Why do wealthy Americans only live as long as poor people in western Europe?

New research published in the New England Journal of Medicine analysed nearly 74,000 people in the US and 16 European countries who were between 50 and 85 years old in 2010, and tracked their survival through 2022.

Across all groups, the US death rate was 6.5 per 1,000 during the study period. That compares with rates of 2.9 in northern and western Europe, 4.9 in southern Europe, and 5.8 in eastern Europe.

Wealthy Americans had lower survival rates than rich people in southern Europe – as well as everyone in northern and western Europe, regardless of how wealthy they were, the study found; the survival rate for wealthy Americans was on par with the poorest people in northern and western Europe, and with eastern Europeans overall.

Why do wealthy Americans only live as long as poor people in western Europe?