Environment or host? A case-control study of risk factors for Mycobacterium avium complex lung disease

Rationale: Mycobacterium avium complex lung disease is an increasingly common and chronically debilitating problem. Several host traits have been suggested or confirmed as risk factors. Potential environmental and behavioral risk factors have also been proposed. Few have been evaluated in comparative studies. Objectives: To determine if aerosol-generating activities in the home and garden, features of the home water supply, or several pulmonary and immune-compromising conditions are associated with Mycobacterium avium complex lung disease. Methods: Cases were recruited from academic medical centers and by informal referrals from nonuniversity practices in Washington and Oregon. Control subjects were recruited by random-digit dialing and matched to cases by age, sex, and partial telephone number. Associations were measured as odds ratios (OR) estimated using conditional logistic regression. Measurements and Main Results: Known and potential risk factors were measured by in-home interview. Fifty-two matched pairs were studied. Six of 12 examined host traits were associated with disease, including history of chronic obstructive pulmonary disease (OR, 10; 95% confidence interval [CI], 1.2-80), pneumonia hospitalization (OR, 3.4; 95% CI, 1.1-11), and steroid use (OR, 8; 95% CI, 1.6-41). In contrast, 11 of the 14 aerosol-generating activities and all five features of home water supply studied bore little or no association with disease. Conclusions: Aerosol-generating activities seem not to be risk factors for Mycobacterium avium complex lung disease in HIV-negative adults, but prior lung disease and immune-suppressing drugs seem to be associated with susceptibility.