Obesity and depression are the two main culprits for daytime sleepiness, according to new research.
In a series of three studies, researchers at Penn State examined a random sample of 1,741 adults and determined that obesity and emotional stress are the root causes of the prevalence of sleepiness and fatigue plaguing the country.
Researchers noted that insufficient sleep and obstructive sleep apnea also play a role, as both have been linked to high blood pressure, heart disease, stroke, depression, diabetes, obesity, and accidents.
“The ‘epidemic’ of sleepiness parallels an ‘epidemic’ of obesity and psychosocial stress,” said Alexandros Vgontzas, M.D., the principal investigator for the three studies.
“Weight loss, depression and sleep disorders should be our priorities in terms of preventing the medical complications and public safety hazards associated with this excessive sleepiness.”
In one study, researchers followed up seven years later with 222 adults who initially reported excessive daytime sleepiness (EDS). For those whose EDS persisted, weight gain was the strongest predicting factor. “In fact, our results showed that in individuals who lost weight, excessive sleepiness improved,” Vgontzas said.
Adults from that same group who developed EDS within the same timespan also were studied. The results show — for the first time, according to the researchers — that depression and obesity are the strongest risk factors for new-onset excessive sleepiness.
The third study, of a group of 103 research volunteers, determined once again that depression and obesity were the best predictors for EDS, he said.
“The primary finding connecting our three studies are that depression and obesity are the main risk factors for both new-onset and persistent excessive sleepiness,” Vgontzas said.
The rate of new-onset excessive sleepiness was 8 percent, and the rate of persistent daytime sleepiness was 38 percent, he noted.
The three studies were presented at SLEEP 2012, the 26th annual meeting of the Associated Professional Sleep Societies (APSS) in Boston.