients in the staged group, but right ventricular end-diastolic pressure at follow-up was comparable between the groups (P = .541). Survival rates were higher among high-risk patients in the staged group (87.5% vs. 21.4% at 15 years; P = .004) but were comparable between groups for standard-risk patients (P = 1.000). Bilateral pulmonary artery banding was a safe, effective procedure. Reintervention for branch pulmonary artery was common but did not affect functional outcomes. Staged repair may play a pivotal role regarding survival in high-risk patients, and risk stratification is vital.No potential conflict of interest relevant to this article was reported.Ovid Technologies (Wolters Kluwer Health)Acta Medica Okayama1044-39833562024Preventable Fraction in the Context of Disease Progression801804ENBronner P.GonçalvesDepartment of Comparative Biomedical Sciences, Faculty of Health and Medical Sciences, University of SurreyEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityThe relevance of the epidemiologic concept of preventable fraction to the study of the population-level impact of preventive exposures is unequivocal. Here, we discuss how the preventable fraction can be usefully understood for the class of outcomes that relate to disease progression (e.g., clinical severity given diagnosis), and, under the principal stratification framework, derive an expression for this quantity for this type of outcome. In particular, we show that, in the context of disease progression, the preventable fraction is a function of the effect on the postdiagnosis outcome in the principal stratum in the unexposed group who would have disease regardless of exposure status. This work will facilitate an understanding of the contribution of principal effects to the impact of preventive exposures at the population level.No potential conflict of interest relevant to this article was reported.Oxford University Press (OUP)Acta Medica Okayama0002-9262193112024Re: “Defining and identifying local average treatment effects”16411642ENEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityEijiYamamotoOkayama University of ScienceNo potential conflict of interest relevant to this article was reported.WileyActa Medica Okayama0271-358667112024Job strain and adverse pregnancy outcomes: A scoping review and meta‐analysis971979ENKotaNakayamaOkayama University Medical SchoolEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityNatalieSlopenDepartment of Social and Behavioral Sciences, Harvard T.H. Chan School of Public HealthIchiroKawachiDepartment of Social and Behavioral Sciences, Harvard T.H. Chan School of Public HealthBackground: Previous studies have shown that job strain is associated with low birthweight (LBW), preterm birth (PTB), and small for gestational age (SGA). We conducted a scoping review and meta-analysis to assess the association between job strain and adverse pregnancy outcomes.<br>
Methods: A literature search was performed on PubMed. We included English-language studies that examined the association between job strain (based on the Karasek demand-control model) and pregnancy outcomes. We excluded letters, posters, reviews, and qualitative studies. Random effects meta-analysis was performed. Heterogeneity was assessed using τ2 and I2 statistics. Potential bias was assessed using standard funnel plots. Asymmetry was evaluated by Egger's test. Leave-one-out analysis was performed for sensitivity analyses.<br>
Results: Three eligible studies were found for LBW, seven for PTB, and four for SGA. The number of subjects ranged from 135 to 4889, and the prevalence of high job strain ranged from 6.64% to 33.9%. The pooled odds ratio and 95% confidence interval (CI) for LBW, PTB, and SGA were 1.23 (95% CI: 0.97, 1.56), 1.10 (95% CI: 1.00, 1.22), and 1.16 (95% CI: 0.97, 1.39) respectively, indicating modest associations. Heterogeneity for LBW and PTB may not be important but may be moderate for SGA. No publication bias was detected for LBW and PTB, but possible publication bias exists for SGA.<br>
Conclusion: We found a modest association between job strain and PTB. Since job strain is only one of the many aspects of an unhealthy work environment, interventions that improve working conditions more broadly are needed.No potential conflict of interest relevant to this article was reported.Ovid Technologies (Wolters Kluwer Health)Acta Medica Okayama1044-39833542024Errors in the Calculation of the Population Attributable Fraction469472ENEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityEijiYamamotoOkayama University of ScienceOne of the common errors in the calculation of the population attributable fraction (PAF) is the use of an adjusted risk ratio in the Levin formula. In this article, we discuss the errors visually using wireframes by varying the standardized mortality ratio (SMR) and associational risk ratio (aRR) when the prevalence of exposure is fixed. When SMR >1 and SMR > aRR, the absolute bias is positive, and its magnitude increases as the difference between SMR and aRR increases. By contrast, when aRR > SMR > 1, the absolute bias is negative and its magnitude is relatively small. Moreover, when SMR > aRR, the relative bias is larger than one, whereas when SMR < aRR, the relative bias is smaller than one. Although the target population of the PAF is the total population, the target of causation of the PAF is not the total population but the exposed group.No potential conflict of interest relevant to this article was reported.Okayama University Medical SchoolActa Medica Okayama0386-300X7762023Fine Particulate Matter and Diabetes Prevalence in Okayama, Japan607612ENYasunariTaniDepartment of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical SciencesSaoriKashimaEnvironmental Health Sciences Laboratory, Graduate School of Advanced Science and Engineering, Center for the Planetary Health and Innovation Science, The IDEC Institute, Hiroshima UniversityToshiharuMitsuhashiCenter for Innovate Clinical Medicine, Okayama University HospitalEtsujiSuzukiDepartment of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical SciencesSoshiTakaoDepartment of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical SciencesTakashiYorifujiDepartment of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical SciencesOriginal Article10.18926/AMO/66152Many studies have shown an association between long-term exposure to particulate matter having an aerodynamic diameter of 2.5 μm or less (PM2.5) and diabetes mellitus (DM), but few studies have focused on Asian subjects. We thus examined the association between long-term exposure to PM2.5 and DM prevalence in Okayama City, Japan. We included 76,591 participants who had received basic health checkups in 2006 and 2007. We assigned the census-level modeled PM2.5 data from 2006 and 2007 to each participant and defined DM using treatment status and the blood testing. PM2.5 was associated with DM prevalence, and the prevalence ratio (95% confidence interval) was 1.10 (1.00-1.20) following each interquartile range increase (2.1 μg/m3) in PM2.5. This finding is consistent with previous results and suggests that long-term exposure to PM2.5 is associated with an increased prevalence of DM in Okayama City, Japan, where the PM2.5 level is lower than in other cities in Asian countries.No potential conflict of interest relevant to this article was reported.Nature PortfolioActa Medica Okayama2045-23221312023A