O2‐06‐02: Parietal lobe white matter hyperintensities but not hippocampal volume predict incident dementia
Year: 2011
Type: article
Study design: Observational Study
Abstract: New onset Alzheimer's disease (AD) is often attributed to degenerative changes in the hippocampus. However, the contribution of regionally distributed small vessel cerebrovascular disease (CVD), visualized as white matter hyperintensities (WMH) on MRI, remains unclear. We examined whether regional WMH and hippocampal volume predict incident dementia in an epidemiological study. Participants were from an ongoing, longitudinal study of aging and dementia in upper Manhattan. At all visits, subjects are evaluated with a comprehensive neuropsychological and medical examination. Between 2005 and 2007, 769 received MRI scans. Fifty-two met criteria for dementia at the time of MRI and were excluded from analyses. Of the remaining 717, 503 returned for follow-up clinical examination an average of 3.4 (SD = 0.81) years later and 46 met criteria for dementia (all but 1 with AD). WMH volume in frontal, temporal, parietal and occipital lobes were derived using in-house developed software. Hippocampal volumes were derived manually and corrected for total cranial volume to yield relative values. Three logistic regression models were run to predict incident dementia. The first included all WMH measurements; the second included relative hippocampal volume; and the third combined the two measurements. All models controlled for age, education, sex, APOE-e4, race/ethnicity and time interval between scan and follow-up. Increased WMH volume in the parietal lobes was associated with incident dementia at follow-up (OR = 1.251, p = 0.044); WMH burden in other regions was not associated with incident dementia. Of the covariates in the model, age (OR = 1.086, p = 0.019), education (OR = 0.868, p = 0.007) and time interval between scan and follow-up (OR = 1.669, p = 0.033) were associated with incident dementia, but not sex, APOE-e4 allele status or race/ethnicity. Relative hippocampal volume did not predict incident dementia when considered alone (OR = 0.310, p = 0.714) or with the WMH measures included in the model (OR = 0.193, p = 0.631). Including hippocampal volume in the model did not notably alter the predictive utility of parietal lobe WMH (OR = 1.235, p = 0.07). The findings highlight the important contribution of small vessel CVD to dementia, particularly when distributed in parietal lobes. It is not clear whether parietal WMH solely represent a marker for CVD burden or point to distinct injury compared to other regions. Future work should elucidate mechanistic links between WMH and AD pathology.
Source: Alzheimer s & Dementia
Institution: Columbia University
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W2041788333