Childhood and Adolescent Pesticide Exposure and Breast Cancer Risk

Abstract

Background To date, epidemiological studies have not strongly supported an association between pesticide exposure and breast cancer. However, few previous studies had the ability to assess specific time periods of exposure. Studies that relied on adult serum levels of metabolites of organochlorine pesticides may not accurately reflect exposure during developmental periods. Further, exposure assessment often occurred after diagnosis and key tumor characteristics, such as hormone receptor status, have rarely been available to evaluate tumor-subtype specific associations. We examine the association between pesticide exposure during childhood and adolescence and breast cancer risk in the prospective Sister Study cohort (N=50,844 women) to assess this relation by tumor subtype. Methods During an average 5-year follow-up, 2,134 incident invasive and in situ breast cancer diagnoses were identified. Residential and farm exposure to pesticides were self-reported at study enrollment during standardized interviews. Multivariable hazard ratios (HR) and 95% confidence intervals for breast cancer risk were calculated with Cox proportional hazards regression. Results HRs were near null for the association between childhood/adolescent pesticide exposure and breast cancer risk overall or among ER+/PR+ invasive tumors. However, among women who were ages 0–18 before the ban of DDT in the U.S., exposure to fogger trucks or planes was associated with a HR=1.3 for premenopausal breast cancer (95% CI: 0.92, 1.7). Conclusion These findings do not support an overall association between childhood and adolescent pesticide exposure and breast cancer risk. However, modest increases in breast cancer risk were associated with acute events in a subgroup of young women.

Childhood Residential and Agricultural Pesticide Exposures in Relation to Adult-Onset Rheumatoid Arthritis in Women

“…For farm-related pesticide exposure, we considered "don't know" responses to be unexposed, under the assumption of greater awareness of pesticide use for those living in agricultural settings. This assumption is consistent with findings of a validation substudy in which 1,000 mothers of participants provided data on early-life factors (A.A.D., unpublished data, 2016) (22). The findings showed a positive predictive value of greater than 90% for pesticides used on crops versus 56% for residential pesticides.…”

“…The study sample was derived from a volunteer cohort of 50,884 women (aged 35-74 years at enrollment; 84% nonHispanic white, 9% black, 8% Hispanic/other) enrolled [2004][2005][2006][2007][2008][2009] in the Sister Study, a national study of environmental factors and health in the United States (22). The Sister Study was approved by the institutional review board of the National Institute of Environmental Health Sciences of the National Institutes of Health.…”

Organochlorine pesticide residues in human breast tissue and their relationships with clinical and pathological characteristics of breast cancer

“…Although controversial, the majority of research examining environmental chemicals has concluded that organochlorine pesticides do not increase risk for developing breast cancer in humans . However, organochlorine exposure may influence key characteristics of disease, such as subtype, growth rate, or aggressiveness of breast disease, rather than initiate disease.…”

Environmental Determinants of Breast Cancer

“…This study, which cannot be replicated because of the unusual nature of the data set, supports the concept that the timing of exposure (i.e., early development window) may be critical to the contribution of EDCs to carcinogenesis (23). Supportive evidence comes from the Sister Study, which found that young girls up to age 18 years who were exposed to fogger truck or plane spraying of DDT were at a nonsignificant increased risk of breast cancer [hazard ratio (HR) = 1.3, 95% CI: 0.92-1.7] for premenopausal breast cancer (100). Similarly, the Long Island Breast Cancer Study Project reported increased odds of ER+/PR+ breast cancer among women who reported chasing after a fogger truck in their youth (143).…”