IJE Advance Access published online on October 27, 2009
International Journal of Epidemiology, doi:10.1093/ije/dyp314
Education reduces the effects of genetic susceptibilities to poor physical health
1Centre for Cognitive Ageing and Cognitive Epidemiology, Department of Psychology, University of Edinburgh, Edinburgh, UK.
2Department of Psychology, University of Minnesota–Twin Cities, MN, Minneapolis, USA.
3Institute of Regional Health Services Research, Southern Denmark University, Odense, Denmark.
4Danish Twin Registry, Epidemiology, Institute of Public Health, University of Southern Denmark, Odense, Denmark.
5Institute of Public Health and Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark.
6Medical Research Council Social and Public Health Sciences Unit, University of Glasgow, Glasgow, UK.
* Corresponding author. Centre for Cognitive Ageing and Cognitive Epidemiology and Department of Psychology, University of Edinburgh, Edinburgh, UK EH8 9JZ. E-mail: wendy.johnson{at}ed.ac.uk
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Abstract |
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Background Greater education is associated with better physical health. This has been of great concern to public health officials. Most demonstrations show that education influences mean levels of health. Little is known about the influence of education on variance in health status, or about how this influence may impact the underlying genetic and environmental sources of health problems. This study explored these influences.
Methods In a 2002 postal questionnaire, 21 522 members of same-sex pairs in the Danish Twin Registry born between 1931 and 1982 reported physical health in the 12-item Short Form Health Survey. We used quantitative genetic models to examine how genetic and environmental variance in physical health differed with level of education, adjusting for birth-year effects.
Results and Conclusions As expected, greater education was associated with better physical health. Greater education was also associated with smaller variance in health status. In both sexes, 2 standard deviations (SDs) above mean educational level, variance in physical health was only about half that among those 2 SDs below. This was because fewer highly educated people reported poor health. There was less total variance in health primarily because there was less genetic variance. Education apparently reduced expression of genetic susceptibilities to poor health. The patterns of genetic and environmental correlations suggested that this might take place because more educated people manage their environments to protect their health. If so, fostering the personal charactieristics associated with educational attainment could be important in reducing the education–health gradient.
Keywords Physical health, education, socio-economic status gradient, genetic and environmental vulnerabilities
Accepted 7 September 2009