Menstrual cycle length changes before menopause may indicate CVD risks
Changes in menstrual cycle lengths as women approach menopause may indicate CVD risks, according to a study published in Menopause.
“The menopause transition is a period where women experience multiple changes, including changes in their menstrual cycle. Changes in menstrual cycle length are linked with hormone levels, and hormones can influence CVD risk,” author Samar R. El Khoudary, PhD, MPH, BPharm, FAHA, associate professor of epidemiology at the University of Pittsburgh Graduate School of Public Health, told Healio.
Previous studies in reproductive-aged women showed a link between menstrual cycle irregularity and health conditions, but “a similar association had not been assessed in women transitioning through menopause, who experience multiple changes that increase their risk for CVD later in life,” said El Khoudary.
Researchers analyzed data from 428 participants in the ongoing Study of Women’s Health Across the Nation, or SWAN, which follows women who enroll at age 45 to 52 years for up to a decade or until they are postmenopausal.
Using menstrual cycle data collected throughout the menopause transition, the researchers identified three trajectories of cycle length that seem to be markers of vascular health.
“This is important because it shows that we cannot lump women together in one group. They experience different changes to their cycle during the menopause transition. Measuring these changes could be a simple way to predict who might be at risk of cardiovascular disease in the future,” said El Khoudary.
According to the study, 62.1% of the participants had stable cycles that did not change appreciably before menopause, 16.2% experienced an early increase as early as 5 years before their final menstrual period and 21.8% experienced a late increase as early as 2 years before their final menstrual period.
The researchers then assessed cardiovascular risk after menopause by measuring carotid intima-media thickness and brachial-ankle pulse wave velocity, which they called early markers of atherosclerosis and indicators of risk for CVD.
Compared with the women with stable cycles, women in the late increase group had significantly more favorable measures of artery hardness and thickness compared with the women with stable cycles and the women in the early increase group, who had the poorest measures of artery health of the three groups.
“We were surprised to find that the majority of women in our study had stable cycles during the menopause transition, and it was surprising that these women had higher cardiovascular disease risk than those who experienced a late increase in cycle length,” said El Khoudary.
Previous studies have found that young women with frequent short cycles have better cardiovascular health, indicating that estrogen is protective for the heart in this age group.
“But we found that women in the late increase group had better measures of cardiovascular health than those in the stable group, suggesting that estrogen may not be as protective later in life,” El Khoudary said.
The study did not compare cycle length patterns with other risk factors such as physical activity or lipid profiles. But women who experienced a late increase in cycle length had better cardiometabolic risk profiles than those who experienced stable trajectories, suggesting that cycle length is a potential marker for cardiometabolic health, El Khoudary said.
Overall, the researchers called these findings consistent with other studies that have linked menstrual irregularities to CVD risk.
“During the last 10 decades, our understanding of the link between the menopause transition and CVD has significantly evolved. We know that early menopause and frequent vasomotor symptoms are associated with greater CVD risk,” said El Khoudary.
“Our work adds patterns of changes in cycle length as a new menopause-related characteristic that could point to women at greater risk of CVD. Doctors should consider menopause-related factors as a constellation when evaluating midlife women. The menopause transition is an impactful period for cardiovascular health, and women as well as their health care providers should advocate for a heart-healthy lifestyle as early as they can,” she said.
Next, the researchers aim to measure hormone levels in women throughout the menopause transition to test their hypothesis that menstrual cycle changes reflect estrogen levels, which influences cardiovascular health.
“Previously, we found that accumulation of abdominal fat during menopause was a risk factor for cardiovascular disease, so we want to examine if menstrual cycle trajectories are linked with this and other risk factors,” El Khoudary said.