Spirometry-defined obstructive airflow limitation and risk of incident dementia: A nationwide cohort study in South Korea
Dongjin Yeo, Soeun Kim, Kyeongmin Lee, Yejun Son, Hayeon Lee, Sunyoung Kim, Hyeon Seok Hwang, Dong Keon YonBackground
Whether spirometry-defined airflow limitation is independently associated with incident dementia and related disability burden remains unclear.
Objective
To investigate the association between obstructive airflow limitation and incident dementia and to estimate dementia-related years lived with disability (YLDs) in a nationwide cohort.
Methods
We conducted a nationwide population-based cohort study linking the Korea National Health and Nutrition Examination Survey (2014–2021) with national health insurance claims data. Adults aged ≥40 years with baseline spirometry and no prior dementia were included. Airflow limitation was defined as FEV1/FVC <0.70, with severity classified by percent-predicted FEV1. Inverse probability of treatment weighting balanced baseline covariates. Cox models estimated adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for incident dementia. Dementia-related YLDs were calculated using Global Burden of Disease Study weights.
Results
During follow-up (2014–2023), 760 cases (4.79%) of dementia occurred among 15,854 adults. Normal pulmonary function was associated with lower dementia risk than airflow limitation (aHR, 0.62 [95% CI, 0.50–0.77]). Within the normal range, risk decreased across increasing FEV1/FVC tertiles (T1 [lowest], 0.76 [0.60–0.96]; T2, 0.63 [0.49–0.81]; T3 [highest], 0.45 [0.34–0.59]). Among those with airflow limitation, risk increased with severity (mild: 1.32 [0.95–1.84]; moderate: 1.87 [1.41–2.46]). Greater severity was also associated with higher YLDs.
Conclusions
Spirometry-defined airflow limitation was associated with higher dementia risk and greater disability burden, suggesting impaired pulmonary function as a potential factor in dementia risk stratification and brain health.