The authors note that among "white women who don’t graduate from high school... life expectancy has declined dramatically over the past 18 years."
Both authors imply that education and economic opportunity are likely the root of the problem. Potts writes:
Researchers have long known that high-school dropouts like Crystal are unlikely to live as long as people who have gone to college. But why would they be slipping behind the generation before them? James Jackson, a public-health researcher at the University of Michigan, believes it’s because life became more difficult for the least-educated in the 1990s and 2000s. Broad-scale shifts in society increasingly isolate those who don’t finish high school from good jobs, marriageable partners, and healthier communities. “Hope is lowered. If you drop out of school, say, in the last 20 years or so, you just had less hope for ever making it and being anything,” Jackson says. “The opportunities available to you are very different than what they were 20 or 30 years ago. What kind of job are you going to get if you drop out at 16? No job.”While that may be true, (and indeed, education is linked to longer life expectancy in general) I suspect it is only part of the answer. Some of the decline may be even more basic: selection bias.
Women, particularly white women, have made huge gains in educational attainment and earnings in the past several decades. While the wage gap and other inequalities remain, progress is undeniable for a substantial proportion of women. But perhaps only the healthiest white women are taking advantage of this progress.
Perhaps there is a third factor contributing to both low educational attainment and poor health of white high school dropouts. Perhaps high school dropouts are subject to social, health, or emotional problems that result in both dropping out and poor(er) health.