What's the cause of this?
(CNN) — Girls in the United States hitting puberty at a much younger age than their mothers or grandmothers did.
Scientists are always looking for reasons, and one of those seems to be weight.
Girls who develop early may be envied by their peers, but doctors say young females who physically mature faster are at higher risk of low self-esteem, depression, promiscuity and lower grades. Research shows they also have a greater risk of becoming obese, developing hypertension and suffering from breast, ovarian and endometrial cancers.
What's the cause of early puberty?
According to a new study reported in pediatrics, weight has a lot to do with it.
The national institutes of health study is one of the largest studies to look at obesity and its effects on prepubescent girls of all races. Scientists examined more than 1,200 girls, who were aged 6 to 8 at the beginning of the study, noting their race or ethnicity along with their breast development as they aged and their weight.
The data was collected in three locations, the San Francisco Bay area, Cincinnati and New York City.
The study found the onset of puberty did vary by race. On the average, early development began in white, non-Hispanic girls at a little more than 9 and a half years, which was earlier than previously reported in other studies. Black girls started puberty about a year earlier than white girls and Hispanic and Asian females around the same age as whites.
But when it came to their weight, overall, the study found body mass index played a bigger role in early puberty than race or ethnicity, and that white girls seemed to be most affected.