In Iran, cancer is the third leading cause of death, after cardiovascular diseases and accidents. In this study, the geographical distribution of gastrointestinal cancers (esophagus, gastric, colon) and the effect of nitrate in drinking water on its incidence have been investigated. This is a descriptive–analytic study that uses two data types to investigate the relationship between nitrate concentration in drinking water and the prevalence of gastrointestinal cancers in Isfahan province, in the center of Iran. Information on gastric, esophagus and colon cancers separately from 2005 to 2009 was obtained from the Isfahan Health Centre database, and the amount of nitrate in the drinking water from each of the cities in the province of Isfahan was collected.

This is a descriptive–analytic study that uses two data types to investigate the relationship between nitrate concentration in drinking water and the prevalence of gastrointestinal cancers (gastric, esophagus and colon) in Isfahan province, Iran. Studies have shown that elevated levels of nitrate in drinking water may be one of the factors influencing the incidence of gastrointestinal cancer. The direct relation between nitrate in drinking water and increased incidence of gastric cancer was (R = 0.42, P = 0.05), esophageal cancer. The incidence of gastric and colon cancer in males over age of 70 and esophageal cancer in females aged 60 to 75 is highest. It is suggested that given the importance of nitrate pollution as one of the environmental and agricultural problems, as well as the value of groundwater resources, especially in arid and semi-arid regions.

在伊朗，癌症是继心血管疾病和事故之后的第三大死亡原因。本研究调查了胃肠癌（食道癌、胃癌、结肠癌）的地理分布以及饮用水中硝酸盐对其发病率的影响。这是一项描述性分析研究，它使用两种数据类型来调查伊朗中部伊斯法罕省饮用水中硝酸盐浓度与胃肠道癌症患病率之间的关系。分别从伊斯法罕卫生中心数据库获得2005年至2009年胃癌、食道癌和结肠癌的信息，收集伊斯法罕省各城市饮用水中的硝酸盐含量。

这是一项描述性分析研究，使用两种数据类型来调查伊朗伊斯法罕省饮用水中硝酸盐浓度与胃肠道癌（胃癌、食道癌和结肠癌）患病率之间的关系。研究表明，饮用水中硝酸盐含量升高可能是影响胃肠癌发病率的因素之一。饮用水中硝酸盐与胃癌发病率增加的直接关系为（R = 0.42，P = 0.05），食管癌。70岁以上男性胃癌和结肠癌发病率最高，60-75岁女性食管癌发病率最高。建议鉴于硝酸盐污染作为环境和农业问题之一的重要性以及地下水资源的价值，