Prevalence and risk factors of cerebral microhemorrhages and superficial siderosis in cognitively unimpaired older adults: analysis from the CHARIOT-PRO SubStudy.

INTRODUCTION

Cerebral microhemorrhages (CMHs) and superficial siderosis (SS) are relatively common side effects of anti-amyloid immunotherapies, termed amyloid-related imaging abnormalities (ARIA-H). They are also observed in treatment-naïve older adults. This study explored relationships with modifiable and non-modifiable risk factors.

METHODS

This cross-sectional study included 1414 cognitively unimpaired, treatment-naïve individuals aged 60 to 85 years from the Cognitive Health in Ageing Register: Investigational, Observational and Trial Studies in Dementia Research (CHARIOT): Prospective Readiness cOhort (PRO) SubStudy. Relationships between CMHs/SS and cardiovascular risk factors, amyloid beta (Aβ) load, apolipoprotein E (APOE) ε4 status, educational attainment, and white matter hyperintensities were investigated using regression analyses and structural equation modeling.

RESULTS

CMHs were observed in 8.3% of participants and SS in 1.3%. Significant risk factors for CMHs included age and hypertension. Higher education attainment appeared to have a protective effect. Elevated amyloid is a risk factor, particularly when adjusting for APOE ε4 status in individuals aged 70 or younger.

DISCUSSION

Increasing age and hypertension are significant risk factors of CMHs. Higher educational attainment may offer a protective effect.

HIGHLIGHTS

Of the 1414 participants from the CHARIOT-PRO SubStudy (CPSS), CMHs were present in 118 (8.3%), and SS was present in 18 (1.3%). Age and hypertension were identified as significant risk factors for CMHs, and the latter had a stronger association with the presence of CMHs among female participants. Having a bachelor's degree or higher was found to be protective. Elevated brain amyloid burden, particularly when adjusted for APOE ε4 carrier status, was identified as a risk factor in individuals aged 70 years and below.