{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,16]],"date-time":"2026-03-16T09:59:52Z","timestamp":1773655192995,"version":"3.50.1"},"reference-count":38,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2026,3,4]],"date-time":"2026-03-04T00:00:00Z","timestamp":1772582400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100011576","name":"Scientific Research Projects (BAP) Unit of Inonu University","doi-asserted-by":"publisher","award":["TSA-2025-4177"],"award-info":[{"award-number":["TSA-2025-4177"]}],"id":[{"id":"10.13039\/501100011576","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background: Smoking adversely affects pulmonary function and systemic health; however, its impact on diaphragm muscle morphology and its relationship with functional capacity and psychosocial outcomes in individuals without clinically diagnosed respiratory disease remain unclear. This study aimed to evaluate diaphragm muscle thickness in smokers and to investigate its associations with pulmonary function, functional capacity, sleep quality, and depression. Methods: This cross-sectional observational study included 20 smokers and 20 age-matched never-smokers. Pulmonary function was assessed using spirometry. Functional capacity was evaluated with the 6-Minute Walk Test (6 MWT) and the 30 s sit-to-stand test (30 s STST). Sleep quality and depression were assessed using the Pittsburgh Sleep Quality Index (PSQI) and the Beck Depression Inventory (BDI). Inspiratory and expiratory diaphragm muscle thicknesses were measured by ultrasonography. Between-group comparisons and correlation analyses were performed. Results: Smokers exhibited significant impairments in all assessed parameters except expiratory diaphragm thickness compared with controls (p &lt; 0.05). Large to very large effect sizes were observed for FEV1, FEF25\u201375%, functional capacity, and inspiratory diaphragm thickness. Inspiratory diaphragm thickness showed moderate to strong positive correlations with pulmonary function parameters and a very strong positive correlation with functional capacity, while strong negative correlations were observed with sleep quality and depression (p &lt; 0.05). Smoking duration was strongly associated with poorer functional and psychosocial outcomes. Conclusions: Smoking is associated with early and multidimensional impairments in diaphragm muscle morphology, pulmonary function, functional capacity, and psychosocial status, even in individuals without overt respiratory disease. Reduced inspiratory diaphragm thickness may represent an early and clinically meaningful marker of smoking-related respiratory muscle dysfunction.<\/jats:p>","DOI":"10.3390\/jcm15051950","type":"journal-article","created":{"date-parts":[[2026,3,4]],"date-time":"2026-03-04T13:11:36Z","timestamp":1772629896000},"page":"1950","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Ultrasonographic Assessment of the Diaphragm and the Effects of Smoking on Respiratory Function in Individuals Attending a Smoking Cessation Center"],"prefix":"10.3390","volume":"15","author":[{"given":"Ahmet","family":"Utus","sequence":"first","affiliation":[{"name":"Department of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Inonu University, 44280 Malatya, Turkey"},{"name":"Department of Cardiopulmonary Physiotherapy and Rehabilitation, Institute of Health Sciences, Bezmialem Vakif University, 34093 Istanbul, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7788-9739","authenticated-orcid":false,"given":"Semiramis","family":"Ozyilmaz","sequence":"additional","affiliation":[{"name":"Department of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Bezmialem Vakif University, 34093 Istanbul, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Turgay","family":"Karatas","sequence":"additional","affiliation":[{"name":"Department of Anatomy, Faculty of Medicine, Inonu University, 44000 Malatya, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9342-0244","authenticated-orcid":false,"given":"Nurullah","family":"Dag","sequence":"additional","affiliation":[{"name":"Department of Radiology, Faculty of Medicine, Inonu University, 44069 Malatya, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gurkan","family":"Ural","sequence":"additional","affiliation":[{"name":"Department of Radiology, Faculty of Medicine, Inonu University, 44069 Malatya, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3805-9214","authenticated-orcid":false,"given":"Ipek","family":"Balikci Cicek","sequence":"additional","affiliation":[{"name":"Biostatistics Department, Faculty of Medicine, Inonu University, 44000 Malatya, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7500-8478","authenticated-orcid":false,"given":"Murat","family":"K\u0131l\u0131c","sequence":"additional","affiliation":[{"name":"Department of Thoracic Surgery, Faculty of Medicine, Inonu University, 44000 Malatya, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,4]]},"reference":[{"key":"ref_1","unstructured":"World Health Organization (2020). WHO Global Report on Trends in Prevalence of Tobacco Use 2000\u20132025, World Health Organization."