Sleep duration and five-year abdominal fat accumulation in a minority cohort: the IRAS family study.

STUDY OBJECTIVES: To study 5-year change in computed tomography (CT)-derived visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) associated with sleep duration in 2 minority groups.

DESIGN: Longitudinal epidemiologic study.

SETTING: Three US communities.

PARTICIPANTS: African Americans (N = 332) and Hispanic Americans (N = 775), aged 18-81 years, participating in the IRAS Family Study.

INTERVENTIONS: none

MEASUREMENTS AND RESULTS: Abdominal CT scans and BMI obtained at a 5-year interval. Sleep duration was assessed by questionnaire at baseline and categorized as < or = 5 h, 6-7 h, and > or = 8 h. Generalized estimating equations assessed the association between sleep duration and 5-year fat accumulation with adjustment for age, race, gender, study site, baseline fat measure, physical activity, total calories, smoking status, and education. Age interacted with sleep duration to predict change in fat measures (P < 0.01). In those younger than 40 years, < or = 5 h of sleep was related to a greater accumulation of BMI (1.8 kg/m2, P < 0.001), SAT (42 cm2, P < 0.0001), and VAT (13 cm2, P > 0.01), compared to sleep duration between 6 and 7 h. Eight hours or more of sleep was also significantly related to a greater accumulation of BMI (0.8 kg/m2, P < 0.001), SAT (20 cm2, P < 0.01) and VAT (6 cm2, P < 0.05) compared to sleep duration between 6 and 7 h. No significant relationship existed between sleep duration and fat depot change in participants older than 40 years old.

CONCLUSIONS: In this minority cohort, extremes of sleep duration are related to increases in BMI, SAT, and VAT in persons younger than 40 years old.