population-based longitudinal study on glycated hemoglobin levels and new-onset chronic kidney disease among non-diabetic Japanese adults13770ENYukariOkawaDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityToshiharuMitsuhashiCenter for Innovative Clinical Medicine, Okayama University HospitalToshihideTsudaDepartment of Human Ecology, Graduate School of Environmental and Life Science, Okayama UniversityTakashiYorifujiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityChronic kidney disease (CKD) is a major global public health problem. Recent studies reported that diabetes and prediabetes are risk factors for developing CKD; however, the exact glycated hemoglobin (HbA1c) cut-off value for prediabetes remains controversial. In this study, we aimed to examine the relationship between HbA1c levels and subsequent CKD development in greater detail than previous studies. Longitudinal data of annual checkups of 7176 Japanese non-diabetic people (male: 40.4%) from 1998 to 2022 was analyzed. HbA1c values were categorized into < 5.0%, 5.0-5.4%, 5.5-5.9%, and 6.0-6.4%. CKD was defined as an estimated glomerular filtration rate < 60 ml/min/1.73 m(2). The descriptive statistics at study entry showed that higher HbA1c values were associated with male, older, overweight or obese, hypertensive, or dyslipidemic people. During a mean follow-up of 7.75 person-years, 2374 participants (male: 40.0%) developed CKD. The Weibull accelerated failure time model was selected because the proportional hazards assumption was violated. The adjusted time ratios of developing CKD for HbA1c levels of 5.5-5.9% and 6.0-6.4% compared with 5.0-5.4% were 0.97 (95% confidence interval: 0.92-1.03) and 1.01 (95% confidence interval: 0.90-1.13), respectively. There was no association between HbA1c in the prediabetic range and subsequent CKD development.No potential conflict of interest relevant to this article was reported.Springer Science and Business Media LLCActa Medica Okayama0021-51556762023Accuracy of ultrasound vs. Fourier-domain optic biometry for measuring preoperative axial length in cases of rhegmatogenous retinal detachment645651ENShuheiKimuraDepartment of Ophthalmology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityMio MorizaneHosokawaDepartment of Ophthalmology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityYusukeShiodeDepartment of Ophthalmology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityRyoMatobaDepartment of Ophthalmology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityYukiKanzakiDepartment of Ophthalmology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityYasuhitoGotoDepartment of Ophthalmology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityKeisukeKanenagaDepartment of Ophthalmology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityYukiMorizaneDepartment of Ophthalmology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityPurpose To identify a method for accurately measuring preoperative axial length (AL) in cases of rhegmatogenous retinal detachment (RRD).<br>
Study design Retrospective study.<br>
Methods This retrospective study included 83 eyes of 83 patients who underwent vitrectomy for RRD and had both preoperative and postoperative data for AL. Preoperative AL measurements for the affected eye were obtained using ultrasound (aUS-AL) and compared with those for affected and fellow eyes measured using optical biometry (aOB-AL and fOB-AL, respectively). Absolute differences between preoperative aUS-AL, aOB-AL, or fOB-AL measurements and postoperative AL (aPost-AL) were examined.<br>
Results In the 41 eyes without macular detachment, the absolute difference between aOB-AL and aPost-AL (0.06±0.07 mm) was significantly smaller than between aUS-AL and aPost-AL (0.21±0.18 mm) and that between fOB-AL and aPost-AL (0.29±0.35 mm) (P = 0.017 and P < 0.001, respectively). In the 42 eyes with macular detachment, the absolute difference between aOB-AL and aPost-AL (1.22±2.40 mm) was significantly larger than between aUS-AL and aPost-AL (0.24±0.24 mm) and between fOB-AL and aPost-AL (0.35±0.49 mm) (P = 0.006, P = 0.016, respectively).<br>
Conclusion The current findings suggest that aOB-AL is more accurate than aUS-AL or fOB-AL in cases of RRD without macular detachment, while aUS-AL or fOB-AL is more accurate than aOB-AL in cases with macular detachment.No potential conflict of interest relevant to this article was reported.Ovid Technologies (Wolters Kluwer Health)Acta Medica Okayama0275-004X4342023IMPACT OF MACULAR INTRARETINAL HEMORRHAGE AND MACULAR HOLE ON THE VISUAL PROGNOSIS OF SUBMACULAR HEMORRHAGE DUE TO RETINAL ARTERIAL MACROANEURYSM RUPTURE585593ENShinichiroDoiDepartment of Ophthalmology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityShuheiKimuraDepartment of Ophthalmology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityShokoSaitoKyorin Eye Center, Kyorin University School of MedicineMakotoInoueKyorin Eye Center, Kyorin University School of MedicineToshiyaSakuraiDepartment of Ophthalmology, Tane Memorial Eye HospitalAkiraKoboriDepartment of Ophthalmology, Fukui Red Cross HospitalToshioHisatomiDepartment of Ophthalmology, Chikushi Hospital, Fukuoka UniversityHisanoriImaiDivision of Ophthalmology, Department of Surgery, Kobe University Graduate School of MedicineShojiKuriyamaOtowa Eye CenterIppeiTakasuTakasu Eye ClinicMio MorizaneHosokawaDepartment of Ophthalmology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityYusukeShiodeDepartment of Ophthalmology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityRyoMatobaDepartment of Ophthalmology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityYukiMorizaneDepartment of Ophthalmology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityPurpose: To compare the effects of macular intraretinal hemorrhage (IRH) and macular hole (MH) on best-corrected visual acuity (BCVA) after displacement of submacular hemorrhage (SMH) due to retinal arterial macroaneurysm (RAM) rupture.<br>
Methods: This multicenter retrospective study included 48 eyes with SMH due to RAM rupture. Cases underwent vitrectomy to displace SMH and were followed up for 6 months. We classified cases according to the presence of IRH and MH and compared the postoperative BCVA among the groups.<br>
Results: We classified the eyes into IRH(+)MH(+) group (10 eyes), IRH(+)MH(−) group (23 eyes), and IRH(−)MH(−) group (15 eyes). The postoperative BCVA was significantly worse in the IRH(+)MH(+) and IRH(+)MH(−) groups than in the IRH(−)MH(−) group (0.91 ± 0.41 in logarithm of the minimal angle of resolution units, Snellen equivalent 20/163, 0.87 ± 0.45, 20/148, and 0.18 ± 0.21, 20/30, respectively; P < 0.001). The postoperative central retinal thickness was significantly lower in the IRH(+) group (IRH(+)MH(+) and IRH(+)MH(−) groups combined) than in the IRH(−) group (IRH(−)MH(−) group) (121.4 ± 70.1 µm and 174.3 ± 32.9 µm, respectively, P = 0.008). The postoperative external limiting membrane and ellipsoid zone continuities were significantly discontinuous in the IRH(+) group (P < 0.001, P = 0.001, respectively). The multiple linear regression analysis showed that both IRH(+)MH(+) and IRH(+)MH(−) were associated with the postoperative BCVA (regression coefficient, 0.799 and 0.711, respectively; P < 0.001 for both).<br>
