Excessive Daytime Sleepiness Associated with Excess Android Region Fat

Excess adipose tissue in the android region, rather than total body adiposity, is a stronger predictor of adverse cardiometabolic outcomes. Obesity—and android fat distribution in particular—are both risk factors for sleep disordered breathing (SDB), of which excessive daytime sleepiness (EDS) is a common symptom. EDS is also being categorized as a cardiovascular disease risk factor. To date, there have not been many studies analyzing the independent relationship between sleepiness and indices of body fat. A study that was published online as part of the ATS 2020 International Conference evaluated how EDS and regional body fat distribution are linked, as well as how comorbid SDB fits into the equation.

Patients who took part in research studies undertaken by the cardiovascular/sleep laboratory at Mayo Clinic were assessed using whole body dual energy X-ray absorptiometry (DEXA) scan, overnight polysomnography, and sleepiness assessment. DEXA was used to estimate total body fat mass, android fat mass, gynoid fat mass, and android-to-gynoid ratio. SDB was defined by the researchers as apnea-hypopnea index >10 events/hour. The Epworth Sleepiness Scale (ESS) was used to measure subjective daytime sleepiness; EDS was defined as an ESS score ≥11.

Of 98 total patients identified (mean age, 37.3 years; 59% were male), 23% (n=23) had EDS. Patients with EDS, compared with those without, were more likely to be older (41.6 years vs. 36.0 years), male (78.3% vs. 53.3%), and have SDB (56.5% vs. 26.7%). EDS patients, compared with those without, had greater android fat mass (3.6 kg vs. 2.6 kg) and android-to-gynoid ratio (0.71 vs. 0.54). Gynoid fat mass, body mass index, and total body fat did not largely differ between the groups. In multiple regression models analyses adjusted for age and sex, sleepiness levels were correlated with android-to-gynoid ratio. Adjusting for SDB did not diminish the relationship.

“We found that EDS is selectively associated with excess fat accumulation in the android region. Importantly, this association is independent of SDB, suggesting that subjective sleepiness per se may be implicated in the increased risk of morbidity and mortality associated with central obesity,” the researchers concluded.