Ecological analyses and case-control studies of gastric cancer and leukaemia in relation to DBCP in drinking water in Fresno County, California

Through ecological analyses and case-control studies, the possible relation of gastric cancer and leukaemia to dibromochloropropane (DBCP) contamination of drinking water in Fresno County, California, has been examined. The ecological analyses examined the correlation between gastric cancer and leukaemia (including the lymphatic varieties), mortality rates, and DBCP concentrations in drinking water by census tract in Fresno County, 1960-83. No correlation was found between gastric cancer or leukaemia and DBCP. The gastric cancer case-control study consisted of 263 deaths from gastric cancer in the county, 1975 to mid-1984, and 1044 controls, using information on residential history and occupation of both cases and controls. Analyses were based on residence at death, as well as one and ten years before death. The case-control study did not find any relation between gastric cancer and DBCP in drinking water. Hispanics in the county were found to experience a relative risk of gastric cancer of 2.77, compared with non-Hispanics. A similar case-control study consisting of 259 cases of leukaemia and 1161 controls found no relation between all leukaemia or lymphatic leukaemia and DBCP in drinking water. Farm workers, however, do appear to have an increased risk of leukaemia.     

An epidemiologic investigation of birth outcomes in relation to dibromochloropropane contamination in drinking water in Fresno County,California, USA

Summary This report describes an epidemiologic investigation of the relationship between dibromochloropropane (DBCP), contamination in drinking water and birth outcomes between 1978 and 1982 in Fresno County, California, USA. Census tracts in the county were categorized according to DBCP level in drinking water. A direct comparison between exposure categories was done by the use of the Mantel-Haenszel chi-square procedure to compute relative ratios or risks for low birth weight and birth defect, adjusting for age, race, percent Hispanic, and parity. No correlation between these birth outcomes and DBCP contamination was found. In addition, we did not find any difference in sex ratio in relation to DBCP contamination.     

An epidemiologic investigation of the relationship between DBCP contamination in drinking water and birth rates in Fresno County, California.

This report describes an epidemiologic investigation of the relationship between DBCP (dibromochloropropane) contamination in drinking water and birth rates between 1978 and 1982 in Fresno County, California. Census tracts in the county were categorized according to DBCP level in their drinking water. Standardized birth ratios and relative birth ratios (adjusted for age, race, per cent Hispanic, and parity) were calculated for these census tracts. No relation between birth ratios and DBCP contamination in drinking water was found.     

Problems associated with collecting drinking water quality data for community studies: a case example, Fresno County, California.

This paper discusses methodology in developing exposure data for the water supply contaminant dibromochloropropane (DBCP) in Fresno County, California. There are 532 drinking water systems (49 large and 483 small) within Fresno County plus 14,000 private wells. We determined the number of wells per system, the output per well, and the population served by each system. The task of deriving water quality estimates for each census tract was complicated by the fact that a single census tract can be served by more than one system; each system usually has more than one well; and a single well can have several episodes of testing for various contaminants. We calculated a series of weighted averages for concentrations of DBCP, arsenic, and nitrates for each census tract, using water production figures for each well as the weighting factor. Water quality data were derived from a total of 14,861 laboratory reports, although the majority did not report on all contaminants. Mean DBCP levels ranged from 0.0041 ppb to 5.7543 ppb among the census tracts. We found no correlation between DBCP levels per census tract compared to either arsenic or nitrates. We believe that we made as complete an exposure assessment as practically feasible.     

A Clinical Survey of a Cross-Section of an Industrial Worker Group

Ground-water contamination with the pesticides 1,2 dibromo-3-chloropropane (DBCP) and ethylene dibromide (EDB) affects Fresno/Clovis city in California. The spatial and temporal distribution of DBCP and EDB in public wells in Fresno/Clovis was examined, using mapping and time-series analyses of chemical test results, during the time periods 1979–1980 and 1992–1993. Health risks were estimated from mean concentrations, lifetime cancer risks were estimated, and monitoring and control programs were reviewed. Mean DBCP concentrations in selected wells declined from 0.56 ppb in 1979–1980 to 0.18 ppb in 1992–1993. Closure of wells and wellhead filtration caused levels to be reduced further (i.e., to 0.06 ppb). Mean EDB concentrations declined from 0.25 ppb to 0.15 ppb during the same time periods. The estimated lifetime cancer risk for DBCP was 1 excess death per 125 000 population in 1992–1993, but this risk varied within the city. The risk for EDB was 1 excess death per 2.2 million. Recommendations were made for the modeling of pesticide movement in ground water and for epidemiological studies.     

Gastric cancer mortality and nitrate levels in Wisconsin drinking water.

