Educational Degrees and Adult Mortality Risk in the United States

Abstract

We present the first published estimates of U. S. adult mortality risk by detailed educational degree, including advanced postsecondary degrees. We use the 1997–2002 National Health Interview Survey (NHIS) Linked Mortality Files and Cox proportional hazards models to reveal wide graded differences in mortality by educational degree. Compared to adults who have a professional degree, those with an MA are 5 percent, those with a BA are 26 percent, those with an AA are 44 percent, those with some college are 65 percent, high school graduates are 80 percent, and those with a GED or 12 or fewer years of schooling are at least 95 percent more likely to die during the follow-up period, net of sociodemographic controls. These differentials vary by gender and cohort. Advanced educational degrees are associated not only with increased workforce skill level but with a reduced risk of death.

This project was funded in part through the Eunice Shriver National Institute of Child Health and Human Development (NICHD) Research Grant #R01 053696. We thank the NICHD-funded University of Colorado Population Center (grant R21 HD51146) and the University of Texas Population Research Center (Grant R24 HD42849) for administrative and computing support; Nancy Mann for editorial suggestions; the anonymous reviewers for their helpful comments and recommendations; and the National Center for Health Statistics (NCHS) for collecting the data. The public-use National Health Interview Survey Linked Mortality File is available from NCHS. The content of this manuscript is solely the responsibility of the authors and does not necessarily represent the official views of the NCHS, the NIH, or the NICHD.

Notes

¹We restrict our analyses to the native-born population to avoid potential confounding between nativity and educational degrees. Nativity can affect the conversion of educational credentials into jobs and income. Immigrants who completed their degrees in another country may have experienced different teaching practices and standards. Further, because of language barriers and discrimination, some immigrants may be prevented from fully using their skills in the United States. Certification may also be a factor; for instance, immigrant MDs may be prohibited from medical practice unless they have successfully passed the U. S. medical boards.

²The NHIS combines MD, DDS, DVM, and JD into a single “Professional Degree” category.

³Some national vital statistics registration areas began including the educational credential item on their death certificates beginning in 2003. However, because most states have not yet adopted the revised educational item, the NCHS currently reports mortality by years of education only (see Kung, Hoyert, Xu, and Murphy 2008).

⁴A 95 percent confidence interval may be calculated as the hazard ratio ± (standard error∗1.96).

⁵All models control for race/ethnicity in Tables 2 and 3, and marriage is controlled for in Table 3, but these controls have little or no effect on the relationship between educational degrees and mortality risk.

⁶To determine whether there are significant differences for this comparison, we calculate which is significant at p ≤ 0.001.

⁷Although Table 2 provides a summary of the overall relationship between educational degrees and U. S. adult mortality risk, it does not pass the proportionality assumption. In contrast, all six gender- and cohort-specific models in Table 3 pass global proportionality assumption tests based upon Shoenfeld residuals using the “estat phtest” commands in Stata 10.