By Kathleen Lees
When women were asked in a recent national survey to name the things they could do to reduce their risk of heart disease—the No. 1 answer was “get more sleep.”
“That’s not surprising,” says Columbia University physician-scientist Lori Mosca, MD, PhD. “There are multiple studies that have found associations between ‘short sleep’ and heart disease and these are widely reported in the media.”
But the evidence is not quite there yet, Dr. Mosca adds. “It’s been a big debate among researchers in the field. We’re not really sure if lack of sleep actually causes the increased risk or if the two are just correlated.”
We’re not really sure if lack of sleep actually causes the increased risk or if the two are just correlated.Dr. Mosca leads a team of Columbia University Medical Center scientists now enrolling women into a multifaceted study to answer the question, with funding from the American Heart Association. The funding also helped to establish a center within the Department of Medicine to research abnormal sleep as a risk factor for developing heart disease in women.
In the study’s initial phase, 500 women between the ages of 20 and 79 will be recruited into a population-based study that examines sleep patterns and other potential heart disease risk factors, including caregiving, menopause, and relationship stressors. “We’re looking at women to see if a woman’s reproductive life stage modifies any relationship that we may find between sleep and cardiovascular health,” says behavioral scientist Brooke Aggarwal, EdD, who is running the observational stage of the study.
“Close relationships are generally thought to be beneficial, but negative relationships might increase the risk of heart disease,” Dr. Aggarwal says. “One’s perception of social support—such as feeling cared about, valued, and loved—may be more important than the simple presence of a spouse or partner.”
In the second phase, study participants will be invited to enroll in a clinical trial in which they will be asked to restrict their sleep by 90 minutes each night for six weeks. A tracking device known as an accelerometer will be worn on the wrist of women to keep track of hours they sleep.
The impact of sleep restriction on diet, exercise habits, measures of body fat, and cardiovascular risk factors will be compared with results when sleep patterns are at baseline.
Previous studies have provided mixed results. Some studies show that heart disease risk factors, particularly a type of pre-diabetes, can be improved by getting more sleep. There’s minimal research on the effect of getting more sleep on inflammation or cholesterol profiles that also predispose women to heart disease, says Marie-Pierre St-Onge, PhD.
Dr. St-Onge will run a trial to see if lack of sleep is a causal factor in the development of heart disease in women.
“If the answer is yes, that means we should include lack of sleep as a major lifestyle risk factor in standard screening guidelines for heart disease, just as we include smoking, physical activity, and diet,” she says.
The third phase of the study will look more deeply at the molecular changes that occur when participants restrict sleep and how those changes raise the risk of heart disease. Sleep apnea expert Sanja Jelic, MD, thinks changes in cells that line blood vessels may play a role, and she has developed a novel technique to directly assess abnormal activation of these cells, which she previously used to study obstructive sleep apnea.
“The goal here is to see whether sleep deprivation affects vascular function at all and to determine the mechanisms,” says Dr. Jelic. “Knowing mechanisms may ultimately lead us to new ways to improve vascular health in people who do not get sufficient sleep.”
There may be times in women’s lives when they cannot get adequate rest, the researchers say, but there are things they can do to combat anticipated health problems.
“If someone is not getting enough sleep because they have small children, or because of hormonal changes during and after menopause, it’s important to try to focus on managing the well-established lifestyle risk factors for heart disease as best as possible,” says Dr. Aggarwal. “These include keeping a healthy diet, being physically active, maintaining a normal body weight for height, not smoking, and not drinking excessive amounts of alcohol.”
- Lori Mosca, MD, PhD, professor emerita in the Department of Medicine, Division of Cardiology
- Brooke Aggarwal, EdD, associate research scientist in the Department of Medicine, Division of Cardiology
- Marie-Pierre St-Onge, PhD, associate professor in the Department of Medicine, Division of Endocrinology
- Sanja Jelic, MD, associate professor in the Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine
The Go Red for Women Strategically Focused Research Network Grant is led by Lori Mosca, a long-time faculty member in the Division of Cardiology; the study is titled “Sleep and Cardiovascular Risk across Women’s Life Stages.”
Last year Dr. Mosca was named the 2015 American Heart Association Physician of the Year for her pioneering efforts to establish Go Red for Women.