Objectively Measured Sleep Patterns in Young Adult Women and the Relationship to Adiposity

Abstract

Purpose. The purpose of this study was to examine the relationship between sleep patterns and adiposity in young adult women. Design. Cross-sectional. Setting. The study took place at two Mountain West region universities and surrounding communities. Subjects. Subjects were 330 young adult women (20.2 ± 1.5 years). Measures. Sleep and physical activity were monitored for 7 consecutive days and nights using actigraphy. Height and weight were measured directly. Adiposity was assessed using the BOD POD. Analysis. Regression analysis, between subjects analysis of variance, and structural equation modeling were used. Results. Bivariate regression analysis demonstrated that sleep efficiency was negatively related to adiposity and that the 7-day standard deviations of bedtime, wake time, and sleep duration were positively related to adiposity (p < .05). Controlling for objectively measured physical activity strengthened the relationship between sleep duration and adiposity by 84% but had a statistically negligible impact on all other relationships that were analyzed. However, multivariate structural equation modeling indicated that a model including sleep efficiency, sleep pattern inconsistency (latent variable consisting of the 7-day standard deviations of bedtime, wake time, and sleep duration), and physical activity was the best for predicting percent body fat. Conclusion. Inconsistent sleep patterns and poor sleep efficiency are related to adiposity. Consistent sleep patterns that include sufficient sleep may be important in modifying risk of excess body fat in young adult women.