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

초록

Backgroud: The studies about the association between white matter lesion and conversion from mild cognitive impairment (MCI) to dementia provided conflicting results. We aimed to determine whether conversion to dementia is associated with deep white matter hyperintensities (DWMH) or periventricular WMH (PWMH) in amnestic MCI. 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. The PWMH was rated as P1 (cap or band < 5 mm), P2 (5 mm ≤ cap or band < 10 mm), or P3 (10 mm ≤ cap or band). The DWMH was rated as D1 (maximum diameter of deep white matter lesion < 10 mm), D2 (≥ 10 mm, < 25 mm), or D3 (≥ 25 mm). Results: One hundred eleven (23.6%) patients were converted to dementia and 100 (90.1%) of them were converted to AD dementia. Univariate analyses showed that severe PWMC (P3) predicted conversion to all-cause dementia (hazard ratio [HR], 1.93; 95% confidence interval [CI], 1.22-3.05; p<0.05) and conversion to AD dementia (HR, 1.86; 95% CI, 1.15-3.02; p<0.05). DWMH did not predict conversion to all-cause dementia or AD dementia. In a multivariate model adjusted for age, gender, hyperlipidemia, ApoE e4, K-MMSE score, DWMH, and PWMH, severe PWMH (P3) also predicted conversion to all-cause dementia (adjusted HR, 2.13; 95% CI, 1.10-4.12; p<0.05) and conversion to AD dementia (adjusted HR, 2.05; 95% CI, 1.02-4.12; p<0.05). Conclusions: This study showed that conversion to any types of dementia or AD is not associated win DWMH, but is associated with PWMH in amnestic MCI.