Lack of an Association Between Household Air Pollution Exposure and Previous Pulmonary Tuberculosis

Abstract

Context: Observational studies investigating household air pollution (HAP) exposure to biomass fuel smoke as a risk factor for pulmonary tuberculosis have reported inconsistent results.

Objective: To evaluate the association between HAP exposure and the prevalence of self-reported previous pulmonary tuberculosis.

Design: We analyzed pooled data including 12,592 individuals from five population-based studies conducted in Latin America, East Africa, and Southeast Asia from 2010 to 2015. We used multivariable logistic regression to model the association between HAP exposure and self-reported previous pulmonary tuberculosis adjusted for age, sex, tobacco smoking, body mass index, secondary education, site and country of residence.

Results: Mean age was 54.6 years (range of mean age across settings 43.8-59.6 years) and 48.6% were women (range of % women 38.3-54.5%). The proportion of participants reporting HAP exposure was 38.8% (range in % HAP exposure 0.48-99.4%). Prevalence of previous pulmonary tuberculosis was 2.7% (range of prevalence 0.6-6.9%). While participants with previous pulmonary tuberculosis had a lower pre-bronchodilator FEV₁ (mean - 0.7 SDs, 95% CI - 0.92 to - 0.57), FVC (- 0.52 SDs, 95% CI - 0.69 to - 0.33) and FEV₁/FVC (- 0.59 SDs, 95% CI - 0.76 to - 0.43) as compared to those who did not, we did not find an association between HAP exposure and previous pulmonary tuberculosis (adjusted odds ratio = 0.86; 95% CI 0.56-1.32).

Conclusions: There was no association between HAP exposure and self-reported previous pulmonary tuberculosis in five population-based studies conducted worldwide.

Keywords: Biomass fuel; Cross-sectional study; Tuberculosis burden.

Figure 1.. Prevalence of previous pulmonary tuberculosis and household air pollution (HAP) exposure by site.

We plotted the ecological relationship between the prevalence of HAP exposure against the prevalence of previous pulmonary tuberculosis across each site. The y-gridline represents the mean prevalence (%) of previous pulmonary tuberculosis, the x-gridline represents the mean prevalence (%) of HAP exposure across all sites in Argentina, Bangladesh, Chile, Peru, Uganda, and Uruguay from primary studies conducted between 2010 to 2015.

Figure 2.. Pre-bronchodilator lung function Z-scores by previous pulmonary tuberculosis status.

Pre-bronchodilator FEV₁ (forced expiratory volume in one second), FVC (forced vital capacity), ratio (FEV₁/FVC ratio), are presented for participants with and without previous pulmonary tuberculosis from primary studies conducted in Argentina, Bangladesh, Chile, Peru, Uganda, and Uruguay between 2010 to 2015.

Figure 3.. Association between household air pollution exposure and pulmonary tuberculosis outcomes obtained from a multivariable regression model adjusted for age, sex, tobacco smoke, BMI, and secondary education obtained for the overall cohort of participants and stratified by site.

Unadjusted (left panel) and adjusted (right panel) overall and site-specific odds ratios with corresponding 95% confidence intervals are represented by diamonds and lines respectively. Data were collected in Argentina, Bangladesh, Chile, Peru, Uganda, and Uruguay from primary studies conducted between 2010 to 2015.