Sleeplessness Linked to Obesity

By Peggy Peck, Senior Editor, MedPage Today
Reviewed by Zalman S. Agus, MD; Emeritus Professor at the University of Pennsylvania School of Medicine.
January 18, 2005
Also covered by: MSNBC

Results from a study of 1001 patients in four primary care practices in southwestern Virginia suggest a relationship between sleep and body mass index (BMI).

Participants were aged 18 to 91 and all underwent weight and height measurement as part of a regularly scheduled primary care visit. Patients were divided into four groups by BMI: normal (BMI 17-24), overweight (BMI 25-29), obese (BMI 30-39) and extremely obese (BMI 40 to 85).

The participants also completed a survey that assessed sleep habits including naps, bed time, wake time, and total estimated sleep for 24 hours as well as use of caffeine, tobacco, alcohol and weight loss products. A total of 924 patients completed the surveys and were included in the analysis.

In a news report Dr. Fred Turek, a physician at Northwestern University, said "we've put so much emphasis on diet and exercise that we've failed to recognize the value of good sleep." Turek co-authored an editorial that was published along with the study in Achieves of Internal Medicine. He added that society actually downplays the benefit of sleep by encouraging-and rewarding-long work days.

The mean SD 24-hour TST for the study population was 467 97 minutes. Total sleep time decreased as BMI increased, except in the extremely obese group. Patients in the obese group slept less than patients in the overweight group (P = .04), but patients in the overweight group did not sleep significantly less than patients with a normal BMI (P = .31).

The difference in total sleep time between patients in the normal weight group (BMI, 22 1.8) and the other patients (BMI, 32 6.6) was 16 minutes per day.

Over 7 days, this difference would reach 112 minutes, or 1.86 hours per week.

Study author Robert D. Vorona, MD and colleagues highlighted four main findings of the study:

• The mean BMI was 30, so normal weight participants were a minority (n = 203). Thus, most patients had weight-associated medical conditions such as GERD, diabetes, arthritis and hypertension.

• The total sleep time (TST) was not affected by use of caffeine, tobacco, alcohol or weight loss products.

• Night shift work, male gender and obesity all were associated with less TST.

• "An increasing BMI-from normal, to overweight, to obese-was associated with a decreasing TST. This association was noted both in the total population of participants and in participants who reported no sleep disorders."

The authors also noted that extremely obese patients-those with BMIs of more than 40-slept more than obese patients. Dr. Verona said this finding may support earlier studies that reported extreme obesity was associated with an increase in production of certain cytokines such as tumor necrosis factor and interleukin 6, which may have soporific effects.

The authors concluded that the study of sleep and obesity deserves further investigation. "If insufficient sleep were to be definitively determined to contribute to obesity, aesthetic and health considerations might lead many Americans to pay more attention to the benefits of adequate sleep," they wrote.

Source: MedPage Today, http://www.medpagetoday.com/PrimaryCare/WeightManagement/tb/299

Primary source: Archives of Internal Medicine
Source reference:
Verona R, Winn M, Babineau T et al. "Overweight and Obese Patients in a Primary Care Population Report Less Sleep Than Patients with a Normal Body Mass Index." Arch Intern Med 2005;165:25-30

Additional source: Archives of Internal Medicine
Source reference:
Bass, J and Turek F. Sleeplessness in America. Arch Intern Med. 2005;165:15-16