Saturday, April 16, 2011

On Early Puberty

You might have heard that girls are reaching puberty much earlier than in previous eras. They are starting periods a little earlier than in the past: "For white girls in the US, the age of first menstruation has remained stable over the past 45 years. In African-American girls, age at menarche has declined by about 6 months in the past 20 to 30 years." Yet, of late mothers are worrying about early puberty. If you follow girls health issues, you've probably read something about early puberty in girls. So what is the story?

I posted on a NYT article last year and noted the tricky use of breast development rather than menstruation that made puberty statistics seem alarming. (Muddying up statistics is a media pastime.) Basically there are stages of puberty, called Tanner stages. Breast development is part of Tanner 2 for girls and typically happens about 2 years before menstruation. Menstruation is usually used as the marker for puberty in scientific studies because it is easy to define. Things like breast development are more subjective. Well nourished girls might be chubby making breast development difficult to judge.

As the report linked above shows, onset of menses hasn't changed dramatically, and to the extent it has can be attributed to health and nutrition. Studies show first breast development has moved forward...when compared to the late 19th century. In the scary articles on early puberty, note that most, if not all, are comparing breast development to the 1900's or earlier. With the strides in health and nutrition in the past 100 years, it is neither shocking nor concerning that modern 7 year old girls might have the appearance of breasts more than their pre-automobile great-great-grandmothers. Junkfoodscience has more details on the issue. Also, I found a paper overview that can give laymen a small peek at how much more complicated and detailed early puberty problems are.

That said, such shoddy medical reporting doesn't simply leave mothers with the impression that early puberty is a problem in need of solution. See this article about what to do about early puberty. Even though it states many of the theories for the problem, discussed below, the article concludes by adding a bunch of the stuff that everyone merely assumes is to blame: [emphasis mine]

Be sure to eat fewer meat and high-fat dairy products, which “are more likely than other foods to harbor chemicals that interfere with hormones,” Janssen says. Additionally, don’t use pesticides, since they can interfere with hormones, says Julia Brody, a scientist with Silent Spring Institute. In other words, eat a diet of mostly fresh, organic vegetables and you’ll be fine. That being said, since most of America eats nothing but pre-prepared foods from plastic containers and cans alongside meat and high-fat dairy products, I think the early puberty epidemic should really have explained itself.
Go organic veg and you'll be fine?!  First off, one might want to weigh the consequences, brain and bone wise, of turning under 10's veg against a hoped for two year delay in breast development, especially since the 'more meat, earlier breasts' studies do not account for the effect of meat on nutrition. That is, the correlation might just be because the girl is well fed. Next, going veg will do nothing for those other correlations often seen, specifically, prematurity, absent father, childhood stress, international adoption, and wealth. Yes, wealth. Apparently there is a correlation for early puberty among wealthy girls with absent biological fathers.

In the many articles I have seen on this subject, however, no one calls for tending to a marriage to keep the biological father around. Few talk of allowing kids more freedom outdoors to burn off calories. Commenters don't talk about having children earlier thereby avoiding IVF and its increased incidence of multiples and prematurity. The only nod to prematurity is "don't smoke.' As for international adoptions, just like weighing the negative consequences of going veg against early breasts, no one could reasonably argue that it would be better for the child to have remained in an orphanage or foster care in the country of origin to avoid early puberty from being well fed.

Rather than look at such hard issues, the media leads, and the mothers follow, to pesticides and hormones. Compared to the above controlling pesticide and hormones is easy, something mothers fancy that they can control. (Tiger mothers and helicopter moms have different methods, but they both seek control.) Just feed them good organic veggies and your a Supermom! In the church of Green, organic veggies seems to be the blood and bread of communion.

As for Silent Spring Institute (last link) chick's nasty little swipe about Americans eating nothing but processed plastic and canned food, well she can take her hyperbole and stick it somewhere dark. Americans eat more processed food, Americans eat too much processed food--those formulations I'd simply disagree with. Americans eat nothing but--that is condescending, insulting, smug... It just gets old. Also, I'm surprised that there is an entity still using "Silent Spring" for a name, since it turned out that the book was wrong and subsequently responsible for the ban of DDT which condemned millions in the Third World to malaria.

UPDATE: More here.

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