Overweight and obese patients in a primary care population report less sleep than patients with a normal body mass index.

Background: Insufficient sleep and obesity are common in the United States. Restricted sleep causes important neurocognitive changes, including excessive daytime sleepiness and altered mood. This may result in work-related injuries and automotive crashes. Evidence links sleep loss to hormonal changes that could result in obesity. This article examines the association between restricted sleep and obesity in a heterogeneous adult primary care population.

Methods: A total of 1001 patients from 4 primary care practices participated in this prospective study. Patients completed a questionnaire administered by a nurse or study coordinator concerning demographics, medical problems, sleep habits, and sleep disorders. Professional staff measured height and weight in the office. The relationship between body mass index (BMI) and reported total sleep time per 24 hours was analyzed after categorizing patients according to their BMI (calculated as weight in kilograms divided by the square of height in meters) as being of normal weight (<25), overweight (25-29.9), obese (30-39.9), or extremely obese (> or =40).

Results: Analyzable forms from 924 patients aged between 18 and 91 years indicated that (1) the mean BMI was 30; (2) women slept more than men; (3) overweight and obese patients slept less than patients with a normal BMI (patients reported less sleep in a nearly linear relationship from the normal through the obese group); and (4) this trend of decreasing sleep time was reversed in the extremely obese patients.

Conclusions: This study found that reduced amounts of sleep are associated with overweight and obese status. Interventions manipulating total sleep time could elucidate a cause-and-effect relationship between insufficient sleep and obesity.