Modification of risk of arsenic-induced skin lesions by sunlight exposure, smoking, and occupational exposures in Bangladesh.
BACKGROUND
The risk of skin lesions associated with arsenic exposure from drinking water in Bangladesh is considerably greater in men than in women.


METHODS
Using baseline data from 11,062 cohort members in the Health Effects of Arsenic Longitudinal Study in Araihazar, Bangladesh, we performed a cross-sectional analysis to evaluate whether the association between arsenic exposure from drinking water and the risk of skin lesions is modified by tobacco smoking, excessive sunlight, the use of fertilizer, and the use of pesticides. A time-weighted well arsenic concentration was estimated for each participant by incorporating history of well use. Relative excess risk for interaction (RERI) and its 95% confidence intervals (CIs) were estimated using adjusted prevalence odds ratios.


RESULTS
We observed a synergistic effect between the highest level of arsenic exposure (> 113 microg/L) and tobacco smoking on risk of skin lesions in men (RERI = 1.5 [95% CI = 0.3 to 2.7] overall and 1.7 [0.2 to 3.4] for the subpopulation with longer-term arsenic exposure). We also observed suggestive synergistic effects between higher levels (28.1-113.0 microg/L and 113.1-864.0 microg/L) of arsenic exposure and fertilizer use in men (RERI = 1.0 [-0.2 to 2.2] and 1.3 [-0.2 to 2.9] respectively). Furthermore, the risk of skin lesions associated with any given level of arsenic exposure was greater in men with excessive sun exposure. The patterns of effect estimates in women indicate similar-but-weaker interaction effects of arsenic exposure with tobacco smoking and fertilizer use.


CONCLUSIONS
These findings help explain why the risk of arsenic-related skin lesions was much greater in men than in women in Bangladesh. Because most arsenic-induced skin cancers arise from these skin lesions, treatment and remediation plans should take into consideration these etiologic cofactors.
Chen
Yu
Y
Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York 10032, USA.
Graziano
Joseph H
JH
Parvez
Faruque
F
Hussain
Iftikhar
I
Momotaj
Hassina
H
van Geen
Alexander
A
Howe
Geoffrey R
GR
Ahsan
Habibul
H
D000328:Adult; D001151:Arsenic / Q000009:adverse effects*; D001459:Bangladesh; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D005308:Fertilizers / Q000009:adverse effects; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D010575:Pesticides / Q000009:adverse effects; D011230:Precancerous Conditions / Q000139:chemically induced*; D012307:Risk Factors; D012871:Skin Diseases / Q000139:chemically induced*; D012907:Smoking / Q000009:adverse effects*; D013472:Sunlight / Q000009:adverse effects*; D014881:Water Supply / Q000032:analysis
D005308:Fertilizers; D010575:Pesticides; D001151:Arsenic