Changes in Menstrual Cycle Length Prior to Menopause Could Help Predict Risk of Atherosclerosis

Samar El Khoudary, PhD

An analysis of data from more than 400 women included in a major study is detailing the insight provided by changes in patterns of menstrual cycle length over the menopause transition on risk of atherosclerosis in aging women.

The study, which leveraged data from women within the Study of Women’s Health Across the Nation (SWAN) Daily Hormone Study (DHS), identified 3 distinct trajectories of cycle length and described their associations with postmenopausal carotid intima-media thickness and brachial-ankle pulse wave velocity.

“Menopause is not just a click of a button. It’s a multistage transition where women experience many changes that could put them at higher risk for cardiovascular disease. Change in cycle length, which is linked to hormone levels, is a simple metric that might tell us who is more at risk,” Samar El Khoudary, PhD, associate professor of epidemiology at Pitt’s Graduate School of Public Health, in a statement from the North American Menopause Society (NAMS).

As organizations and institutions push to improve the cardiovascular care of women, identifying potential risk factors for cardiovascular disease stand to have a major potential impact on a societal level. With this in mind, El Khoudary and colleagues sought to assess whether trajectories of menstrual cycle length were associated with markers of subclinical atherosclerosis.

Briefly, the SWAN study, which was co-sponsored by the National Institute on Aging (NIA), the National Institute of Nursing Research (NINR), and the National Institutes of Health (NIH), designed with the intent of collecting data related to potential physical, biological, psychological, and social changes during their transition to menopause. The SWAN DHS study is a subsidy of the SWAN study and recorded additional data, such as vasomotor menopausal symptoms in daily diaries for 12-50 days.

From SWAN DHS, investigators identified 428 women with 1,808 cycles over the menopause transition for inclusion in the current study. To be included in the study, women needed to have an observed date of final menstrual period, have recorded cycle lengths from 2 or more annual menstrual cycles, and have measurements of postmenopausal carotid intimal-media thickness and/or brachial-ankle pulse wave velocity.

The study population had a mean age of 45.1±2.3 years at baseline visit and the mean number of menstrual cycles recorded was 4.22±1.91 cycles. Of the 428 included, 263 had carotid intimal-media thickness and 213 had brachial-ankle pulse wave velocity measured after the transition to menopause. Investigators pointed out carotid intimal-media thickness was measured a mean of 13.88±0.42 years after the baseline visit and brachial-ankle pulse wave velocity was measured a mean of 15.25±0.7 years after the baseline visit.

When assessing patterns of cycle length, investigates identified 3 distinct trajectories. In total, 62.1% were considered to have stable cycle length, 21.8% experienced a late increase in cycle length, and 16.2% experienced an early increase in cycle length. Investigators defined stable as no chances in length over the menopause transition, late increase was defined as a late increase 2 years before the final menstrual period, and early increase was defined as an increase 5 years before final menstrual period.

Results of the investigators’ analysis, which were adjusted for race, concurrent age, socioeconomic status, physical activity level, and premenopausal cardiovascular risk profile, suggested women with a late-increase pattern had significantly lower postmenopausal carotid intima-media thickness (0.72 mm) and brachial-ankle pulse wave velocity (1392 cm/s) than those in the stable group (0.77 mm and 1508 cm/s, respectively).

“These findings are important because they show that we cannot treat women as one group: Women have different menstrual cycle trajectories over the menopause transition, and this trajectory seems to be a marker of vascular health,” said El Khoudary. “This information adds to the toolkit that we are developing for clinicians who care for women in midlife to assess cardiovascular disease risk and brings us closer to personalizing prevention strategies.”

This study, “Patterns of menstrual cycle length over the menopause transition are associated with subclinical atherosclerosis after menopause,” was published in Menopause.