Background: The association between low household income and COPD in young population remains unclear. We aimed to evaluate the association between low household income and COPD development in young population using a nationwide cohort.

Methods: We screened individuals aged 20?39 who underwent the national health examination between 2009 and 2012 using the Korean National Health Information Database, searched until December 2019. We identified 5,965,366 eligible individuals, and 13,296 had newly developed COPD based. We categorized them into quartiles and ?Medical aid? (the lowest 3% income group) and assessed the income status annually in the preceding 4 years. We used multivariate Cox proportional hazard models to estimate the adjusted hazard ratio (aHR) of risk factors for COPD.

Results: In the Medical aid group, the incidence rate for developing COPD was 0.56/1,000 person-year with aHR of 2.44 (95% confidence interval [CI] 1.91?3.12) compared with the highest income quartile group. This association was prominent in consecutive recipients of Medical aid (aHR 2.37, 95% CI 1.80?3.11) compared with those who had never been Medical aid beneficiaries. Those who experienced household income declines between the previous (preceding 4 years) and baseline time points had an increased risk of developing COPD, regardless of previous income status.

Conclusions: Low household income was associated with an increased risk of developing in the young population. The risks were augmented by sustained periods and declining income status. 

Funds: National Research Foundation of Korea (2023R1A2C2006688, RS-2023-00222687), Bio & Medical Techonology Development Program (2022M3A9G8017220)