Obesity and sleep mismatch between weekends and weekdays in the Korean population according to working status

To investigate whether sleep mismatch between weekends and weekdays is correlated with obesity according to working status and sex in the Korean population.

This study was conducted using data from the Korea National Health and Nutritional Examination Survey (KNHANES) in 2016. A total of 5,684 subjects (2,453 men and 3,231 women) were divided into subgroups according to age, sex and working status. Sleep mismatch was defined as the difference in sleep duration between weekdays and weekends. In this study, multivariable logistic regression analysis was applied to obtain odds ratios (ORs) for obesity in those with sleep mismatch ≥ 90 min when referenced to those with sleep mismatch < 90 min.

In the working group, adjusted ORs for obesity were mostly less than 1, but they were not statistically significant among any age or sex groups. However, for the non-working group, men over 60 years of age with sleep mismatch ≥ 90 min showed significantly increased ORs when referenced to those with sleep mismatch < 90 min in every model; the OR in model 4 was 2.89. Women over 60 years of age with sleep mismatch ≥ 90 min also showed higher ORs but they were not statistically significant.

Men who are not working and over 60 years of age in Korea may be at increased risk of obesity if their sleep mismatch is ≥ 90 min. Therefore, it might be possible to lower the prevalence of obesity in the elderly population by correcting sleep irregularity or through reemployment.