Poor sleep in midlife may increase women’s risk of later-life cardiovascular disease events

Women who experience poor sleep during midlife, including persistent insomnia and short sleep duration, may be at greater risk of cardiovascular disease events in later life. According to NIA-funded research published in Circulation, persistent insomnia symptoms, alone and when accompanied by short sleep duration, were associated with up to a 75% increased risk. The findings underscore the importance of considering sleep patterns when evaluating women's cardiovascular health and their future risk for related disease.

Cardiovascular disease, also known as heart disease, affects the heart or blood vessels, or both. It is the leading cause of death in women and about 30% of women die from some form of it. Poor sleep quality and insomnia are prevalent among women, especially during midlife, often defined as age 40 to 65 years, with up to 50% of women reporting sleep issues during this time. Symptoms of menopause can also contribute to sleep problems. Previous studies have shown that inadequate sleep is linked to a higher risk of developing cardiovascular disease. However, the potential link between sleep problems and later-life cardiovascular events (i.e., heart attacks, strokes, and heart failure) is not well understood.

To address this gap, researchers conducted a study using data from the Study of Women's Health Across the Nation (SWAN). SWAN is an ongoing long-term study of 3,320 women who were age 42 to 52 years and premenopausal when they entered the study in 1994. A wide variety of data was collected from SWAN participants, including cardiovascular disease risk factors such as blood glucose and cholesterol levels, blood pressure, and smoking status. Additionally, cardiovascular disease events were documented. Researchers also examined the sleep patterns of SWAN participants repeatedly over 22 years, including insomnia symptoms (trouble falling asleep, waking up multiple times a night, waking too early) and sleep duration.

For this study, the research team evaluated the relationship between sleep disturbances during midlife and later-life cardiovascular disease events in SWAN participants. They looked at both insomnia symptoms and sleep duration separately and together, considering how they might affect heart health differently. SWAN participants were first placed into four groups based on severity and frequency of insomnia: low, moderate-decreasing over time, low-increasing over time, and persistently high. The categories were further refined to include sleep duration to evaluate the combined effect of insomnia and sleep duration on subsequent risk for cardiovascular events.

Researchers found that persistent insomnia symptoms and short sleep duration were both associated with an increased risk of developing cardiovascular disease later in life. Nearly one-quarter of SWAN participants (23%) experienced persistent insomnia symptoms over midlife and had an elevated risk for subsequent heart disease events. Short sleep duration throughout midlife, experienced by 14% of participants, was also associated with increased risk for cardiovascular disease events later in life, but to a lesser extent. Notably, women with both persistent insomnia symptoms and short sleep duration had the highest risk of cardiovascular disease events, with a 70% to 75% increased risk.

Overall, these findings highlight the importance of considering sleep patterns, particularly insomnia symptoms and short sleep duration, in understanding cardiovascular health risks in women during midlife and beyond. Further research is needed to better understand the mechanisms underlying the relationship between poor sleep and cardiovascular health.

This research was supported in part by NIA grantsU01AG012505, U01AG012535, U01AG012531, U01AG012539, U01AG012546, U01AG012553, U01AG012554, U01AG012495, and U19AG063720.

Reference: Thurston RC, et al. Trajectories of sleep over midlife and incident cardiovascular disease events in the study of women's health across the nation.Circulation. 2024;149(7):545-555. doi: 10.1161/CIRCULATIONAHA.123.066491.