Some studies suggest that telomere length (TL) may be influenced by environmental exposures, including pesticides. We examined associations between occupational
pesticide use reported at three time points and relative telomere length (RTL) in the Agricultural Health Study (AHS), a prospective cohort study of
pesticide applicators in Iowa and North Carolina. RTL was measured by qPCR using leukocyte
DNA from 568
cancer-free male AHS participants aged 31-94 years with blood samples collected between 2006 and 2008. Self-reported information, including
pesticide use, was collected at three time points: enrollment (1993-1997) and two follow-up questionnaires (1998-2003, 2005-2008). For each
pesticide, we evaluated cumulative use (using data from all three questionnaires), and more recent use (using data from the last follow-up questionnaire). Multivariable linear regression was used to examine the associations between
pesticide use (ever, lifetime days, intensity-weighted lifetime days (lifetime days*intensity score)) and RTL, adjusting for age at blood draw and use of other pesticides. Of the 57 pesticides evaluated with cumulative use, increasing lifetime days of
2,4-D (p-trend=0.001),
diazinon (p-trend=0.002), and
butylate (p-trend=0.01) were significantly associated with shorter RTL, while increasing lifetime days of
alachlor was significantly associated with longer RTL (p-trend=0.03). Only the association with
2,4-D was significant after adjustment for multiple comparisons. Of the 40 pesticides evaluated for recent use,
malathion was associated with shorter RTL (p=0.03), and
alachlor with longer RTL (p=0.03). Our findings suggest that leukocyte TL may be impacted by cumulative use and recent use of certain pesticides.