LAUSR

Biomass fuels (wood) are commonly used indoors in under-ventilated environments for cooking in the developing world, but the impact on lung physiology is poorly understood. Quantitative computed tomography (qCT) can provide sensitive metrics to compare the lungs of women cooking with wood vs. liquified petroleum gas (LPG). We prospectively assessed (qCT and spirometry) 23 primary female cooks (18 biomass, 5 LPG) with no history of cardiopulmonary disease in Thanjavur, India. CT was obtained at coached total lung capacity (TLC) and residual volume (RV). qCT assessment included texture-derived ground-glass-opacity (GGO: Adaptive Multiple Feature Method (AMFM)), air-trapping (expiratory voxels ≤-856HU) and image registration-based assessment (Disease Probability Measure (DPM)) of emphysema, functional small airways disease (%AirTrapDPM) and regional lung mechanics. Additionally, within-kitchen exposure assessments included particulate matter <2.5μm(PM2.5), black carbon, β-(1,3)-D-glucan (surrogate for fungi), and endotoxin. Air-trapping went undetected at RV via the threshold-based measure (voxels≤-856HU), possibly due to density shifts in the presence of inflammation. However, DPM, utilizing image-matching, demonstrated significant air-trapping in biomass vs. LPG cooks (p=0.049). A subset of biomass cooks (6/18), identified using k-means clustering, had markedly altered DPM-metrics: greater air-trapping (p<0.001); lower TLC-RV volume change (p<0.001), a lower mean anisotropic deformation index (ADI) (p<0.001) and elevated % GGO (p<0.02). Across all subjects, a texture measure of bronchovascular bundles was correlated to the log-transformed β-(1,3)-D-glucan concentration (p=0.026, R=0.46), and black carbon (p=0.04, R=0.44). This pilot study identified environmental links with qCT-based lung pathologies and a cluster of biomass cooks (33%) with significant small airways disease.