Are Irregular Menstrual Cycles Associated with Higher Risk for Premature Death?

Irregular menstrual cycles have been associated with higher risk for chronic diseases such as coronary heart disease and cancer, but whether such irregularity is also linked to premature mortality (defined by the WHO as death before age 70) is less clear. Investigators analyzed long-term, prospectively collected data from 79,505 participants in the Nurses' Health Study (mean age, 38; range, 29–46) with no history of cardiovascular disease, cancer, or diabetes at enrollment. Participants reported on their menstrual cycles at ages 14–17, 18–22, and 29–46; cycle regularity was defined as very regular (within 3–4 days), regular (within 5–7 days), usually regular, and always irregular or amenorrheic. For each age range, users of oral contracepti…