Conclusion: Both IRH and MH were poor prognostic indicators in cases with SMH due to RAM rupture.No potential conflict of interest relevant to this article was reported. WileyActa Medica Okayama2047-99801262023Heat Exposure Following the Rainy Season Is Associated With an Increased Risk of Cardiovascular Emergency Among the Elderly in Japane027046ENRyoheiFujimotoDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University SaoriKashimaEnvironmental Health Sciences Laboratory, Graduate School of Advanced Science and Engineering, Hiroshima UniversityKazufumiNakamuraDepartment of Cardiovascular Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityHiromichiNaitoDepartment of Emergency, Critical Care and Disaster Medicine, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama UniversityAtsunoriNakaoDepartment of Emergency, Critical Care and Disaster Medicine, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama UniversityHiroshiItoDepartment of Cardiovascular Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityTakashiYorifujiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityBackground: Despite the impact of heat exposure caused by global warming, few studies have investigated the hourly effects of heat exposure and the risk of cardiovascular disease (CVD) in the elderly. We examined the associations between short-term heat exposure and the risk of CVD in the elderly in Japan and evaluated possible effect-measure modifications by rainy seasons that occur in East Asia. <br>
Methods and Results: We conducted a time-stratified case-crossover study. The study included 6527 residents in Okayama City, Japan, aged >= 65 years who were transported to emergency hospitals between 2012 and 2019 for the onset of CVD during and a few months after the rainy seasons. We examined the linear associations between temperature and CVD-related emergency calls for each year and for hourly preceding intervals before the emergency call during the most relevant months. Heat exposure during 1 month after the end of the rainy season was associated with CVD risk; the odds ratio (OR) for a 1 degrees C increase in temperature was 1.34 (95% CI, 1.29-1.40). When we further explored the nonlinear association by using the natural cubic spline model, we found a J-shaped relationship. Exposures 0 to 6 hours before the case event (preceding intervals 0-6 hours) were associated with CVD risk, particularly for the preceding interval 0 to 1 hour (OR, 1.33 [95% CI, 1.28-1.39]). For longer periods, the highest risk was at preceding intervals 0 to 23 hours (OR, 1.40 [95% CI, 1.34-1.46]).<br>
Conclusions: Elderly individuals may be more susceptible to CVD after heat exposure during the month after the rainy season. As shown by finer temporal resolution analyses, short-term exposure to increasing temperature can trigger CVD onset.No potential conflict of interest relevant to this article was reported.Japan Epidemiological AssocActa Medica Okayama0917-50402022Exchangeability of Measures of Association Before and After Exposure Status Is Flipped: Its Relationship With Confounding in the Counterfactual ModelENEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityMichioYamamotoGraduate School of Environmental and Life Science, Okayama UniversityEijiYamamotoOkayama University of ScienceBackground: The counterfactual definition of confounding is often explained in the context of exchangeability between the exposed and unexposed groups. One recent approach is to examine whether the measures of association (eg, associational risk difference) are exchangeable when exposure status is flipped in the population of interest. We discuss the meaning and utility of this approach, showing their relationships with the concept of confounding in the counterfactual framework.<br>
Methods: Three hypothetical cohort studies are used, in which the target population is the total population. After providing an overview of the notions of confounding in distribution and in measure, we discuss the approach from the perspective of exchangeability of measures of association (eg, factual associational risk difference vs counterfactual associational risk difference).<br>
Results: In general, if the measures of association are non-exchangeable when exposure status is flipped, confounding in distribution is always present, although confounding in measure may or may not be present. Even if the measures of association are exchangeable when exposure status is flipped, there could be confounding both in distribution and in measure. When we use risk difference or risk ratio as a measure of interest and the exposure prevalence in the population is 0.5, testing the exchangeability of measures of association is equivalent to testing the absence of confounding in the corresponding measures.<br>
Conclusion: The approach based on exchangeability of measures of association essentially does not provide a definition of confounding in the counterfactual framework. Subtly differing notions of confounding should be distinguished carefully.No potential conflict of interest relevant to this article was reported.De GruyterActa Medica Okayama2193-36771112023Attributable fraction and related measures: Conceptual relations in the counterfactual frameworkENEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityEijiYamamotoOkayama University of ScienceThe attributable fraction (population) has attracted much attention from a theoretical perspective and has been used extensively to assess the impact of potential health interventions. However, despite its extensive use, there is much confusion about its concept and calculation methods. In this article, we discuss the concepts of and calculation methods for the attributable fraction and related measures in the counterfactual framework, both with and without stratification by covariates. Generally, the attributable fraction is useful when the exposure of interest has a causal effect on the outcome. However, it is important to understand that this statement applies to the exposed group. Although the target population of the attributable fraction (population) is the total population, the causal effect should be present not in the total population but in the exposed group. As related measures, we discuss the preventable fraction and prevented fraction, which are generally useful when the exposure of interest has a preventive effect on the outcome, and we further propose a new measure called the attributed fraction. We also discuss the causal and preventive excess fractions, and provide notes on vaccine efficacy. Finally, we discuss the relations between the aforementioned six measures and six possible patterns using a conceptual schema.No potential conflict of interest relevant to this article was reported.Oxford University Press on behalf of The Japanese Radiation Research Society and Japanese Society for Radiation OncologyActa Medica Okayama0449-30602022Tumor size before image-guided brachytherapy is an important factor of local control after radiotherapy for cervical squamous cell carcinoma: analysis in cases using central shieldingENKotaroYoshioDepartment of Proton Beam Therapy, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityHirokiIharaDepartment of Radiology, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityKazuhiroOkamotoDepartment of Obstetrics and Gynecology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityTakeshiOgataDepartment of Radiology, Tsuyama Central HospitalSoichiSugiyamaDepartment of Proton Beam Therapy, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityKeiichiroNakamuraDepartment