Wallace J, Jiang K, Goldsmith-Pinkham P, et al. - In this study, the relationship of Medicare with racial and ethnic disparities in access to care and health. Researchers designed a cross-sectional study using regression discontinuity to correlate racial and ethnic disparities before and after age 65 years, the age at which US adults are eligible for Medicare. Between January 2008 and December 2018, they enrolled a total of 2,434,320 respondents in the Behavioral Risk Factor Surveillance System and 44,587 state-age-year observations in the US Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research Data (eg, the mortality rate for individuals age 63 years in New York in 2017). The data were analyzed between February and May 2021. Eligibility for Medicare at age 65 years was correlated with marked reductions in racial and ethnic disparities in insurance coverage, access to care, and self-reported health in this cross-sectional study that uses a regression discontinuity design.