Researchers performed a search in PubMed (Medline) and Embase to search for studies on chronic obstructive pulmonary disease (COPD) in never-smokers. Through their search, 557 papers were used, and 20 met the designated inclusion criteria that included populations from the United States, Latin America, Asia, and Africa. Risk factors that were seen in never-smokers were diverse, including exposure to biomass, occupational exposure, passive smoking, asthma history, tuberculosis, and childhood respiratory infections. The greatest risk factor that was seen was prior respiratory diseases of any type.
It was unclear if there was an impact of COPD related to residential radon. One study that was included in the review looked at a large cohort study in the United States, that examined the link between radon and COPD mortality. Researchers found that there was a considerable positive linear trend in COPD mortality with heightened categories of concentrations of radon. A greater number of well-designed studies need to be conducted to examine the if indoor radon has any impact on the onset of COPD.
Reference: Mannino DM, Buist AS. Global burden of COPD: risk factors, prevalence, and future trends. The Lancet. 2007;370(9589):765-773.
