Lee Yesung, Lee Woncheol, Kim Hyoung-Ryoul
Department of Occupational and Environmental Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
Department of Occupational and Environmental Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Epidemiol Health. 2022;44:e2022104. doi: 10.4178/epih.e2022104. Epub 2022 Nov 8.
Long working hours have been reported to cause various health problems, but are currently practiced in many countries. Building upon a previous cross-sectional study, the authors aimed to elucidate the causal relationship between long working hours and hypothyroidism through a longitudinal study.
Data were collected at baseline from 45,259 participants without thyroid disease and with consistent weekly working hours (36-40, 41-52, 53-60, and >60 hours) during the follow-up period. Hypothyroidism was defined using the reference limits of serum thyroid-stimulating hormone and free thyroxine levels. By estimating hazard ratios (HRs) and 95% confidence intervals (CIs) using Cox proportional hazards regression analysis, the risk of incident hypothyroidism was evaluated with 36-40 hours of work per week as the reference.
During 138,261.7 person-years of follow-up, 2,914 participants developed hypothyroidism (incidence density, 2.11/102 person-years). The multivariable-adjusted HRs of incident hypothyroidism for 41-52 hours, 53-60 hours, and >60 hours of work per week were 1.13 (95% CI, 1.03 to 1.24), 2.53 (95% CI, 2.17 to 2.95), and 2.57 (95% CI, 2.09 to 3.15), respectively. In dose-response analyses, long working hours had an approximately linear relationship with hypothyroidism incidence. The risk of incident hypothyroidism in those who worked 53-60 hours and >60 hours per week compared with the reference group was significantly higher among the older age group (≥36 years, stratified by median age), men, and daytime workers.
This large-scale cohort study demonstrated the association between long working hours and an increased risk of incident hypothyroidism with a dose-response relationship.
据报道，长时间工作会导致各种健康问题，但目前许多国家仍存在这种情况。基于之前的一项横断面研究，作者旨在通过纵向研究阐明长时间工作与甲状腺功能减退之间的因果关系。
在基线时收集了45259名无甲状腺疾病且在随访期间每周工作时间一致（36 - 40、41 - 52、53 - 60和>60小时）的参与者的数据。甲状腺功能减退是根据血清促甲状腺激素和游离甲状腺素水平的参考范围来定义的。通过使用Cox比例风险回归分析估计风险比（HRs）和95%置信区间（CIs），以每周工作36 - 40小时作为参考来评估甲状腺功能减退发病的风险。
在138261.7人年的随访期间，2914名参与者出现了甲状腺功能减退（发病密度，2.11/102人年）。每周工作41 - 52小时、53 - 60小时和>60小时的甲状腺功能减退发病的多变量调整后HR分别为1.13（95% CI，1.03至1.24）、2.53（95% CI，2.17至2.95）和2.57（95% CI，2.09至3.15）。在剂量反应分析中，长时间工作与甲状腺功能减退发病率呈近似线性关系。与参考组相比，每周工作53 - 60小时和>60小时的人群中，甲状腺功能减退发病风险在老年组（≥36岁，按年龄中位数分层）、男性和白天工作的人群中显著更高。
这项大规模队列研究证明了长时间工作与甲状腺功能减退发病风险增加之间存在关联，且具有剂量反应关系。
