Differences due to sex in cortical thickness and CSF biomarkers in normal aging and Alzheimer’s dementia

Abstract

AbstractBackgroundIn normal aging, a thinner cortex in males has been reported by various studies. Longitudinal trends in cortical thinning in males and females in healthy aging and in Alzheimer’s Dementia (AD) have yet to explored. In addition, CSF biomarkers also play an important role in detecting AD. In this study, we explored the differences in cortical thinning and CSF biomarkers between males and females in both healthy and AD subjects.MethodBaseline differences and differences up to two‐ years were studied using the data from two publicly available datasets ‐ Alzheimer's Disease Neuroimaging Initiative (ADNI) [Baseline scans‐ healthy control (HC): 423, AD: 330; follow up scans ‐ HC: 1191, AD: 536] and Australian Imaging Biomarkers and Lifestyle Study of Ageing (AIBL) [Baseline scans only ‐ HC: 319, AD: 72.] Only stable subjects (diagnosis does not change in the follow up scans) healthy controls and AD subjects were used. Generalized linear regression models were used to control the effect for age, intracranial volume, and scanner effects. For analyzing the differences between CSF biomarker levels, only age was controlled.ResultIn the Healthy control group, males showed a thinner cortex than females at baseline. Both males and females showed significant cortical thinning in different regions over two years. In the AD group, males showed a thinner cortex than females at baseline and over two years; however, the number of regions showing a significantly thinner cortex in males compared to females were less as opposed to the case in the control group. On the other hand, no significant differences were observed in the level of CSF biomarkers between males and females at either baseline and follow up measurements for both control and AD groups.ConclusionIn AD, females appear to experience greater cortical thinning than males such that the sex difference was less evident in AD than in controls. In the AD group, the sex difference in cortex continued to decrease through the two‐year study period. For CSF biomarkers, no significant difference was observed for males and females. This result suggests that neuro‐imaging is more sensitive to male and female differences than CSF biomarkers.