Menstrual Cycle Irregularities May Increase Risk for Cardiometabolic Events in Later Life

A history of irregular menstrual cycles and cycles that are either frequent or infrequent both may increase a woman’s risk for adverse cardiometabolic outcomes in later life, according to a nationwide cohort study in the UK. Among the more than 700 000 participants seen in primary care practice, investigators found the strongest associations with cardiometabolic events among women who had abnormal patterns in frequency of their menstrual cycles.

Specifically, in adjusted models, the research team observed a significant 24% greater risk of a composite cardiovascular disease (CVD) outcome for women who had variations in frequency of menstrual cycle.

Writing in BMC Medicine, Kelvin Okoth, MBChB, MPH, honorary research fellow at the Institute of Applied Health Research, University of Birmingham, UK, and colleagues observe that even as female reproductive factors are gaining research attention for their potential role in future CV risk, menstrual cycle characteristics have not been included in those investigations and, they believe, are an underrecognized contributor to adverse CV outcomes in women.

Even as female reproductive factors are gaining research attention for their potential role in future CV risk, menstrual cycle characteristics have not been included in those investigations and are an underrecognized contributor to adverse CV outcomes in women.

Okoth et al cite research demonstrating that long or irregular menstrual cycles are linked to CV risk factors such as dyslipidemia, hypertension, and diabetes. Moreover, the American College of Obstetricians and Gynecologists recommends that menstrual cycle history be included as a vital sign to improve early detection of potential adverse health outcomes in later life.

Okoth and colleagues conducted the current study to evaluate and also to raise awareness for the association between menstrual cycle characteristics and long-term risk for cardiometabolic outcomes.

Menstrual history, matched controls

For the retrospective cohort study the authors tapped data from The Health Improvement Network, a UK-based database of anonymized electronic health records (ERH) contributed by 787 general practices. Data collected were provided by patients as part of routine primary care between 1995 and 2021. Eligible participants were aged 18 to 40 years.

The investigators examined 2 exposures related to menstrual history—regularity and frequency of menstrual cycles and created 2 study cohorts: The first comprised women with irregular or no menstrual cycle (exposed group) and matched controls from the general population with no history of irregular menstrual cycles. The second group included women with a pattern of infrequent or frequent menstrual cycles (exposed group) and matched controls with no such history. The research team compared rates of cardiometabolic outcomes between exposed and control groups.

The specified primary outcome was incident diagnosis of CVD, a composite of ischemic heart disease (IHD), heart failure (HF), or cerebrovascular disease (stroke or transient ischemic attack [TIA]). For secondary outcomes, the researchers identified each of the CV conditions alone as well as hypertension and type 2 diabetes (T2D).

FINDINGS

The full cohort numbered 704 743 participants including 215 378 with a history of irregular menstrual cycles and 36 947 with a history of frequent or infrequent cycles. Median age of women in both groups was approximately 27 years.

During 26 years of follow-up, a total of 20 605 cardiometabolic events occurred among the full 704 743-participant cohort.

Regularity. In adjusted models, when compared to women with regular menstrual cycles, the adjusted hazard ratio (aHR) (95% CI) for women with irregular menstrual cycles for composite CVD was 1.08 (95% CI 1.00–1.19). For the individual CV conditions, aHR were: IHD 1.18 (1.01–1.37), cerebrovascular disease 1.04 (0.92–1.17), HF 1.30 (1.02–1.65), hypertension 1.07 (1.03–1.11), and T2D 1.37 (1.29–1.45).

Frequency. The aHR comparing frequent or infrequent menstrual cycles to menstrual cycles of normal frequency for compositive CVD was 1.24 (1.02–1.52). For secondary outcomes, aHR were IHD 1.13 (0.81–1.57), cerebrovascular disease 1.43 (1.10–1.87), HF 0.99 (0.57–1.75), hypertension 1.31 (1.21–1.43), and T2D 1.74 (1.52–1.98).

The authors state that their findings on the impact of abnormal menstrual cycle patterns on several components of later cardiometabolic health support calls for menstrual cycle history to be included as an additional vital sign when assessing young women’s overall health status. They suggest that abnormal menstruation may “act as a window” into a woman’s cardiometabolic health and prompt periodic evaluation of other potential risk factors.

Research going forward, they add, should focus on understanding the pathophysiologic mechanisms that support a link between menstrual cycle complications and adverse cardiometabolic health.

Reference: Okoth K, Smith WP, Thomas GN, Nirantharakumar K, Adderley NJ. The association between menstrual cycle characteristics and cardiometabolic outcomes in later life: a retrospective matched cohort study of 704,743 women from the UK. BMC Med. Published online March 10, 2023. doi:10.1186/s12916-023-02794-x