Supplementary Material for: Racial Discrimination and Multiple Health Outcomes: An Umbrella Review of Systematic Reviews and Meta-Analyses

Objective: We aimed to systematically investigate the associations between racial discrimination and various health outcomes and to evaluate the certainty of evidence from existing meta-analyses of observational studies. Method: We systemically searched the associations between racial discrimination and health outcomes for PubMed/MEDLINE, Embase, WoS, and Google Scholar up until January 31, 2024. Notably, the included studies were predominantly conducted in the United States and Europe, limiting the generalizability of our findings to a global context. Results: Eight meta-analyses of observational studies involving over 1 million individuals were included, describing 15 potential health outcomes related to racial discrimination. The quality assessment revealed that most included meta-analyses were of low quality. For oncological health outcomes, significant associations were found with the mortality of hepatocellular carcinoma (HCC); Black patients had a higher risk, while Asian patients had a lower risk when compared to White patients. In addition, Black patients with disparities on the cancer care continuum are a protective factor for early-stage HCC diagnosis. For gastroenterological health outcomes, Hispanic patients with nonalcoholic fatty liver disease and Black patients with socioeconomic status/differential access to health care, compared to white patients (reference) showed significant associations. For mental health outcomes, racial discriminations were significantly associated with increased odds of psychotic experiences, suicidal ideation, and suicidal attempts. Numerous significant associations were from weak to suggestive evidence levels, indicating variability in the evidence. Conclusion: Despite the complexity of measuring its impact, racial discrimination shows a profound influence across clinical areas, including an unexpected protective association in early-stage hepatocellular carcinoma diagnosis among Black patients.