Sex differences in the association between short sleep duration and obesity among US adults: findings from NHANES, 2015-2020.

Background: Obesity is an important public health problem in the United States. Identifying modifiable risk factors could guide public health intervention efforts. In this study, we leveraged a nationally representative sample of the US population to examine sex differences in the association between short sleep and obesity among US adults.

Methods: Publicly available cross-sectional national data were extracted from the National Health and Nutrition Examination Survey, 2015 through 2020. A multivariable survey logistic regression model was fitted for the association between short sleep (defined as less than 7 h of sleep in 24 h) and obesity, accounting for sample stratification, clustering, and weighing. Heterogeneity was assessed using interaction terms overall and by fitting a sex-stratified model.

Results: A total of 15,562 persons aged 18 years and older were included in the study. The majority were non-Hispanic whites, 18-44 years of age, with at most a high school education. Short sleepers tended to be female (55.9%; 95% CI: 53.9, 57.9) while long (59.6%; 95% CI: 57.4, 61.7) and normal sleepers (51.9%; 95% CI: 50.5, 53.2) tended to be male. As compared with normal sleep duration, 7-9 h, short sleep duration was not significantly associated with obesity in the study population overall (OR = 0.95; 95% CI: 0.83-1.08) or among males (OR = 0.98; 95% CI: 0.86-1.12). However, short sleep was associated with increased odds of obesity among females (OR = 1.22; 95% CI: 1.01-1.49).

Conclusions: There is sex-based heterogeneity in the association between short sleep and obesity among US adults. Further research should explore the factors responsible, and investigate the underlying mechanism.