Low-Moderate Arsenic Exposure and Respiratory Health in American Indian Communities

Abstract

Background: Exposure to inorganic arsenic through drinking water is an established cause of lung cancer. However, evidence on the impact of arsenic exposure on non-malignant lung disease is less conclusive. The available evidence, mostly from populations exposed to water arsenic levels >100 µg/L, suggests that arsenic exposure is associated with lower lung function. Prospective studies and studies examining low-moderate levels (<50 µg/L), the level relevant for most populations worldwide, are limited.Methods: The Strong Heart Study is a prospective study of American Indian adults. The present analysis (n=2,166) used urinary arsenic measurements at baseline (1989-1991) and lung function measured by standardized spirometry at the second examination (1993-1995). We evaluated associations between arsenic exposure and airflow obstruction (FEV1/FVC ratio <0.70) and restrictive pattern (FVC <80% predicted with FEV1/FVC ratio >0.70); respiratory symptoms; and self-reported diagnosis of nonmalignant respiratory disease.Results: Airflow obstruction was present in 21.5% (458/2,132), and a restrictive pattern was present in 18.3% among those without obstruction (307/1,674). The odds ratio (95% confidence interval) for obstructive and restrictive patterns comparing the IQR of arsenic (µg/g creatinine) was 1.13 (0.96, 1.32) and 1.27 (1.01, 1.60), respectively, after full adjustment, including smoking, kidney function, and history of tuberculosis. Self-reported diagnosis of emphysema, frequent cough, phlegm with cough, and stopping for breath were also positively associated with arsenic.Conclusions: In this American Indian population, low-moderate inorganic arsenic exposure was positively associated with a lung restrictive pattern, higher self-reported emphysema, and respiratory symptoms, independent of smoking status. These findings suggest that low-moderate arsenic exposure can contribute to nonmalignant lung disease and may be associated with restrictive lung disease.