Link between short sleep and obesity in patients with chronic medical problems

Dec 17 2007

A study published in the December 15 issue of the Journal of Clinical Sleep Medicine (JCSM) demonstrates an association between short sleep times and obesity in patients with chronic medical problems.

The study surveyed 200 patients attending internal medicine clinics to determine their sleep habits, lifestyle characteristics, and medical diagnoses.

According to the results, subjects with short sleep times (less than seven hours) had a significantly increased likelihood of obesity defined by a body mass index greater than 30 kg/meters2 when compared to the reference group of eight to nine hours. There was a U-shaped relationship between obesity and sleep time in women indicating that women who had both short and long sleep times were more likely to be obese. This relationship was not present in men. Other factors predicting obesity in these clinic patients included young age (18 to 49 years), not smoking, drinking alcohol, hypertension, diabetes, and sleep apnea.

“Our study demonstrates that short sleep times have an association with obesity in adults with chronic medical problems and that chronic disease and attendant therapies and/or changes in physical activities do not obscure this relationship,” said Kenneth Nugent, MD, of Texas Tech University, lead author of the study. “This study suggests that adults should sleep eight to nine hours per night to maintain optimal weight. Whether or not manipulating sleep time in adults will prevent additional weight gain or facilitate weight loss is unclear. This question will require therapeutic trials in which sleep hygiene is addressed during weight loss studies.”

A strong relationship exists between weight and obstructive sleep apnea (OSA), in that your neck gets thicker as you gain weight. This increases the level of fat in the back of the throat, narrowing the airway. With more fat in the throat, your airway is more likely to be blocked.

People with OSA are often obese and have a neck size of more than 17 inches. Many people with OSA also have high blood pressure.

It is estimated that four percent of men and two percent of women have OSA, and millions more remain undiagnosed.

First introduced as a treatment option for OSA in 1981, continuous positive airway pressure (CPAP) is the most common and effective treatment for OSA. CPAP provides a steady stream of pressurized air to patients through a mask that they wear during sleep. This airflow keeps the airway open, preventing the pauses in breathing that characterize sleep apnea and restoring normal oxygen levels.