Nitrate Ingestion from Drinking Water and Ovarian Cancer Risk in the Agricultural Health Study
Year: 2022
Type: conference-abstract
Abstract: Background/Aim: N-nitroso compounds (NOCs) formed endogenously after nitrate/nitrite ingestion cause ovarian cancer in animals. Few epidemiologic studies have evaluated the association of drinking water nitrate with ovarian cancer risk, and the only previous investigation observed increased risks with higher intake. Methods: We evaluated nitrate exposure from drinking water and ovarian cancer risk in the Agricultural Health Study, a cohort of pesticide applicators and their spouses in Iowa and North Carolina. For the enrollment water source (1993-1997; N=29,408), we computed average nitrate concentrations for women on public water supplies (20% of participants) from historical monitoring data and estimated nitrate concentrations in private wells (76%) using random forest models; 4% used other water sources and were excluded. We used Cox regression models adjusted for age, body mass index, smoking status, and menopausal status to estimate hazard ratios (HR) and 95% confidence intervals (CI) for nitrate quartiles and the 90th percentile. Among those with dietary data (collected at first follow-up; N=13,465), we calculated HRs for < and ≥ median nitrate concentration (1.47 mg/L), stratified by median dietary intakes of vitamin C (145.1 mg/day), as higher intake decreases endogenous NOC formation. Results: We identified 122 ovarian cancer cases through 2018 (Iowa) and 2014 (North Carolina). Risk was elevated (HR=1.67, CI:0.82–3.37, P-trend=0.19) for women in the 90th percentile (≥6.81 mg/L NO3-N) versus the lowest quartile (≤0.75 mg/L). The association with higher average nitrate exposure (> median) was stronger among women with low vitamin C intake (HR median=1.14, CI:0.58-2.25), although the interaction was not significant (P-interaction=0.28). Conclusions: Although we cannot rule out the possibility our findings are due to chance, they suggest that higher average nitrate levels in drinking water may increase ovarian cancer risk and that vitamin C intake may modify this relationship. Keywords: nitrate, ovarian cancer
Source: ISEE Conference Abstracts
Language: English
Subfield: Health, Toxicology and Mutagenesis
Field: Environmental Science
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4317178332