A meta-analysis of observational studies including dose-response relationship between long working hours and risk of obesity

We aimed to conduct a meta-analysis with stick reference and uniform cut-off of obesity to evaluate the relationship between long working hours and risk of obesity, using a quantitative dose-response method. The PubMed and Web of Science databases were searched through February 26, 2021, odds ratios (ORs) were pooled by using random-effects models and restricted cubic spline analysis with four knots was used to explore the dose-response relationship of working time and risk of obesity. Ten observational studies with 20 independent reports involving 189,590 participants were included in the present analysis. The summarized adjusted OR for the relationship between long working hours and obesity risk was 1.13 (95% CI: 1.01 to 1.26), when compared with weekly working hours less than and equal to 40 h using the random-effects model. A J-shaped association between long working hours and risk of obesity was observed (P < 0.001 for nonlinearity) for the dose-response relationship. Exclusion of any single study did not alter the combined relative risk. Individuals involved in long working hours are more likely to be obesity. Further studies are needed to confirm the results, and optimized and proper job arrangement should be established for improving the health of workers.