Menstrual cycle irregularity and risk for future cardiovascular disease

Area of Science:

• Cardiovascular Epidemiology
• Reproductive Endocrinology

Background:

• Cross-sectional studies indicate a link between irregular menstrual cycles, hyperandrogenism, and increased cardiovascular disease (CVD) risk.
• Prospective data on the association between menstrual cycle irregularity and subsequent CVD risk are limited.

Purpose of the Study:

• To prospectively evaluate the risk of coronary heart disease (CHD) and stroke in relation to a history of irregular menstrual cycles.
• To investigate menstrual cycle regularity as a potential predictor of cardiovascular events in women.

Main Methods:

• Prospective cohort study involving 82,439 female nurses followed for 14 years (1982-1996).
• Participants reported menstrual regularity between ages 20-35 years.
• Cardiovascular events, including nonfatal myocardial infarction, fatal CHD, and stroke, were ascertained and medically confirmed.

Main Results:

• Women with usually irregular or very irregular cycles had a significantly increased risk for nonfatal or fatal CHD compared to those with very regular cycles (RR 1.25 and 1.67, respectively).
• Increased CHD risk associated with cycle irregularity persisted after adjusting for BMI and other confounders.
• A nonsignificant trend towards increased overall stroke and ischemic stroke risk was observed with very irregular cycles.

Conclusions:

• Menstrual cycle irregularity may serve as a marker for underlying metabolic abnormalities that predispose women to a higher risk of cardiovascular disease.
• History of irregular menstrual cycles is associated with an elevated risk of coronary heart disease.