The study of women in eight European countries doesn't confirm that early puberty causes diabetes, but it does point to an association.
"The body is undergoing many changes during puberty," said Cathy Elks, a research fellow at the MRC epidemiology unit at the University of Cambridge in England. "Our research, as well as previous related studies, suggests that the biological factors implicated in the timing of development may have a role in the development of type 2 diabetes, despite the fact that these processes occur many years before the manifestation of disturbed [blood sugar] control."
For the study, published in the November issue of Diabetes Care, Elks and colleagues examined the medical records of more than 15,000 women and found that those who began to menstruate between the ages of 8 and 11 were 70 percent more likely to develop type 2 diabetes than those who began to menstruate at age 13, the median age.
Other studies have shown that girls who start puberty earlier are more likely to develop obesity, heart disease and some kinds of cancer.
Could obesity, which is more common among girls who get their first period early, play a role? The researchers adjusted their statistics to remove any effect of obesity and found that those who began puberty earlier still had a higher risk of diabetes, although excess weight often appears to play a role overall.
"These findings suggest that early puberty has an effect on metabolic disease risk, which is partially mediated by increased BMI [a measurement of body fat based on height and weight], but also has some direct effect through other biological pathways which act independently of adiposity [body fat]," the study authors noted in a news release from the American Diabetes Association.
Incidence of type 2 diabetes has surged in recent decades, coinciding with a decrease in the average age of puberty, the researchers pointed out. However, having a first period later than average (after age 15) did not confer greater protection from type 2 diabetes in adulthood, the authors said.
For more about diabetes, visit the U.S. National Library of Medicine.