Post‑tuberculosis lung disease remains a significant cause of chronic respiratory morbidity despite microbiological cure. The presence of cigarette smoking may further impair lung mechanics and reduce functional capacity in survivors of pulmonary tuberculosis. The authors aimed to evaluate and compare pulmonary function and exercise capacity between smokers and nonsmokers with post‑TB sequelae to clarify the additive impact of tobacco exposure.
This was a hospital‑based cross‑sectional study conducted in the Department of Pulmonary Medicine at a tertiary care hospital in Chengalpattu District, Tamil Nadu, India. The enrollment period extended from June 2024 to November 2025. A total of 110 patients with documented post‑tuberculosis pulmonary sequelae were included, divided equally into 55 smokers and 55 nonsmokers. Ethical approval was obtained from the Institutional Human Ethics Committee (IEC No. 994/24; dated April 22, 2024), and written informed consent was secured from all participants.
Pulmonary function testing was performed using spirometry and included forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), the FEV1/FVC ratio, and peak expiratory flow rate (PEFR). Functional capacity was assessed with the 6‑min walk test (6MWT). Symptom burden during exertion was quantified using the Modified Borg Dyspnea Scale. These objective and subjective measures were selected to provide complementary information on ventilatory mechanics and exercise tolerance in the post‑TB population.
Collected data were analyzed with SPSS version 29. Statistical significance was defined as P < 0.05. Group comparisons between smokers and nonsmokers included demographic variables, nutritional status, spirometry parameters, pattern of ventilatory defects, 6‑min walk distance, and Borg dyspnea scores.
Most participants across both groups were aged between 40 and 60 years; there was no statistically significant age difference between smokers and nonsmokers (P = 0.593). Gender distribution differed markedly: smokers were predominantly male (87.3%), a difference that reached statistical significance (P < 0.001). Nutritional status also varied by smoking status: underweight prevalence was higher among smokers (23.6%) compared with nonsmokers (9.1%) (P = 0.019).
Smokers with post‑TB sequelae demonstrated worse spirometric indices compared with nonsmokers. Specifically, smokers had significantly lower absolute FEV1 (P = 0.027) and lower FEV1% predicted (P = 0.001). The FEV1/FVC ratio, reflecting airflow limitation, was reduced in smokers (P = 0.009). Peak expiratory flow rate (PEFR) was also significantly lower in the smoking group (P < 0.001). When ventilatory patterns were categorized, obstructive ventilatory defects occurred more frequently among smokers (43.6%) than among nonsmokers (23.6%) (P = 0.028).
Functional exercise capacity measured by the 6‑min walk test was significantly lower in smokers: mean distance for smokers was 398.2 ± 63.0 meters versus 441.6 ± 58.5 meters in nonsmokers (P < 0.001). Subjective dyspnea measured by the Modified Borg Scale was higher in smokers, with the difference reaching statistical significance (P < 0.001). These results indicate a clinically meaningful reduction in exercise tolerance and increased perceived breathlessness associated with smoking in the post‑TB population.
The study findings indicate that among patients with post‑tuberculosis sequelae, smoking is associated with significantly worse pulmonary mechanics, a higher prevalence of obstructive ventilatory defects, reduced exercise capacity, and greater exertional dyspnea. These data support the concept that tobacco exposure acts as an additive risk factor that exacerbates long‑term respiratory impairment after TB.
From a clinical perspective, the results underscore the need to integrate targeted interventions into post‑TB care pathways. Specifically, the authors emphasize the importance of smoking cessation strategies and structured pulmonary rehabilitation for survivors of pulmonary TB to address persistent airflow limitation, improve exercise tolerance, and reduce symptom burden.
The source reports that this was a cross‑sectional, hospital‑based study and provides the study period, sample size (110 patients), and ethical approval details (IEC No. 994/24). The report does not provide additional information on potential confounders such as duration and intensity of smoking, prior TB disease severity, radiological extent of sequelae, comorbidities, or longitudinal follow‑up. Those details were not reported in the abstracted source.
In this cohort of 110 post‑TB patients, smokers had significantly poorer spirometry results, a higher rate of obstructive ventilatory defects, shorter 6‑min walk distances, and greater dyspnea compared with nonsmokers. The authors conclude that smoking significantly worsens pulmonary function and exercise capacity in patients with post‑tuberculosis lung disease. They recommend integrating smoking cessation services and pulmonary rehabilitation into routine post‑TB management to mitigate long‑term respiratory impairment.
(Study citation: L Shreya et al., Annals of African Medicine; PMID 42559984; DOI 10.4103/aam.aam_481_26.)