{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T12:49:26Z","timestamp":1791809366248,"version":"4.3.4"},"reference-count":25,"publisher":"PAGEPress Publications","license":[{"start":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T00:00:00Z","timestamp":1791763200000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Monaldi Arch Chest Dis"],"abstract":"<jats:p>Chronic obstructive pulmonary disease (COPD) is heterogeneous, yet severity is conventionally graded by spirometry [forced expiratory volume in 1 second (FEV1)] on the assumption that airflow limitation reflects parenchymal damage. Biomass-related non-smoking COPD (NS-COPD) is common in low- and middle-income countries. In this hospital-based cross-sectional study, we compared the physiological phenotypes of smoking COPD (S-COPD) and biomass-related NS-COPD and tested the concordance between Global Initiative for Chronic Obstructive Lung Disease (GOLD) spirometric severity and diffusion-based gas-exchange impairment. A total of 91 stable COPD patients (S-COPD, n=54; NS-COPD, n=37) underwent post-bronchodilator spirometry, single-breath diffusing capacity of the lung for carbon monoxide (DLCO) with transfer coefficient (KCO), residual volume to total lung capacity ratio, and the 6-minute walk test; cohorts were stratified by exposure (&gt;10 pack-years vs. &gt;60 hour-years of biomass) and compared using the Student t-test and Fisher's exact test. Compared with smokers, non-smokers had higher DLCO (71.4\u00b112.4 vs. 57.7\u00b117.5% predicted; p&lt;0.001) and KCO (0.95\u00b10.19 vs. 0.71\u00b10.22 mmol\/min\/kPa\/L; p&lt;0.001). All non-smokers with severe (GOLD 3) airflow limitation (8\/8, 100%) retained normal or only mildly impaired diffusion [7\/8 (87.5%) strictly normal], whereas 14\/28 (50.0%) GOLD 3 smokers had impaired gas exchange [4\/28 (14.3%) severe]. Non-smokers more often retained a normal DLCO [31\/37 (83.8%) vs. 26\/54 (48.1%); odds ratio 5.6, 95% confidence interval 2.0-15.5; p&lt;0.001]. This difference persisted after multivariable adjustment for age, sex and body mass index (odds ratio 30.0, 95% confidence interval 2.5-358.5; p=0.007) and after further adjustment for FEV1 percent predicted (odds ratio 21.1, 95% confidence interval 1.6-282.7; p=0.021), indicating that the dissociation was not explained by these covariates or by the degree of airflow limitation itself. GOLD staging tended to overestimate parenchymal severity in biomass-related NS-COPD, in which airflow obstruction was largely uncoupled from gas-exchange loss, whereas in smokers the two were more tightly coupled. These cross-sectional, single-center findings, limited by a sex imbalance and the absence of imaging confirmation, support routine DLCO\/KCO measurement to phenotype these patients and, where imaging is scarce, as a low-cost structural surrogate.<\/jats:p>","DOI":"10.4081\/monaldi.2026.4174","type":"journal-article","created":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T12:29:03Z","timestamp":1791808143000},"source":"Crossref","is-referenced-by-count":0,"title":["The diagnostic blind spot of spirometric staging in biomass-related non-smoking chronic obstructive pulmonary disease: a cross-sectional study of spirometry-diffusion discordance in a rural South Indian population"],"prefix":"10.4081","author":[{"given":"Chittin","family":"N. Swamy","sequence":"first","affiliation":[{"name":"Department of Respiratory Medicine, Adichunchanagiri Institute of Medical Sciences (a constituent college of Adichunchanagiri University), B.G. Nagara (Balagangadharanatha Nagara), Nagamangala Taluk, Mandya District, Karnataka"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sandeepa","family":"H. S.","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine, Adichunchanagiri Institute of Medical Sciences (a constituent college of Adichunchanagiri University), B.G. Nagara (Balagangadharanatha Nagara), Nagamangala Taluk, Mandya District, Karnataka"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Deepu","family":"C. C.","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine, Adichunchanagiri Institute of Medical Sciences (a constituent college of Adichunchanagiri University), B.G. Nagara (Balagangadharanatha Nagara), Nagamangala Taluk, Mandya