Inverse and Direct Effect of Serum DDE Exposure on the Distribution of Leukocyte Telomere Length in Brazilian Adults: The Pró-Saúde Study.

Background: The current literature on associations between organochlorine pesticides and leukocyte telomere length (LTL) is conflicted, showing positive, inverse, or no association, findings that might be related to methodological issues and population characteristics, including the baseline LTL. Alternative exploration of this relationship over the whole LTL distribution may add information to help understand the role of pesticides in telomere shortening or enlargement.

Objective: We evaluated the association between environmental dichlorodiphenyldichloroethylene (DDE) exposure and percentiles of LTL in a sample of adults living in the urban area of Rio de Janeiro, Brazil.

Methods: LTL, serum pesticide concentration, and the covariates were determined cross-sectionally in a sample of 471 adults from the Pró-Saúde Study, a cohort of civil servants at a university campus in Rio de Janeiro, Brazil, conducted from July 2012 to October 2013. The percentiles (5th to 95th) of LTL (outcome variable) were modeled using quantile regression (QR) models with DDE as exposure and adjusted for age, sex, educational level, total body fat mass, total serum lipids, smoking, alcohol intake, and caloric share of in natura and ultra-processed foods.

Results: $\text{Mean}\pm \text{standard deviation\hspace{0.17em}}\left(\text{SD}\right)$ LTL and serum DDE were $0.578\pm 0.158$ telomere to single-copy gene ratio (T/S ratio) and $0.17\pm 0.34\text{\hspace{0.17em}ng}/\mathrm{mL}$ , respectively. Serum DDE was not detected in 44% of the samples. QR coefficients were positive and significant in the first percentiles (up to the 15th percentile) and inverse and significant at the 95th percentile. No significant association was observed between serum DDE and mean LTL ( $\beta =-0.001$ ; $p=0.93$ ).

Discussion: DDE exposure predicts some quantiles of LTL distribution, with a positive relationship in the first quantiles and inverse at the highest quantile. This study added new information to help understand the role of pesticides in telomere shortening or enlargement; however, given the few studies and the conflicting results, longitudinal investigations are needed to clarify this association. https://doi.org/10.1289/JHP1033.