Abstract Body:
(1) Background: Cerebral microbleeds (MBs) and cortical superficial siderosis (cSS) can be seen in a multitude of etiologies. The risk factors for cerebral MB and cSS and their relationship with cognitive decline are not well known.
(2) Objective: This study aimed to explore the risk factors for cerebral MBs and cSS and to examine their impact on cognitive function in a cohort of cognitively impaired patients.
(3) Methods: We conducted a case-control study involving 415 patients who underwent a brain magnetic resonance imaging (MRI) with a dementia protocol and cognitive assessments at the University Health Network, Mount Sinai Hospital, and Women's College Hospital in Toronto from 2014 to 2022. Cognition was assessed using the Mini-Mental State Examination (MMSE) and/ or the Montreal Cognitive Assessment (MoCA)
The case group (n=137) included patients with cerebral MBs and/or cSS, while the control group (n=278) was comprised of randomly selected patients for cognitive impairment and underwent the same MRI protocol. We also evaluated the location of the MB including if deep, lobar or mixed MB. White matter hyperintensities (WMH) were graded using the Fazekas scale, wherein severity is assessed from 0 to 3. We performed Multivariate logistic regression to identify risk factors associated with cerebral MBs and cSS.
(4) Results: Patients with MBs and/or cSS were older and had a higher prevalence of hypertension compared to the control group. In the multivariate analysis, age (OR = 1.05, 95% CI: 1.02-1.08, p = 0.002), hypertension (OR = 2.67, 95% CI: 1.75-4.08, p < 0.001), and higher Fazekas scores (OR = 1.58, 95% CI: 1.22-2.06, p < 0.001) were associated with cerebral MBs and cSS. Cognitive scores were significantly lower in the group with MB and cSS (MMSE: 22.3 vs. 26.1; MoCA: 19.7 vs. 24.8, both p < 0.001). Regression analysis showed that MB location did not significantly affect cognitive scores. The estimates for deep (0.45, 95% CI: -0.38 to 1.27; p < 0.286), lobar (-0.17, 95% CI: -0.55 to 0.21; p < 0.379), and mixed (-0.12, 95% CI: -0.47 to 0.24; p < 0.522)

(5) Conclusions: Age, hypertension, and small vessel disease as measured by Fazekas scale are significant risk factors for cerebral MBs and cSS. Cognitive impairment was more severe in those with MBs and cSS and not related to their location. It is essential to manage vascular risk factors, such as hypertension,as this is ssociated with MBs and cSS , which are associated with worse cognitive impairment