title: [An epidemiological study on the incidence rates of colorectal cancer through different drinking water sources].
abstract: OBJECTIVE
  In order to identify the association of incidence rates of colorectal cancer and different drinking water sources.
  
  
  METHODS
  With the retrospective cohort method, 8 villages or townships in Haining city were randomly selected as the study area where a total 408 cases were collected during 1977 to 1996. The incidence rates according to the drinking water sources were calculated by sex and sites of the cancer. The RR estimates were given to each sex and site by comparing to that in well water source.
  
  
  RESULTS
  The incidence rates of colorectal cancer by sequence of the sources were shown as follows drinking water: (male: pool water 126.04/10(5); female: 81.76/10(5)), river water (male: 45.06/10(5); female: 63.43/10(5)), tap water (male: 7.99/10(5); female: 5.17/10(5)) and well water (male: 3.19/10(5); female: 3.06/10(5)). All of them were statistically significance through chi(2) trend tests. Poisson test was used to have found the differences of incidences of colorectal cancer between different drinking water sources (P < 0.01). RR estimates showed that the risk of colorectal cancer with pool or river water sources were 7 times higher than that with well water.
  
  
  CONCLUSIONS
  Study of this kind might uncover the differences which accounted for the associations between the drinking water sources and colorectal cancer.
authors.affiliation: Department of Epidemiology, School of Public Health, Zhejiang University, Hangzhou, 310006, China.
authors.forename: K
authors.initials: K
authors.lastname: Chen
authors.forename: L
authors.initials: L
authors.lastname: Zhou
authors.forename: G
authors.initials: G
authors.lastname: Shen
authors.forename: H
authors.initials: H
authors.lastname: Yu
mesh_terms: D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D016012:Poisson Distribution; D012189:Retrospective Studies; D014874:Water Pollutants, Chemical / Q000009:adverse effects*; D014881:Water Supply / Q000706:statistics & numerical data
chemical_list: D014874:Water Pollutants, Chemical