title: Bladder cancer and arsenic through drinking water: a systematic review of epidemiologic evidence.
abstract: Exposure to inorganic arsenic (As) through drinking water is a major international public health issue. We carried out a systematic review of the existing literature examining the association between the risk of bladder cancer in humans and exposure to arsenic through drinking water. We searched electronic databases for studies published from January 2000 up to April 2013. Eight ecological studies, six case-control studies, four cohort studies and two meta-analyses were identified. The vast majority of the studies were carried out in areas with high arsenic concentrations in drinking water such as southwestern and northeastern Taiwan, Pakistan, Bangladesh, Argentina (Cordoba Province), USA (southeastern Michigan, Florida, Idaho) and Chile. Most of the studies reported higher risks of bladder cancer incidence or mortality in areas with high arsenic concentrations in drinking water compared to the general population or a low arsenic exposed control group. The quality assessment showed that among the studies identified, arsenic exposure was assessed at the individual level only in half of them and only three assessed exposure using a biomarker. Further, five out of eight ecological studies presented results with adjustment for potential confounders except for age; all cohort and case-control studies presented results with adjustment for cigarette smoking status in the analysis. The majority of the studies with varying study designs carried out in different areas provided evidence of statistically siginificant increases in bladder cancer risk at high concentrations of arsenic (>50 μg L(-1)). Assessing bladder cancer risk at lower exposure concentrations requires further investigation.
authors.affiliation: Department of Hygiene, Epidemiology and Medical Statistics, Medical School of Athens, Athens, Greece. echristof@med.uoa.gr
authors.forename: Eleni P
authors.initials: EP
authors.lastname: Christoforidou
authors.forename: Elena
authors.initials: E
authors.lastname: Riza
authors.forename: Stefanos N
authors.initials: SN
authors.lastname: Kales
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Hadjistavrou
authors.forename: Melina
authors.initials: M
authors.lastname: Stoltidi
authors.forename: Anastasia N
authors.initials: AN
authors.lastname: Kastania
authors.forename: Athina
authors.initials: A
authors.lastname: Linos
mesh_terms: D001151:Arsenic / Q000032:analysis / Q000633:toxicity*; D060766:Drinking Water / Q000032:analysis*; D004781:Environmental Exposure; D004784:Environmental Monitoring; D006801:Humans; D015994:Incidence; D018570:Risk Assessment; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced* / Q000453:epidemiology / Q000401:mortality; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D060766:Drinking Water; D014874:Water Pollutants, Chemical; D001151:Arsenic