Drinking water nitrate, disinfection byproducts, and prostate cancer incidence in the Agricultural Health Study
Menée à l'aide de données portant sur 40 403 hommes (durée moyenne de suivi : 21,9 ans), cette étude analyse l'association entre une exposition aux nitrates et aux sous-produits de désinfection présents dans l'eau potable et le risque de cancer de la prostate (3 625 cas)
Drinking water can be an important source of exposure to nitrate and disinfection by-products, including trihalomethanes (THMs) and haloacetic acids (HAAs). N-nitroso compounds formed endogenously after nitrate ingestion are animal carcinogens, and THM and HAA exposures increase the risk of some cancers. Our objectives were to evaluate associations of drinking water nitrate and DBPs with total and aggressive (distant stage, poorly differentiated grade, fatal, or Gleason score ≥7) prostate cancer in the Agricultural Health Study (AHS) cohort.Male participants who were cancer-free and used private wells or public water supplies (PWS) for drinking water at enrollment (1993-1997, N = 40,403) were followed through 2021 (mean = 21.9 years). Average nitrate-nitrogen (nitrate-N) concentrations were estimated for private well users based on state-specific geologic and meteorologic factors. We used monitoring data to compute average nitrate-N, THMs and HAAs for PWS users. We estimated hazard ratios (HRs, 95%CIs) per doubling and categories of exposure for total (N = 3,625) and aggressive (N = 2,200) prostate cancer using Cox proportional hazards regression.Median (interquartile range) average water nitrate-N was 1.49 (0.76-3.01) mg/L; 6% >10mg/L (PWS maximum contaminant level). Compared to nitrate-N ≤ 1mg/L, exposures >10mg/L were significantly positively associated with total (1.16, 1.01-1.35); ptrend = 0.10) and aggressive disease (1.22, 1.02-1.47, ptrend = 0.03). We observed weak associations between higher nitrate-N (Q4vsQ1) and total (1.05, 0.95-1.16) and aggressive (1.13, 0.99-1.27) disease. We did not observe associations with total THMs or HAAs.These findings suggest that drinking water nitrate-N exposure, at average levels > 10 mg/L, is a risk factor for prostate cancer, particularly aggressive disease.
Journal of the National Cancer Institute , résumé, 2025