M G Mostafa,1 J C McDonald,2 N M Cherry3
1 National Institute of Cancer
Research and Hospital, Dhaka,
Bangladesh;
2 National Heart
and Lung Institute, Imperial
College, London, UK; 3 University
of Alberta, Edmonton, Alberta,
Canada
Occup Environ Med 2008;65:765–768. doi:10.1136/oem.2007.037895ABSTRACT
Background: Arsenic is a known carcinogen but the risk
of lung cancer from the widespread contamination of
drinking water in rural Bangladesh has not been
estimated.
Objectives: To determine whether estimated exposure of
villagers in Bangladesh to arsenic in drinking water
differed between those with lung cancer and those with
non-malignant lesions.
Methods: Data were obtained from 7286 subjects who
underwent lung biopsy in 2003–2006 at a diagnostic
centre taking referrals from throughout Bangladesh.
Analysis was limited to 5372 people living in villages for
the last 10 years who reported using tube well water. Of
these, 3223 with a primary lung tumour were enrolled as
cases and 1588 with non-malignant lesions as referents in
an unmatched analysis. Arsenic exposure was estimated
by average concentrations for each of 64 districts.
Logistic regression was used to test the effects of age,
arsenic and smoking on risk and to investigate relationship
to cell type.
Results: Male cases were older than referents and more
likely to smoke, to smoke .20 units/day and to smoke
bidi—small, hand-rolled cigarettes. Odds ratios for lung
cancer increased steadily with mean arsenic concentration,
but the confidence interval excluded 1.0 only at
concentrations .100 mg/l (OR 1.45, 95% CI 1.16 to
1.80). This trend was seen only in smokers where the
increased risk at .100 mg/l was 1.65 (95% CI 1.25 to
2.18). A similar trend was seen in women smokers.
Squamous cell lung cancer was more frequent in smokers
and, having adjusted for smoking, in districts with arsenic
concentrations .100 mg/l.
Conclusions: Among Bangladeshis who smoke, those
whose drinking water is contaminated with arsenic at
concentrations .100 mg/l are at increased risk of lung
cancer. With high levels of exposure misclassification and
short latency of exposure, the study cannot estimate or
exclude the likely long term risk in non-smokers and at
lower arsenic concentrations.
