Do working hours and type of work affect obesity in south Korean female workers? Analysis of the Korean community health survey

Background: The prevalence of obesity and the female labor participation rate have been rapidly increasing in South Korea. To examine the relationship between these factors, we investigated the association between timing and type of work and obesity in the Korean female working population. Methods: Data collected by the 2008 Community Health Survey (CHS) were analyzed using a complex, stratified, multistage, probability cluster sampling method. Descriptive analysis of relevant variables was performed using the chi-square test, and work-related variables by work type were identified using multivariate logistic regression. The relationship between long working hours, night/shift work, and body-mass index in female workers and explanatory, stratifying, and dependent variables and covariates was analyzed using multiple logistic regression models. Results: A total of 42,234 CHS participants were eligible for study inclusion. Among both manual and nonmanual workers, working less than 40 (adjusted odds ratio [aOR] 1.18, 95% confidence interval [CI] 1.07-1.31 and aOR 1.29; 95% CI 1.09-0.52, respectively) or more than 60 (aOR 1.18, 95% CI 1.06-1.30 and aOR 1.28, 95% CI 1.04-1.57, respectively) hours per week was significantly associated with obesity after controlling for covariates. However, working type (day or night/shift) was significantly associated with obesity only in nonmanual workers (aOR 1.20, 95% CI 1.01-1.42). When we controlled working type in the model, manual workers who work more than 60 hours show higher likelihood of being obese (OR 1.10, 95% CI 1.02-1.18). Conclusion: Working fewer (<40) or more than (>60) hours per week is significantly associated with obesity in the Korean female working population, regardless of the type of work. The type of work (day vs. night/shift work) was significantly associated with obesity only in only nonmanual workers.