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Background: N-nitroso compounds are hypothesized human bladder carcinogens. We investigated ingestion of N-nitroso compound precursors nitrate and nitrite from drinking water and diet and bladder cancer in the New England Bladder Cancer Study.Methods: Using historical nitrate measurements for public water supplies and measured and modeled values for private wells, as well as self-reported water intake, we estimated average nitrate concentrations (mg/L NO3-N) and average daily nitrate intake (mg/d) from 1970 to diagnosis/reference date (987 cases and 1,180 controls). We estimated overall and source-specific dietary nitrate and nitrite intakes using a food frequency questionnaire (1,037 cases and 1,225 controls). We used unconditional logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI). We evaluated interactions with factors that may affect N-nitroso compound formation (i.e., red meat, vitamin C, smoking), and with water intake.Results: Average drinking water nitrate concentration above the 95th percentile (>2.07 mg/L) compared with the lowest quartile (≤0.21 mg/L) was associated with bladder cancer (OR = 1.5, 95% CI = 0.97, 2.3; P trend = 0.01); the association was similar for average daily drinking water nitrate intake. We observed positive associations for dietary nitrate and nitrite intakes from processed meat (highest versus lowest quintile OR for nitrate = 1.4, 95% CI = 1.0, 2.0; P trend = 0.04; OR for nitrite = 1.5, 95% CI = 1.0, 2.1; P trend = 0.04, respectively), but not other dietary sources. We observed positive interactions between drinking water nitrate and red meat (P-interaction 0.05) and processed red meat (0.07).Conclusions: Our results suggest the importance of both drinking water and dietary nitrate sources as risk factors for bladder cancer. [ABSTRACT FROM AUTHOR]

Background: N-nitroso compounds formed endogenously after nitrate/nitrite ingestion are animal renal carcinogens. Previous epidemiologic studies of drinking water nitrate did not evaluate other potentially toxic water contaminants, including the suspected renal carcinogen chloroform. Methods: In a cohort of postmenopausal women in Iowa (1986-2010), we used historical measurements to estimate long-term average concentrations of nitrate-nitrogen (NO3-N) and disinfection by-products (DBP) in public water supplies. For NO3-N and the regulated DBP (total trihalomethanes [THM] and the sum of five haloacetic acids [HAA5]), we estimated the number of years of exposure above one-half the current maximum contaminant level (>1/2-MCL NO3-N; >5 mg/L). Dietary intakes were assessed via food frequency questionnaire. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) with Cox models, and evaluated interactions with factors influencing N-nitroso compound formation. Results: We identified 125 incident kidney cancers among 15,577 women reporting using water from public supplies >10 years. In multivariable models, risk was higher in the 95th percentile of average NO3-N (HRp95vsQ1 = 2.3; CI: 1.2, 4.3; Ptrend = 0.33) and for any years of exposure >1/2-MCL; adjustment for total THM did not materially change these associations. There were no independent relationships with total THM, individual THMs chloroform and bromodichloromethane, or with haloacetic acids. Dietary analyses yielded associations with high nitrite intake from processed meats but not nitrate or nitrite overall. We found no interactions. Conclusions: Relatively high nitrate levels in public water supplies were associated with increased risk of renal cancer. Our results also suggest that nitrite from processed meat is a renal cancer risk factor. [ABSTRACT FROM AUTHOR]

Objective: Studies of physical activity and colon cancer risk by anatomic site have provided inconsistent results. Methods: We analyzed data from a population-based case-control study conducted in Iowa involving 685 colon cancer cases and 2434 control subjects. Results: Among those who reported recreational activity more than twice per week, a 30% risk reduction of colon cancer was observed for all sites with a 40% risk reduction for cancer of the right colon. Occupational physical activity was also associated with a reduced risk of colon cancer. The risk was the lowest for those with both high occupational and recreational physical activity (odds ratio, 0.5; 95% confidence interval, 0.3-0.8). Conclusions: In- creased physical activity was inversely associated with colon cancer risk. The inverse associations were stronger for the right than for the left colon. [ABSTRACT FROM AUTHOR]

Objective: Previous epidemiological studies have inconsistently linked various occupations and industries to pancreatic cancer risk. Methods: We analyzed data from a population-based case-control study conducted in Iowa involving 376 histologically confirmed incident pancreatic cancer cases and 2434 control subjects. Results: A significantly increased risk was observed among men who worked in the following industries: chemical and allied products, transportation, and elementary and secondary schools. Increased risks also were observed in men who were employed as truck drivers; railroad brake, signal, and switch operators; purchasing agents and buyers; teachers; insurance agents; and retail supervisors. Among women, a significantly increased risk of pancreatic cancer was found for employment in furniture and home furnishing stores, and a borderline significantly increased risk among textile sewing machine operators and tenders. Conclusions: Working in several occupations and industries was associated with an increased risk of pancreatic cancer in this study, and these associations warrant further investigation. [ABSTRACT FROM AUTHOR]

