Evidence suggests that individuals who report fewer total hours of sleep are more likely to be overweight or obese. Few studies have prospectively evaluated weight-loss success in relation to reported sleep quality and quantity. This analysis sought to determine the association between sleep characteristics and weight loss in overweight or obese women enrolled in a randomized clinical trial of a weight-loss program. We hypothesized that in overweight/obese women, significant weight loss would be demonstrated more frequently in women who report a better Pittsburgh Sleep Quality Index (PSQI) Global Score or sleep >7 h/night as compared to women who report a worse PSQI score or sleep ≤7 h/night. Women of ages 45.5 ± 10.4 (mean ± SD) years and BMI of 33.9 ± 3.3 (n = 245) were randomized and completed PSQI at baseline and 6 months; 198 had weight change assessed through 24 months. At baseline, 52.7% reported PSQI scores above the clinical cutoff of 5. Better subjective sleep quality increased the likelihood of weight-loss success by 33% (relative risk (RR), 0.67; 95% confidence interval (CI), 0.52–0.86), as did sleeping >7 h/night. A worse Global Score at 6 months was associated with a 28% lower likelihood of continued successful weight loss at 18 months, but unassociated by 24 months. These results suggest that sleep quality and quantity may contribute to weight loss in intervention-based studies designed to promote weight control in overweight/obese adult women.

Chronic sleep deprivation (< 7 hours of sleep for more than 3 consecutive days), has been associated with higher BMI and weight gain, possibly secondary to elevated serum cortisol levels. Whether weight loss results in a reduction in cortisol levels and/or improved sleep patterns in overweight adults is unknown. We tested this hypothesis in a cohort subsample of overweight women enrolled in a randomized, controlled, multi‐center weight loss intervention trial (n=144). Subjects were assessed at baseline and 6 months for sleep duration and quality, using the self‐reported Pittsburg Sleep Quality Index (PSQI), and a.m. serum cortisol levels. Baseline weight among participants was 91.7 ± 10.0 kg (mean + SD). A significant weight loss of 8.1 ± 5.9 kg was observed at 6 months (p <0.0001). PSQI scores were stable from baseline to 6 months (5.2, 5.3, respectively). Regression analysis suggested a small, statistically significant improvement in PSQI score with weight loss at 6 months (p < 0.015), controlling for baseline age, weight and PSQI score. Cortisol levels were stable and within reference normal limits throughout (13.7 ± 6.1 µg/dL). This preliminary analysis suggests that an average weight loss of 8.1 ± 5.7 kg is associated with improved PSQI scores, though not cortisol levels, among overweight adult women. Funded by a contract with Jenny Craig, Inc. and the University of Arizona Nutritional Sciences Graduate Program.Grant Funding SourceContract with Jenny Craig, Inc. and University of Arizona Graduate Department