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     

High Nitrate Content in Drinking Water: Cytogenetic Effects in Exposed Children

The potential genotoxicity of nitrates and nitrites—contaminants of drinking water that have been implicated in carcinogenesis—was investigated in this study. Sister chromatid exchanges and frequency of chromatid/hromosome aberrations were studied in peripheral blood lymphocytes of 70 children who were 12–15 y of age. These children were permanent residents in geographical areas of Greece, where elevated concentrations of nitrates (i.e., 55.70–87.98 mg/l) existed in drinking water. The control group comprised 20 healthy children who resided in areas with very low nitrate concentrations (i.e., 0.7 mg/l). A significant increase in the mean number of chromatid/chromosome breaks was observed in children exposed to nitrate concentrations that exceeded 70.5 mg/l (p < .01), but there was no significant increase in the mean number of sister chromatid exchanges per cell. The results indicate that chronic administration of elevated concentrations of nitrate in drinking water has the capability of inducing cytogenetic effects.     

Epidemiological characteristics of gastric cancer in Vojvodina

Epidemiological characteristics of gastric cancer in the province of Vojvodina were analyzed on the basis of official data of the Cancer Registry of Vojvodina and the records of the Bureau of Census of Vojvodina for the years 1982–1991. In the year 1991, the cases of gastric cancer accounted for 7.8% of all malignant neoplasms in males, ranking thus third, whereas in females, with 5%, it was in seventh place. At the same time, in the structure of deaths from malignant neoplasms, gastric cancer was on the second place both in males (9.1%) and females (7.8%). The male/female gastric cancer mortality ratio was 1.7:1. Incidence and mortality rates showed the tendency of a slow but steady decrease in both sexes during the observation period. The age-standardized incidence rate (world population) was 25.9 per 100,000 for men and 9.4 for women in average. In comparison with the corresponding data of the registries of Europe and of the world, Vojvodina falls in the range of moderately high rates. The age-specific incidence and mortality rates show a strong increase after the age of 55, reaching the highest values in the ages 75– 79. Thus it can be said that gastric cancer is a disease of the elderly. Total five-year survival is low, which is a common observation for this kind of neoplasm.     

Need for revision of nitrates standards for drinking water: a case study of Rajasthan

An attempt has been made to classify ground waters in various districts of Rajasthan based on distribution of nitrate in their drinking water samples. It is seen that nitrate in ground water is unevenly distributed in the state. Major parts of Churu, Alwar, Bharatpur, Jalore, Jaipur, Sikar, Tonk and Jhunjhunu, are inherited by nitrate rich ground waters while districts like Banswara, Bundi, Bikaner, Chittor, Kota and Jhalawar have low nitrates in their ground waters at many places. It is well documented internationally that water supplied containing high levels of nitrate have been responsible for cases of infantile methemoglobinemia which may ultimately lead to death. A very high infant mortality rate in Rajasthan might be a consequence of high nitrates in drinking water supply. Some recent studies have shown that nitrates in drinking water besides causing methemoglobinemia can result in various other clinical manifestations like recurrent stomatitis, recurrent respiratory tract infections (RRTI) etc. These findings have indicated that a rethinking has to be given to the existing standards for nitrates in drinking water. Based on potential nitrate toxicity studies in view of above health effects the whole region has been classified into five water quality zones, namely, safe, mild, moderately problematic, highly problematic and dangerous. For areas falling under fourth and fifth zones it is recommended that immediate measures be taken to overcome the adverse health effects.     

Dietary Nitrates,Nitrites, and Nitrosamines Intake and the Risk of Gastric Cancer: A Meta-Analysis

The potential associations between dietary consumption of nitrates, nitrites, and nitrosamines and gastric cancer risk have been investigated by several studies, but yielded inconclusive results. We conducted a meta-analysis to provide a quantitative assessment of their relationships. Relevant articles were identified by a systematic literature searching of PubMed and Embase databases prior to August 2015. Random-effects models were employed to pool the relative risks. A total of 22 articles consisting of 49 studies—19 studies for nitrates, 19 studies for nitrites, and 11 studies for N-nitrosodimethylamine (NDMA)—were included. The summary relative risk of stomach cancer for the highest categories, compared with the lowest, was 0.80 (95% confidence interval (CI), 0.69–0.93) for dietary nitrates intake, 1.31 (95% CI, 1.13–1.52) for nitrites, and 1.34 (95% CI, 1.02–1.76) for NDMA (p for heterogeneity was 0.015, 0.013 and <0.001, respectively). The study type was found as the main source of heterogeneity for nitrates and nitrites. The heterogeneity for NDMA could not be eliminated completely through stratified analysis. Although significant associations were all observed in case-control studies, the cohort studies still showed a slight trend. The dose-response analysis indicated similar results as well. High nitrates intake was associated with a weak but statistically significant reduced risk of gastric cancer. Whereas increased consumption of nitrites and NDMA seemed to be risk factors for cancer. Due to the lack of uniformity for exposure assessment across studies, further prospective researches are warranted to verify these findings.     

