Insomnia symptoms, short sleep duration in midlife women linked to CVD risk

Persistent insomnia symptoms, alone and combined with short sleep duration, in women ages 42 to 52 years were associated with a subsequent 70% to 75% increased risk of cardiovascular disease (CVD).

Insomnia symptoms that persist over midlife or occur with short sleep duration are linked with a higher risk of cardiovascular disease (CVD) among women, according to new study results.

The findings are based on sleep data from 2,964 participants in the multicenter Study of Women's Health Across the Nation, collected up to 16 times over the span of 22 years. All participants were between ages 42 and 52 years at baseline, were premenopausal or early perimenopausal, did not use hormone therapy, and did not have baseline CVD. Questionnaires assessed insomnia symptoms, including waking up several times a night or having trouble falling asleep, and participants' typical daily sleep duration. Trajectories of insomnia symptoms were divided into low symptoms (39%), moderate symptoms that decreased over time (19%), low symptoms that increased over time (20%), and high symptoms that persisted (23%). Results were published by Circulation on Jan. 29.

Women with persistently high insomnia symptoms had a higher risk for CVD than those with low symptoms (hazard ratio [HR], 1.71 [95% CI, 1.19 to 2.46]; P=0.004). In addition, women with persistently short sleep duration (~5 hours, 15%) also had a higher CVD risk (HR, 1.51 [95% CI, 0.98 to 2.33]; P=0.06) compared with women who had moderate sleep duration (~6 hours, 55%). Those with short sleep duration and persistent high insomnia systems had a significantly greater risk for CVD than women with low insomnia symptoms and moderate or moderate to long sleep duration (HR, 1.75 [95% CI, 1.03 to 2.98]; P=0.04). Insomnia symptoms were still linked with a heightened risk of CVD after researchers adjusted for snoring, depression, or vasomotor symptoms.

To the authors' knowledge, the study is the first to characterize sleep over the full span of women's midlife and the first to include an extended follow-up period to characterize CVD events. The study also assessed the relationship between sleep characteristics and CVD across five racial or ethnic groups, "suggesting a consistency of associations between sleep and CVD risk across these diverse groups of women," the authors wrote.

Limitations to the study include that sleep was self-reported by participants. Researchers also did not include data on timing, regularity, and efficiency of sleep. "These findings point to the importance of considering sleep when conducting women's CVD risk assessment and underscore the importance of chronic exposure to poor sleep for its cardiovascular implications," the researchers concluded.