of Obstetrics and Gynecology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityShojiNagaoDepartment of Obstetrics and Gynecology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityHisashiMasuyamaDepartment of Obstetrics and Gynecology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityTakaoHirakiDepartment of Radiology, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityWe analyzed the local control (LC) of cervical squamous cell carcinoma treated by computed tomography (CT)-based image-guided brachytherapy (IGBT) using central shielding (CS). We also examined the value of tumor diameter before brachytherapy (BT) as a factor of LC. In total, 97 patients were analyzed between April 2016 and March 2020. Whole-pelvic (WP) radiotherapy (RT) with CS was performed, and the total pelvic sidewall dose was 50 or 50.4 Gy; IGBT was delivered in 3-4 fractions. The total dose was calculated as the biologically equivalent dose in 2 Gy fractions, and distribution was modified manually by graphical optimization. The median follow-up period was 31.8 months (6.3-63.2 months). The 1- and 2-year LC rates were 89% and 87%, respectively. The hazard ratio was 10.11 (95% confidence interval: 1.48-68.99) for local recurrence in those with a horizontal tumor diameter >= 4 cm compared to those with < 4 cm before BT. In CT-based IGBT for squamous cell carcinoma, favorable LC can be obtained in patients with a tumor diameter < 4 cm before BT. However, if the tumor diameter is >= 4 cm, different treatment strategies such as employing interstitial-BT for dose escalation may be necessary.No potential conflict of interest relevant to this article was reported.Elsevier BVActa Medica Okayama1047-279726112016Errors in causal inference: an organizational schema for systematic error and random error788793ENEtsujiSuzukiDepartment of Epidem iology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityToshihideTsudaDepartment of Human Ecology, Graduate School of Environmenta l and Life Science, Okayama UniversityToshiharuMitsuhashiCenter for Innovative Clinical Medicine, Okayama University Hospital, Okayama University,Mohammad AliMansourniaDepartment of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical SciencesEijiYamamotoDepartment of Information Science, Faculty of Informatics, Okayama University of SciencePurpose<br>
To provide an organizational schema for systematic error and random error in estimating causal measures, aimed at clarifying the concept of errors from the perspective of causal inference.<br>
<br>
Methods<br>
We propose to divide systematic error into structural error and analytic error. With regard to random error, our schema shows its four major sources: nondeterministic counterfactuals, sampling variability, a mechanism that generates exposure events and measurement variability.<br>
<br>
Results<br>
Structural error is defined from the perspective of counterfactual reasoning and divided into nonexchangeability bias (which comprises confounding bias and selection bias) and measurement bias. Directed acyclic graphs are useful to illustrate this kind of error. Nonexchangeability bias implies a lack of “exchangeability” between the selected exposed and unexposed groups. A lack of exchangeability is not a primary concern of measurement bias, justifying its separation from confounding bias and selection bias. Many forms of analytic errors result from the small-sample properties of the estimator used and vanish asymptotically. Analytic error also results from wrong (misspecified) statistical models and inappropriate statistical methods.<br>
<br>
Conclusions<br>
Our organizational schema is helpful for understanding the relationship between systematic error and random error from a previously less investigated aspect, enabling us to better understand the relationship between accuracy, validity, and precision.No potential conflict of interest relevant to this article was reported.Elsevier BVActa Medica Okayama1047-27972812018Covariate balance for no confounding in the sufficient-cause model4853ENEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityToshihideTsudaDepartment of Human Ecology, Graduate School of Environmental and Life Science, Okayama UniversityEijiYamamotoDepartment of Information Science, Faculty of Informatics, Okayama University of SciencePurpose: To show conditions of covariate balance for no confounding in the sufficient-cause model and discuss its relationship with exchangeability conditions.<br>
Methods: We consider the link between the sufficient-cause model and the counterfactual model, emphasizing that the target population plays a key role when discussing these conditions. Furthermore, we incorporate sufficient causes within the directed acyclic graph framework. We propose to use each of the background factors in sufficient causes as representing a set of covariates of interest and discuss the presence of covariate balance by comparing joint distributions of the relevant background factors between the exposed and the unexposed groups.<br>
Results: We show conditions for partial covariate balance, covariate balance, and full covariate
balance, each of which is stronger than partial exchangeability, exchangeability, and full exchangeability, respectively. This is consistent with the fact that the sufficient-cause model is a “finer” model than the counterfactual model.<br>
Conclusions: Covariate balance is a sufficient, but not a necessary, condition for no confounding irrespective of the target population. Although our conceptualization of covariate imbalance is closely related to the recently proposed counterfactual-based definition of a confounder, the concepts of covariate balance and confounder should be clearly distinguished.No potential conflict of interest relevant to this article was reported.Ovid Technologies (Wolters Kluwer Health)Acta Medica Okayama1044-39833262021Marginal Sufficient Component Cause Model - An Emerging Causal Model With Merits?838845ENEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityEijiYamamotoOkayama University of ScienceFor decades, the sufficient cause model and the counterfactual model have shaped our understanding of causation in biomedical science, and the link between these two models has enabled us to obtain a deeper understanding of causality. Recently, a new causal model―the marginal sufficient component cause model―was proposed and applied in the context of interaction or mediation. The proponents of this model have emphasized its utility in visualizing the presence of “agonism” (a subtype of mechanistic interaction) in the counterfactual framework, claiming that the concept of agonism has not been clearly defined in causal inference and that agonistic interaction cannot be visualized by the conventional sufficient cause model. In this article, we illustrate that careful scrutiny based on the conventional sufficient cause model yields further insights into the concept of agonism in a more
biologic sense. We primarily focus on the following three points: a) “agonism” defined in the