Association between gastric cancer mortality and nitrate content of drinking water: Ecological study on small area inequalities

The carcinogenic feature of N-nitroso compounds has been well established. Similarly, the transformation of ingested nitrate to N-nitroso compounds in the stomach has been thoroughly documented, nevertheless nitrates' carcinogenic effect has not been proved convincingly in human. The present study was aimed to investigate a population of small villages provided by drinking water with high and widely variable nitrate content (72 mg/l median, 290.7 mg/l 95-percentile concentration). Empirical Bayes estimates for settlement-specific age-, sex-, and year-standardised mortality ratios of gastric cancer (GC) were related to the settlement level average nitrate concentrations in drinking water controlling for confounding effects of smoking, ethnicity and education. The log-transformed average nitrate concentration showed significant positive association with stomach cancer mortality in linear regression analysis (p = 0.014). The settlements were aggregated according to the nitrate concentration into 10-percentile groups and the standardised mortality ratios (SMRs) were calculated. Those groups with higher than 88 mg/l average nitrate concentration showed substantial risk elevation and the log-transformed exposure variables proved to be significant predictors of mortality (p equals; 0.032) at this level of aggregation also. The association seemed to be fairly strong (r ² equals; 0.46). Although this investigation constituting an ecological study has certain limitations, it supports the hypothesis that the high level of nitrate in drinking water is involved in the development of GC.     

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.     

A review of nitrates in drinking water: maternal exposure and adverse reproductive and developmental outcomes

In this review we present an update on maternal exposure to nitrates in drinking water in relation to possible adverse reproductive and developmental effects, and also discuss nitrates in drinking water in the United States. The current standard for nitrates in drinking water is based on retrospective studies and approximates a level that protects infants from methemoglobinemia, but no safety factor is built into the standard. The current standard applies only to public water systems. Drinking water source was related to nitrate exposure (i.e., private systems water was more likely than community system water to have nitrate levels above the maximum contaminant limit). Animal studies have found adverse reproductive effects resulting from higher doses of nitrate or nitrite. The epidemiologic evidence of a direct exposure-response relationship between drinking water nitrate level and adverse reproductive effect is still not clear. However, some reports have suggested an association between exposure to nitrates in drinking water and spontaneous abortions, intrauterine growth restriction, and various birth defects. Uncertainties in epidemiologic studies include the lack of individual exposure assessment that would rule out confounding of the exposure with some other cause. Nitrates may be just one of the contaminants in drinking water contributing to adverse outcomes. We conclude that the current literature does not provide sufficient evidence of a causal relationship between exposure to nitrates in drinking water and adverse reproductive effects. Future studies incorporating individual exposure assessment about users of private wells--the population most at risk--should be considered.     

2005-2014年中国前列腺癌流行特征

  目的  分析《中国肿瘤登记年报》中2005—2014年男性前列腺癌发病率与死亡率的变化趋势,为开展前列腺癌防治提供参考。  方法  利用Excel 2019软件提取2005—2014年中国男性前列腺癌发病率和死亡率的全部数据;运用Joinpoint回归分析模型分析2005—2014年中国男性前列腺癌发病率和死亡率的变化趋势。  结果  2005—2014年中国前列腺癌标化发病率和标化死亡率整体呈上升趋势,城市的两标化率均高于农村。全国标化发病率由2005年的5.8/10万增至2014年的8.1/10万,增加39.65%;全国标化死亡率由2005年的2.3/10万增至2014年的2.4/10万,增加4.34%。城市、农村男性标化发病率平均每年的增长速度分别为1.40%、6.10%;城乡标化死亡率平均每年的增长速度分别为2.51%、2.62%。60岁后的男性前列腺癌的发病率和死亡率随年龄的增长而增长,中国60岁以上的男性是前列腺癌防治的重点人群。  结论  与2005年相比,2014年中国前列腺癌的发病及死亡率趋势呈现增加,应积极制定并完善前列腺癌的防治措施,重点加强对60岁以上男性的综合预防工作。     

