The Brown study I cited above concludes differently, and is strictly a longitudinal, retrospective cohort study involving adults 50 to 85 years of age.
Within that 50-85 cohort, among 73,838 adults (mean [±SD] age, 65±9.8 years), the participants in the top wealth quartiles in northern and western Europe and southern Europe appeared to be higher than that among the wealthiest Americans. Survival in the wealthiest U.S. quartile appeared to be similar to that in the poorest quartile in northern and western Europe.
https://www.nejm.org/doi/full/10.1056/NEJMsa2408259
Within that 50-85 cohort, among 73,838 adults (mean [±SD] age, 65±9.8 years), the participants in the top wealth quartiles in northern and western Europe and southern Europe appeared to be higher than that among the wealthiest Americans. Survival in the wealthiest U.S. quartile appeared to be similar to that in the poorest quartile in northern and western Europe.