Sleep times influenced by race, ethnicity and country of origin

The first study, out of the State University of New York (SUNY), looked at 400,000 respondents from the National Health Interview Surveys between 2004 and 2010. Results show that Americans born in the United States were more likely to report sleeping longer than the recommended seven to nine hours each night. African-born Americans were more likely to report sleeping six hours or less, and Indian-born Americans reported six to eight hours a night.

"We think social desirability might be playing a role in the self-reported data," said Abhishek Pandey, MD, the study's lead author. "We think that insufficient sleep might be more prevalent in the population than the actual self report data, but under- or over-reported to project a better image of one's perceived sleep health."

On a smaller scale, sleep researchers at Northwestern University Feinberg School of Medicine in Chicago analyzed the sleep measurements of 439 randomly selected Chicago men and women, including surveys about sleep quality and daytime sleepiness. They found that white participants slept significantly longer than the other groups, and blacks reported the worst sleep quality. Asians had the highest reports of daytime sleepiness.

"These racial/ethnic differences in sleep persisted even following statistical adjustment for cardiovascular disease risk factors that we already know to be associated with poor sleep, such as body mass index, high blood pressure and diabetes," said Mercedes Carnethon, PhD, principal investigator and lead author of the Northwestern study. "And we excluded participants who had evidence of mild to moderate sleep apnea. Consequently, these differences in sleep are not attributable to underlying sleep disorders but represent the sleep experience of a 'healthy' subset of the population."

Pandey's investigation also indicated that foreign-born Americans were less likely to report short or long sleep than U.S.-born Americans after adjusting for effects of age, sex, education, income, smoking, alcohol use, body mass index (BMI) and emotional distress.

Research shows that habitually sleeping shorter or longer than the recommended seven to nine hours for adults can be linked to certain higher health risks, such as cardiovascular disease, stroke and accidents, as well as instances of mental or emotional disorders like depression.

Pandey said the SUNY study's goals were aligned with the National Heart, Lung and Blood Institute (NHLBI) Workshop on Reducing Health Disparities: The Role of Sleep Deficiency and Sleep Disorders. The purpose is to better understand insufficient sleep, especially across population subgroups, and to shed light on acculturation and miscegenation. Carnethon was a participant in that 2011 workshop.