The association between nitrate levels in public and private sources of drinking water and gastric cancer mortality in Wisconsin was investigated in a case-control study. All gastric cancer deaths of Wisconsin residents from 1982 through 1985 were compared with deaths from other causes (controls), and nitrate levels in the home drinking water of these residents were determined. Nitrate measures for public sources were obtained from historic nitrate data from municipal sources that existed in 1970. Nitrate measures for private water sources were obtained by testing the wells individually at the existing residences. Controls were matched individually to gastric cancer cases with respect to sex, year of birth, year of death, Wisconsin birth, and Wisconsin residency at the time of death. Matched-pair analyses were performed on the paired data, and the following levels of nitrate-nitrogen exposure were used as indicators of exposure: 0.5, 2.5, 5.0, and 10.0 mg/l. Matched-pair analysis was also performed for which private water supply constituted exposure. Odds ratios and 95% confidence intervals were, respectively, 0.92 (0.75, 1.12); 0.97 (0.74, 1.35); 0.86 (0.69, 1.08); 1.50 (0.12, 18.25); and 1.09 (0.82, 1.47) for exposure to private well-water sources. These results did not indicate an increased risk of gastric cancer at any level.     

政和县饮用水水质与居民死因的相关性研究

「目的」探索饮用水质对居民死因的影响。「方法」对政和县高山、平原及城区的居民饮用水进行检测，并对居民全死因进行回顾性分析。「结果」经统计学分析饮用水中与脑血管病呈正相关的是：总硬度、镉、铅、呈负相关的有铁、锌等；与肝癌呈下相关的有铁、硫酸盐、氟化物、细菌总数。「结论」政和县饮用水水质和居民死因有一定的相关性，但需进一步深入研究。     

海安县胃癌危险因素研究

「目的」探讨海安县胃癌的危险因素。「方法」对１７７例胃癌新发病例进行１：１的病例对照研究。「结果」精神创伤史、慢性胃病史、１５年前低收入、生气时吃饭、１５年前饮用河塘水与胃癌的发生呈正相关;常吃新鲜蔬菜、常吃豆制品、１５年前每日饭量大能减少胃癌的发生。「结论」海安县胃癌的发生与生活条件、饮食习惯、精神因素有关。     

Gastric Cancer Mortality and Drinking Water Qualities in Taiwan

The possible association between the risk of gastric cancer and nitrate and hardness in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. Data on gastric cancer deaths among eligible residents in Taiwan from 1987 through 1991 (6,766 cases) were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes (6,766 controls) and were matched individually to the cases by sex, year of birth, and year of death. Data on nitrate–nitrogen (NO₃–N) and hardness levels in drinking water throughout Taiwan were collected from the Taiwan Water Supply Corporation (TWSC). The municipality of residence for cases and controls was assumed to be the source of the subject's nitrate and hardness exposure via drinking water. There was no difference in gastric cancer rates between the groups with different levels of nitrate. The odds ratios (95% confidence interval) for death from gastric cancer was 0.95 (0.87–1.03) for the group with water nitrate levels between 0.23 and 0.44 mg/L, and 1.02 (0.93–1.11) for the group with nitrate levels greater than 0.45 mg/L. However, the results show a significant negative relationship between drinking water hardness and gastric cancer mortality. Odds ratios were 1.16 (1.07–1.26) and 1.65 (1.52–1.79), respectively, for exposure to moderately hard water and soft water compared with the use of hard water. This is an important finding for the Taiwan water industry and human health risk. Received: 27 November 1996/Accepted: 16 April 1997     

大姚县农村生活饮用水青石棉污染与消化道癌症关联的病例-对照研究

目的探讨大姚县受青石棉污染的生活饮用水与消化道恶性肿瘤死亡风险的关系。方法选取已有27年队列人群(n=1249)中因消化道恶性肿瘤死亡的研究对象作为病例组(n=54),并按年龄、性别、死亡时间等匹配因素,选取108名对照,进行1∶2匹配的病例-对照研究,分析当地饮水情况对消化道恶性肿瘤死亡风险的影响。结果 Logistic回归分析表明,使用石棉炉的时间越长,消化道癌症死亡危险性越高(使用6~10年:OR=2.920,95%CI 1.501~5.604;使用11~15年:OR=3.966,95%CI 2.156~7.950;使用15年以上:OR=4.122,95%CI 1.211~7.584),喝生水导致消化道癌症死亡危险性增高(OR=1.43,95%CI 1.07~1.88),饮水类型与消化道恶性肿瘤死亡危险性相关,与饮用自来水比较,饮用井水的风险为OR=1.770,95%CI 1.001~2.444,饮用河水的风险为OR=2.442,95%CI 0.956~3.950,饮用宅泯沟水的风险为:OR=2.554,95%CI 1.961~6.584,饮用池塘水的风险为OR=3.121,95%CI 1.872~6.566。结论青石棉污染区饮水相关因素与大姚县主要消化道恶性肿瘤死亡有较强的关联。     

Cancer of the pancreas and drinking water: a population-based case-control study in Washington County, Maryland.

