Global ethnic disparities in cerebral small vessel disease imaging markers and vascular risk factors: a systematic review and meta-analysis.

Ethnic disparities in cerebral small vessel disease (CSVD) have been reported, but no systematic synthesis has compared markers and vascular risk factors across populations. We conducted a PROSPERO-registered systematic review and meta-analysis (CRD42024518105) including over two million community-dwelling adults. A two-tier ethnicity framework was applied. Tier 1 used broad US Office of Management and Budget-aligned categories to maximize comparability, showing that Asians with higher cerebral microbleeds, Whites with greater metabolic risks, Blacks with higher hypertension, and Hispanics with elevated diabetes. Tier 2 enabled finer intra-Asian subgrouping, revealing Chinese cohorts with greater white matter hyperintensity (WMH) and hemorrhagic burden, Japanese with a lacunar-predominant profile but lower microbleeds, and Koreans with blood pressure-linked WMH. Ethnicity also moderated key risk-lesion associations, including stronger effects of diabetes on WMH and lacunes in Chinese and of systolic blood pressure on WMHs in Koreans. These findings highlight that CSVD phenotypes differ across populations, reflecting complex interactions between vascular, genetic, and environmental factors. HIGHLIGHTS: First meta-analysis of CSVD markers stratified by global ethnic groups. Tier 1: Asians had higher CMBs and lacunes; Whites had higher metabolic risk. Tier 2: Chinese showed higher WMHs and CMBs; Japanese had more lacunes, fewer CMBs. Risk-CSVD associations varied by ethnicity, including diabetes and blood pressure. Results suggest need for ethnicity-informed prevention and harmonised reporting.