Serum concentrations of persistent organic pollutants (POPs) have been reported to be associated with the prevalence of type 2 diabetes in the U.S. general population, and this association appears to be higher among obese people than among the nonobese. However, because most previous studies were cross-sectional and because studies among subjects with high POPs exposure reported inconsistent associations, Lee et al. (p. 1235) investigated whether several POPs prospectively predict type 2 diabetes within the Coronary Artery Risk Development in Young Adults (CARDIA) cohort.