The literature indicates Black women tend to lose less weight after pregnancy than White women. Sleep duration and quality have been associated with body weight and fat in other populations. Thus, the purpose of this study was to determine whether associations between sleep characteristics and changes in body weight and fat during postpartum in Black and White women were different. Black (n=29) and White (n=76) women who gave birth to a singleton infant at ≥37 weeks gestation participated in the study. They were instructed to wear an actigraph monitor to measure sleep at 6-8 weeks, 4 months, and 6 months postpartum for 7 days, and to complete a sleep diary. Total sleep time, wake time after sleep onset, and the sleep fragmentation index (an estimate of sleep disruption) were determined. Percent body fat (by dual-energy X-ray absorptiometry) and body weight were determined at 6-8 weeks and 6 months postpartum. A race by sleep characteristic interaction term was included in linear regression models to determine whether Black and White women had different bivariate correlations between sleep characteristics at each time point and changes in body weight and percent body fat from 6-8 weeks to 6 months. Results indicate significant interaction terms of sleep fragmentation index at 6-8 weeks and race for both weight and fat change (p=0.006, and 0.028, respectively) . Specifically, in Black women, sleep fragmentation index at 6-8 weeks were negatively associated with changes in percent body fat and weight (p= 0.027 and 0.032, respectively) , so that greater sleep disruption at 6-8 weeks was associated with less reduction in weight and percent body fat. In White women, these significant associations were absent.
In conclusion, these results suggest different contributions of sleep characteristics to postpartum weight and fat changes in Black and White women. The reasons for the differences need further investigation.
X.Wang: None. E.Kishman: None.
National Institutes of Health (R21MD012740)