Comparing cumulative prevalence of Breast Stage 2+ for non-Hispanic black participants between the BCERP Puberty Study and PROS. Higher body mass index (BMI) was the strongest predictor of earlier age at breast stage 2 in this study. Graphic: Biro, et al., 2013

[Greenspan and Deardorff also research how obesity affects the onset of puberty, e.g., “Onset of Breast Development in a Longitudinal Cohort”, 2013. –Des]

2 December 2014 (NPR) – Many girls are beginning puberty at an early age, developing breasts sooner than girls of previous generations. But the physical changes don't mean the modern girls' emotional and intellectual development is keeping pace.

Two doctors have written a book called The New Puberty that looks at the percentage of girls who are going through early puberty, the environmental, biological, and socioeconomic factors that influence when puberty begins, and whether early puberty is linked with an increased risk of breast cancer.

"It has been established that girls who enter puberty earlier are more likely to have symptoms of anxiety, higher levels of depression, initiate sex earlier and sexual behaviors earlier," Julianna Deardorff tells Fresh Air's Terry Gross.

Deardorff and Louise Greenspan are co-investigators in a long-term study of puberty. They've been following 444 girls from the San Francisco Bay area since 2005, when the girls were 6 to 8 years old. The study is funded by the National Cancer Institute and the National Institute of Environmental Health Sciences.

Deardorff says that while early puberty could be hard on a young girl, family and school support matters.

"The family can serve as a huge buffer against some of those negative effects of early puberty," she says. "There's also been some research to show that certain aspects of the neighborhood context and also schools can be protective. … It can completely mitigate the risk associated with early puberty on girls' emotional and behavioral functioning." […]

On how early puberty could be linked environmental exposure

Julianna Deardorff: What I find concerning is that puberty is a process that's very sensitive to the environment and we can move the timing of puberty, unintentionally, vis-a-vis environmental exposures.

… Puberty in and of itself in starting early has a lot of disconcerting aspects … [I wonder if] this [is] kind of a canary in a coal mine, or a barometer for other things that we're all being exposed to in our environments that may not be healthy for other reasons — we're just not seeing those as obviously.

On chemicals that are hormone mimickers

Deardorff: They're referred to endocrine disrupting chemicals, or EDCs, or another term for that is "hormone mimickers." That's because in the body, they mimic hormones and, in this case, when we're talking about girls' early puberty, estrogen is the hormone that we're most concerned about.

Greenspan: There [are] several chemicals that may mimic estrogen in the body. In animal studies, a big one that we're looking at — the culprit is called Bisphenol A, or BPA. BPA was actually invented as a medical estrogen, it's a weak estrogen, and it ended up becoming ubiquitous in plastics [and] … it's also on paper, receipts and in other compounds. The concern is that it may leech out of those and into our bodies and may act like an estrogen.

Our study has not yet demonstrated that this one, single chemical is causing early puberty, but it is one of the ones we're looking at. One of the problems with deciding which chemical is that there's no one single smoking gun. We live in a toxic milieu of many, many, many chemicals and it's actually becoming impossible to isolate the single one, so we're looking at the ones that may work together. [more]

How Girls Are Developing Earlier In An Age Of 'New Puberty'



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