A case-control study was done to assess a potential association between drinking water and pancreatic cancer in Washington County, Maryland. Cases of pancreatic cancer occurring from 1975 through 1989 were identified from the cancer registry. Controls were selected from the private 1975 census of Washington County. There were 101 cases and 206 controls. Chlorinated municipal water was used as a source of drinking water by 79% of cases and 63% of controls, yielding a significant odds ratio of 2.2. Adjustment for age and smoking had almost no effect on the risk, although both age and smoking were independently associated with an increased risk of pancreatic cancer. Although these findings must be interpreted with caution because of limitations in exposure assessment, these results have implications for the prevention of pancreatic cancer because chlorination of water is so widely practiced.     

Rectal cancer mortality and total hardness levels in Taiwan's drinking water.

The possible association between the risk of rectal cancer and hardness levels in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. All eligible rectal cancer deaths (986 cases) of Taiwan residents from 1990 through 1994 were compared with deaths from other causes (986 controls), and the hardness levels of the drinking water used by these residents were determined. Data on water hardness throughout Taiwan were collected from Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes and the controls were pair matched to the cases by sex, year of birth, and year of death. The results show a significant negative relationship between drinking water hardness and rectal cancer mortality. Odds ratio and 95% confidence intervals were 1.24 (1.01-1. 55) and 1.38 (1.10-1.73), respectively, for exposure to moderately hard water and soft water compared with the use of hard water. Trend analyses showed an increasing odds ratio for rectal cancer with decreasing levels of hardness in drinking water. This is an important finding for the Taiwan water industry and human health.     

Esophageal cancer mortality and total hardness levels in Taiwan's drinking water

The possible association between the risk of esophageal cancer and hardness levels in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. All eligible esophageal cancer deaths (2084 cases) of Taiwan residents from 1987 through 1996 were compared with deaths from other causes (2084 controls), and the hardness levels of the drinking water used by these residents were determined. Data on water hardness throughout Taiwan have been collected from the Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes and the controls were pair-matched to the cases by sex, year of birth, and year of death. The results show that there is a 42% excess risk of mortality from esophageal cancer in relation to the use of soft water (adjusted odds ratio and 95% confidence intervals was 1.42 (1.22-1.66). This is an important finding for the Taiwan water industry and human health.     

Colon Cancer Mortality and Total Hardness Levels in Taiwan's Drinking Water

The possible association between the risk of colon cancer and hardness levels in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. All eligible colon cancer deaths (1,714 cases) of Taiwan residents from 1989 through 1993 were compared with deaths from other causes (1,714 controls) and the hardness levels of the drinking water used by these residents were determined. Data on water hardness throughout Taiwan have been collected from Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes and the controls were pair matched to the cases by sex, year of birth, and year of death. The results show a significant negative relationship between drinking water hardness and colon cancer mortality. Odds ratio and 95% confidence intervals were 1.22 (1.04–1.43) and 1.46 (1.22–1.75), respectively, for exposure to moderately hard water and soft water compared with the use of hard water. Trend analyses showed an increasing odds ratio for colon cancer with decreasing levels of hardness in drinking water. This is an important finding for the Taiwan water industry and human health. Received: 8 July 1997/Accepted: 29 November 1997     

胃癌高,低发区饮用水有机污染及致突变性研究

本文采用蚕豆根尖细胞微核（ＭＣＮ）、耗氧量（ＣＯＤ）对胃癌高、低发区饮用水水质进行监测,结果表明高发区地表水两项指标均明显高于地下水,也高于低发区地表水（Ｐ＜０．０５）。大型自来水厂的出厂水的诱变活性明显低于水源水（Ｐ＜０．０５）,不同饮用水的ＣＯＤ、ＭＣＮ与胃癌死亡率有较好的一致性,提示饮水污染可能是致胃癌高发的因素之一。     

Effect modification of the association between trihalomethanes and pancreatic cancer by drinking water hardness: Evidence from an ecological study

