The first menstrual period, or menarche, is happening at a younger age for girls in the U.S., particularly for those from racial minority groups and lower socioeconomic backgrounds, a new study from researchers at Harvard T.H. Chan School of Public Health revealed. Additionally, the study showed that it is taking longer for the menstrual cycle to become regular.
According to a new study published in JAMA Network Open, it has been discovered that the time it takes for the menstrual cycle to become regular is increasing. The study is part of the Apple Women’s Health Study, which is a long-term research project focused on menstrual cycles, gynecological conditions, and women’s overall health. The study is a collaboration between the Harvard Chan School, the National Institute of Environmental Health Sciences, and Apple. The findings aim to improve the understanding of menstrual health and its relationship to the environment.
Paraphrasing the given text, the article discusses a study conducted by Harvard Chan School assistant professor Shruthi Mahalingaiah on the trends of earlier menarche and menstrual cycle regularity among different racial and socioeconomic groups. The study utilized the Apple Women’s Health Study’s extensive dataset to address the lack of data on these trends. The study enrolled 71,341 participants between November 2018 and March 2023.In a study, participants reported the age at which they started menstruating, as well as their race and socioeconomic status. The researchers categorized the participants into five age groups based on their birth year. They also classified the age of first menstruation as early (under 11 years old), very early (under 9 years old), and late (16 years old and older). A subset of participants also reported the time it took for their menstrual cycle to become regular and were divided into five categories based on the length of time it took.The study looked at the data from 20,973 women who provided information on their age of menarche, as well as their body mass index (BMI) at that time. The researchers found that as the birth year of the participants increased, the average age at menarche decreased. Additionally, the time from menarche to menstrual cycle regularity also increased. For those born between 1950-1969, the average age of menarche was 12.5 years, with early and very early menarche rates at 8.6% and 0.6% respectively. However, for those born between 2000-2005, the average age of menarche was 11.9 years, with early and very early menarche rates at 15.5% and 1.4% respectively. These findings suggest a significant shift in the age of menarche over time.The study found that the percentage of participants who achieved regular menstrual cycles within two years of starting their period decreased from 76% to 56%. The researchers noted that these patterns were seen across all demographic groups but were particularly prominent among those who identified as Black, Hispanic, Asian, or mixed race, and those who considered themselves to be from a low socioeconomic background.
The results indicated that BMI at the time of menarche may account for some of the shift towards earlier periods. In other words, childhood obesity, which is a risk factor for early puberty and a growing problem in the U.S., could be a contributing factor to earlier menstruation.The trend in early menarche may be influenced by various factors including dietary habits, stress, adverse childhood experiences, and environmental factors like endocrine-disrupting chemicals and air pollution,” said Zifan Wang, postdoctoral research fellow in Harvard Chan School’s Department of Environmental Health. “Understanding the drivers of early menarche is crucial as it is linked to increased risk of health issues such as cardiovascular disease and cancer. Addressing these health concerns is important based on our findings.The need for more investment in menstrual health research is becoming increasingly important as it continues to affect more people, especially those who are already disadvantaged. The study highlighted the limitations of relying on retrospective self-reporting. The authors of the study included researchers from the Harvard Chan School and the study was funded by Apple, Inc. and the National Institutes of Health. (Journal Reference: Zifan Wang, Gowtham Asokan, Jukka-Pekka Onnela, Michelle Williams, Russ Hauser, and Brent Coull)In a study published in JAMA Network Open, researchers including ukka-Pekka Onnela, Donna D. Baird, Anne Marie Z. Jukic, and others examined the relationship between menarche (the onset of menstruation) and the time it takes for individuals born between 1950 and 2005 in the US to establish a regular menstrual cycle.