A review of nitrates in drinking water: maternal exposure and adverse reproductive and developmental outcomes

In this review, we present an update on maternal exposure to nitrates in drinking water in relation to possible adverse reproductive and developmental effects, and discuss nitrates in drinking water in the United States. The current standard for nitrates in drinking water is based on retrospective studies and approximates a level that protects infants from methemoglobinemia, but no safety factor is built into the standard. The current standard applies only to public water systems. Animal studies have found adverse reproductive effects resulting from higher doses of nitrate or nitrite. The epidemiologic evidence of a direct exposure-response relationship between drinking water nitrate level and adverse reproductive effect is still not clear. However, some reports have suggested an association between exposure to nitrates in drinking water and spontaneous abortions, intrauterine growth restriction, and various birth defects. Uncertainties in epidemiologic studies include the lack of individual exposure assessment that would rule out confounding of the exposure with some other cause. We conclude that the current literature does not provide sufficient evidence of a causal relationship between exposure to nitrates in drinking water and adverse reproductive effects.     

The importance of water testing for public health in two regions in Rio de Janeiro: a focus on fecal coliforms, nitrates, and aluminum

In developing countries, due to poor sanitation conditions and poor quality of drinking water, typical water-borne diseases and more recently diseases caused by drinking water with high concentrations of nitrates and certain metals like aluminum have increased the concern over the health effects of these compounds. Several articles have shown associations between nitrates and methemoglobinemia in children, and aluminum and Alzheimer disease in adults. This study identified water quality with several parameters in non-conformity with Brazilian drinking water standards (Ruling 36/90): more than 50% of all samples from both regions contained fecal coliforms; some 31% of water samples from wells in Duque de Caxias had excessive nitrate concentrations; 100% of all groundwater samples from both regions showed aluminum concentrations not conforming to the norm, with the same result for 100% of samples from the drinking water distribution system in S?o Gon?alo and 75% of same in Duque de Caxias. This lack of conformity poses several health risks for the local population.     

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.     

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.     

Nitrates in drinking water and methemoglobin levels in pregnancy: a longitudinal study

Background  

Private water systems are more likely to have nitrate levels above the maximum contaminant level (MCL). Pregnant women are considered vulnerable to the effects of exposure to high levels of nitrates in drinking water due to their altered physiological states. The level of methemoglobin in the blood is the biomarker often used in research for assessing exposure to nitrates. The objective of this study was to assess methemoglobin levels and examine how various factors affected methemoglobin levels during pregnancy. We also examined whether differences in water use practices existed among pregnant women based on household drinking water source of private vs. public supply.     

Does testing for prostate-specific antigen contribute to declining prostate cancer mortality?

Key variables associated with prostate cancer mortality were examined using Canadian province level time-series data over the period 1979–1999 in a multiple regression framework. The key variables driving the prostate cancer mortality rate are per capita income, per capita number of family physicians, rate of prostate cancer incidence, real per capita total health spending, and a time trend. As well, provincial dummy variables show that regional differences exist with higher rates of mortality in eastern Canada. Econometric results show a positive and significant relationship between incidence and mortality, suggesting that the increased amount of prostate-specific antigen (PSA) testing may not have been responsible for mortality declines. However, there is also a downward trend in mortality from prostate cancer when all other factors are controlled for that can be attributed partly to the onset of PSA testing given that the benefits should emerge over time. A 1% increase in incidence is associated with a 0.2% increase in mortality. A 1% increase in real per capita income is associated with a 0.5% increase in mortality when real per capita income is below Canadian $20,054. A 1% increase in the per capita number of family physicians reduces the mortality rate by 0.5%. A 1% increase in real per capita total health expenditures is associated with a 0.7% decline in the mortality rate. Finally, by 1999 there were 4.74 fewer deaths per 100,000 population due to the effect of time after controlling for all other factors—a decrease of approx. 15%.     

Is nitrate in the drinking water associated with the risk of cancer in the urban UK?

