USA research says:

Study ties girls' body weight to early puberty

30th March 2001, author & source unknown

Black and Hispanic girls in the US are significantly more likely than whites and Asian Americans to start puberty at an early age, new research shows. They are also more likely to be overweight -- bolstering the belief that the US trends of rising childhood obesity and early puberty are closely linked.

Looking at health data on 6,500 teenage girls, researchers found that blacks were 55% more likely than whites to have their first menstrual periods before age 11, while Hispanic girls were 76% more likely. Asian girls were least likely to mature early, and were 65% more likely than whites to hit puberty at age 14 or older.

All of these trends were related to the girls' weight, according to a report in the April issue of the American Journal of Public Health, journal of the American Public Health Association.

Overall, more than 40% of girls who had their first periods before age 11 were overweight. That compares with one quarter of girls who reached puberty later.

Lead author Dr. Linda S. Adair of the University of North Carolina in Chapel Hill said that while this study did not look at the girls' weights before puberty, studies have shown that girls who are heavier at ages 5, 6 and 7 reach puberty faster.

Indeed, since a 1997 study suggested American children are increasingly reaching puberty at a tender age -- as early as age 8 among black girls -- there has been growing concern about what the trend means.

Some experts believe that the rising rate of obesity among US children has been a deciding factor in spurring early maturation. Both have health consequences. Obesity puts young people at risk for diabetes and raises their odds of heart disease and other health problems down the road. For girls, early puberty increases their lifetime exposure to estrogens, which may elevate the risk for breast cancer and possibly ovarian cancer.

The two trends of rising obesity and early puberty are particularly marked among blacks and Hispanics. Adair said her team's findings highlight the need to target these children in obesity prevention efforts. "It's really important to begin obesity intervention at a very young age," Adair said. "The key," she added, "will be increasing physical activity and spending less time in front of the TV."

American Journal of Public Health - 2001;91: 642-644.