Race and Ethnic Background in Parkinson’s Disease: A Literature Review and Risk Factor Analysis

Abstract Importance: Parkinson’s disease (PD) is a common, neurodegenerative disorder. Inclusion of ethno-racial groups is critical to expanding current understanding of PD risk factors, pathogenesis, and increasing generalizability across diverse research populations. Presently, there is a lack of large-scale studies that evaluate links between race/ethnicity and PD risk. Objective: (1) Using a literature review, we aimed to evaluate and assess the inclusion of ethno-racial factors in studies on PD risk. (2) Using a cross-sectional study, we aimed to validate findings in the literature and compare the relationship between PD prevalence, race, and risk factors. Design, Setting and Participants: Targeted literature review: A PubMED search was conducted to identify studies published 2000-2023 detailing PD risk and epidemiology. Cross-sectional analysis: data downloaded in March 2022 from the Fox Insight study cohort was analysed. Exposures: Literature review: inclusion of race/ethnicity. Cross-sectional analysis: current PD diagnosis, sex, age of diagnosis, smoking status, family history of PD, select DNA markers, history of anosmia, depression and anxiety. Main Outcomes and Measures: Literature review: accounting for race/ethnicity in the data set. Cross-sectional analysis: logistic regression modelling was used to determine the prevalence odds ratios for PD, pairwise comparisons of age at PD diagnosis across race were conducted and minor allele frequencies were calculated. Results: Literature review: only 22 of 497 (4.4%) articles reviewed included ethno-racial factors as an integral part of their analysis. Cross-sectional analysis: out of the 48,566 respondents, 22,776 were male (46.9%), the mean age was 65.8 (SD=12.1), 34,859 (71.7%) respondents had a diagnosis of PD, 45,712 (94.1%) self-identified with the White race. Multiracial respondents had 22% reduced odds of PD (POR=0.78 95% CI [0.65-0.93]) compared to the White race group, adjusted for age, sex and income. Race did not impact the association between PD prevalence and known risk factors. Conclusions and Relevance: Our literature search revealed that race/ethnicity has been understudied in the context of PD risk; despite this, our data analysis demonstrated that race groups differ in prevalence. To best inform understanding of PD pathogenesis and future care, further analyses are needed with consideration of access to care and other determinants of health.