Hypothesis: Some significant fraction of the wealthy/poor disparity is because the poor now smoke significantly more than the rich.
Over 80% of Americans are obese or overweight, largely due to lifestyle choice, food addiction, and food abuse. Obesity and related disease are by far the leading cause of death and illness in the USA, it's an extraordinarily costly epidemic that nobody wants to acknowledge.
https://www.niddk.nih.gov/health-information/health-statisti...