There appears to be a strong correlation between teenage obesity and exposure to phthalates—endocrine-disrupting compounds found in many personal care products and a myriad of plastic and vinyl products.
A recent study of pre-adolescent girls living in Harlem showed that the heaviest girls in the cohort of roughly 400 kids, aged 9–11, had the highest levels of phthalate metabolites in their urine, reported Philip J. Landrigan, MD, chairman of the Department of Community & Preventive Medicine, Mount Sinai Medical Center, New York. The study is part of a large scale project titled, "Growing Up Healthy in East Harlem," that looks at determinants of health and illness among children in this predominantly poor, Black and Hispanic neighborhood.
The phthalate-obesity findings were published in the journal Epidemiology, and received considerable attention when New York Times reporter Jennifer Lee covered the study in the April 17 edition.
The data so far suggest that kids in this community are growing up anything but healthy. Roughly 40% of all school-age children in East Harlem are overweight or obese. Dr. Landrigan and colleagues found that even among normal weight girls, phthalate metabolite levels were markedly higher than national averages reported by the Centers for Disease Control and Prevention. The girls are most likely being exposed to phthalates through cosmetics and nail polish, but also from plastic water bottles, vinyl pacifiers, and processed food packaging.
The Mount Sinai investigators stressed that this is simply a correlation not a causal link between phthalate exposure and obesity and they urged caution in jumping to premature conclusions. Still, given what is known from animal studies about phthalates and other plastic-derived endocrine disruptors like Bisphenol-A, the issue warrants further attention. The findings also underscore the fact that there's more to the obesity equation than genetic predisposition, excess calories, and lack of exercise.
Phthalates are fat soluble, so one could explain the correlation by suggesting that the girls with the most adipose tissue simply stored and then excreted more phthalates than leaner girls. From a public health perspective, though, that's cold comfort: Animal studies show phthalates to be carcinogenic, diabetogenic, and long-lasting.