A clean fuel cookstove is associated with improved lung function: Effect modification by age and secondhand tobacco smoke exposure

Household air pollution (HAP) secondary to the burning of solid fuels is a major risk factor for the development of COPD. Our study seeks to examine the impact of a clean cookstove, liquid petroleum gas (LPG), on respiratory outcomes. Women (n = 200) from neighboring Indian communities, one cooking with LPG and one with biomass, were enrolled. Spirometry was performed. Relationships between primary cooking fuel and spirometry measures, as raw values, Global Lung Initiative (GLI) percent predicted (pp), and GLI z-scores, were examined using linear regression. Effect modification by age was explored. Women were young (average age 33.3 years), with low education (median 5.0 years), and the majority had multiple sources of air pollution exposures. Overall, the lung function in both groups was poor [FEV1 z-score median -2.05, IQR (-2.64, -1.41). Biomass was associated with lower FEV1/FVC (raw values -7.0, p = 0.04; GLI pp -7.62, p = 0.05, and z-score -0.86, p = 0.05) and FEF25-75 (GLI pp -25.78, p = 0.05, z-score -1.24, p = 0.05), after adjusting for confounders. Increasing impairment in lung function with age was found among biomass users (p-interaction = 0.01). In conclusion, use of a clean fuel cookstove may improve lung function. These findings have broad implications for research and public policy.