title: Arsenic in drinking water and skin lesions: dose-response data from West Bengal, India.
abstract: BACKGROUND
  Over 6 million people live in areas of West Bengal, India, where groundwater sources are contaminated with naturally occurring arsenic. The key objective of this nested case-control study was to characterize the dose-response relation between low arsenic concentrations in drinking water and arsenic-induced skin keratoses and hyperpigmentation.
  
  
  METHODS
  We selected cases (persons with arsenic-induced skin lesions) and age- and sex-matched controls from participants in a 1995-1996 cross-sectional survey in West Bengal. We used a detailed assessment of arsenic exposure that covered at least 20 years. Participants were reexamined between 1998 and 2000. Consensus agreement by four physicians reviewing the skin lesion photographs confirmed the diagnosis in 87% of cases clinically diagnosed in the field.
  
  
  RESULTS
  The average peak arsenic concentration in drinking water was 325 microg/liter for cases and 180 microg/liter for controls. The average latency for skin lesions was 23 years from first exposure. We found strong dose-response gradients with both peak and average arsenic water concentrations.
  
  
  CONCLUSIONS
  The lowest peak arsenic ingested by a confirmed case was 115 microg/liter. Confirmation of case diagnosis and intensive longitudinal exposure assessment provide the basis for a detailed dose-response evaluation of arsenic-caused skin lesions.
authors.affiliation: School of Public Health, University of California, Berkeley, Berkeley, CA 94720-7360, USA.
authors.forename: Reina
authors.initials: R
authors.lastname: Haque
authors.forename: D N Guha
authors.initials: DN
authors.lastname: Mazumder
authors.forename: Sambit
authors.initials: S
authors.lastname: Samanta
authors.forename: Nilima
authors.initials: N
authors.lastname: Ghosh
authors.forename: David
authors.initials: D
authors.lastname: Kalman
authors.forename: Meera M
authors.initials: MM
authors.lastname: Smith
authors.forename: Soma
authors.initials: S
authors.lastname: Mitra
authors.forename: Amal
authors.initials: A
authors.lastname: Santra
authors.forename: Sarbari
authors.initials: S
authors.lastname: Lahiri
authors.forename: Subhankar
authors.initials: S
authors.lastname: Das
authors.forename: Binay K
authors.initials: BK
authors.lastname: De
authors.forename: Allan H
authors.initials: AH
authors.lastname: Smith
mesh_terms: D000293:Adolescent; D000328:Adult; D001151:Arsenic / Q000009:adverse effects* / Q000032:analysis; D016022:Case-Control Studies; D002648:Child; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D017495:Hyperpigmentation / Q000139:chemically induced / Q000453:epidemiology*; D007194:India / Q000453:epidemiology; D007642:Keratosis / Q000139:chemically induced / Q000453:epidemiology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012424:Rural Population; D014881:Water Supply
chemical_list: D001151:Arsenic