title: Nitrate in public water supplies and the risk of renal cell carcinoma.
abstract: Drinking water and dietary sources of nitrate and nitrite can react in vivo with amines and amides to form N-nitroso compounds (NOC), potent animal carcinogens. Nitrate is a widespread contaminant of drinking water supplies especially in agricultural areas. We conducted a population-based case-control study of renal cell carcinoma in 1986-1989 in Iowa, a state with elevated levels in many public water supplies. We collected a lifetime water source history, but due to limited monitoring data, most analyses focused on the subpopulation, who used Iowa public supplies with nitrate measurements (actual or imputed data) for > or = 70% of their person-years since 1960 (201 cases, 1,244 controls). We computed the average nitrate level and years using a public supply with nitrate levels >5 and >10 mg/l. Dietary nitrate and nitrite were estimated from a 55-item food frequency questionnaire. There was no association of renal cell carcinoma with the average nitrate level and years using public supplies >5 and >10 mg/l nitrate-nitrogen (10+ years >5 mg/l odds ratio (OR) = 1.03, 95% confidence interval (CI) 0.66, 1.60). However, higher nitrate exposure was associated with an increased risk among subgroups with above the median red meat intake (10+ years >5 mg/l OR = 1.91, 95% CI 1.04-3.51) or below the median vitamin C intake (10+ years >5 mg/l OR = 1.90, 95% CI 1.01, 3.56), dietary factors that increase the endogenous formation of NOC. Exclusion of long-term Des Moines residents, a large proportion of the high exposure categories, attenuated the association. These findings deserve additional study in populations with high water nitrate intake and information on dietary intakes.
authors: Division of Cancer Epidemiology and Genetics, Occupational and Environmental Epidemiology Branch, National Cancer Institute, NIH/DHHS, Bethesda, MD 20892, USA. wardm@mail.nih.gov
authors: Mary H
authors: MH
authors: Ward
authors: Jennifer A
authors: JA
authors: Rusiecki
authors: Charles F
authors: CF
authors: Lynch
authors: Kenneth P
authors: KP
authors: Cantor
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000588:Amines / Q000378:metabolism; D002292:Carcinoma, Renal Cell / Q000139:chemically induced* / Q000453:epidemiology; D005260:Female; D005506:Food Contamination; D006801:Humans; D007484:Iowa; D007680:Kidney Neoplasms / Q000139:chemically induced* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000009:adverse effects* / Q000378:metabolism; D009603:Nitroso Compounds / Q000378:metabolism; D012189:Retrospective Studies; D012307:Risk Factors; D018426:SEER Program; D014867:Water; D014874:Water Pollutants, Chemical / Q000009:adverse effects*; D014881:Water Supply
chemical_list: D000588:Amines; D009566:Nitrates; D009603:Nitroso Compounds; D014874:Water Pollutants, Chemical; D014867:Water