Not other potential reasons, such as exponential increase in incarcerations? That has to have an effect on life expentancy, and numbers of prisoners have ballooned in the USA.

"Life Expectancy for White Americans Declines"
"African-American men gained 0.4 year of life expectancy in 2014, to 72.2 years"
https://www.wsj.com/articles/life-expectancy-for-white-americans-declines-146112486

I'm feeling the heat.