Supplementary Material for: The joint contributions of overweight/obesity and physical and mental working conditions to short and long sickness absence among young and midlife Finnish employees: a register-linked follow-up study

Introduction: Overweight/obesity and strenuous working conditions are associated with work disability, but their joint contributions to sickness absence (SA) are unknown. We aimed to examine their joint contributions to SA periods of 1–7 and ≥8 days. Methods: Self-reported data on body mass index and working conditions, including perceived physically and mentally strenuous work and hours per day spent in heavy physical work, were linked to the employer’s SA register for the City of Helsinki, Finland, employees (n=4323, women 78%), who were 19–39 years old at baseline. We calculated rate ratios (RR) and 95% confidence intervals (CI) for SA periods using negative binomial regression models among participants with healthy weight and overweight/obesity, with and without exposure to strenuous working conditions. The mean follow-up time was 2.1 years. Results: Participants with overweight/obesity and exposure to physically strenuous working conditions had the highest age- and gender-adjusted RRs for SA periods of both 1–7 and ≥8 days (physically strenuous work: RR 1.38, CI 1.25–1.52, and RR 1.87, CI 1.60–2.18, respectively; ≥3 hours per day spent in physical work: RR 1.40, CI 1.26–1.55 and 2.04, CI 1.73–2.40, respectively). The interaction between overweight/obesity and physically strenuous working conditions was additive for SA periods of 1–7 days and weakly synergistic for SA periods of ≥8 days. For mentally strenuous work, participants with overweight/obesity and exposure to mentally strenuous work had the highest age-adjusted RRs for SA periods of ≥8 days, and the interaction was additive. Conclusion: The joint contributions of overweight/obesity and exposure to strenuous working conditions to SA should be considered when aiming to reduce employees’ SA. Employers might benefit from providing employees adequate support for weight management and adherence to healthy lifestyles while improving employees’ working conditions.

引言：超重/肥胖与高强度工作环境均与工作失能相关，但二者对病假缺勤（sickness absence, SA）的联合作用尚未明确。本研究旨在探讨二者对1~7天及≥8天病假缺勤时长的联合影响。
方法：本研究将研究对象自评的身体质量指数（body mass index, BMI）、工作相关信息（包括自评体力与脑力高强度工作情况、每日重体力劳动时长）与芬兰赫尔辛基市雇主方的病假缺勤登记系统进行关联。研究对象共4323名，其中女性占78%，基线时年龄为19~39岁。本研究采用负二项回归模型（negative binomial regression models），针对健康体重组与超重/肥胖组分别计算有无高强度工作环境暴露时的病假缺勤时长的率比（rate ratio, RR）及95%置信区间（confidence interval, CI），平均随访时长为2.1年。
结果：同时存在超重/肥胖与体力高强度工作环境暴露的研究对象，其1~7天及≥8天病假缺勤时长的年龄与性别校正后率比最高：体力高强度工作亚组中，对应率比分别为1.38（95%CI：1.25~1.52）与1.87（95%CI：1.60~2.18）；每日重体力劳动≥3小时亚组中，对应率比分别为1.40（95%CI：1.26~1.55）与2.04（95%CI：1.73~2.40）。超重/肥胖与体力高强度工作环境的交互作用在1~7天病假缺勤中表现为相加交互作用，在≥8天病假缺勤中则呈弱协同效应。针对脑力高强度工作而言，同时存在超重/肥胖与脑力高强度工作环境暴露的研究对象，其≥8天病假缺勤时长的年龄校正后率比最高，且二者的交互作用同样为相加交互作用。
结论：在致力于降低员工病假缺勤率时，应考虑超重/肥胖与高强度工作环境暴露二者对病假缺勤的联合影响。雇主可通过为员工提供体重管理与健康生活方式依从性的充分支持，同时改善员工工作环境，从而实现获益。