counterfactual model can be visualized as sets of sufficient causes in the conventional sufficient cause model; b) although the so-called independent competing assumption or no redundancy assumption may seem irrelevant in the marginal sufficient component cause model, researchers do need to assume that potential completion times of relevant marginal sufficient causes differ; c) possibly differing potential completion times of marginal sufficient causes cannot be discerned until their hidden mechanistic paths are considered in the conventional sufficient cause model. In this rapidly progressing field of research, decades after its introduction, the sufficient cause model retains its worth.No potential conflict of interest relevant to this article was reported.Springer Science and Business Media LLCActa Medica Okayama0393-29903692021Strength in causality: discerning causal mechanisms in the sufficient cause model899908ENEtsujiSuzukiGraduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityEijiYamamotoOkayama University of ScienceThe assessment of causality is fundamental to epidemiology and biomedical sciences. One well-known approach to distinguishing causal from noncausal explanations is the nine Bradford Hill viewpoints. A recent article in this journal revisited the viewpoints to incorporate developments in causal thinking, suggesting that the sufficient cause model is useful in elucidating the theoretical underpinning of the first of the nine viewpoints―<i>strength</i> of association. In this article, we discuss how to discern the causal mechanisms of interest in the sufficient cause model, which pays closer attention to the relationship between the sufficient cause model and the Bradford Hill viewpoints. To this end, we explicate the link between the sufficient cause model and the potential-outcome model, both of which have become the cornerstone of causal thinking in epidemiology and biomedicine. A clearer understanding of the link between the two models provides significant implications for interpretation of the observed risks in the subpopulations defined by exposure and confounder. We also show that the concept of potential completion times of sufficient causes is useful to fully discerning completed sufficient causes, which leads us to pay closer attention to the fourth of the nine Bradford Hill viewpoints―<i>temporality</i>. Decades after its introduction, the sufficient cause model may be vaguely understood and thus implicitly used under unreasonably strict assumptions. To <i>strengthen</i> our assessment in the face of multifactorial causality, it is significant to carefully scrutinize the observed associations in a complementary manner, using the sufficient cause model as well as its relevant causal models.No potential conflict of interest relevant to this article was reported.岡山医学会Acta Medica Okayama0030-155813312021データサイエンスにおける人工知能 (AI) と疫学の位置付け ―予測と因果推論の違い―5557ENTakashiYorifujiDepartment of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical SciencesEtsujiSuzukiDepartment of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical SciencesNo potential conflict of interest relevant to this article was reported.SpringerActa Medica Okayama1068-9265282020A Simple Prognostic Benefit Scoring System for Sarcoma Patients with Pulmonary Metastases: Sarcoma Lung Metastasis Score38843890ENHaruchikaYamamotoDepartment of Thoracic Surgery, Okayama University HospitalHiromasaYamamotoDepartment of Thoracic Surgery, Okayama University HospitalJunichiSohDepartment of Thoracic Surgery, Okayama University HospitalEtsujiSuzukiDepartment of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical SciencesKeiNambaDepartment of Thoracic Surgery, Okayama University HospitalKenSuzawaDepartment of Thoracic Surgery, Okayama University HospitalKentarohMiyoshiDepartment of Thoracic Surgery, Okayama University HospitalShinjiOtaniDepartment of Thoracic Surgery, Okayama University HospitalMikioOkazakiDepartment of Thoracic Surgery, Okayama University HospitalSeiichiroSugimotoDepartment of Thoracic Surgery, Okayama University HospitalMasaomiYamaneDepartment of Thoracic Surgery, Okayama University HospitalTakashiYorifujiDepartment of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical SciencesKatsuhitoTakahashiCenter for Multidisciplinary Treatment of Sarcoma, Department of Sarcoma Medicine, Kameda Medical CenterShinichiToyookaDepartment of Thoracic Surgery, Okayama University HospitalBackground</br>
Pulmonary metastasectomy could be considered one of the treatment options for disease control in sarcoma patients with pulmonary metastases; however, there is little consensus regarding the suitable criteria for predicting the likely outcomes in these patients. The aim of this study was to establish a prognostic benefit scoring system based on preoperatively examined prognostic factors for sarcoma patients with pulmonary metastases.</br>
Methods</br>
This was a single-center, retrospective cohort study conducted in a cohort of 135 sarcoma patients who underwent a first pulmonary metastasectomy at Okayama University Hospital between January 2006 and December 2015. Based on the results of a multivariable logistic regression analysis performed to determine the factors influencing 3-year mortality, a Sarcoma Lung Metastasis Score was created and its correlation with 3-year survival was analyzed.</br>
Results</br>
The results of the multivariate analysis revealed significant differences in the disease-free interval (< 2 years vs. ≥ 2 years; odds ratio (OR) 4.22, 95% confidence interval (CI) 1.67–10.70), maximum tumor diameter (≥ 15 mm vs. < 15 mm; OR 3.86, 95% CI 1.75–8.52), and number of pulmonary metastases (≥ 6 vs. < 6; OR 2.65, 95% CI 1.06–6.620). The Sarcoma Lung Metastasis Score, which was defined as the total score of these three factors, reliably predicted 3-year survival (score: 0, 89.5%; 1, 63.2%; 2, 39.0%; 3, 10.5%).</br>
Conclusions</br>
Our newly proposed simple Sarcoma Lung Metastasis Score appears to be a useful prognostic predictor for sarcoma patients with pulmonary metastases, in that it could be helpful for the selection of appropriate treatments for these patients.No potential conflict of interest relevant to this article was reported.ElsevierActa Medica Okayama2049-0801582020Continuing surgical education of non-technical skills177186ENMasaomiYamaneDepartments of General Thoracic Surgery and Breast and Endocrinological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical SciencesSeiichiroSugimotoDepartments of General Thoracic Surgery and Breast and Endocrinological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical SciencesEtsujiSuzukiDepartment of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical SciencesKeijuAokageDepartment of Thoracic Surgery, National Cancer Center Hospital EastMikioOkazakiDepartments of General Thoracic Surgery and Breast and Endocrinological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical SciencesJunichiSohDivision of Thoracic Surgery, Department of Surgery, Kindai University Faculty of MedicineMakioHayamaDepartment of Thoracic Surgery, Japanese Red Cross Okayama HospitalYujiHiramiDepartment of General Thoracic Surgery, National Hospital Organization Okayama Medical CenterTakashiYorifujiDepartment of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical SciencesShinichiToyookaDepartments of General Thoracic Surgery and Breast and Endocrinological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical SciencesBackground</br>
The non-technical skills for surgeons (NOTSS) system was developed as a tool to assess surgical skills for patient safety during surgery. This study aimed to develop a NOTSS-based training system for surgical trainees to acquire non-technical skills using a chest surgery scenario in a wet lab.</br>
