Proportion and clinical characteristics of non-asthmatic non-smokers among adults with airflow obstruction

BACKGROUND AND OBJECTIVES: Chronic obstructive pulmonary disease (COPD) mainly develops after long-term exposure to cigarette or biomass fuel smoke, but also occurs in non-smokers with or without a history of asthma. We investigated the proportion and clinical characteristics of non-smokers among mi...

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Detalles Bibliográficos
Autores principales: Takiguchi, Hiroto, Takeuchi, Tomoe, Niimi, Kyoko, Tomomatsu, Hiromi, Tomomatsu, Katsuyoshi, Hayama, Naoki, Oguma, Tsuyoshi, Aoki, Takuya, Urano, Tetsuya, Asai, Satomi, Miyachi, Hayato, Asano, Koichiro
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2018
Materias:
Research Article
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5942827/
https://www.ncbi.nlm.nih.gov/pubmed/29742176
http://dx.doi.org/10.1371/journal.pone.0196132
Descripción
Sumario:BACKGROUND AND OBJECTIVES: Chronic obstructive pulmonary disease (COPD) mainly develops after long-term exposure to cigarette or biomass fuel smoke, but also occurs in non-smokers with or without a history of asthma. We investigated the proportion and clinical characteristics of non-smokers among middle-aged to elderly subjects with airflow obstruction. METHODS: We retrospectively analyzed 1,892 subjects aged 40–89 years who underwent routine preoperative spirometry at a tertiary university hospital in Japan. Airflow obstruction was defined as a forced expiratory volume in 1 second (FEV(1))/forced vital capacity < 0.7 or as the lower limit of the normal. RESULTS: Among 323 patients presenting with FEV(1)/forced vital capacity < 0.7, 43 had asthma and 280 did not. Among the non-asthmatic patients with airflow obstruction, 94 (34%) were non-smokers. A larger number of women than men with airflow obstruction had asthma (26% vs. 7.6%, p < 0.001), or were non-smokers among non-asthmatics (72% vs. 20%, p < 0.001). Non-asthmatic non-smokers, rather than non-asthmatic smokers, asthmatic non-smokers, and asthmatic smokers, exhibited better pulmonary function (median FEV(1): 79% of predicted FEV(1) vs. 73%, 69%, and 66%, respectively, p = 0.005) and less dyspnea on exertion (1% vs. 12%, 12%, and 28%, respectively, p = 0.001). Pulmonary emphysema on thoracic computed tomography was less common in non-smokers (p < 0.001). Using the lower limit of the normal to define airflow obstruction yielded similar results. CONCLUSIONS: There are a substantial number of non-smokers with airflow obstruction compatible with COPD in Japan. In this study, airflow obstruction in non-smokers was more common in women and likelier to result in mild functional and pathological abnormalities than in smokers. Further studies are warranted to investigate the long-term prognosis and appropriate management of this population in developed countries, especially in women.

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