The mystery of early puberty
A new study available from the journal Pediatrics (subscription required) shows that girls are entering puberty at steadily younger ages. WebMD explains:
The researchers assessed the onset of puberty by a standard measurement of breast development. They compared the findings to a 1997 study of age of puberty. They found the following in a study of girls aged 6-8:The early onset of puberty is found to be correlated with both race and body-mass index (BMI). But what's causing girls to enter puberty sooner?
- 10.4% of white girls in the current study had breast development, compared to 5% in the 1997 study.
- 23.4% of African-American girls had breast development, compared to 15.4% in the 1997 study.
The researchers also collected urine and blood specimens from the girls to look at levels of compounds called endocrine-disrupting chemicals, Biro says, to see what role these environmental exposures might play in early puberty. ''It appears that some of the endocrine-disrupting chemicals are interacting with body composition and this may be the reason some girls are going into puberty earlier and others later," Biro tells WebMD. "That would have to be speculation," he says of the interaction idea. "But we do know BMI is doing it."