Nontuberculous Mycobacteria Infection Risk and Trace Metals in Surface Water: A Population-based Ecologic Epidemiologic Study in Oregon

Abstract

Rationale: Nontuberculous mycobacteria (NTM) are ubiquitous environmental bacteria, and some pathogenic species cause lung disease. Environmental factors contribute to increased NTM abundance, with higher potential for exposure and infection. Objectives: To identify water-quality constituents that influence the risk of NTM infection in Oregon. Methods: We conducted a population-based cohort study using patient incidence data from the Oregon statewide NTM laboratory data collected as part of a public health surveillance project from 2007 through 2012. To estimate the risk of NTM pulmonary infection (PI) from exposure to water constituents, we extracted water-quality data from the Water Quality Portal and associated these data with corresponding patient county of residence. Using generalized linear models, we modeled two outcomes: Mycobacterium avium complex species PI and Mycobacterium abscessus group species PI. Results: For every 1-unit increase in the log concentration of vanadium in surface water, infection risk increased by 49% among persons with Mycobacterium avium complex PI. Among those with Mycobacterium abscessus PI, we observed that for every 1-unit increase in the log concentration of molybdenum in surface water, infection risk increased by 41%. The highest risk of infection due to Mycobacterium abscessus group infection was concentrated in counties within the Northwestern region of Oregon. High infection risk associated with Mycobacterium avium complex species did not show any geographic pattern. Conclusions: Concentrations of the trace metals molybdenum and vanadium in surface water sources were associated with NTM infection in Oregon. These findings may help identify regions at higher risk of NTM infection to guide risk reduction strategies.

Keywords: environmental epidemiology; molybdenum; nontuberculous mycobacteria; surface water; vanadium.

Figure 1.

Risk of MAC infection for counties where NTM patients resided based on a vanadium regression model (Model 2; Table 2). Gray lines represent county line boundaries in Oregon. The county names are printed in boldface type. The city names are printed in capital font. MAC = Mycobacterium avium complex species; NTM = nontuberculous mycobacteria.

Figure 2.

Risk of Mycobacterium abscessus infection for counties where NTM patients resided based on a molybdenum regression model (Model 3; Table 3). Gray lines represent county line boundaries in Oregon. The county names are printed in boldface type. The city names are printed in capital font. MABSC = Mycobacterium abscessus complex; NTM = nontuberculous mycobacteria.