Education, health-based selection, and the widening mortality gap between Americans with and without a four-year college degree.

Background: Gaps in life expectancy between Americans with and without a college degree have widened markedly over the past three decades. One explanation points to increasing educational attainment changing the type of people with and without a degree. If pre-existing health in the two education groups changes as the fraction with a degree changes, health selection might explain the widening mortality gap.

Methods: We examine this explanation using (a) education and mortality in each birth cohort of men and women from 1940 to 1988, and (b) the natural experiment caused by the Vietnam War, which increased the fractions of men with a degree in affected birth cohorts. For each cohort, we examine the relationship between the mortality gap and the fraction with a degree.

Results: We find no relationship between the fraction of a birth cohort with a degree and the corresponding mortality gap. For men, the large increase in college going spurred by Vietnam has no perceptible counterpart in the mortality gap.

Conclusion: The evidence from the natural experiment induced by the Vietnam War does not support a health-selection explanation for the widening mortality gap.