Arsenic-related Lung Disease and Susceptibility Associated With Metabolism and Early Life Exposure

Abstract

S-29B7-1 Background/Aims: The human lung appears to be particularly susceptible to the toxic effects of ingested arsenic. Two recent studies were performed in arsenic-exposed regions in South America on 2 potential susceptibility factors, which may play a role in arsenic-related lung disease risks. These include interindividual differences in arsenic metabolism and arsenic exposure in early life. Methods: In the first study, urinary arsenic metabolites including monomethylarsonic (MMA) were assessed in 45 lung cancer cases and 75 matched population controls from Cordoba, Argentina. In the second study, lung function and respiratory symptoms were measured in 32 adults exposed to >800 μg/L of arsenic before age 10 and 65 adults without high early life exposure, selected using a non-random convenience sample in northern Chile. Results: In the first study, in analyses limited to subjects with metabolite concentrations above detection, the mean %MMA was higher in lung cancer cases than in controls (P = 0.01), and the lung cancer odds were about 3 times higher in subjects with %MMA in the upper tertile than in those in the lower tertile (P < 0.05). In the second study, early life arsenic exposure was associated with about a 10% decrease in pulmonary function parameters (P = 0.02) and a 5-fold increase in dyspnea, decades after high exposure ended. The decrease in lung function observed was similar in magnitude to that reported for a 35 pack-year smoking history, although further research is needed to confirm these findings. Conclusion: As a whole, these 2 studies provide evidence that the risks of arsenic-associated lung disease may be related to exposure in early life and interindividual differences in arsenic metabolism.