Early onset of puberty in girls linked to obesity; local girls involved in study

CINCINNATI - If you think it seems like girls are growing up sooner these days, you're right.

A study involving Tri-State girls shows that girls of all races are entering puberty earlier than ever before.


Researchers are linking it to obesity, particularly in white girls.  The report, published online today in the journal Pediatrics. This multi-institutional study strengthens a growing body of research documenting the earlier onset of puberty. 

Published online Nov. 4, the multi-institutional study strengthens a growing body of research documenting the earlier onset of puberty in girls of all races. Early puberty has been linked to an increased risk of breast and ovarian cancer as well as high blood pressure and depression.

In the study, white girls began developing breasts at the median age of 9.7 years, that is four months earlier than found in a separate study in 1997.

The research finds that a higher body mass index, which is ratio of height and weight, was the "strongest predictor" of early breast development across all races.

"The impact of earlier maturation in girls has important clinical implications involving psychosocial and biologic outcomes," said Frank Biro, MD, lead investigator and a physician in the Division of Adolescent Medicine at Cincinnati Children's Hospital Medical Center. "The current study suggests clinicians may need to redefine the ages for both early and late maturation in girls."

Girls with earlier maturation are at risk for a multitude of challenges, including lower self-esteem, higher rates of depression, norm-breaking behaviors and lower academic achievement. Early maturation also results in greater risks of obesity, hypertension and several cancers – including breast, ovarian and endometrial cancer.

The study was conducted through the Breast Cancer and Environmental Research Program, established by the National Institute of Environmental Health Science. Pediatrics is the journal of the American Academy of Pediatrics.

Researchers at centers in the San Francisco Bay Area, Cincinnati and New York City examined the ages of 1,239 girls at the onset of breast development and the impact of body mass index and race/ethnicity. The girls ranged in age from 6 to 8 years at enrollment and were followed at regular intervals from 2004 to 2011. Researchers used well-established criteria of pubertal maturation, including the five stages of breast development known as the Tanner Breast Stages.

Breast development began in white, non-Hispanic girls, at a median age of 9.7 years, earlier than previously reported. Black girls continue to experience breast development earlier than white girls, at a median age of 8.8 years. The median age for Hispanic girls in the study was 9.3 years, and 9.7 years for Asian girls.

View BiroPediatrics Puberty study report

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