New York, Oct 1 : Irregular and long menstrual cycles in adolescence and adulthood are associated with a greater risk of early death (before age 70), warn researchers.
These associations were stronger for deaths related to cardiovascular disease and when long and irregular cycles were consistently present during adolescence and throughout adulthood.
They were also slightly stronger among women who smoked, according to the study, published in the journal BMJ.
"The results highlight the need to consider the menstrual cycle as a vital sign of general health in women throughout their reproductive lifespan," said study authors from the University of Harvard in the US.
Irregular and long menstrual cycles are common among women of reproductive age and have been associated with a higher risk of major chronic diseases including ovarian cancer, coronary heart disease, type 2 diabetes, and mental health problems.
But the evidence linking irregular or long menstrual cycles with mortality is scant.
So a team of researchers set out to evaluate whether irregular or long menstrual cycles throughout the life course are associated with premature death (before age 70).
Their findings are based on data from 79,505 premenopausal women (average age 38 years) with no history of cardiovascular disease, cancer, or diabetes who were taking part in the Nurses' Health Study II.
Women reported the usual length and regularity of their menstrual cycles at ages 14-17 years, 18-22 years, and 29-46 years.
During 24 years of follow-up, 1,975 premature deaths were documented, including 894 from cancer and 172 from cardiovascular disease.
The researchers found that women who reported always having irregular menstrual cycles experienced higher mortality rates than women who reported very regular cycles in the same age ranges.
Mortality rates per 1,000 person-years for women reporting very regular cycles and women reporting always irregular cycles 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.
"These relations were strongest for deaths related to cardiovascular disease than for cancer or death from other causes.
The higher mortality associated with long and irregular menstrual cycles was also slightly stronger among current smokers," the authors wrote.