The relationship of pulmonary function to copper concentrations in drinking water

Copper has been shown to be an important cofactor for certain enzymatic reactions. Specifically, cross-linking of elastin is inhibited by copper deficiency. In animal models, this inhibition leads to weakened connective tissue and pathologic changes in the lungs consistent with emphysema. To explore the potential relationship of copper exposure to level of pulmonary function in humans, we examined copper concentrations in tap water in the homes of 297 adult male subjects involved in the Normative Aging Study. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were obtained by standard techniques. The relationship of tap water copper concentration to pulmonary function was explored using multiple regression analysis, controlling for other potential confounding variables (age, height, smoking status, and educational attainment). Separate regressions were performed for each of 3 smoking status groups: never, former, and current. Among never smokers, tap water copper was significantly and positively related to levels of both FVC (p = 0.014) and FEV1 (p = 0.027). No significant trend was found among former or current smokers. These data suggest that copper intake may be an important determinant of level of pulmonary function and deserves further investigation.