Telomere shortening among male applicators in the Agricultural Health Study

Abstract

Background: Telomere length in surrogate tissues (i.e., blood or buccal cells) may be influenced by several different mechanisms associated with pesticide exposure. Aims: To determine if pesticides use is associated with telomere length. Methods: We examined buccal cell telomere length in relation to lifetime use of 48 pesticides for 1,234 cancer-free White male pesticide applicators participating in a prospective cohort study of 57,310 licensed pesticide applicators. Participants provided detailed information on lifetime use of 50 pesticides at enrollment (1993-7). Buccal cells were collected from 1999 to 2006. Relative telomere length (RTL) was measured using quantitative real-time PCR. Linear regression modeling was used to evaluate the associations between use of specific pesticides and the logarithm of RTL while adjusting for age at buccal cell collection, state of residence, applicator license type, chewing tobacco use, and total life-time days of all pesticide use. Results: The mean RTL for participants decreased significantly with increased life-time days of pesticide use for alachlor (P=0.002); 2,4-D (P=0.004); metolachlor (P=0.01); trifluralin (P=0.05); permethrin (for animal application) (P=0.02) and toxaphene (p=0.04). A generally similar pattern of RTL shortening was observed with the metric lifetime intensity-weighted days of pesticide use. For dichloro-diphenylchloroethane (DDT), significant RTL shortening was observed for lifetime intensity-weighted days (P=0.04), but not for lifetime days of DDT use (P=0.08). No significant RTL lengthening was observed for any pesticide. Conclusion: Seven pesticides previously linked to increased cancer risk in the epidemiologic literature, were inversely associated with RTL in buccal cell DNA among cancer-free pesticide applicators.