Brain cortical thickness in the general elderly population: the Rotterdam Scan Study.

Cortical thickness is considered a potentially relevant marker for neurodegenerative diseases. However, the relationship of demographic and vascular risk factors with cortical thickness remains unclear. In a population-based sample of 1022 non-demented elderly persons (mean age 68.4±7.3 years), we examined aging effects on global and lobar cortical thickness and the relationship with demographic variables and cardiovascular risk factors. We used a validated model-based approach to calculate mean cortical thickness (μm) in brain MR-images. We found that women had a significant thicker cortex than men (p<0.01). Further, with increasing age, cortical thickness decreased (approximately 0.2% per year), with the largest age effects for the occipital and temporal lobes, and the decrease in the frontal lobe being more apparent in men than in women (p-interaction<0.001). Additionally, higher education, higher diastolic blood pressure and larger intra-cranial volume were related to a larger cortical thickness, whilst diabetes mellitus and higher HDL cholesterol levels were related to a thinner cortex.