Materials and methods</br>
Trainees were categorized into three subgroups according to the years of experience as follows: Level A: 6 years or more; Level B: 3–5 years; and Level C: 1–2 years. Three stages of surgical procedure were designed: 1. chest wall resection and right upper lobe lobectomy, 2. right middle lobe sleeve lobectomy, and 3. right lower lobe lobectomy. One instructor was assigned to each operation table, who evaluated each participant's NOTSS scores consisting of 16 elements.</br>
Results</br>
When comparing average NOTSS score of all the three procedures, significant differences were observed between Level A, B, and C trainees. As an example of varying elements by procedure, Level A trainees demonstrated differences in Situation Awareness, and a significant difference was observed in Level C trainees regarding the elements of Decision Making. On the contrary, no significant difference was observed among Level B trainees. In the comparison between first-time and experienced participants, a significant improvement was observed in some elements in Level B and C trainees.</br>
Conclusion</br>
This study highlights the usefulness and feasibility of the NOTSS scoring system for surgeons with different experiences and the effectiveness of providing feedback to trainees during intraoperative handoffs in a wet lab.No potential conflict of interest relevant to this article was reported.Japan Epidemiological AssociationActa Medica Okayama0917-50403042020Causal Diagrams: Pitfalls and Tips153162ENEtsujiSuzukiDepartment of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama UniversityTomohiroShinozakiDepartment of Information and Computer Technology, Faculty of Engineering, Tokyo University of ScienceEijiYamamotoOkayama University of ScienceGraphical models are useful tools in causal inference, and causal directed acyclic graphs (DAGs) are used extensively to determine the variables for which it is sufficient to control for confounding to estimate causal effects. We discuss the following ten pitfalls and tips that are easily overlooked when using DAGs: 1) Each node on DAGs corresponds to a random variable and not its realized values; 2) The presence or absence of arrows in DAGs corresponds to the presence or absence of individual causal effect in the population; 3) "Non-manipulable" variables and their arrows should be drawn with care; 4) It is preferable to draw DAGs for the total population, rather than for the exposed or unexposed groups; 5) DAGs are primarily useful to examine the presence of confounding in distribution in the notion of confounding in expectation; 6) Although DAGs provide qualitative differences of causal structures, they cannot describe details of how to adjust for confounding; 7) DAGs can be used to illustrate the consequences of matching and the appropriate handling of matched variables in cohort and case-control studies; 8) When explicitly accounting for temporal order in DAGs, it is necessary to use separate nodes for each timing; 9) In certain cases, DAGs with signed edges can be used in drawing conclusions about the direction of bias; and 10) DAGs can be (and should be) used to describe not only confounding bias but also other forms of bias. We also discuss recent developments of graphical models and their future directions.No potential conflict of interest relevant to this article was reported.International Society for Environmental EpidemiologyActa Medica Okayama1044-39832015Thyroid Cancer Detection by Ultrasound Among Residents Ages 18 Years and Younger in FukushimaENToshihideTsudaAkikoTokinobuEijiYamamotoEtsujiSuzukiBackground: After the Great East Japan Earthquake and Tsunami in March 2011, radioactive elements were released from the Fukushima Daiichi Nuclear Power Plant. Based on prior knowledge, concern emerged about whether an increased incidence of thyroid cancer among exposed residents would occur as a result.
Methods: After the release, Fukushima Prefecture performed ultrasound thyroid screening on all residents ages <=18 years. The first round of screening included 298,577 examinees, and a second round began in April 2014. We analyzed the prefecture results from the first and second round up to December 31, 2014, in comparison with the Japanese annual incidence and the incidence within a reference area in Fukushima Prefecture.
Results: The highest incidence rate ratio, using a latency period of 4 years, was observed in the central middle district of the prefecture compared with the Japanese annual incidence (incidence rate ratio = 50; 95% confidence interval [CI] = 25, 90). The prevalence of thyroid cancer was 605 per million examinees (95% CI = 302, 1,082) and the prevalence odds ratio compared with the reference district in Fukushima Prefecture was 2.6 (95% CI = 0.99, 7.0). In the second screening round, even under the assumption that the rest of examinees were disease free, an incidence rate ratio of 12 has already been observed (95% CI = 5.1, 23).
Conclusions: An excess of thyroid cancer has been detected by ultrasound among children and adolescents in Fukushima Prefecture within 4 years of the release, and is unlikely to be explained by a screening surge.No potential conflict of interest relevant to this article was reported.Okayama University Medical SchoolActa Medica Okayama0386-300X6862014Living Will Interest and Preferred End-of-life Care and Death Locations among Japanese Adults 50 and over: A Population-based Survey339348ENHiroyukiNishieSatoshiMizobuchiEtsujiSuzukiKenjiSatoYuichiroTodaJunjiMatsuokaHiroshiMorimatsuOriginal Article10.18926/AMO/53023The main purpose of this study was to determine the relationships between Japanese individualsʼ interest in living wills and their preferred end-of-life care and death locations. Questionnaires were mailed to 1,000 individuals aged ｧ50 to measure these 2 factors. We examined the associations between the respondentsʼ characteristics and their preferred care and death locations by using multinomial logistic regression models. The response rate was 74%. Home was the most frequently preferred place for end-of-life care (64%), and a palliative care unit (PCU) was the most commonly preferred place to die (51%). Living will interest was associated with a preference for care (odds ratio [OR] 4.74, 95% confidence interval [CI] 1.95-12.1) and death (OR 2.75, 95% CI 1.70-4.47) in a PCU rather than a hospital, but it was not associated with the choice between receiving care or dying at home instead of a hospital. We must consider why Japanese people think home death is impracticable. The Japanese palliative care system should be expanded to meet patientsʼ end-of-life needs, and this includes not only facilitating home care but also increasing access to PCU care.No potential conflict of interest relevant to this article was reported.Public Library ScienceActa Medica Okayama1932-6203912014The Bright Side and Dark Side of Workplace Social Capital: Opposing Effects of Gender on Overweight among Japanese EmployeesENTomokoKobayashiEtsujiSuzukiTuulaOksanenIchiroKawachiSoshiTakaoBackground: A growing number of studies have sought to examine the health associations of workplace social capital; however, evidence of associations with overweight is sparse. We examined the association between individual perceptions of workplace social capital and overweight among Japanese male and female employees.
