Growing Out Makes You Grow Up

Did you know that the age a woman begins her period is tied to a host of serious health conditions?

Early menarche, the onset of menstruation, is linked to greater chances of developing breast cancer, endometrial cancer, obesity, type 2 diabetes and cardiovascular disease later in life.

Now scientists from 104 worldwide institutions have discovered 30 new genes that control the age of sexual maturation in women, and many of these genes act as biological pathways related to fat metabolism and to body-weight regulation. Many of the genes that increase risk for weight gain and obesity in adulthood also influence the onset of puberty. Menarche usually begins between ages 11 and 14 and is in part triggered by body weight, about 45 kilograms.

Senior author Joanne Murabito, MD ScM, an associate professor of medicine at BUSM, and Clinic Director and Investigator of the Framingham Heart Study, said the study showed that the timing of puberty is controlled by a complex range of biological processes.

“Several of the genes for menarche have been associated with body weight and obesity in other studies suggesting some women may have a genetic susceptibility to weight gain and early puberty,” Murabito said.

She added that these genetic factors can be modified by changes in lifestyle.

“Efforts to reduce or prevent childhood obesity should in turn help reduce the early onset of puberty in girls,” she said.   

The study also found genes associated with other mechanisms involved in the onset of puberty, including hormone regulation and cell development.The meta-analysis of 32 genome-wide association studies observed more than 87,000 women from the U.S., Europe and Australia and performed replication studies in nearly 15,000 more women.

Study co-author Enda Byrne, MD, of the Queensland Institute of Medical Research, said the findings support the idea that “the body launches into puberty once it reaches a certain level of nutrient stores.”

Therefore overweight and obese girls are more likely to undergo early puberty.

Study leaders believe the same factors may influence the onset of puberty in boys.

“One of the next stages of this study will be to test whether the same genes also influence timing of puberty in males,” Byrne said.