title: Long-term exposure to low-level arsenic in drinking water and diabetes incidence: a prospective study of the diet, cancer and health cohort.
abstract: BACKGROUND
  Established causes of diabetes do not fully explain the present epidemic. High-level arsenic exposure has been implicated in diabetes risk, but the effect of low-level arsenic exposure in drinking water remains unclear.
  
  
  OBJECTIVE
  We sought to determine whether long-term exposure to low-level arsenic in drinking water in Denmark is associated with an increased risk of diabetes using a large prospective cohort.
  
  
  METHODS
  During 1993-1997, we recruited 57,053 persons. We followed each cohort member for diabetes occurrence from enrollment until 31 December 2006. We traced and geocoded residential addresses of the cohort members and used a geographic information system to link addresses with water-supply areas. We estimated individual exposure to arsenic using all addresses from 1 January 1971 until the censoring date. Cox proportional hazards models were used to model the association between arsenic exposure and diabetes incidence, separately for two definitions of diabetes: all cases and a more strict definition in which cases of diabetes based solely on blood glucose results were excluded.
  
  
  RESULTS
  Over a mean follow-up period of 9.7 years for 52,931 eligible participants, there were a total of 4,304 (8.1%) diabetes cases, and 3,035 (5.8%) cases of diabetes based on the more strict definition. The adjusted incidence rate ratios (IRRs) per 1-μg/L increment in arsenic levels in drinking water were as follows: IRR = 1.03 (95% CI: 1.01, 1.06) and IRR = 1.02 (95% CI: 0.99, 1.05) for all and strict diabetes cases, respectively.
  
  
  CONCLUSIONS
  Long-term exposure to low-level arsenic in drinking water may contribute to the development of diabetes.
authors.affiliation: Diet, Genes and Environment, Danish Cancer Society Research Centre, Copenhagen, Denmark.
authors.forename: Elvira Vaclavik
authors.initials: EV
authors.lastname: Bräuner
authors.forename: Rikke Baastrup
authors.initials: RB
authors.lastname: Nordsborg
authors.forename: Zorana Jovanovic
authors.initials: ZJ
authors.lastname: Andersen
authors.forename: Anne
authors.initials: A
authors.lastname: Tjønneland
authors.forename: Steffen
authors.initials: S
authors.lastname: Loft
authors.forename: Ole
authors.initials: O
authors.lastname: Raaschou-Nielsen
mesh_terms: D001151:Arsenic / Q000633:toxicity*; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D003920:Diabetes Mellitus / Q000139:chemically induced / Q000453:epidemiology*; D004032:Diet / Q000706:statistics & numerical data; D060766:Drinking Water / Q000737:chemistry*; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data; D014881:Water Supply / Q000706:statistics & numerical data*
chemical_list: D060766:Drinking Water; D014874:Water Pollutants, Chemical; D001151:Arsenic