Early menstruation in young girls is linked to childhood obesity and higher risks of adverse health outcomes, including cardiovascular disease and cancer, according to a new study. The research, conducted on more than 70,000 women in the US, was led by Harvard University's School of Public Health and published in The Journal of the American Medical Association (JAMA) Network Open.
The study found that the average age for a first period has decreased from 12.5 years among women born between 1950 and 1969 to 11.9 years among women born between 2000 and 2005. This trend was more pronounced in racial minorities such as Black, Hispanic, Asian, or mixed-race women and in those with low socioeconomic status.
Zifan Wang, a postdoctoral research fellow at Harvard's School of Public Health and corresponding author of the study, emphasized the importance of continuing to investigate early menarche and its causes. "Early menarche is associated with a higher risk of adverse health outcomes, such as cardiovascular disease and cancer," Wang said. He added that addressing these health concerns, which disproportionately impact disadvantaged populations, requires greater investment in menstrual health research.
The study also found that menstrual cycles are taking longer to become regular. Among women born from 2000 to 2005, 56% reported regular periods within two years of their first period, compared to 76% among those born from 1950 to 1969. Using the diverse dataset from the Apple Women's Health Study, the researchers enrolled 71,341 women between November 2018 and March 2023. Nearly 62,000 participants self-reported the time it took for their menstrual cycles to become regular, and another subset provided their body mass index (BMI) at the time of their first period.
The authors noted a significant decline in the age at menarche, from an average of 12.5 years in women born between 1950 and 1969 to 11.9 years in those born between 2000 and 2005. They reported an increase in the percentage of individuals experiencing early menarche (before age 11) from 8.6% to 15.5%, and very early menarche (before age 9) from 0.6% to 1.4%. Conversely, the percentage of individuals experiencing late menarche (at age 16 or later) decreased from 5.5% to 1.7%.
BMI, an indicator of obesity, was found to explain the early onset of menstruation in nearly half of the women reporting that information. Within a subset of 9,865 participants with data on BMI at menarche, exploratory mediation analysis estimated that 46% of the temporal trend in age at menarche was explained by BMI.
(Input from various sources)
(Rehash/Susmita Bhandary/MSM)
