Association between reduced sleep and weight gain in women.
Level 3 - non-randomized controlled study
Prospective longitudinal cohort study followed over 16 years
PubMed 16914506 · doi:10.1093/aje/kwj280
What was done
Researchers evaluated the association between self-reported habitual sleep duration and subsequent weight gain among 68,183 women in the Nurses' Health Study who reported baseline sleep duration in 1986 and were followed prospectively for 16 years. Analyses evaluated total weight gain, major weight gain (>=15 kg), and incident obesity (BMI >30 kg/m2), adjusting for age, baseline BMI, dietary consumption, physical activity, and other covariates.
What was found
Compared with women sleeping 7 hours, women sleeping 5 hours or less gained 1.14 kg more (95% CI: 0.49, 1.79) over 16 years, and women sleeping 6 hours gained 0.71 kg more (95% CI: 0.41, 1.00). Relative risks of a >=15-kg weight gain were 1.32 (95% CI: 1.19, 1.47) for <=5 hours and 1.12 (95% CI: 1.06, 1.19) for 6 hours. Relative risks for incident obesity were 1.15 (95% CI: 1.04, 1.26) for <=5 hours and 1.06 (95% CI: 1.01, 1.11) for 6 hours. Adjusting for physical activity or dietary consumption did not affect these associations.
Why it matters
This large prospective study indicates that reduced sleep duration is an independent predictor of long-term weight gain and incident obesity, though the absolute difference in average weight gain is modest.
Limits
Sleep duration was self-reported rather than objectively measured. The cohort comprised female registered nurses, limiting generalizability to men and broader populations. Residual confounding cannot be entirely excluded given the observational design.