Risk of Dementia Among Patients With Asthma: A Nationwide Longitudinal Study

Background: Previous studies have suggested an association between asthma and dementia, but the results are still inconsistent. Methods: Using the Taiwan National Health Insurance Database, we enrolled 11,030 participants aged more than 45 years with asthma and 44,120 (1:4) age-/sex-matched controls between 1998 and 2008, and followed them to the end of 2011. Cases of any dementia or Alzheimer's disease that developed during the follow-up period were identified. Results: Asthma was associated with an increased risk of developing any dementia [hazard ratio (HR): 2.17, 95% confidence interval (CI): 1.87-2.52] and Alzheimer's disease (HR: 2.62, 95% CI: 1.71-4.02). Stratified by age, both asthma in midlife (>45 years and <65 years) and in late life (>= 65 years) was associated with a greater likelihood of any dementia (HR: 2.48, 95% CI: 1.80-3.41; HR: 2.06, 95% CI: 1.74-2.44). Discussion: Asthma in midlife and in late life increased the risk of developing any dementia and Alzheimer's disease. The underlying mechanisms between asthma and dementia require further investigation. (C) 2014 AMDA - The Society for Post-Acute and Long-Term Care Medicine.