District, Karnataka"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chirag","family":"K. C.","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine, Adichunchanagiri Institute of Medical Sciences (a constituent college of Adichunchanagiri University), B.G. Nagara (Balagangadharanatha Nagara), Nagamangala Taluk, Mandya District, Karnataka"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nandakishore","family":"Bommeri","sequence":"additional","affiliation":[{"name":"Department of Respiratory Medicine, Adichunchanagiri Institute of Medical Sciences (a constituent college of Adichunchanagiri University), B.G. Nagara (Balagangadharanatha Nagara), Nagamangala Taluk, Mandya District, Karnataka"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"2549","published-online":{"date-parts":[[2026,10,12]]},"reference":[{"key":"88575","unstructured":"Global Initiative for Chronic Obstructive Lung Disease. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease (2024 report). 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Global strategy for the diagnosis, management, and prevention of chronic obstructive lung disease 2017 report: GOLD executive summary. Am J Respir Crit Care Med 2017;195:557-82.","DOI":"10.1164\/rccm.201701-0218PP"},{"key":"88580","doi-asserted-by":"crossref","unstructured":"Jones PW. Health status measurement in chronic obstructive pulmonary disease. Thorax 2001;56:880-7.","DOI":"10.1136\/thorax.56.11.880"},{"key":"88581","doi-asserted-by":"crossref","unstructured":"Topalovic M, Exadaktylos V, Peeters A, et al. Computer quantification of airway collapse on forced expiration to predict the presence of emphysema. Respir Res 2013;14:131.","DOI":"10.1186\/1465-9921-14-131"},{"key":"88582","doi-asserted-by":"crossref","unstructured":"Sheikh K, Coxson HO, Parraga G. This is what COPD looks like. Respirology 2016;21:224-36.","DOI":"10.1111\/resp.12611"},{"key":"88583","doi-asserted-by":"crossref","unstructured":"Dal Negro RW, Turco P, Povero M. 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ERS\/ATS technical standard on interpretive strategies for routine lung function tests. Eur Respir J 2022;60:2101499.","DOI":"10.1183\/13993003.01499-2021"},{"key":"88591","doi-asserted-by":"crossref","unstructured":"Golpe R, Sanju\u00e1n L\u00f3pez P, Cano Jim\u00e9nez E, et al. Distribution of clinical phenotypes in patients with chronic obstructive pulmonary disease caused by biomass and tobacco smoke. Arch Bronconeumol 2014;50:318-24.","DOI":"10.1016\/j.arbr.2014.06.003"},{"key":"88592","doi-asserted-by":"crossref","unstructured":"Olloquequi J, Jaime S, Parra V, et al. Comparative analysis of COPD associated with tobacco smoking, biomass smoke exposure or both. Respir Res 2018;19:13.","DOI":"10.1186\/s12931-018-0718-y"},{"key":"88593","doi-asserted-by":"crossref","unstructured":"Lamprecht B, McBurnie MA, Vollmer WM, et al. COPD in never smokers: results from the population-based burden of obstructive lung disease study. 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The burden of chronic respiratory diseases and their heterogeneity across the states of India: the Global Burden of Disease Study 1990-2016. Lancet Glob Health 2018;6:e1363-74."},{"key":"88598","doi-asserted-by":"crossref","unstructured":"Mannino DM, Buist AS. Global burden of COPD: risk factors, prevalence, and future trends. Lancet 2007;370:765-73.","DOI":"10.1016\/S0140-6736(07)61380-4"},{"key":"88599","unstructured":"Rivera RM, Cosio MG, Ghezzo H, et al. Comparison of lung morphology in COPD secondary to cigarette and biomass smoke. Int J Tuberc Lung Dis 2008;12:972-7."}],"container-title":["Monaldi Archives for Chest Disease"],"original-title":[],"link":[{"URL":"https:\/\/www.monaldi-archives.org\/macd\/article\/download\/4174\/2292","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.monaldi-archives.org\/macd\/article\/download\/4174\/2292","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T12:29:17Z","timestamp":1791808157000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.monaldi-archives.org\/macd\/article\/view\/4174"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,10,12]]},"references-count":25,"URL":"https:\/\/doi.org\/10.4081\/monaldi.2026.4174","relation":{},"ISSN":["2532-5264","1122-0643"],"issn-type":[{"value":"2532-5264","type":"electronic"},{"value":"1122-0643","type":"print"}],"subject":[],"published":{"date-parts":[[2026,10,12]]}}}