Associations between nocturnal sleep duration, midday nap duration and body composition among adults in Southwest China.

Abstract

We aim to explore the relationship between nocturnal sleep duration (NSD) and midday nap duration (MND) with body composition among Southwest Chinese adults. Data on sleep duration of 3145 adults in Southwest China (59.4% women) were obtained between 2014 and 2015 through questionnaires. Height, weight, and waist circumference (WC) were measured to calculate body composition (body mass index (BMI), percentage of body fat (%BF), and fat mass index (FMI)). Linear regression models were used to assess gender-specific associations between NSD and body composition. The relationship between MND with the odds of overweight and central obesity has been evaluated by logistic regression models. NSD has the inverse relation with males' BMI, WC, %BF and FMI after adjusting for all covariates (all P <0.0007), exclusive of females' (all P >0.4). After adjustment for potential confounders, compared to the subjects in the no midday nap group, the subjects who napped 0.1-1 hour were independently associated with a less prevalence of overweight in both women (OR: 0.72, 95%CI: 0.55-0.95) and men (OR: 0.71, 95%CI: 0.52-0.98). MND was not associated with central obesity. Among Southwest Chinese adults, lower NSD might be related to higher BMI, WC, %BF and FMI among men. Additionally, MND is associated with overweight in adults.