Associations of Respiratory Symptoms and Lung Function with Measured Carbon Monoxide Concentrations among Nonsmoking Women Exposed to Household Air Pollution: The RESPIRE Trial, Guatemala. Environ Health Perspect, Nov 2014.
Authors: Daniel Pope, Esperanza Diaz, et al.
Background: With 40% of the World’s population relying on solid fuel, household air pollution (HAP) represents a major preventable risk factor for COPD. Meta-analyses have confirmed this relationship, however constituent studies are observational with virtually none measuring exposure directly.
Objectives: We estimated associations between HAP exposure and respiratory symptoms and lung function in young, non-smoking women in rural Guatemala, using measured CO concentrations in exhaled breath and personal air to assess exposure.
Methods: The Randomised Exposure Study of Pollution Indoors and Respiratory Effects (RESPIRE) Guatemala study was a trial comparing respiratory outcomes among 504 women using improved chimney stoves versus traditional cookstoves. The present analysis included 456 women with data from post-intervention surveys including 6-monthly interviews (respiratory symptoms), spirometry and CO (ppm) in exhaled breath measurements. Personal CO was measured using passive diffusion tubes at variable times during the study. Associations between CO concentrations and respiratory health were estimated using random intercept regression models.
Results: Respiratory symptoms (cough, phlegm, wheeze or chest tightness) during the previous six months were positively associated with breath CO measured at the same time of symptom reporting and with average personal CO concentrations during the follow-up period. CO in exhaled breath at the same time as spirometry was associated with lower lung function [average reduction in FEV1 (in mL) for a 10% increase in CO was 3.33 mL (95% CI: -0.86, -5.81)]. Lung function measures were not significantly associated with average post-intervention personal CO concentrations.
Conclusions: Our results provide further support for the effects of HAP exposures on airway inflammation. Further longitudinal research modelling continuous exposure to particulate matter against lung function will help understand more fully the impact of HAP on COPD.