Methodology/Principal Findings: We conducted a cross-sectional survey among full-time employees at a company in Osaka prefecture in February 2012. We used an 8-item measure to assess overall and sub-dimensions of workplace social capital, divided into tertiles. Of 1050 employees, 849 responded, and 750 (624 men and 126 women) could be linked to annual health check-up data in the analysis. Binomial logistic regression models were used to calculate odds ratios and 95% confidence intervals for overweight (body mass index: >= 25 kg/m(2), calculated from measured weight and height) separately for men and women. The prevalence of overweight was 24.5% among men and 14.3% among women. Among men, low levels of bonding and linking social capital in the workplace were associated with a nearly 2-fold risk of overweight compared to high corresponding dimensions of social capital when adjusted for age, sleep hours, physiological distress, and lifestyle. In contrast, among women we found lower overall and linking social capital to be associated with lower odds for overweight even after covariate adjustment. Subsequently, we used multinomial logistic regression analyses to assess the relationships between a 1 standard deviation (SD) decrease in mean social capital and odds of underweight/overweight relative to normal weight. Among men, a 1-SD decrease in overall, bonding, and linking social capital was significantly associated with higher odds of overweight, but not with underweight. Among women, no significant associations were found for either overweight or underweight.
Conclusions/Significance: We found opposite gender relationships between perceived low linking workplace social capital and overweight among Japanese employees.No potential conflict of interest relevant to this article was reported.Acta Medica Okayama1471-2458132013Group involvement and self-rated health among the Japanese elderly: an examination of bonding and bridging social capitalENYokoKishimotoEtsujiSuzukiToshihideIwaseHiroyukiDoiSoshiTakaoBackground: To date, only a small amount of research on bonding/bridging social capital has separately examined their effects on health though they have been thought to have differential effects on health outcomes. By using a large population-based sample of elderly Japanese people, we sought to investigate the association between bonding and bridging social capital and self-rated health for men and women separately.
Methods: In August 2010, questionnaires were sent to all residents aged >= 65 years in three municipalities in Okayama prefecture (n = 21232), and 13929 questionnaires were returned (response rate: 65.6%). Social capital was measured from survey responses to questions on participation in six different types of groups: a) the elderly club or sports/hobby/culture circle; b) alumni association; c) political campaign club; d) citizen's group or environmental preservation activity; e) community association; and f) religious organization. Participant perception of group homogeneity (gender, age, and previous occupation) was used to divide social capital into bonding or bridging. Odds ratios (ORs) and 95% confidence intervals (CIs) for poor self-rated health were calculated.
Results: A total of 11146 subjects (4441 men and 6705 women) were available for the analysis. Among men, bonding and bridging social capital were inversely associated with poor self-rated health (high bonding social capital; OR: 0.55, 95% CI: 0.31-0.99; high bridging social capital; OR: 0.62, 95% CI: 0.48-0.81) after adjusting for age, educational attainment, smoking status, frequency of alcohol consumption, overweight, living arrangements, and type-D personality. The beneficial effect among women was more likely limited to bonding social capital (high bonding social capital; OR: 0.34, 95% CI: 0.12-1.00), and the association between bridging social capital and self-rated health was less clear (high bridging social capital; OR: 0.69, 95% CI: 0.44-1.07).
Conclusions: Bonding/bridging social capital could have differential associations with self-rated health among the Japanese elderly depending on the individual's sex. Considering the lack of consensus on how to measure bonding and bridging social capital, however, we need to carefully assess the generalizability of our findings. Further research is warranted to identify health-relevant dimensions of social capital in different cultural or economic settings.No potential conflict of interest relevant to this article was reported.Public Library ScienceActa Medica Okayama1932-62038102013Type D Personality Is Associated with Psychological Distress and Poor Self-Rated Health among the Elderly: A Population-Based Study in JapanENYosukeKasaiEtsujiSuzukiToshihideIwaseHiroyukiDoiSoshiTakaoWe investigated the association between Type D personality, psychological distress, and self-ratings of poor health in elderly Japanese people. In August 2010, questionnaires were sent to all residents aged >= 65 in three municipalities (n = 21232) in Okayama Prefecture, Japan, and. 13929 questionnaires were returned (response rate: 65.6%). To assess mental and physical health outcomes, we used the Kessler Psychological Distress Scale and a single item question regarding perceived general health. We analyzed 9759 questionnaires to determine odds ratios (ORs) and 95% confidence intervals (CIs) for several health outcomes, adjusting for sex, age, smoking status, frequency of alcohol consumption, overweight status, educational attainment, socioeconomic status, and number of cohabiters. The multiple imputation method was employed for missing data regarding Type D personality. The prevalence of Type D personality in our sample was 46.2%. After adjusting for covariates, we found that participants with Type D personality were at 4-5 times the risk of psychological distress, and twice the risk of poor self-rated health. This association was stronger in participants aged 65-74 years (psychological distress; OR: 5.80, 95% CI: 4.96-6.78, poor self-rated health; OR: 2.84, 95% CI: 2.38-3.38) than in those aged over 75 years (psychological distress; OR: 4.54, 95% CI: 3.96-5.19, poor self-rated health; OR: 2.05, 95% CI: 1.79-2.34). Type D personality is associated with adverse health status among Japanese elderly people in terms of mental and physical risk; therefore, further research into the implications of this personality type is warranted.No potential conflict of interest relevant to this article was reported.Okayama University Medical SchoolActa Medica Okayama0386-300X6822014Trends in Geographic Distribution of Nursing Staff in Japan from 2000 to 2010:A Multilevel Analysis101110ENMasatoIzutsuEtsujiSuzukiYukakoIzutsuHiroyukiDoiOriginal Article10.18926/AMO/52406The aim of this study was to examine trends in the geographic distribution of nursing staff in Japan from 2000 to 2010. We examined time trends in the rates of nursing staff per 100,000 population across 349 secondary health service areas. Using the Gini coefficient as a measure of inequality, we separately analyzed the data of 4 nursing staff types:public health nurses (PHN), midwives (MW), nurses (NS), and associate nurses (AN). Then, using multilevel Poisson regression models, we calculated the rate ratios (RRs) and their 95% confidence intervals (CIs) for each type of nursing staff per 1-year change. Overall, the distribution of PHN, MW, and NS improved slightly in terms of