Vascular risk factors, white matter hyperintensities and hippocampal volume in normal elderly individuals

Hippocampal atrophy has been identified as marker for the development of Alzheimer's dementia (AD). To what extent vascular risk factors and white matter hyperintensities (WMH) affect hippocampal volume (HV) in asymptomatic elderly subjects and thus may impact such a predictive capacity is controversial.

We analysed 287 participants of the Austrian Stroke Prevention Study (mean age 66.6 ± 6.6 years) with a Mini Mental State Examination score ≥27 who were free of neuropsychiatric disease and had undergone MRI including coronal T(1)-weighted sequences allowing for semi-automatic assessment of HV. Global brain volume (BV) was measured using SIENAX. WMH were rated according to the Fazekas scale and segmented to obtain WMH volumes.

Higher age was associated with lower absolute and normalized HV, a lower BV and higher WMH volume. None of the vascular risk factors had an impact on HV except for high-density lipoprotein. This effect disappeared after normalization of HV. WMH severity and volume did not affect HV either.

Our data indicate HV loss in parallel with the whole brain and suggest no specific vulnerability towards vascular risk factors or age-related WMH in a cognitively intact normal elderly population. This also supports the utility of HV measurements to identify impending AD.