Article on Puberty Before Age 10, Today's New York Times

Hi, Everyone.  A big article on signs of puberty at younger ages came out in today's New York Times.  Part of the discussion in it is about what defines "normal puberty".  Some in the medical community feel that earlier breast development without the activation of the brain found in central precocious puberty (CPP) should not be considered abnormal.  In an earlier post, I made my own opinion about that approach clear. 


The possible causes of early development that are discussed in the NYT piece include many that we have already mentioned in this blog, such as: obesity, certain environmental chemicals, and family factors.


I don't think that I am allowed to attach the full text, but I have included excerpts below. The full article can be found on the NYT website here.  

March 30, 2012

Puberty Before Age 10: A New ‘Normal’?

By ELIZABETH WEIL

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So why are so many girls with no medical disorder growing breasts early? Doctors don’t know exactly why, but they have identified several contributing factors.
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... animal studies show that the exposure to some environmental chemicals can cause bodies to mature early. Of particular concern are endocrine-disrupters, like “xeno-estrogens” or estrogen mimics. These compounds behave like steroid hormones and can alter puberty timing.  
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One concern, among parents and researchers, is the effect of simultaneous exposures to many estrogen-mimics, including the compound BPA, which is ubiquitous. Ninety-three percent of Americans have traces of BPA in their bodies. BPA was first made in 1891 and used as a synthetic estrogen in the 1930s. In the 1950s commercial manufacturers started putting BPA in hard plastics. Since then BPA has been found in many common products, including dental sealants and cash-register receipts. More than a million pounds of the substance are released into the environment each year.

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 Adding to the anxiety is the fact that we know so little about how early puberty works. A few researchers, including Robert Lustig, of Benioff Children’s Hospital, are beginning to wonder if many of those girls with early breast growth are in puberty at all. Lustig is a man prone to big, inflammatory ideas. (He believes that sugar is a poison, as he has argued in this magazine.) To make the case that some girls with early breast growth may not be in puberty, he starts with basic science. True puberty starts in the brain, he explains, with the production of gonadotropin-releasing hormone, or GnRH. “There is no puberty without GnRH,” Lustig told me. GnRH is like the ball that rolls down the ramp that knocks over the book that flips the stereo switch. Specifically, GnRH trips the pituitary, which signals the ovaries. The ovaries then produce estrogen, and the estrogen causes the breasts to grow. But as Lustig points out, the estrogen that is causing that growth in young girls may have a different origin. It may come from the girls’ fat tissue (postmenopausal women produce estrogen in their fat tissue) or from an environmental source. “And if that estrogen didn’t start with GnRH, it’s not puberty, end of story,” Lustig says. “Breast development doesn’t automatically mean early puberty. It might, but it doesn’t have to.” Don’t even get him started on the relationship between pubic-hair growth and puberty. “Any paper linking pubic hair with early puberty is garbage. Gar-bage. Pubic hair just means androgens, or male hormones. The first sign of puberty in girls is estrogen. Androgen is not even on the menu.”

Frank Biro, lead author of the August 2010 Pediatrics paper and director of adolescent medicine at Cincinnati Children’s Hospital, began having similar suspicions last spring after he flew to Denmark to give a lecture. Following his talk, Biro looked over the published data on puberty of his colleague Anders Juul. In Juul’s study, some of the girls with early breast development had unexpectedly low levels of estradiol, the predominant form of estrogen in women’s bodies from the onset of puberty through menopause. Biro had seen a pattern like this in his data, suggesting to him that the early breast growth might be coming from nonovarian estrogens. That is to say, the headwaters for the pubertal changes might not be in the girls’ brains. He is now running models on his own data to see if he can determine where the nonovarian estrogens are coming from.

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Elizabeth Weil is a contributing writer for the magazine and the author of a new memoir about marriage, “No Cheating, No Dying.”