Neighborhood deprivation and lung cancer incidence and mortality in patients with asthma: a nationwide cohort study in Sweden, 1997-2018.

OBJECTIVE: This population-based study aimed to investigate the association between neighborhood deprivation and the incidence and mortality of lung cancer in patients with asthma. METHODS: This nationwide cohort study included 596,215 individuals aged ≥ 25 years with asthma who were followed from 1997 to 2018 in Sweden. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for lung cancer incidence and mortality associated with neighborhood deprivation. All models were stratified by sex and adjusted for individual-level characteristics, including age, education level, sociodemographic factors, and comorbidities. RESULTS: Neighborhood deprivation was independently associated with both lung cancer incidence and mortality in patients with asthma, even after adjustment for individual-level characteristics. In fully adjusted models, compared with individuals living in low-deprivation neighborhoods, those in high-deprivation neighborhoods had a significantly elevated risk of lung cancer incidence (HR = 1.37) and mortality (HR = 1.40), with more pronounced associations observed in women. Histological subtype analyses revealed differential patterns: high deprivation was associated with increased risks of adenocarcinoma (HR = 1.19) and large cell carcinoma (HR = 1.58), whereas squamous cell carcinoma (HR = 1.75) and small cell carcinoma (HR = 1.65) showed increased risks in both moderate- and high-deprivation neighborhoods. CONCLUSION: Neighborhood deprivation may be a critical social determinant of lung cancer incidence and mortality among patients with asthma, with effects varying by age, sex, and histological subtype. Targeted interventions in deprived communities could consider prioritizing high-risk groups, individuals with low educational attainment, and those with comorbid chronic obstructive pulmonary disease.