HEIDI DOUGLASS | h.douglass@unsw.edu.au

Software developed by researchers at the Centre for Healthy Brain Ageing (CHeBA), UNSW Sydney has enabled an investigation into the relationship between sex differences and cerebral small vessel disease.

The research, published in Neurobiology of Aging, specifically addressed the moderation effect of sex in the association between known risk factors and white matter hyperintensities in normal ageing. 

White matter hyperintensities are changes in the white matter that are evident in Magnetic Resonance Imaging (MRI), especially on T2-weighted scans. White matter hyperintensities are known to be related to cerebral small vessel disease which is a significant risk factor for cognitive decline and dementia.

White matter hyperintensities are particularly common in the brains of the elderly.

Until now, sex differences in white matter hyperintensities have not been comprehensively investigated.

Lead author and PhD student with CHeBA, Abdullah Alqarni, said that examining the role of sex might provide new insights in the relationship between known risk factors and white matter hyperintensities.

The research used two datasets with the exploratory sample drawn from CHeBA’s Sydney Memory and Ageing Study and an independent validation sample from CHeBA’s Older Australian Twins Study. None of the individuals involved in the study had dementia. 

"We used a software that extracts and quantifies white matter hyperintensities called the UBO detector."

Abdullah Alqarni, Lead Author and PhD Candidate

The software was built by Associate Professor Wei Wen and Dr Jiyang Jiang of CHeBA’s Neuroimaging Group, with funding from the J Holden Family Foundation.

Leader of CHeBA’s Neuroimaging Group, Associate Professor Wei Wen, said that a key finding of this study indicates a higher burden of cardiovascular risk factors such as ageing, hip to waist ratio and Body Mass Index for total white matter hyperintensities in men.

"In this research it was also shown that high density lipoprotein (HDL) was – in men only - associated with higher periventricular white matter hyperintensity volume, and hypertension was only associated with deep white matter hyperintensity, suggesting different mechanisms of risk factors for males."

Associate Professor Wei Wen

In women, ageing and hip to waist ratio were the main risk factors associated with higher volume of white matter hyperintensities.

Interestingly, the use of lipid lowering medication was associated with lower periventricular white matter hyperintensities.

In examining the interaction between sex and risk factors, higher Body Mass Index was associated with increased deep white matter hyperintensities in men but not in women. This sex moderation effect was validated in an independent sample.

Although white matter hyperintensity in women tended to be less influenced by the examined risk factors than men, higher white matter hyperintensity volume was found in women compared to men, which might indicate other contributors to the increase of white matter hyperintensity in women such as genetical or hormonal factors.

This study indicates that designed strategies regarding the management of different risk factors in both sexes might help with reducing the impact of cerebral small disease.