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"394","DOI":"10.1016\/j.chest.2017.11.023","article-title":"Current concepts in pathogenesis, diagnosis, and management of smoking-related interstitial lung diseases","volume":"154","author":"Kumar","year":"2018","journal-title":"Chest"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Strzelak, A., Ratajczak, A., Adamiec, A., and Feleszko, W. (2018). Tobacco smoke induces and alters immune responses in the lung triggering inflammation, allergy, asthma and other lung diseases: A mechanistic review. Int. J. Environ. Res. Public Health, 15.","DOI":"10.3390\/ijerph15051033"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Caramori, G., Casolari, P., Barczyk, A., Durham, A.L., Di Stefano, A., and Adcock, I. (2016). COPD immunopathology. Seminars in Immunopathology, Springer.","DOI":"10.1007\/s00281-016-0561-5"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Kawasaki, T., Ikegawa, M., and Kawai, T. (2022). Antigen presentation in the lung. Front. Immunol., 13.","DOI":"10.3389\/fimmu.2022.860915"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"268","DOI":"10.18632\/oncotarget.13613","article-title":"Impacts of cigarette smoking on immune responsiveness: Up and down or upside down?","volume":"8","author":"Qiu","year":"2016","journal-title":"Oncotarget"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"19480","DOI":"10.1038\/s41598-020-76556-7","article-title":"The effect of smoking on chronic inflammation, immune function and blood cell composition","volume":"10","author":"Elisia","year":"2020","journal-title":"Sci. Rep."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"648","DOI":"10.33594\/000000163","article-title":"Cigarette smoking impairs the diaphragm muscle structure of patients without respiratory pathologies: An autopsy study","volume":"53","author":"Nucci","year":"2019","journal-title":"Cell. Physiol. Biochem."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"392","DOI":"10.1111\/bcpt.13781","article-title":"Changes in diaphragm contractility in cigarette smoking-exposed and smoking cessation rats are associated with alterations in mitochondrial morphology and homeostasis","volume":"131","author":"Zhang","year":"2022","journal-title":"Basic Clin. Pharmacol. Toxicol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"e70003","DOI":"10.1111\/cpf.70003","article-title":"Diaphragm thickness and physical performance in regular smokers and non-smokers: A pilot study","volume":"45","author":"Can","year":"2025","journal-title":"Clin. Physiol. Funct. Imaging"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"e32560","DOI":"10.1097\/MD.0000000000032560","article-title":"Ultrasonographic evaluation of diaphragm function in patients with chronic obstructive pulmonary disease: A systematic review and meta-analysis","volume":"101","author":"Liang","year":"2022","journal-title":"Medicine"},{"key":"ref_12","first-page":"13","article-title":"Spirometry in primary care","volume":"20","author":"Coates","year":"2013","journal-title":"Can. Respir. J."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1183\/09041950.005s1693","article-title":"Lung volumes and forced ventilatory flows","volume":"6","author":"Quanjer","year":"1993","journal-title":"Eur. Respir. J."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1186\/s40248-018-0158-z","article-title":"Utility of the six-minute walk test in patients with idiopathic pulmonary fibrosis","volume":"13","author":"Lancaster","year":"2018","journal-title":"Multidiscip. Respir. Med."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"907","DOI":"10.26603\/001c.36432","article-title":"Normative reference values and validity for the 30-second chair-stand test in healthy young adults","volume":"17","author":"Lein","year":"2022","journal-title":"Int. J. Sports Phys. Ther."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1097\/TGR.0b013e31823415fa","article-title":"Measurement of sit-to-stand among older adults","volume":"28","author":"Bohannon","year":"2012","journal-title":"Top. Geriatr. Rehabil."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1016\/0165-1781(89)90047-4","article-title":"The Pittsburgh Sleep Quality Index: A new instrument for psychiatric practice and research","volume":"28","author":"Buysse","year":"1989","journal-title":"Psychiatry Res."},{"key":"ref_18","first-page":"107","article-title":"Pittsburgh uyku kalitesi indeksinin gecerligi ve guvenirligi","volume":"7","author":"Kara","year":"1996","journal-title":"T\u00fcrk Psikiyatr. Derg."},{"key":"ref_19","first-page":"3","article-title":"Beck depresyon envanterinin universite ogrencileri icin gecerliligi, guvenilirligi. (A reliability and validity study of Beck Depression Inventory in a university student sample)","volume":"7","author":"Hisli","year":"1989","journal-title":"J. Psychol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1016\/0272-7358(88)90050-5","article-title":"Psychometric properties of the Beck Depression Inventory: Twenty-five years of evaluation","volume":"8","author":"Beck","year":"1988","journal-title":"Clin. Psychol. Rev."