Early puberty is on the rise, especially among girls. More girls develop breasts and start menstruating earlier, and American girls reach physical maturity sooner than they did only 30 years ago.
Previously, girls were expected to show the first signs of puberty between the ages of eight and 14. Breast development before age eight or the onset of menstruation before age nine are currently considered early.
Obesity changes a young girl's hormonal cocktail and can trigger premature breast development and periods. While there are definitely other potential causes of early puberty, childhood obesity rates are skyrocketing and the possibility of an early puberty along with its related risks is yet another reason to take it very seriously.
BMI 'The Strongest Predictor Of Early Breast Development'
The new study followed over 1,200 girls from age six to eight in three highly urban US areas: the San Francisco Bay Area, Greater Cincinnati, and New York City. The researchers followed the girls for seven years between 2004 and 2011 and monitored their pubertal maturation through well-established criteria during multiple visits.
A higher Body Mass Index was found to be the strongest predictor of early breast development. Overweight and obese girls were found to start breast development an average of one year earlier than their peers with a healthy BMI.
Does overweight or obesity actually cause an early puberty? The study's authors point out that their research does not establish that to be true, though it certainly seems likely when you take into account what's already known about the impact of obesity on hormones. The study authors write that "the obesity epidemic appears to be a prime driver in the decrease in age at onset of breast development in contemporary girls".
Frank Biro MD made it clear that his team's findings have important clinical implications, and that the study suggests that "clinicians may need to redefine the ages for both early and late maturation in girls".
How Does Early Puberty Impact Girls?
It's already clear that an early puberty (by the current definition, that is) increases a girl's risk of diabetes, high blood pressure, and heart disease. The early onset of menstruation also gives a girl a higher risk of developing breast cancer.
Beside those physical health risks, anyone can see that being physically mature early on in life can lead to social and psychological problems too. These early birds may have breasts and the capability to become pregnant, but they're still kids. Being a kid in a mature body has got to be tough. Frank Biro MD put it like this:
"Just because you’re developing more quickly physically doesn’t mean you’re maturing emotionally or socially."
Referencing earlier studies, the authors say that girls who go through puberty early on "are more likely to be influenced by older peers and more deviant peers, and initiate intercourse, substance use, and other norm-breaking behaviors at younger ages."
Parents of pre-pubescent girls might wonder if the new study has practical implications for them. While the answer is not simple by any means, the common wisdom of making sure your children eat a healthy and balanced diet and exercise regularly still stands. A healthy BMI may well decrease your child's risk of an early puberty. In addition, you may want to start talking about puberty and its social impact a whole lot earlier than you previously thought you should.