"Abstract. The education-mortality gradient has increased sharply in the last three decades, with the life-expectancy gap between people with and without a college degree widening from 2.6 years in 1992 to 6.3 years in 2019 (Case and Deaton 2023). During the same period, mortality inequality across counties rose 30 percent, accompanied by an increasing rural health penalty. Using county- and state-level data from the 1992–2019 period, we demonstrate that these three trends arose due to a fundamental shift in the geographic patterns of mortality among college and non-college populations. First, we find a sharp decline in both mortality rates and geographic inequality for college graduates. Second, the reverse was true for people without a college degree; spatial inequality became amplified. Third, we find that rates of smoking play a key role in explaining all three empirical puzzles, with secondary roles attributed to income, other health behaviors, and state policies. Less well-understood is why 'place effects' matter so much for smoking (and mortality) for those without a college degree."
I think parent comment was pointing to lack of establishing a causation link. The finding in their abstract is extrapolated by statistical inference. For example smokers tend to drink more etc. The paper does take such factors into account. Personally I wouldn't jump to such a strong conclusion from statistical inference because it closes the door on other factors that might be even stronger when combined together. The paper reflects motivated reasoning more than a discovery outcome. That said, smoking is of course a major health risk, I am just pointing at the research approach.
In the paper they claim it matters for midlife mortality too:
> People who start smoking at age 18 begin to exhibit higher mortality several decades later, with particularly large effects beginning at ages 45–64 (Lawton et al. 2025). A health-capital model allows the mortality rates of older persons to be determined not only by their current smoking behavior but also by smoking in earlier years. In the United States, smoking rates started falling for college graduates earlier than they did for the non-college population.
...
> [...] with rapidly improving treatments and screening for lung cancer (Howladeret al. 2020), the major impact of smoking over the longer-term—particularly for people aged 55–64 arises from other more-common tobacco-related diseases such as chronic obstructive pulmonary disease (COPD); cardiovascular diseases such as strokes, aneurysms, and heart
attacks; diabetes; and other types of cancers (Carter et al. 2015). Perhaps more surprising is that past county-level smoking rates are highly predictive of deaths of despair. This finding, however, is consistent with an emerging literature in biology that points to a causal influence
of smoking on drug addiction [...]
Actually, later in their paper they say: "Although we have argued for a causal role for smoking in generating these patterns, the growing mortality gaps still seem too large and the causes of death too varied to blame the patterns on the adverse health effects of tobacco use alone. As noted above, smoking is likely
to play a role in amplifying the impact of other factors adversely affecting midlife mortality, such as the marketing efforts by opioid manufacturers targeted to areas with high rates of smoking-related illness, coupled with epigenetic changes making smokers more susceptible to opioid use disorders. Still, the strength of our findings that smoking is predictive of spatial trends in midlife mortality points towards different mechanisms needed to explain
the troubling trends that have unfolded since 1990."
> manufacturers targeted to areas with high rates of smoking-related illness
Oof
> epigenetic changes making smokers more susceptible to opioid use disorders
This one seems… a bit mystic to me. I would have been much quicker to suggest that a psychological propensity to start smoking mirrors a propensity to start using other drugs vs. arguing for emergent effects of cellular behavior.
