Indoor air pollution exposure is associated with greater morbidity in cystic fibrosis

Background: Exposure to higher levels of outdoor air pollution is associated with increased morbidity in individuals with cystic fibrosis. Limited information exist regarding the potential adverse effects of indoor air pollution on those with cystic fibrosis. Methods: Individuals with cystic fibrosis who were enrolled in the Twin and Sibling Study from 2000-2013, self-reported exposure to four known sources of indoor air pollution (secondhand smoke, forced hot air, wood stove and fireplace). Change in lung function, rates of hospitalizations and pulmonary exacerbations were followed over 4 years to compare outcomes in those who were exposed to those who were not exposed. Results: Of 1432 participants with data on secondhand smoke exposure, 362 (25.3%) were exposed. Of 765 individuals with data on forced hot air exposure, 491 (64.2%) were exposed. Of 1247 participants with data on wood stove exposure and 830 with data on fireplace exposure, 182 (14.6%) and 373 (44.9%) were exposed, respectively. In longitudinal analysis, pediatric individuals either exposed to secondhand smoke or to forced hot air had a 0.60% predicted/year decrease in FEV₁% predicted (P=0.002) or a 0.46% predicted/year decrease in FEV1% predicted (P=0.048), respectively compared to individuals who were not exposed. Adults exposed to secondhand smoke had a 42% increased yearly risk of hospitalization compared to those who were not exposed (P=0.045). Conclusions: Our questionnaire-based data suggest that exposure to sources of indoor air pollution increase morbidity in both the pediatric and adult cystic fibrosis populations. Future studies with quantitative indoor air quality assessments are needed.