Ethnicity may be factor in sleep disorders

By Jasminee Sahoye

Black people may be more prone to sleeping problems, a study suggests.
Black people may be more prone to sleeping problems, a study suggests.

Sleep disturbances and undiagnosed sleep apnea occur more frequently among racial /ethnic minorities and they are common among middle-aged and older adults in the U.S., according to a recent study.

The study population was recruited from six U.S. communities and comprised 2,230 racially and ethnically diverse men and women between 54 and 93 years. The data were gathered between 2010 and 2013.

After adjustment for sex, age and study site, Blacks were most likely to have short sleep duration of less than six hours and were more likely than whites to have sleep apnea syndrome, poor sleep quality and daytime sleepiness.

Hispanics and Chinese were more likely than whites to have sleep-disordered breathing and short sleep duration but Chinese were least likely to report having insomnia.

Findings reveal that 34% of participants had moderate or severe sleep-disordered breathing measured by polysomnography which records brain waves, the oxygen level in blood, heart rate and breathing, as well as eye and leg movements during the sleep study.

Thirty-one percent had short sleep duration with less than six hours per night measured by actigraphy, a non-invasive method of monitoring human rest and activity cycles.

Twenty-three percent of the validated questionnaires showed participants having insomnia and 14% reported excessive daytime sleepiness. Only nine percent of participants reported being told by a doctor they had sleep apnea.

“Our findings underscore the very high prevalence of undiagnosed sleep disturbances in middle-aged and older adults and identify racial / ethnic disparities that include differences in short sleep duration, sleep apnea and daytime sleepiness,” said lead author Dr. Xiaoli Chen, research fellow in the Department of Epidemiology at Harvard T.H. Chan School of Public Health in Boston.

According to Chen and her colleagues, this is the first study that has comprehensively evaluated objective measures of sleep apnea, short sleep and poor sleep, as well as subjective measures of habitual snoring, insomnia and daytime sleepiness in a multi-ethnic U.S. population that includes Chinese Americans.

“As sleep apnea has been implicated as a risk factor for cardiovascular disease, stroke, diabetes and mortality, our findings highlight the need to consider undiagnosed sleep apnea in middle-aged and older adults, with potential value in developing strategies to screen and improve recognition in groups such as in Chinese and Hispanic populations,” said senior author Dr. Susan Redline, professor of medicine at Harvard Medical School and Division of Sleep Medicine at Brigham and Women’s Hospital and Beth Israel Deaconess Medical Centre in Boston.

In a similar study, it was found that poor people and minorities appear to disproportionately suffer from problems with sleep and chronic disease but the two do not appear to be directly linked.

“Since the racial differences in many diseases mirror the racial differences we see in sleep, we checked to see if sleep causes differences in these diseases,” said lead author Rebecca S. Piccolo, Sc.M., associate director for health services and disparities research at the New England Research Institutes.

Study participants included 5,502 men and women aged 30 to 79 years, in three racial groups, Black, Hispanic and white. Each participant answered questions during an in-home interview regarding their health status and the quality and amount of their usual sleep. Baseline interviews took place between 2002 and 2005 with five year follow-up interviews between 2006 and 2010.

The researchers found Black and Hispanic men were more likely than white men to report sleeping less than five hours each night.  Poorer men were also likelier to report short sleep.

In fact, the authors found that being of a lower socioeconomic class was a greater driver of sleep disparities than were ethnic differences.