(Reuters Health)—Middle-aged women who get poor quality sleep have elevated levels of inflammatory markers, suggesting their risk for heart disease and other illnesses may be increased, U.S. researchers say.
Based on sleep monitoring and blood tests of 295 women, most of whom were past menopause, researchers found those who had trouble falling asleep or who had disrupted sleep also had increased circulating levels of interleukin (IL) 6 and von Willebrand factor antigen.
Markers of inflammation, such as IL-6 and C-reactive protein (CRP), have been linked to risk for cardiovascular events, high blood pressure and Type 2 diabetes. Von Willebrand factor, which is involved in blood clotting, has also been tied to blood vessel dysfunction and inflammation, the study team writes in the journal Sleep, online March 30.1
Many studies have investigated the association between sleep and health, but few have examined the relationship between inflammatory markers in women during midlife and the menopause transition, saysa lead author Sara Nowakowski, a clinical psychologist and assistant professor of obstetrics and gynecology at the University of Texas Medical Branch in Galveston.
“I really think this study drives home the point that we need to consider disturbed sleep a significant health risk factor just like we do for diet and physical activity,” she says in a phone interview.
One-third of adults ages 18–60 in the U.S. report that they usually get less than the recommended seven hours of sleep per night, according to the Centers for Disease Control and Prevention.
Menopausal women in particular often report sleep troubles, and they are known to be at increased risk for heart disease, though little is understood about the connection between sleep and heart troubles in this group, the authors note.
For the study, researchers had participants, whose average age was 54, complete questionnaires about sleep apnea and undergo three days of physical monitoring of hot flashes and sleep patterns. The women also kept sleep diaries during the study period and underwent blood tests for inflammatory markers.
Researchers found that 75% of participants slept less than seven hours, and half slept about six hours. Half also awoke from sleep for a total of 41 minutes or more during the night, indicating short and disrupted sleep.
Total sleep time alone wasn’t linked to any of the inflammatory markers, but women who had the most trouble staying asleep during the night had higher circulating levels of von Willebrand factor. Those with trouble falling asleep had higher levels of that factor and IL-6.
However, CRP was not associated with total sleep time or sleep disturbance.
“The association is relatively small, so there’s no cause for alarm currently—however, more specific research should be pursued,” says C. Noel Bairey Merz, director of the Barbra Streisand Women’s Heart Center at Cedars-Sinai in Los Angeles.
“Specifically, whether poor sleep leads to higher inflammation or whether higher inflammation leads to poor sleep is a critical question,” she says in an email.
Night-time snacking, low physical activity and belly fat raise systemic inflammatory markers and contribute to poor sleep, adds Merz, who was not involved in the study.
“There is quite a lot of experimental and epidemiological evidence that has shown that disturbances in sleep are associated with disease and death,” says Susan Redline, a senior physician at Brigham and Women’s Hospital and professor of medicine at Harvard Medical School, Boston.
“If a woman is having persistent trouble sleeping lasting more than a few weeks, they should talk with their primary care doctor. If the problem can’t be readily addressed, ask to speak to a sleep specialist,” Redline, who was not involved in the research, says in a telephone interview.
The American College of Physicians recommends that all adult patients receive cognitive behavioral therapy for insomnia.
Among the study’s limitations is that it measured sleep activity for only three days and at just one point in time, the authors acknowledge. The study doesn’t prove that poor sleep causes changes in inflammation. It also did not examine any health effects of the increased inflammatory markers that were observed in women who slept poorly.
“I hope this study underscores the need to treat sleep problems so we can improve a woman’s inflammatory profile and prevent chronic conditions like vascular disease or diabetes,” Nowakowski says.
- Nowakowski S, Matthews KA, von Känel R, et al. Sleep characteristics and inflammatory biomarkers among midlife women. Sleep. 2018 Mar 30. [Epub ahead of print]