Association of Sleep Duration and Obesity According to Gender and Age in Korean Adults: Results from the Korea National Health and Nutrition Examination Survey 2007-2015

Background: This study aimed to investigate associations between self-reported sleep duration and general and abdominal obesity in Korean adults stratified according to gender and age. Methods: Data from 41,805 adults, 18-110 years of age, collected by the Korea National Health and Nutrition Examination Survey (KNHANES) in 2007 and 2015, were analyzed. Multivariable logistic regression was used to calculate adjusted odds ratios (AORs) and 95% confidence intervals (CIs) for obesity and abdominal obesity by sleep duration after controlling for sociodemographic and lifestyle variables. Results: Among individuals 30-49 years of age, there was an increased AOR for obesity only for sleep duration ${\leq}5hour/day$ compared with sleep duration 6 to 8 hour/day, both in men (OR, 1.25; 95% CI, 1.02-1.54) and women (OR, 1.56; 95% CI, 1.29-1.90), after controlling for covariates. Regarding women, there was increased AOR for abdominal obesity for sleep duration ${\leq}5hour/day$ (OR, 1.45; 95% CI, 1.18-1.78) and ${\geq}9hour/day$ (OR, 1.38; 95% CI, 1.09-1.76) compared with sleep duration 6 to 8 hour/day. However, for elderly individuals (${\geq}65years$), there was a negative association between sleep duration ${\leq}5hour/day$ and obesity, but not with abdominal obesity, in both men and women. Conclusion: This study demonstrated a significant association between sleep duration and obesity, which varied according to gender and age.