Impact of white matter changes on conversion from amnestic mild cognitive impairment to dementia

초록

Backgroud and Objective: Cerebrovascular disease may play an important role in determining the presence and severity of the clinical symptoms of Alzheimer’s disease (AD). We aimed to determine whether magnetic resonance imaging (MRI) white matter changes (WMC) and cardiovascular risk factors predict the conversion from amnestic mild cognitive impairment (MCI) to dementia. Methods: Four hundred seventy patients with amnestic MCI were recruited from the Clinical Research Center for Dementia of South Korea and followed for incident dementia for mean (SD) 1.2 (0.6) years. Vascular risk factors and WMC on brain MRI were evaluated at baseline in all patients. The patients with severe WMC to suggest subcortical vascular MCI were excluded. High WMC was defined as periventricular WMC with a cap or rim larger than 10 mm in maximum diameter or single or grouped lesions larger than 10 mm in deep subcortical white matter area. Results: One hundred eleven (23.6%) patients were converted to dementia and 100 (90.1%) of them were converted to AD dementia. Twenty-nine (6.2%) patients reverted from MCI to normal. Univariate analyses showed that high WMC predicted conversion to all-cause dementia (hazard ratio [HR], 1.63; 95% confidence interval [CI], 1.09-2.45; p=0.02) and conversion to AD dementia (HR, 1.69; 95% CI, 1.10-2.59; p=0.02). Hypertension, diabetes mellitus, hyperlipidemia, and heart disease did not predict conversion to all-cause dementia or AD dementia. In a multivariate model adjusted for age, sex, and educational level, high WMC also predicted conversion to all-cause dementia (adjusted HR, 1.59; 95% CI, 1.05-2.41; p=0.03) and conversion to AD dementia (adjusted HR, 1.64; 95% CI, 1.06-2.54; p=0.03). Conclusion: These findings suggest that WMC are associated with the risk of conversion from MCI to dementia.