Assessment of Metal Concentrations and Associations with Pulmonary Function among Children with Asthma in Chicago, Illinois

Abstract

Individuals living in areas with the potential for elevated metal exposure from industrial sources may have reduced pulmonary function. We evaluated cross-sectional associations of toenail concentrations of 17 metals within a community area of residence and asthma control in 75 children, and pulmonary function measures [forced expiratory volume in one second (FEV1; liters), forced vital capacity (FVC; liters), FEV1 to FVC ratio (FEV1:FVC), and mid-exhalation forced expiratory flow rate (FEF 25–75%; liters/second)], in a subsample of 39 children with diagnosed asthma in Chicago, Illinois. Linear regression models were used to estimate adjusted regression coefficients and standard errors (SE) for the associations between ≥ median versus <median metal exposures and natural log-transformed (ln) pulmonary function test parameters. Toenail levels of cadmium, cobalt, iron, manganese, and vanadium were higher among children residing near an industrial corridor than those in a comparison community. Copper concentrations were inversely associated with lnFEV1 (β = −0.10, SE = 0.04, p = 0.01), lnFEV1:FVC (β = −0.07, SE = 0.03, p = 0.02) and lnFEF 25–75% (β = −0.25, SE = 0.09, p = 0.01); manganese concentrations were inversely associated with lnFEV1 (β = −0.11, SE = 0.04, p = 0.01), lnFEV1:FVC (β = −0.07, SE = 0.03, p = 0.02), and lnFEF 25–75% (β = −0.28, SE = 0.10, p = 0.004), and vanadium concentrations were inversely associated with lnFEV1 (β = −0.08, SE = 0.04, p = 0.05) and lnFVC (β = −0.07, SE = 0.03, p = 0.03). Nickel and copper were associated with uncontrolled asthma (OR = 6.8; 95% CI 2.0, 22.8 and OR = 4.6; 95% CI 1.0, 21.0, respectively). These data suggest that selected metal exposures may be associated with impaired pulmonary function parameters and reduced asthma control among children with preexisting asthma.