By Nick Patterson
Sleep matters. And it matters more depending on your race, according to a study by a group of Auburn University scientists. Blacks get less sleep than whites and suffer relatively worse health outcomes because of it, their research found.
“Sleep is a fundamental biological process that plays a critical role in the maintenance of mental and physical health,” according to an article recently published in the journal Sleep Medicine. “Insufficient or low-quality sleep has been consistently associated with adverse health outcomes.”
Auburn scientists Thomas E. Fuller-Rowell, David S. Curtis, and Mona El-Sheikh were among five scientists who conducted the study. The Auburn research team analyzed data from 2009 findings of the “Midlife in the United States (MIDUS)” study, in which the sleep of 426 adults were monitored via what Curtis describes as a “Fitbit-like” wearable device.
Of the research participants, 31 percent were African-American adults living in Milwaukee, Wisc., compared with 69 percent white adults from the same region. According to the study, blacks get much less sleep than whites. For women, in particular, that can lead to wide disparities in health conditions down racial lines.
Curtis said in an interview that there is a difference of about 45 minutes sleep per night, comparing the sleep rates for blacks and whites as a whole. Three studies have made similar findings, he said.
“All three of these different studies in different samples found the differences” to range from 45 to 50 minutes a night, Curtis said. “White adults are receiving about six hours on average, and black adults are receiving closer to five. That’s pretty substantial.”
The study also found:
- Sleep problems are risk factors for coronary heart disease, stroke, hypertension, and diabetes.
- Sleep differences between blacks and whites are not fully understood, but factors including discrimination, chronic stress, and health behaviors likely play a role.
- Neighborhood factors contribute to and may partially explain racial disparities in waking episodes.
- Insufficient or low-quality sleep can have significant consequences for the U.S. as a whole.
Over a period of seven days, black participants slept on average 341 minutes per night versus 381 minutes for white participants. Some 41 percent of the disparity between blacks and whites in cardiovascular metabolic disease rates was tied to the amount of sleep the participants got. Another 58 percent of the disparity could be traced to “sleep efficiency” or quality of sleep, where blacks experienced 72.3 percent efficiency versus 82.2 percent for whites.
Why are blacks and whites experiencing differences in how they sleep? There are several likely reasons, the researchers suggested.
“In addition to differences in sleep being an issue of public health, the presence of these sleep differences appears to be, in part, a result of social factors,” they pointed out. “Specifically, sleep has been robustly associated with exposure to social stress. Moreover, household and area-level socioeconomic conditions and experiences of discrimination help explain a portion of racial sleep differences.”
What was most striking was probably the extent to which sleep accounted for racial disparities and cardiometabolic disease risk, Curtis said. He noted that when women participants alone were taken into account, time sleeping amounted to 33 percent of the disparity between blacks and whites and sleep efficiency amounted to 65 percent of the disparity.
“So, just to quantify that to some degree, we find that there are big differences in mortality,” Curtis said. “For black females, about 1.6 years of life is lost on average, and there’s also a difference in hypertension and diabetes. … These are really substantial once you think about the population level. And if we’re finding that two thirds of that effect is due to sleep, then that would really suggest that our health policy needs to seriously consider trying to intervene on sleep to try to reduce some of the disparities.”
Sleep differences between blacks and whites are not fully understood, but could be a result of discrimination, chronic stress, health behaviors, and exposure to environmental toxins, according to the researchers.
“For example, living in a disadvantaged neighborhood with higher crime rates, less access to healthy food, and greater exposure to toxins has been associated with higher rates of obesity, stress, and physiologic dysregulation; all of these conditions have been associated with low sleep quality,” they noted.
The researchers added, “Neighborhood location and, therefore, availability of health-promoting resources, such as parks and community centers, may influence physical activity and psychosocial factors related to sleep quality.”
Insufficient or low-quality sleep can have significant consequences on the nation, the researchers determined: “All told, sleep problems are a significant impediment to health and well-being, which collectively, in the United States alone, carries an economic burden of hundreds of billions of dollars each year.”