A new study is suggesting that the rapid rise in female early-onset puberty has to do with the BMI and amount of body fat in toddlers. The study followed 354 girls age 3-12 who were either normal weight, at risk of being overweight, or overweight, and found an association between elevated body weights and the early onset of puberty (determined by breast development and the onset of menstruation).
This link has been suggested before, but has always been a question of chicken and egg - was early puberty causing the obesity, or the obesity causing the early puberty? The PI for the study, Joyce Lee, says that by tracking the girls from such a young age, the "study shows that it is increased body fatness that causes the early onset of puberty and not the other way around."
Given what we know about the problems associated with precocious puberty, from later reproductive issues to more immediate concerns about the sexualization of a nine year old, this seems to justify further public health intervention in the obesity epidemic. Of course, the question becomes how to intervene. Is a ban on transfats going to solve the problem? Hardly. Bringing physical education back into schools, a opposed to once a week - if kids are lucky? Possibly. But without a radical overhaul of our diet, of how we eat, and what food is available at what price, I have a hard time imagining that the obesity epidemic and associated problems, are going away any time soon.