Drinking water arsenic in northern chile: high cancer risks 40 years after exposure cessation.
BACKGROUND
Millions of people worldwide are exposed to arsenic-contaminated water. In the largest city in northern Chile (Antofagasta), more than 250,000 people were exposed to high arsenic drinking water concentrations from 1958 until 1970 when a water treatment plant was installed. Because of its unique geology, limited water sources, and good historical records, lifetime exposure and long-term latency patterns can be assessed in this area with better accuracy than in other arsenic-exposed areas worldwide.


METHODS
We conducted a population-based case-control study in northern Chile from October 2007 to December 2010 involving 232 bladder and 306 lung cancer cases and 640 age- and gender-matched controls, with detailed information on past exposure and potential confounders, including smoking and occupation.


RESULTS
Bladder cancer ORs for quartiles of average arsenic concentrations in water before 1971 (<11, 11-90, 91-335, and >335 μg/L) were 1.00, 1.36 [95% confidence interval (CI), 0.78-2.37], 3.87 (2.25-6.64), and 6.50 (3.69-11.43), respectively. Corresponding lung cancer ORs were 1.00, 1.27 (0.81-1.98), 2.00 (1.24-3.24), and 4.32 (2.60-7.17). Bladder and lung cancer ORs in those highly exposed in Antofagasta during 1958 to 1970 but not thereafter were 6.88 (3.84-12.32) and 4.35 (2.57-7.36), respectively.


CONCLUSIONS
The lung and bladder cancer risks that we found up to 40 years after high exposures have ended are very high.


CONCLUSIONS
Our findings suggest that prevention, treatment, and other mortality reduction efforts in arsenic-exposed countries will be needed for decades after exposure cessation.
University of California, Berkeley, School of Public Health, 50 University Hall, MC7360, Berkeley, CA 94720-7360, USA. craigs@berkeley.edu
Craig M
CM
Steinmaus
Catterina
C
Ferreccio
Johanna Acevedo
JA
Romo
Yan
Y
Yuan
Sandra
S
Cortes
Guillermo
G
Marshall
Lee E
LE
Moore
John R
JR
Balmes
Jane
J
Liaw
Todd
T
Golden
Allan H
AH
Smith
D000328:Adult; D000368:Aged; D001151:Arsenic / Q000009:adverse effects* / Q000032:analysis; D020261:Arsenic Poisoning / Q000453:epidemiology / Q000209:etiology*; D016022:Case-Control Studies; D002677:Chile / Q000453:epidemiology; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012307:Risk Factors; D001749:Urinary Bladder Neoplasms / Q000453:epidemiology / Q000209:etiology*; D014874:Water Pollutants, Chemical / Q000009:adverse effects*; D014881:Water Supply / Q000032:analysis
D014874:Water Pollutants, Chemical; D001151:Arsenic