We all remember that awkward day. But for the first time, researchers have determined the genetic markers that determine the timing of a woman’s first period, opening the doors to determining a woman’s risk for disease later in life.
In an analysis of more than 180,000 women, researchers were able to identify 123 genetic variations associated with the timing of when women had their first period. The research, lead by senior author Dr. Joanne Murabito, an associate professor of medicine at Boston University School of Medicine, has the potential to open the doors to discovering correlations between when women enter puberty and their risk for diseases later in life.
“Our findings demonstrate a complex network of genetic factors underlying the timing of menarche. Menarche is associated with the development of health conditions later in life in women such as diabetes, cardiovascular disease, and breast cancer,” said Dr. Murabito in a statement about the research, which was published in the July 2014 issue of Nature. “By studying genetic factors we hope to better understand how puberty timing in girls is linked to important health conditions in women.”
The timing of menarche has been associated with increased risks for breast cancer, diabetes, and heart disease. For instance, in a 2013 study published in the Journal of Clinical Endocrinology and Metabolism, the early onset of a woman’s first menstrual cycle was associated with being a predictor of cardiovascular disease. Women who had their period earlier had an increased likelihood of having a higher body mass index (BMI), waist circumference, and being obese. In the past couple of years, researchers have found that more girls are going through puberty before 10 years old. A study in the American Academy of Pediatrics found that out of 17,000 girls, white girls were beginning puberty just before age 10. For African American girls, puberty began just before age 9 on average.
These imprinted genes are inherited by both the mother and the father, but researchers determined by analyzing the family trees of more than 35,000 women in Iceland that there is some biological conflict around which parent’s gene will determine the timing of puberty in girls. In different women, some genes are only active when inherited from the mother and others are only active when inherited by the father, but researchers found that there was no even trade-off between the parents.
“This research is the first step in understanding the genetics involved with the onset of puberty in girls,” said Dr. Douglas P. Kiel, Director of the Musculoskeletal Research Center at Harvard Medical School–affiliated Hebrew SeniorLife Institute for Aging Research (IFAR) in Boston, Mass. in a statement about the study’s release. “By uncovering which genes influence menarche, we can then focus on its link to increased disease risks, such as osteoporosis or diabetes, in later life.”