Exposure to hormonally active chemicals could plausibly affect pubertal timing, so the authors are investigating this in the Breast Cancer and the Environment Research Programme. Persistent organic pollutants (POPs) were investigated in relation to pubertal onset. Ethnically diverse cohorts of 6-8 year old girls (n=645) provided serum for measure of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and lipids. Tanner stages (breast (B) and pubic hair (PH)), and body mass index (BMI) were measured at up to seven annual clinic visits. Using accelerated failure time models, time ratios (TRs) were calculated for age at Tanner stages two or higher (2+) and POPs quartiles (Q1-4), adjusting for confounders (race/ethnicity, site, caregiver education and income). In addition, prevalence ratios (PRs) were calculated of Tanner stages 2+ at time of blood sampling. Cross-sectionally, the prevalence of B2+ and PH2+ was inversely related to chemical serum concentrations, but after adjustment for confounders, only the associations with B2+, not PH2+ were statistically significant. Longitudinally, the age at pubertal transition was consistently older with greater chemical concentrations; for example: B2+ and Q4 adjusted TR for ?PBDE = 1.05; 95% CI: 1.02, 1.08, for ?PCB = 1.05; 95% CI: 1.01, 1.08, and for ?OCP = 1.10; 95% CI: 1.06,1.14, indicating median ages of about 6 and 11 months older than least exposed, and with similar effect estimates for PH2+. Adjusting for BMI attenuated associations for PCBs and OCPs but not for PBDEs. The authors concluded that this longitudinal study of puberty in girls with serum POPs measurements reveals a delay in onset with higher concentrations.
Authors: Windham GC, Pinney SM, Voss RW, Sjodin A, Biro FM, Greenspan LC, Stewart S, Hiatt RA, Kushi LH. ;Full Source: Environmental Health Perspectives. 2015 May 8. [Epub ahead of print] ;