title: Arsenic exposure and hypertension: a systematic review.
abstract: BACKGROUND
  Environmental exposure to arsenic has been linked to hypertension in persons living in arsenic-endemic areas.
  
  
  OBJECTIVE
  We summarized published epidemiologic studies concerning arsenic exposure and hypertension or blood pressure (BP) measurements to evaluate the potential relationship.
  
  
  METHODS
  We searched PubMed, Embase, and TOXLINE and applied predetermined exclusion criteria. We identified 11 cross-sectional studies from which we abstracted or derived measures of association and calculated pooled odds ratios (ORs) using inverse-variance weighted random-effects models.
  
  
  RESULTS
  The pooled OR for hypertension comparing the highest and lowest arsenic exposure categories was 1.27 [95% confidence interval (CI): 1.09, 1.47; p-value for heterogeneity = 0.001; I(2) = 70.2%]. In populations with moderate to high arsenic concentrations in drinking water, the pooled OR was 1.15 (95% CI: 0.96, 1.37; p-value for heterogeneity = 0.002; I(2) = 76.6%) and 2.57 (95% CI: 1.56, 4.24; p-value for heterogeneity = 0.13; I(2) = 46.6%) before and after excluding an influential study, respectively. The corresponding pooled OR in populations with low arsenic concentrations in drinking water was 1.56 (95% CI: 1.21, 2.01; p-value for heterogeneity = 0.27; I(2) = 24.6%). A dose-response assessment including six studies with available data showed an increasing trend in the odds of hypertension with increasing arsenic exposure. Few studies have evaluated changes in systolic and diastolic BP (SBP and DBP, respectively) measurements by arsenic exposure levels, and those studies reported inconclusive findings.
  
  
  CONCLUSIONS
  In this systematic review we identified an association between arsenic and the prevalence of hypertension. Interpreting a causal effect of environmental arsenic on hypertension is limited by the small number of studies, the presence of influential studies, and the absence of prospective evidence. Additional evidence is needed to evaluate the dose-response relationship between environmental arsenic exposure and hypertension.
authors.affiliation: Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, USA.
authors.forename: Lalita N
authors.initials: LN
authors.lastname: Abhyankar
authors.forename: Miranda R
authors.initials: MR
authors.lastname: Jones
authors.forename: Eliseo
authors.initials: E
authors.lastname: Guallar
authors.forename: Ana
authors.initials: A
authors.lastname: Navas-Acien
mesh_terms: D001151:Arsenic / Q000032:analysis / Q000633:toxicity*; D001794:Blood Pressure; D004305:Dose-Response Relationship, Drug; D060766:Drinking Water / Q000032:analysis; D004781:Environmental Exposure; D006801:Humans; D006973:Hypertension / Q000139:chemically induced* / Q000453:epidemiology*; D015995:Prevalence
chemical_list: D060766:Drinking Water; D001151:Arsenic