Department of Epidemiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558, Japan.
BMC Public Health. 2012 May 31;12:395. doi: 10.1186/1471-2458-12-395.
The link between long working hours and health has been extensively studied for decades. Despite global concern regarding metabolic syndrome, however, no studies to date have solely evaluated the relationship between long working hours and that syndrome. We therefore examined the association between long working hours and metabolic syndrome in a cross-sectional study.
Between May and October 2009, we collected data from annual health checkups and questionnaires from employees at a manufacturing company in Shizuoka, Japan. Questionnaires were returned by 1,601 workers (response rate: 96.2%; 1,314 men, 287 women). After exclusions, including women because of a lack of overtime work, the analysis was performed for 933 men. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for metabolic syndrome. Further, we conducted a stratified analysis by age-group (<40 years vs. ≥ 40 years).
Metabolic syndrome was identified in 110 workers (11.8%). We observed a positive association between working hours and metabolic syndrome after adjusting for age, occupation, shift work, smoking status, frequency of alcohol consumption, and cohabiting status. Compared with subjects who worked 7-8 h/day, multivariate ORs for metabolic syndrome were 1.66 (95% CI, 0.91-3.01), 1.48 (95% CI, 0.75-2.90), and 2.32 (95% CI, 1.04-5.16) for those working 8-9 h/day, 9-10 h/day, and >10 h/day, respectively. Similar patterns were obtained when we excluded shift workers from the analysis. In age-stratified analysis, the corresponding ORs among workers aged ≥ 40 years were 2.02 (95% CI, 1.04-3.90), 1.21 (95% CI, 0.53-2.77), and 3.14 (95% CI, 1.24-7.95). In contrast, no clear association was found among workers aged <40 years.
The present study suggests that 10 h/day may be a trigger level of working hours for increased risk of metabolic syndrome among Japanese male workers.
数十年来，人们广泛研究了长时间工作与健康之间的关系。然而，尽管人们对代谢综合征全球关注，但迄今为止，尚无研究专门评估长时间工作与该综合征之间的关系。因此，我们进行了一项横断面研究，以调查长时间工作与代谢综合征之间的关联。
在 2009 年 5 月至 10 月期间，我们从日本静冈县一家制造公司的年度体检和问卷调查中收集数据。共有 1601 名员工（应答率：96.2％；1314 名男性，287 名女性）返回了问卷。排除女性（因为缺乏加班工作）后，对 933 名男性进行了分析。我们计算了代谢综合征的比值比（OR）和 95％置信区间（CI）。此外，我们还按年龄组（<40 岁与≥40 岁）进行了分层分析。
在 110 名工人（11.8％）中发现了代谢综合征。在调整年龄、职业、轮班工作、吸烟状况、饮酒频率和同居状况后，我们观察到工作时间与代谢综合征之间存在正相关。与每天工作 7-8 小时的人相比，每天工作 8-9 小时、9-10 小时和>10 小时的代谢综合征的多变量 OR 分别为 1.66（95％CI，0.91-3.01）、1.48（95％CI，0.75-2.90）和 2.32（95％CI，1.04-5.16）。当我们从分析中排除轮班工人时，也得到了类似的结果。在年龄分层分析中，≥40 岁工人的相应 OR 为 2.02（95％CI，1.04-3.90）、1.21（95％CI，0.53-2.77）和 3.14（95％CI，1.24-7.95）。相比之下，<40 岁的工人则没有明显的关联。
本研究表明，10 小时/天可能是日本男性工人代谢综合征风险增加的工作时间触发水平。
