Menstrual Irregularity Appears to Be Predictor of Early Death

Jill D. Pivovarov

October 27, 2020

Women who experience irregular and long menstrual cycles in adolescence and adulthood are more likely to die before the age of 70 years than women with regular or short cycles, reported Yi-Xin Wang, PhD, of Harvard TH Chan School of Public Health, Boston, and associates. This is particularly true in the presence of cardiovascular disease and a history of smoking.

In a peer-reviewed observational study of 79,505 premenopausal women enrolled in the Nurses' Health Study II, the researchers sought to determine whether a life-long history of irregular or long menstrual cycles was associated with premature death. Patients averaged a mean age of 37.7 years and had no history of cardiovascular disease, cancer, or diabetes at enrollment.

Although irregular and long menstrual cycles are common and frequently linked with an increased risk of major chronic diseases – such as ovarian cancer, coronary heart disease, type 2 diabetes, and mental health problems – in women of reproductive age, actual evidence linking irregular or long menstrual cycles with mortality is scant, the researchers noted in the BMJ.

During the study, participants checked in at ages 14-17 years, 18-22 years, and 29-46 years to report the usual length and regularity of their menstrual cycles. Over 24 years of follow-up, a total of 1,975 premature deaths were noted, including 894 from cancer and 172 from cardiovascular disease.

Irregular Cycles Appear to Bring Risks

After considering other possible factors of influence, including age, weight, lifestyle, and family medical history, Wang and associates noted higher rates of mortality among those consistently reporting irregular cycles than women in the same age ranges with very regular cycles. Specifically, women aged 18-22 years and 29-46 years with cycles of 40 days or more were at greater risk of dying prematurely than were those in the same age ranges with cycles of 26-31 days.

Cardiovascular disease was a stronger predictor of death than cancer or other causes. Also included in the higher-risk group were those who currently smoked.

Among women reporting very regular cycles and women reporting always irregular cycles, mortality rates per 1,000 person-years were 1.05 and 1.23 at ages 14-17 years, 1.00 and 1.37 at ages 18-22 years, and 1.00 and 1.68 at ages 29-46 years, respectively.

The study also found that women reporting irregular cycles or no periods had a higher body mass indexes (28.2 vs. 25.0 kg/m2); were more likely to have conditions including hypertension (13.2% vs. 6.2%), high blood cholesterol levels (23.9% vs. 14.9%), hirsutism (8.4% vs. 1.8%), or endometriosis (5.9% vs. 4.5%); and uterine fibroids (10.0% vs. 7.8%); and a higher prevalence of family history of diabetes (19.4% vs. 15.8%).

Wang and associates also observed – using multivariable Cox models – a greater risk of premature death across all categories and all age ranges in women with decreasing menstrual cycle regularity. In models that were fully adjusted, cycle lengths that were 40 days or more or too irregular to estimate from ages 18-22 and 29-46 expressed hazard ratios for premature death at the time of follow-up of 1.34 and 1.40, compared with women in the same age ranges reporting cycle lengths of 26-31 days.

Of note, Wang and colleagues unexpectedly discovered an increased risk of premature death in women who had used contraceptives between 14-17 years. They suggested that a greater number of women self-reporting contraceptive use in adolescence may have been using contraceptives to manage symptoms of polycystic ovary syndrome (PCOS) and other conditions such as endometriosis.

Relying on the potential inaccuracy inherent in patient recall of their menstrual cycle characteristics, and the likelihood for other unmeasured factors, may have affected study results. Study strengths included the significant number of participants who had a high follow-up rate over many years, and the availability of menstrual cycle data at three different points across the reproductive lifespan.

Because the mechanisms underlying these associations are likely related to the disrupted hormonal environment, the study results "emphasize the need for primary care providers to include menstrual cycle characteristics throughout the reproductive life span as additional vital signs in assessing women's general health status," Wang and colleagues cautioned.

Expert Suggests a Probable Underlying Link

"Irregular menstrual cycles in women have long been known to be associated with significant morbidities, including the leading causes of mortality worldwide such as cardiovascular disease and cancer," Reshef Tal, MD, PhD, assistant professor of obstetrics, gynecology & reproductive sciences at Yale University, New Haven, Conn., said in an interview. "The findings of this large study that irregular menstrual cycles are associated with premature death, most strongly from cardiovascular causes, are therefore not surprising."

Tal acknowledged that one probable underlying link is PCOS, which is recognized as the most common hormonal disorder affecting women of reproductive age. The irregular periods that characterize PCOS are tied to a number of metabolic risk factors, including obesity, insulin resistance, dyslipidemia, and hypertension, which increase the long-term risk of cardiovascular disease and cancer of the uterus.

"The study did not have information on patients' pelvic ultrasound findings and male hormone levels, which would have helped to establish PCOS diagnosis. However, women in this study who had irregular cycles tended to have more hirsutism, high cholesterol, hypertension as well as higher BMI, suggesting that PCOS is at least partly responsible for the observed association with cardiovascular disease. Interestingly, the association between irregular cycles and early mortality was independent of BMI, indicating that mechanisms other than metabolic factors may also play a role," observed Tal, who was asked to comment on the study.

"Irregular periods are a symptom and not a disease, so it is important to identify underlying metabolic risk factors. Furthermore, physicians are advised to counsel patients experiencing menstrual irregularity, [to advise them to] maintain a healthy lifestyle and be alert to health changes," Tal suggested.

The study was funded by the National Institutes of Health. The investigators had no relevant financial disclosures. Tal said he had no relevant financial disclosures.

SOURCE: Chavarro J et al. BMJ. 2020. doi: 10.1136/bmj.m3464.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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