Lifetime exposure to arsenic in drinking water and bladder cancer: a population-based case-control study in Michigan, USA.
OBJECTIVE
Arsenic in drinking water has been linked with the risk of urinary bladder cancer, but the dose-response relationships for arsenic exposures below 100 microg/L remain equivocal. We conducted a population-based case-control study in southeastern Michigan, USA, where approximately 230,000 people were exposed to arsenic concentrations between 10 and 100 microg/L.


METHODS
This study included 411 bladder cancer cases diagnosed between 2000 and 2004, and 566 controls recruited during the same period. Individual lifetime exposure profiles were reconstructed, and residential water source histories, water consumption practices, and water arsenic measurements or modeled estimates were determined at all residences. Arsenic exposure was estimated for 99% of participants' person-years.


RESULTS
Overall, an increase in bladder cancer risk was not found for time-weighted average lifetime arsenic exposure >10 microg/L when compared with a reference group exposed to <1 microg/L (odds ratio (OR) = 1.10; 95% confidence interval (CI): 0.65, 1.86). Among ever-smokers, risks from arsenic exposure >10 microg/L were similarly not elevated when compared to the reference group (OR = 0.94; 95% CI: 0.50, 1.78).


CONCLUSIONS
We did not find persuasive evidence of an association between low-level arsenic exposure and bladder cancer. Selecting the appropriate exposure metric needs to be thoughtfully considered when investigating risk from low-level arsenic exposure.
Meliker
Jaymie R
JR
Graduate Program in Public Health, Department of Preventive Medicine, Stony Brook University Medical Center, Stony Brook, NY 11794-8338, USA. jrmeliker@gmail.com
Slotnick
Melissa J
MJ
AvRuskin
Gillian A
GA
Schottenfeld
David
D
Jacquez
Geoffrey M
GM
Wilson
Mark L
ML
Goovaerts
Pierre
P
Franzblau
Alfred
A
Nriagu
Jerome O
JO
D000328:Adult; D000367:Age Factors; D000368:Aged; D001151:Arsenic / Q000009:adverse effects* / Q000032:analysis; D016022:Case-Control Studies; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure / Q000009:adverse effects* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008824:Michigan / Q000453:epidemiology; D008875:Middle Aged; D016017:Odds Ratio; D012307:Risk Factors; D017678:Sex Distribution; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced* / Q000453:epidemiology*; D014881:Water Supply / Q000032:analysis* / Q000706:statistics & numerical data
D001151:Arsenic