the Gini coefficient. After adjusting for prefectural capital and population density, PHN, MW, and NS significantly increased;the RRs per 1-year increment were 1.022 (95% CI:1.020-1.023), 1.021 (95% CI:1.019-1.022), and 1.037 (95% CI:1.037-1.038), respectively. In contrast, AN significantly decreased;the RR per 1-year increment was 0.993 (95% CI:0.993-0.994). Despite the considerable increase in the absolute number of nursing staff in Japan (excluding AN), this increase did not lead to a sufficient improvement in distribution over the last decade.No potential conflict of interest relevant to this article was reported.Okayama University Medical SchoolActa Medica Okayama0386-300X6712013Shift Work and Diabetes Mellitus among Male Workers in Japan:Does the Intensity of Shift Work Matter?2533ENKatsuhikoIkaEtsujiSuzukiToshiharuMitsuhashiSoshiTakaoHiroyukiDoiOriginal Article10.18926/AMO/49254The purpose of this study was to examine the association between shift work and diabetes mellitus by separating shift workers according to the intensity of their shift work (seasonal shift work and continuous shift work). Between May and October 2009, we collected data from annual health checkups and questionnaires at a manufacturing company in Shizuoka, Japan. Questionnaires were returned by 1,601 workers (response rate:96.2%, men/women＝1,314/287). Diabetes mellitus was defined as hemoglobin A1c≥6.5% and fasting blood sugar≥126mg/dl. After exclusions, which included all the women and clerical workers because they did not work in shifts, we analyzed 475 skilled male workers. After adjusting for age, smoking status, frequency of alcohol consumption, and cohabitation status, odds ratios for diabetes mellitus were 0.98 (95% confidence interval [CI]:0.28-4.81) and 2.10 (95% CI:0.77-5.71) among seasonal shift workers and continuous shift workers, respectively, compared with non-shift workers. In an age-stratified analysis (＜45 years vs.≥45 years), the association between continuous shift work and diabetes mellitus was more pronounced among older participants. Compared with non-shift workers, the risk of diabetes mellitus was increased among continuous shift workers, whereas its effect is limited among seasonal shift workers.No potential conflict of interest relevant to this article was reported.Okayama University Medical SchoolActa Medica Okayama0386-300X6562011The Usefulness of Pre-Radiofrequency Ablation SUVmax in 18F-FDG PET/CT to Predict the Risk of a Local Recurrence of Malignant Lung Tumors after Lung Radiofrequency Ablation395402ENSosukeHaradaShuheiSatoEtsujiSuzukiYoshihiroOkumuraTakaoHirakiHideoGobaraHidefumiMimuraSusumuKanazawaMitsumasaKajiToshiyoshiFujiwaraOriginal Article10.18926/AMO/47265The aim of the present study was to assess the diagnostic usefulness of Fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in the prediction of local recurrence of malignant lung tumors by analyzing the pre-radiofrequency ablation (RFA) maximal standardized uptake value (SUVmax). We performed a historical cohort study of consecutive malignant lung tumors treated by RFA from January 2007 to May 2008 at Okayama University Hospital. We selected only lung tumors examined by PET/CT within 90 days before RFA and divided them (10 primary and 29 metastatic) into 3 groups according to their tertiles of SUVmax. We calculated recurrence odds ratios in the medium group and the high group compared to the low group using multivariate logistic analysis. After we examined the relationship between SUVmax and recurrence in a crude model, we adjusted for some factors. Tumors with higher SUVmax showed higher recurrence odds ratios (medium group;1.84, high group;4.14, respectively). The tumor size also increased the recurrence odds ratio (2.67);we thought this was mainly due to selection bias because we excluded tumors less than 10mm in diameter. This study demonstrated the pre-RFA SUVmax in PET/CT may be a prognostic factor for local recurrence of malignant lung tumors.No potential conflict of interest relevant to this article was reported.Okayama University Medical SchoolActa Medica Okayama0386-300X6522011Environmental Factors and Seasonal Influenza Onset in Okayama City, Japan: Case-Crossover Study97103ENYuukiTsuchihashiTakashiYorifujiSoshiTakaoEtsujiSuzukiShigeruMoriHiroyukiDoiToshihideTsudaOriginal Article10.18926/AMO/45268Seasonal influenza infection is a major challenge in public health. The term "seasonal influenza" refers to the typical increase in the number of influenza patients in the winter season in temperature zones. However, it is not clear how environmental factors within a single flu season affect influenza infection in a human population. Therefore, we evaluated the effects of temperature and humidity in the 2006-7 flu season on the onset of seasonal influenza using a case-crossover study. We targeted patients who attended one pediatric clinic in Okayama city, Japan and who were diagnosed as being infected with the seasonal influenza virus. Using 2 references (time-stratified and symmetric bidirectional design), we estimated the effects of average temperature and relative humidity from the onset day (lag0) to 10 days before (lag10). The total number of subjects was 419, and their onset days ranged from 26 December 2006 to 30 April 2007. While the onset was significantly associated with lower temperature, relative humidity was not related. In particular, temperatures before the 3-day incubation period had higher-magnitude odds ratios. For example, the odds ratio and 95% confidence interval for average temperature at time lag 8 was 1.12 (1.08-1.17) per 1.0℃ decrease. Low environmental temperature significantly increased the risk of seasonal influenza onset within the 2006-7 winter season.No potential conflict of interest relevant to this article was reported.Okayama University Medical SchoolActa Medica Okayama0386-300X6522011Outbreak of Salmonella Braenderup Infection Originating in Boxed Lunches in Japan in 20086369ENYoshinoriMizoguchiEtsujiSuzukiHiroakiTsuchidaToshihideTsudaEijiYamamotoKatsumiNakaseHiroyukiDoiOriginal Article10.18926/AMO/45264There have been only 2 reports of a large-scale foodborne outbreak arising from Salmonella enterica serotype Braenderup infection worldwide. On August 9, 2008, an outbreak originating in boxed lunches occurred in Okayama, Japan. We conducted a cohort study of 786 people who received boxed lunches from a particular catering company and collected 644 questionnaires (response rate:82%). Cases were defined as those presenting with diarrhea (≧4 times in 24h) or fever (≧38℃) between 12 am on August 8 and 12 am on August 14. We identified 176 cases (women/men:39/137);younger children (aged＜10 years) appeared to more frequently suffer severe symptoms. Three food items were significantly associated with higher risk of illness;tamagotoji (soft egg with mixed vegetables and meat) (relative risk (RR):11.74, 95% confidence interval (CI):2.98-46.24), pork cooked in soy sauce (RR:3.17, 95% CI:1.24-8.10), and vinegared food (RR:4.13, 95% CI:1.60-10.63). Among them, only the RR of tamagotoji was higher when we employed a stricter case definition. Salmonella Braenderup was isolated from 5 of 9 sampled cases and 6 food handlers. It is likely that unpasteurized liquid eggs contaminated by Salmonella Braenderup and used in tamagotoji caused this outbreak.No potential conflict of interest relevant to this article was reported.