The trend of rising childhood obesity seems to be the most commonly mentioned potential factor contributing to early puberty in girls. What might be the connection?
Here is a link to a WebMD article on the topic:
Our fat cells make [the hormone,] leptin. The more fat we have, the more leptin in our systems. Leptin seems to play a key role in regulating appetite, body type, and reproduction. Leptin doesn't trigger puberty on its own. But there's evidence that for puberty to start, a child has to have enough leptin in her system, Kaplowitz [Paul Kaplowitz, MD, PhD, Chief of the Division of Endocrinology at Children's National Medical Center] says. Girls who have high leptin levels -- because they are overweight -- could be more prone to early puberty.
For those of you who are interested in more scientific details, there are several other pathways for how the increased prevalence of overweight and obesity could trigger early pubertal development. In their article the authors, CM Solorzano and CR McCartney, discuss some of those.
The primary article referenced to support the obesity and early puberty link seems to be one published in 1997 by ME Herman-Giddens et al. In a large cross-sectional study [side note: see my earlier post about study designs; cross-sectional is not the best, but a large sample is good[, they found that obesity as measured by Body Mass Index, BMI, was significantly associated with early puberty, although the association was less strong in African-American girls than in white girls. What this means is that girls who are obese appear to be more likely than girls who are not obese to experience early puberty. However, please keep in mind that showing an association does not equal proving a causal link between the two.
Part of my discomfort with what sometimes seems like a default focus on the obesity-early puberty connection in the literature and general media is that I know girls who have never been overweight or obese who have been diagnosed with central precocious puberty. If obesity is a contributing factor, it must not be the only one.
