More educated adults enjoy better health. Nearly everyone assumes this means that acquiring education improves health. That assumption is implicit in the phrase the “education gradient in health” or the statement that education is a “social determinant of health.”
Our research highlights a different explanation: healthier adolescents become more educated. Among 15-year-olds, those who will later finish high school and college already rate their health better than those who will drop out. This accounts for nearly all of the health gap between more and less educated adults at age 31.
- Source: Lynch, J.L. & von Hippel, P.T. (2016) “An education gradient in health, a health gradient in education, or a confounded gradient in both?” Social Science and Medicine 154:18-27. doi:10.1016/j.socscimed.2016.02.029. Epub Feb 23, 2016. Also available as SSRN working paper 2583971.
For body mass index (BMI), we see a mix. 29-year-olds with a bachelor’s degree have lower body mass index (BMI) than 29-year olds without. But about half that BMI gap was present at age 15, before anybody had a bachelor’s degree or had even finished high school.
- See also: von Hippel, P. T., & Lynch, J.L. (2014). “Why are educated adults slim—causation or selection?” Social Science and Medicine 105: 131-139. PubMed 24524908. Also available as an SSRN working paper 2054843.
In a more recent study, we followed individuals from age 18 to age 48. The BMI gap between adults with and without a high diploma/GED is no greater at age 48 than it was age 48. But the BMI gap between high school completers with and without a bachelor’s degree grows substantially over that 30-year period. Finishing college helps adults keep the pounds off, but finishing high school doesn’t seem to help much.
- Source: Benson, Rebecca and von Hippel, Paul T. and Lynch, Jamie L. (2017). Does More Education Cause Lower BMI, or Do Lower-BMI Individuals Become More Educated? Evidence from the National Longitudinal Survey of Youth 1979. Social Science and Medicine, doi.org/10.1016/j.socscimed.2017.03.042. Also available as an SSRN working paper: https://ssrn.com/abstract=2945097.
In short, although education does have benefits for BMI, those benefits are considerably smaller than you would guess just by looking at the BMI difference between more and less educated adults. You need to realize that more educated adults were already slimmer long before they completed their education.