The objective of this study was to examine the relationship between total trihalomethanes (TTHM) levels in public water supplies and risk of pancreatic cancer and to determine whether calcium (Ca) and magnesium (Mg) levels in drinking water modify the effects of TTHM on risk to develop pancreatic cancer. A matched case-control study was used to investigate the relationship between the risk of death attributed to pancreatic cancer and exposure to TTHM in drinking water in 53 municipalities in Taiwan. All pancreatic cancer deaths in the 53 municipalities from 1998 through 2007 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair matched to the cancer cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each cancer case. Data on TTHM levels in drinking water were collected from Taiwan Environmental Protection Administration. Information on the levels of Ca and Mg in drinking water was obtained from the Taiwan Water Supply Corporation. The municipality of residence for cancer cases and controls was presumed to be the source of the subject's TTHM, Ca, and Mg exposure via drinking water. Relative to individuals whose TTHM exposure level<4.9 ppb, the adjusted OR (95% CI) for pancreatic cancer was 1.01 (0.85-1.21) for individuals who resided in municipalities served by drinking water with a TTHM exposure>4.9 ppb. There was no evidence of an interaction of drinking water TTHM levels with low Ca intake via drinking water. However, we observed evidence of an interaction between drinking water TTHM concentrations and Mg intake via drinking water. Our findings showed that the correlation between TTHM exposure and risk of pancreatic cancer is influenced by Mg in drinking water. Increased knowledge of the interaction between Mg and TTHM in reducing pancreatic cancer risk will aid in public policy making and standard setting.     

饮用农田边水源水与消化道恶性肿瘤关系的病例对照研究

目的分析农田边饮用水源水是否为农村消化道恶性肿瘤高发的危险因素,为肿瘤防控提供依据。方法应用病例对照研究,以青田、龙泉和缙云3个县（市）2009—2011年报告确诊的180例消化道恶性肿瘤为病例组,按居住乡镇、年龄与性别1∶2配比360名健康人群为对照组,分析饮用农田边水源水对消化道恶性肿瘤致病的影响。结果 3个县（市）调查点的全部病例组饮用农田边水源的暴露比高于对照组（OR=4.005,95%CI为2.228~7.199）,青田县病例组饮用农田边水源水人群的消化道恶性肿瘤发病危险性是饮用非农田边水源水人群的5.375倍（95%CI为2.287~12.635）,而龙泉市和缙云县则未见统计学关联（P〉0.05）。胃癌组暴露农田边水源水比例高于对照组（OR=4.875,95%CI为2.007~11.839）,但肝癌、结直肠癌和食管癌病例组农田边水源水暴露比例与对照组差异均无统计学意义（P〉0.05）。青田县胃癌组病例暴露农田边水源水的比例是对照组的5.750倍（95%CI为1.683~19.649）,其他病种病例组与对照组的暴露比例差异无统计学意义（P〉0.05）。结论农田边饮用水源水可能是农村部分地区胃癌高发的危险因素之一。     

Case-control study of bladder cancer and exposure to arsenic in Argentina

Studies have found increased bladder cancer risks associated with high levels of arsenic in drinking water, but little information exists about risks at lower concentrations. Ecologic studies in Argentina have found increased bladder cancer mortality in Córdoba Province, where some wells are contaminated with moderate arsenic concentrations. This population-based bladder cancer case-control study in two Córdoba counties recruited 114 case-control pairs, matched on age, sex, and county, during 1996-2000. Water samples, particularly from wells, were obtained from subjects' current residences and residences in the last 40 years. Statistical analyses showed no evidence of associations with exposure estimates based on arsenic concentrations in drinking water. However, when well-water consumption per se was used as the exposure measure, time-window analyses suggested that use of well water more than 50 years before interview was associated with increased bladder cancer risk. This association was limited to ever smokers (odds ratio = 2.5, 95% confidence interval: 1.1, 5.5 for 51-70 years before interview), and the possibility that this association is due to chance cannot be excluded. This study suggests lower bladder cancer risks for arsenic than predicted from other studies but adds to evidence that the latency for arsenic-induced bladder cancers may be longer than previously thought.     

胃癌高发区饮水对整体动物DNA合成抑制及其致癌性研究

为探讨赞皇县胃癌高发区居民饮水与胃癌发生的关系，用整体动物ＤＮＡ合成抑制实验与 行病学调查相结合的方法进行研究。结果发现胃癌高发区饮水浓缩物对ＤＮＡ合成有明显抑制作用，并有明显的剂量－效应关系；饮水污染越严重，该水对ＤＮＡ合成抑制作用越强，饮此水的居民胃癌死亡率也越高；饮水中可能含有的致突致癌物质，既有ＤＮＡ损伤剂，又有ＤＮＡ合成代谢抑制剂，提示饮水可能与当地居民胃癌高发有密切关系。