Background: Exposure to disinfection byproducts in drinking water has been associated with an increased risk of bladder cancer. We pooled the primary data from 6 case-control studies of bladder cancer that used trihalomethanes as a marker of disinfection byproducts.Methods: Two studies were included from the United States and one each from Canada, France, Italy, and Finland. Inclusion criteria were availability of detailed data on trihalomethane exposure and individual water consumption. The analysis included 2806 cases and 5254 controls, all of whom had measures of known exposure for at least 70% of the exposure window of 40 years before the interview. Cumulative exposure to trihalomethanes was estimated by combining individual year-by-year average trihalomethane level and daily tap water consumption.Results: There was an adjusted odds ratio (OR) of 1.24 in men exposed to an average of more than 1 microg/L (ppb) trihalomethanes compared with those who had lower or no exposure (95% confidence interval [CI] = 1.09-1.41). Estimated relative risks increased with increasing exposure, with an OR of 1.44 (1.20-1.73) for exposure higher than 50 microg/L (ppb). Similar results were found with other indices of trihalomethane exposure. Among women, trihalomethane exposure was not associated with bladder cancer risk (0.95; 0.76-1.20).Conclusions: These findings strengthen the hypothesis that the risk of bladder cancer is increased with long-term exposure to disinfection byproducts at levels currently observed in many industrialized countries. [ABSTRACT FROM AUTHOR]

A case-control study involving 406 incident cases and 2434 controls was conducted in Iowa to examine the association between occupational exposures and renal cell carcinoma risk. After adjusting for major confounders, an increased risk was observed for men among mechanics and repairers (odds ratio [OR] 1.9, 95% confidence interval [CI] = 1.2-2.9); assemblers (OR 2.5, 95% CI = 0.8-7.6); automotive dealership and service station employees (OR 1.9, 95% CI = 0.9-3.9); wholesale traders of durable goods (OR 1.5, 95% CI = 0.7-3.2); farm product vendors (OR 4.4, 95% CI = 1.3-15.5); service organization managers (OR 2.2, 95% CI = 1.0-5.1); financial specialists (OR 2.7, 95% CI = 1.0-7.6); sales occupation supervisors (OR 1.8, 95% CI = 1.0-3.3); guards (OR 5.4, 95% CI = 1.4-20.7); and general farm workers (OR 1.9, 95% CI = 1.0-3.7). Among women, an increased risk was found for employees in depository institutions (OR 3.6, 95% CI = 1.1-11.3); colleges and universities (OR 7.6-95% CI = 2.3-25.6); and retail, including those in grocery stores (OR 2.2, 95% CI = 1.0-4.7). Our results indicate that occupational exposures may increase the risk of renal cell carcinoma. [ABSTRACT FROM AUTHOR]

Nitrate is a precursor compound in the formation of N-nitroso compounds, most of which are potent animal carcinogens. N-nitroso compounds and their precursors have not been extensively evaluated as bladder cancer risk factors.We conducted a population-based case-control study of bladder cancer in Iowa. Cases were men and women newly diagnosed with bladder cancer in 1986-1989. Nitrate data for Iowa public water supplies were sparse before the 1960s. To reduce misclassification by unknown nitrate levels, we included only those who used public supplies with nitrate data for 70% or more of their person-years since 1960 (808 cases, 1259 controls).Among controls, the median average nitrate level for their Iowa residences with public water supplies was 1.3 mg/liter nitrate-nitrogen (interquartile range = 0.6-3.0). After adjustment for confounders, we found no increased risk of bladder cancer with increasing average nitrate levels in drinking water; the highest quartile odds ratio for women was 0.8 (95% confidence interval = 0.4-0.8), and for men 0.5 (0.4-0.8). We observed no association among those with high water nitrate exposure (>median) and low (

Presents a study that investigated the role of occupation and industry in the risk of bladder cancer among employees in Iowa. Background on bladder cancer; Analysis of the risk for bladder cancer by industry and occupation among men and women in the state; Examination of the distribution of age, smoking habits and bladder cancer in men and women.

Presents information on a study of brain glioma in Iowa to explore the possible association between occupations and industries and risk of brain cancer. Materials and methods; Industries that showed a significantly increased risk of brain cancer among women; Other results and discussion.

Background: Nitrate is a widespread contaminant of drinking water, but its potential health effects are unclear. In the body, nitrate is reduced to nitrite, which can react with amines and amides by nitrosation to form N-nitroso compounds, known animal carcinogens. N-nitroso compound formation is inhibited by certain nutrients, such as vitamin C, and increased by meat intake., Methods: We investigated the association of nitrate in public water supplies with incident colon and rectum cancers in a case-control study conducted in Iowa from 1986 to 1989. Nitrate levels in Iowa towns were linked to the participants' water source histories. We focused our analyses on the period from 1960 onward, during which nitrate measurements were more frequent, and we restricted analyses to those persons with public water supplies that had nitrate data (actual or imputed) for greater than 70% of this time period (376 colon cancer cases, 338 rectum cancer cases, and 1244 controls)., Results: There were negligible overall associations of colon or rectum cancers with measures of nitrate in public water supplies, including average nitrate and the number of years with elevated average nitrate levels. For more than 10 years with average nitrate greater than 5 mg/L, the odds ratio (OR) for colon cancer was 1.2 (95% confidence interval [CI] = 0.9-1.6) and for rectum the OR was 1.1 (CI = 0.7-1.5). However, nitrate exposure (>10 years with average nitrate >5 mg/L) was associated with increased colon cancer risk among subgroups with low vitamin C intake (OR = 2.0; CI = 1.2-3.3) and high meat intake (OR = 2.2; CI = 1.4-3.6). These patterns were not observed for rectum cancer., Conclusions: Our analyses suggest that any increased risk of colon cancer associated with nitrate in public water supplies might occur only among susceptible subpopulations.