Abstract Rationale Biomass use is known to lead to severe fibrotic disease (‘hut lung’) and is thought to be a significant risk factor in COPD prevalence in women in the developing world. Cooking indoors with biomass fuels results in high concentrations of inspirable particulate matter and endotoxins, leading to lung function decline over decades of exposure, often with no reported symptoms. We previously demonstrated evidence of functional small airways disease (fSAD) and parenchymal inflammation assessed via quantitative computed tomography (qCT) metrics in asymptomatic women cooking with biomass fuels compared with LP gas in rural India. We hypothesize that mucus hypersection and plugging may associate with fSAD, representing an opportunity for early intervention to prevent progressive functional decline. Methods We retrospectively assessed qCT images acquired at total lung capacity (TLC), from a cohort of asymptomatic women cooking with either liquified petroleum gas (LPG, n = 5), or wood biomass (n = 18). Images were reviewed by an expert chest Radiologist (RMB), blinded to participant group. Image asssessment utilized a semi-automated, AI-driven mucus scoring workflow (VIDA Diagnostics Inc., Coralville, IA). 18 anatomical segments were reviewed for mucus plugs (≥2mm), bronchiectasis, and occlusions, resulting in a 0-18 score per category for each participant. The cumulative counts in each category were used for comparisons. Results The qCT metrics from this cohort have previously been reported in which we identified a cluster of participants (n = 6), all biomass cooks, with severe air-trapping (functional small airways disease) correlated to indoor black carbon and fungal material assessments. In the current study, mucus plugs were detected in 8 participants: 6 biomass cooks (all belonging to the previously identified cluster), and 2 LPG users. The LPG users had the lowest score (1 each). Within the vulnerable biomass subgroup, the mean (SD) mucus plug score was 5.5 (4.68). In the most severe cases, one participant had 11 mucus plugs and 3 occluded airways, and another had 12 mucus plugs. There was heterogenous presentation with mucus plugs distributed across all 18 airway segments across subjects. Participants with the highest mucus plugs also had the highest air-trapping. Statistical testing was limited owing to the sample size and significant heterogeneity. Conclusion Our results suggest that biomass use may increase airway obstruction through increased prevalence of mucus plugs. Mucus plugging may represent early preclinical manifestations and the interventions promoting resolution of these plugs may help arrest the development of progressive disease in this vulnerable population. This abstract is funded by: University of Iowa Environmental and Health Science Research Center (NIH/NIEHS 5P30 ES005605), Bowers Emphysema Research Fund, Origins of Cystic Fibrosis Airway Disease NIH PPG HL091842-11, NIH R01HL112986, NIH R01HL126838, and NIH R01HL130883
Puliyakote et al. (Fri,) studied this question.