Study Links Obesity and Sleep

Are sleep duration and bodymass index (BMI) connected Researchersat Columbia Universityfound a correlation. The results oftheir study were reported in Sleep(October 26, 2005). These researchersconducted a longitudinalanalysis of data on >9500 participantsin the 1982-1984, 1987, and1992 Epidemiologic Follow-up Studiesof the first National Health andNutrition Examination Survey. Theirfindings showed that individualsaged 32 to 49 who slept <7 hourswhen initially interviewed had a higherBMI and were more likely to beobese, compared with participantswho slept 7 hours. Yet, this findingwas not seen in older participants.

In an editorial responding to thestudy, investigators reported ontheir evaluations of 13 other populationand longitudinal studies conductedsince 1992. Although acausal relationship between obesityand sleep has not been observed,genetic studies with animals andsmall-scale experiments using sleeprestrictions with individuals suggestedthat sleep deprivation may beassociated with obesity in 3 ways:(1) compromising the body's sensitivityto insulin; (2) increasing thegrowth hormone ghrelin that affectsappetite and energy level; and (3)decreasing leptin.