The study involved 1,107 adults between 18 and 81 years of age. Data were collected from 332 African-Americans and 775 Hispanics. Sixty-two percent of participants were female.
Body mass index (BMI) and abdominal fat were measured at a five-year interval. Belly fat was measured using abdominal computed tomography (CT) scans.
Results show that the mean self-reported nightly sleep duration was 6.7 hours at baseline. Seventeen percent of the sample reported sleeping five hours or less per night.
There was no link between sleep duration and abdominal fat change in people older than 40 years of age. But short and long sleep durations were associated with increases in BMI and belly fat in people younger than 40 years of age. The association was strongest in people who reported sleeping five hours or less per night.
They had an average BMI increase over five years that was 1.8 kg/m2 higher than people who slept six to seven hours each night. They also gained more abdominal fat.
“Appropriate amounts of sleep are important for maintenance of healthy weight,” lead author Dr. Kristen Hairston told the AASM. “In a group of African-American and Hispanic participants, those who slept less than this had greater increases in belly fat over a five-year period.”
The CDC reports that blacks are 51 percent more likely to be obese than whites. Hispanics are 21 percent more likely to be obese than whites.
The authors proposed that short sleep may promote abdominal fat gain by increasing hunger and caloric intake. It also may increase fatigue and reduce energy expenditure. Both increased caloric intake and decreased vigorous activity were observed in the short sleep group.
The authors also suggested that doctors should educate young adults about the important role of sleep in a healthy lifestyle. This is most important when young adults transition to life stages that often involve sleep deprivation. These include entering college, getting married and having children.
Last year a study found that blacks had a 78 percent increased risk of obesity related to short sleep. The risk of obesity related to short sleep in whites was increased by 43 percent.
Read more about sleep and weight gain and sleep and race.
Image by Jen R