Arsenic in drinking water and the prevalence of respiratory effects in West Bengal, India

Abstract

BACKGROUND: A large population in West Bengal, India has been exposed to naturally occurring inorganic arsenic through their drinking water. A cross-sectional survey involving 7683 participants of all ages was conducted in an arsenic-affected region between April 1995 and March 1996. The main focus of the study was skin keratoses and pigmentation alterations, two characteristic signs of ingested inorganic arsenic. Strong exposure-response gradients were found for these skin lesions. The study also collected limited information concerning respiratory system signs and symptoms, which we report here because increasing evidence suggests that arsenic ingestion also causes pulmonary effects. METHODS: Participants were clinically examined and interviewed, and the arsenic content in their current primary drinking water source was measured. There were few smokers and analyses were confined to non-smokers (N = 6864 participants). RESULTS: Among both males and females, the prevalence of cough, shortness of breath, and chest sounds (crepitations and/or rhonchi) in the lungs rose with increasing arsenic concentrations in drinking water. These respiratory effects were most pronounced in individuals with high arsenic water concentrations who also had skin lesions. Prevalence odds ratio (POR) estimates were markedly increased for participants with arsenic-induced skin lesions who also had high levels of arsenic in their current drinking water source (> or = 500 microg/l) compared with individuals who had normal skin and were exposed to low levels of arsenic (<50 microg/l). In participants with skin lesions, the age-adjusted POR estimates for cough were 7.8 for females (95% CI : 3.1-19.5) and 5.0 for males (95% CI : 2.6-9.9); for chest sounds POR for females was 9.6 (95% CI : 4.0-22.9) and for males 6.9 (95% CI : 3.1-15.0). The POR for shortness of breath in females was 23.2 (95% CI : 5.8-92.8) and in males 3.7 (95% CI : 1.3-10.6). CONCLUSION: These results add to evidence that long-term ingestion of inorganic arsenic can cause respiratory effects.