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Siniscalchi, C., Nouvenne, A., Cerundolo, N., Meschi, T., Ticinesi, A., and on behalf of the Parma Post-Graduate Specialization School in Emergency-Urgency Medicine Interest Group on Thoracic Ultrasound (2024). Diaphragm ultrasound in different clinical scenarios: A review with a focus on older patients. Geriatrics, 9.","DOI":"10.3390\/geriatrics9030070"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1002\/mus.23671","article-title":"Neuromuscular ultrasound for evaluation of the diaphragm","volume":"47","author":"Sarwal","year":"2013","journal-title":"Muscle Nerve"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Li, L., Gong, Y., Hou, D., Song, Y., Bi, J., Li, M., Han, J., Song, Y., and She, J. (2024). Contribution of small airway inflammation to the development of COPD. BMC Pulm. Med., 24.","DOI":"10.1186\/s12890-024-02911-3"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"169","DOI":"10.1186\/s12931-025-03244-3","article-title":"Lung function decline and incidence of chronic obstructive pulmonary disease in participants with spirometry-defined small airway dysfunction: A 15-year prospective cohort study in China","volume":"26","author":"Zhou","year":"2025","journal-title":"Respir. Res."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Zhou, R., Wang, H., Zhang, Y., Mai, J., and Yang, L. (2025). Small airway disease as a key factor in COPD: New perspectives and insights. Front. Med., 12.","DOI":"10.3389\/fmed.2025.1648612"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"e70","DOI":"10.1164\/rccm.201908-1590ST","article-title":"Standardization of spirometry 2019 update. An official American thoracic society and European respiratory society technical statement","volume":"200","author":"Graham","year":"2019","journal-title":"Am. J. Respir. Crit. Care Med."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1900753","DOI":"10.1183\/13993003.00753-2019","article-title":"Technical standards for respiratory oscillometry","volume":"55","author":"King","year":"2020","journal-title":"Eur. Respir. J."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"114","DOI":"10.1016\/j.chest.2021.03.047","article-title":"Seven pillars of small airways disease in asthma and COPD: Supporting opportunities for novel therapies","volume":"160","author":"Usmani","year":"2021","journal-title":"Chest"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"920","DOI":"10.4187\/respcare.03999","article-title":"Standardization of sonographic diaphragm thickness evaluations in healthy volunteers","volume":"61","author":"Monteros","year":"2016","journal-title":"Respir. Care"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"369","DOI":"10.1159\/000506016","article-title":"Evaluation of respiratory muscle strength and diaphragm ultrasound: Normative values, theoretical considerations, and practical recommendations","volume":"99","author":"Spiesshoefer","year":"2020","journal-title":"Respiration"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1286","DOI":"10.1016\/j.sleep.2012.06.026","article-title":"How smoking affects sleep: A polysomnographical analysis","volume":"13","author":"Jaehne","year":"2012","journal-title":"Sleep Med."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1093\/ntr\/ntw140","article-title":"The association of cigarette smoking with depression and anxiety: A systematic review","volume":"19","author":"Fluharty","year":"2016","journal-title":"Nicotine Tob. Res."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Aldabayan, Y.S. (2023). Mental health and sleep quality among patients with asthma and COPD. Front. Med., 10.","DOI":"10.3389\/fmed.2023.1181742"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1785","DOI":"10.4314\/ahs.v20i4.32","article-title":"The relationship between sleep quality and dyspnoea severity in patients with COPD","volume":"20","author":"Serin","year":"2020","journal-title":"Afr. Health Sci."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"565","DOI":"10.1007\/s11571-017-9449-x","article-title":"The effects of depression, anxiety and sleep disturbances on cognitive impairment in patients with chronic obstructive pulmonary disease","volume":"11","author":"Aras","year":"2017","journal-title":"Cogn. Neurodynamics"},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Dikmen Ho\u015fba\u015f, B., Mustafao\u011flu, R., \u015ei\u015fman \u00dcnl\u00fc, C., and Noyan, C.O. (2024). Dyspnea, respiratory muscle strength, cough capacity, and sleep quality in individuals with substance use disorder. J. Ethn. Subst. Abus., 1\u201317.","DOI":"10.1080\/15332640.2024.2417235"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"884","DOI":"10.1002\/mus.23702","article-title":"Two-dimensional ultrasound imaging of the diaphragm: Quantitative values in normal subjects","volume":"47","author":"Boon","year":"2013","journal-title":"Muscle Nerve"},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Shinohara, T., Yamada, T., Ouchi, S., Mabuchi, S., Hanazawa, R., Nakagawa, K., Yoshimi, K., Mayama, T., Horike, A., and Toyoshima, K. (2025). Relationship Between Diaphragm Function and Sarcopenia Assessed by Ultrasound: A Cross-Sectional Study. Diagnostics, 15.","DOI":"10.3390\/diagnostics15010090"}],"container-title":["Journal of Clinical Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/5\/1950\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,3,16]],"date-time":"2026-03-16T09:04:46Z","timestamp":1773651886000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/5\/1950"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,3,4]]},"references-count":38,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2026,3]]}},"alternative-id":["jcm15051950"],"URL":"https:\/\/doi.org\/10.3390\/jcm15051950","relation":{},"ISSN":["2077-0383"],"issn-type":[{"value":"2077-0383","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,3,4]]}}}