Several studies have suggested that nitrate levels in drinking water may be linked with stomach cancer. Recent investigations of this hypothesis in rural areas of the UK, where nitrate levels can be high, have been inconclusive. The present study examined mortality data for the years 1969-1973 in 253 urban areas in relation to treated water nitrate levels. Variations in socioeconomic status and urban area size were taken into account. Drinking water nitrate levels were negatively associated with mortality from stomach cancer even when the analysis was restricted to urban areas with nitrate levels above the EEC guide. There was no evidence of a positive association between nitrate in the drinking water and the risk of stomach cancer in the urban areas of the UK, an important finding for the British water industry.     

Comparative analysis of results from studies of goitre in children from Bulgarian villages with nitrate pollution of drinking water in 1995 and 1998

The role of nitrates in goitre genesis has been discussed for a long time. In the present report a comparative analysis is made of results obtained in villages with nitrate pollution of the drinking water. In two pairs of villages children aged between 3 and 14 were included, whose thyroid status was investigated by a clinical examination. The study was carried out in 2 stages--in 1995 and 1998. In this period the goitre incidence was significantly reduced in both sexes. Both investigations showed a higher relative risk of goitre in children exposed to water pollution by nitrates. In the first, as well as in the second examination, goitre was diffuse. We concluded that nitrate pollution of drinking water undoubtedly participated in goitre genesis. We did not underestimate the strumigenic effect of nitrates in the diet as they were not the object of our investigation and which, according to WHO experts, have a less strumigenic effect. After the first investigation we recommended a higher antistrumin dose as prophylaxis. That is why we conclude that the considerable goitre reduction in the second investigation was the positive result of the doubled antistrumin prophylaxis during the period between the two investigations.     

Nitrogen-nitrate exposure from drinking water and colorectal cancer risk for rural women in Wisconsin, USA

One unintentional result of widespread adoption of nitrogen application to croplands over the past 50 years has been nitrate contamination of drinking water with few studies evaluating the risk of colorectal cancer. In our population-based case-control study of 475 women age 20–74 years with colorectal cancer and 1447 community controls living in rural Wisconsin, drinking water nitrate exposure were interpolated to subjects residences based on measurements which had been taken as part of a separate water quality survey in 1994. Individual level risk factor data was gathered in 1990–1992 and 1999–2001. Logistic regression models estimated the risk of colorectal cancer for the study period, separately and pooled. In the pooled analyses, an overall colorectal cancer risk was not observed for exposure to nitrate-nitrogen in the highest category (10 ppm) compared to the lowest category (<0.5 ppm). However, a 2.9 fold increase risk was observed for proximal colon cancer cases in the highest compared to the lowest category. Statistically significant increased distal colon or rectal cancer risk was not observed. These results suggest that if an association exists with nitrate-nitrogen exposure from residential drinking water consumption, it may be limited to proximal colon cancer.     

Mortality of nitrate fertiliser workers.

An epidemiological cohort study was conducted to investigate the mortality patterns among a group of workers engaged in the production of nitrate based fertilisers. This study was designed to test the hypothesis that individuals exposed to high concentrations of nitrates might be at increased risk of developing cancers, particularly gastric cancer. A total of 1327 male workers who had been employed in the production of fertilisers between 1946 and 1981 and who had been occupationally exposed to nitrates for at least one year were followed up until 1 March 1981. In total, 304 deaths were observed in this group and these were compared with expected numbers calculated from mortality rates in the northern region of England, where the factory was located. Analysis was also carried out separately for a subgroup of the cohort who had been heavily exposed to nitrates--that is, working in an environment likely to contain more than 10 mg nitrate/m3 for a year or longer. In neither the entire cohort nor the subgroup was any significant excess observed for all causes of mortality or for mortality from any of five broad categories of cause or from four specific types of cancer. A small excess of lung cancer was noted more than 20 years after first exposure in men heavily exposed for more than 10 years. That men were exposed to high concentrations of nitrate was confirmed by comparing concentrations of nitrates in the saliva of a sample of currently employed men with control men, employed at the same factory but not in fertiliser production. The men exposed to nitrate had substantially raised concentrations of nitrate in their saliva compared with both controls within the industry and with men in the general population and resident nearby. The results of this study therefore weight against the idea that exposure to nitrates in the environment leads to the formation in vivo of material amounts of carcinogens.