Objective: We investigated the association of nocturnal sleep duration with body fatness, energy, and macronutrient intake in female adults.
Methods: Thirty healthy Greek women 30-60 y of age and under no medication were recruited for an observational, cross-sectional study in Athens, Greece, in 2005. Participants' height, weight, skinfold thickness, and waist and hip circumferences were measured. All subjects completed a Sleep Habits Questionnaire and a 7-d sleep diary to estimate nocturnal sleep duration. Two 24-h dietary recall interviews were conducted to assess dietary intake.
Results: Nocturnal sleep duration was negatively associated with body fatness (r = -0.614, P < 0.001) and body mass index (r = -0.401, P < 0.05). Each 1-h decrease in nocturnal sleep duration was associated with a significant increase in body fat of 2.8% (95% confidence interval -4.6 to -1.0) when the effects of age and energy intake were held constant. A weak positive association between sleep duration and saturated fat was observed (r = 0.392, P < 0.05). However, no significant association of sleep duration with certain central obesity indices, energy intake, or a preference for fat or carbohydrate consumption was found.
Conclusion: The present study identifies an independent negative association of nocturnal sleep duration with body fatness. Therefore, the shorter the sleep duration, the greater is the body fatness. The hypothesis that sleep duration is associated with energy intake and a preference for fat or carbohydrate consumption was not supported.