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Associations Between Prior Lung Diseases and Risk of Lung Cancer in Populations With No Smoking History: A Systematic
Nishwant Swami1, Ji Hyun Hong2, Sooyeon Kho3
1Department of Internal Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA.
Background:
Individuals who do not smoke account for a growing proportion of lung cancer (LC) incidence, but the impact of prior lung diseases on lung cancer risk in this population remains unclear.
Research Question:
What is the association of TB, asthma, and chronic bronchitis (CB) with lung cancer risk among individuals who do not smoke?
Study Design And Methods:
PubMed and Embase were searched from inception through July 15, 2025, for studies examining the association between TB, asthma, or CB with lung cancer risk in populations older than 18 years who never smoked. Summary effect estimates with 95% CIs were calculated for case-control (OR) and cohort (hazard ratio [HR]) studies using random effects models with inverse variance weighting. Subgroup meta-analyses and metaregressions were conducted by continent. Study quality was reviewed using the Newcastle-Ottawa scale; bias was evaluated using funnel plots and methods by Egger et al. RESULTS: Among 20 case-control studies, TB (16 studies) and CB (9 studies) were associated significantly with increased lung cancer risk (TB: OR, 1.76 [95% CI, 1.47-2.11; I2 = 20]; CB: OR, 1.36 [95% CI, 1.07-1.72; I2 = 0]); asthma (11 studies) was associated with increased lung cancer risk, but was not statistically significant (OR, 1.34 [95% CI, 0.94-1.91; I2 = 46]). Among 5 cohort studies, TB (4 studies) was associated with increased lung cancer risk, but was not statistically significant (HR, 1.64 [95% CI, 0.98-2.72; I2 = 75]). Based on meta-regression, study continent (Asian studies vs non-Asian studies) did not explain between-study variance.
Interpretation:
History of TB and CB were associated with increased lung cancer risk among populations with no smoking history. Future studies examining these associations should analyze more diverse populations and disaggregate findings by sex, race and ethnicity, and socioeconomic status.
Clinical Trial Registration:
International Prospective Register of Systematic Reviews; No.: CRD42022323851; URL: https://www.crd.york.ac.uk/prospero/.
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