The Mediating Effect of Cigarette Smoking on the Education-Mortality Gap in the United States

Justin T. Denney, University of Colorado at Boulder
Richard G. Rogers, University of Colorado at Boulder

We examine the extent to which the education gap in U.S. adult mortality is mediated by one of the most harmful individual health behaviors, cigarette smoking. Using National Health Interview Survey Linked Mortality File (NHIS-LMF) data for selected years from 1995-2002, we determine (1) if cigarette smoking mediates the relationship between education and all cause mortality, and (2) whether the mediating influences of smoking differ by age and sex. Using Cox proportional hazard models, we find that smoking reduces the gap for all males and for younger females (under age 70). Education-mortality gaps for men ages 25-49 and ages 50-69 narrow considerably – by over 30% – when smoking is included in the model. Men aged 70 and older experienced more modest reductions, and older women experienced no reduction in the education-mortality gap. Thus, smoking accounts for a sizable portion of the education-mortality gap, especially among younger adults and men.