The risk of NTM pulmonary infection associated with trace metal exposure from public distribution system water in the United States.

backgroundThe prevalence of nontuberculous mycobacterial (NTM) pulmonary infection (NTM PI) varies geographically in the United States (US). Previous studies indicate that trace metals in environmental source water increase NTM PI risk.

objectiveTo examine the effect of trace metals, chromium (Cr), cobalt (Co), molybdenum (Mo), strontium (Sr), and vanadium (V) in public distribution system water on NTM PI risk among susceptible persons in the US.

methodsWe studied NTM PI risk as a function of trace metal exposure from public distribution system water in two US patient populations: (1) The Cystic Fibrosis Foundation Patient Registry. (2) The Centers for Medicare and Medicaid Services. Patient data were extracted for the period 2010-2019. We obtained data on trace metal concentrations from the US Environmental Protection Agency, Third Unregulated Contaminant Monitoring Rule dataset. We used logistic and negative binomial generalized linear models to estimate NTM PI risk as a function of trace metal exposure in treated drinking water at the county level. Our models were adjusted for patient demographics, source water type, climate variables, and the type of disinfectant used.

resultsOur cystic fibrosis (CF) population comprised 14,251 persons with CF, including 4020 NTM cases and 10,231 controls. Our Medicare population comprised 27,146,753 beneficiaries, including 84,075 NTM cases. In the Medicare analysis, V was associated with increased NTM PI risk in the Midwest, South, and West, while Mo increased NTM PI risk in the West. In the CF analysis, V increased NTM PI risk in the South, while Mo was associated with increased NTM PI risk in the West. In both the CF and Medicare populations, using chloramine as a disinfectant significantly increased NTM PI risk. SIGNIFICANCE: Mo and V in treated water was associated with increased risk among persons susceptible to NTM PI. The effect of trace metals varies by geographic region IMPACT: The incidence and prevalence of NTM, a waterborne pulmonary infection, have been increasing in the US and have been shown to vary geographically. Our study has shown that trace metals, specifically molybdenum and vanadium, in treated drinking water significantly increase the risk of NTM pulmonary infection across the US. Our study also shows that the effect of trace metals varies by geographic region. Our research may lead to the monitoring of trace metals in drinking water as well as in susceptible populations, and ultimately, may be incorporated into a framework for NTM prevention efforts.