Association between reduced mid-expiratory flow and early airway impairment in smokers with preserved spirometry: a cross-sectional analysis

Abdurrahman Koç; Abdullah Enes Ataş; Hasan Eryeşil

Association between reduced mid-expiratory flow and early airway impairment in smokers with preserved spirometry: a cross-sectional analysis

Abstract

Aims: To determine whether active smokers with preserved post-bronchodilator spirometry (FEV₁/FVC ≥ lower limit of normal [LLN]) and normal thoracic computed tomography (CT) show lower FEF₂₅₋₇₅ values and a higher prevalence of isolated small airway dysfunction than never-smokers, and to assess PEF-FEV₁ agreement for Global Initiative for Chronic Obstructive Lung Disease (GOLD) severity staging. Methods: We analysed spirometry data from 286 consecutive adults (≥40 years) at a single pulmonary function laboratory. Two chest radiologists independently reviewed all thoracic CT scans (ICC=0.95). Logistic regression included FVC z-score as a prespecified covariate to account for the volume-dependence of FEF₂₅-₇₅; model stability was confirmed by penalised regression and bootstrap validation. Results: Among 244 participants with preserved FEV₁/FVC (136 smokers, 108 never-smokers), FEF₂₅₋₇₅ was lower in smokers (76.2±26.1% vs 93.5±21.9%; p<0.001; rank-biserial r=0.40). Isolated Spirometric small airway dysfunction (sSAD) prevalence was 28.7% versus 4.6% (OR 8.28; p<0.001). After FVC z-score adjustment, smoking remained the strongest predictor (aOR 13.15; 95% CI 4.07-42.42; optimism-corrected AUC=0.848). Female smokers showed greater impairment than males despite equivalent pack-year exposure (66.3% vs 80.9%; p<0.001), and combined biomass-plus-smoking exposure carried the highest sSAD prevalence (58.1%). PEF showed poor agreement with FEV₁ for GOLD staging (unweighted κ=0.095; mean bias -20.0%). Conclusion: Active smoking is independently associated with spirometric small airway dysfunction before FEV₁/FVC falls below the LLN, with women and biomass co-exposed individuals at greatest risk. PEF cannot replace FEV₁ for GOLD severity classification in this population.

Keywords

Supporting Institution

The authors declared that this study has received no financial support.

Ethical Statement

The study was conducted with the permission of the KTO Karatay University Non-Drug and Medical Device Research Ethics Committee (Date: 27/11/2025, Decision No: 2025/014).

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Details

Primary Language

English

Subjects

Chest Diseases

Journal Section

Research Article

Authors

Abdurrahman Koç ^*
0000-0002-4462-0944
Türkiye

Abdullah Enes Ataş
0000-0001-6623-3024
Türkiye

Hasan Eryeşil
0000-0002-9353-4647
Türkiye

Publication Date

May 22, 2026

Submission Date

April 6, 2026

Acceptance Date

May 18, 2026

Published in Issue

Year 2026 Volume: 8 Number: 3

IZ

https://izlik.org/JA75XB66WW

Cite

RIS / Bibtex

APA

Koç, A., Ataş, A. E., & Eryeşil, H. (2026). Association between reduced mid-expiratory flow and early airway impairment in smokers with preserved spirometry: a cross-sectional analysis. Anatolian Current Medical Journal, 8(3), 560-568. https://izlik.org/JA75XB66WW

AMA

1.Koç A, Ataş AE, Eryeşil H. Association between reduced mid-expiratory flow and early airway impairment in smokers with preserved spirometry: a cross-sectional analysis. Anatolian Curr Med J / ACMJ / acmj. 2026;8(3):560-568. https://izlik.org/JA75XB66WW

Chicago

Koç, Abdurrahman, Abdullah Enes Ataş, and Hasan Eryeşil. 2026. “Association Between Reduced Mid-Expiratory Flow and Early Airway Impairment in Smokers With Preserved Spirometry: A Cross-Sectional Analysis”. Anatolian Current Medical Journal 8 (3): 560-68. https://izlik.org/JA75XB66WW.

EndNote

Koç A, Ataş AE, Eryeşil H (May 1, 2026) Association between reduced mid-expiratory flow and early airway impairment in smokers with preserved spirometry: a cross-sectional analysis. Anatolian Current Medical Journal 8 3 560–568.

IEEE

[1]A. Koç, A. E. Ataş, and H. Eryeşil, “Association between reduced mid-expiratory flow and early airway impairment in smokers with preserved spirometry: a cross-sectional analysis”, Anatolian Curr Med J / ACMJ / acmj, vol. 8, no. 3, pp. 560–568, May 2026, [Online]. Available: https://izlik.org/JA75XB66WW

ISNAD

Koç, Abdurrahman - Ataş, Abdullah Enes - Eryeşil, Hasan. “Association Between Reduced Mid-Expiratory Flow and Early Airway Impairment in Smokers With Preserved Spirometry: A Cross-Sectional Analysis”. Anatolian Current Medical Journal 8/3 (May 1, 2026): 560-568. https://izlik.org/JA75XB66WW.

JAMA

1.Koç A, Ataş AE, Eryeşil H. Association between reduced mid-expiratory flow and early airway impairment in smokers with preserved spirometry: a cross-sectional analysis. Anatolian Curr Med J / ACMJ / acmj. 2026;8:560–568.

MLA

Koç, Abdurrahman, et al. “Association Between Reduced Mid-Expiratory Flow and Early Airway Impairment in Smokers With Preserved Spirometry: A Cross-Sectional Analysis”. Anatolian Current Medical Journal, vol. 8, no. 3, May 2026, pp. 560-8, https://izlik.org/JA75XB66WW.

Vancouver

1.Abdurrahman Koç, Abdullah Enes Ataş, Hasan Eryeşil. Association between reduced mid-expiratory flow and early airway impairment in smokers with preserved spirometry: a cross-sectional analysis. Anatolian Curr Med J / ACMJ / acmj [Internet]. 2026 May 1;8(3):560-8. Available from: https://izlik.org/JA75XB66WW