Elsevier

Intelligence

Volume 53, November–December 2015, Pages 23-32
Intelligence

Intelligence in youth and health at age 50

https://doi.org/10.1016/j.intell.2015.08.001Get rights and content
Under a Creative Commons license
open access

Highlights

  • We examined links between intelligence in youth and health at age 50 in NLSY-1979.

  • Higher intelligence in youth is linked with better physical health at age 50.

  • Higher intelligence in youth is linked with lower risk for chronic illnesses.

  • Adult but not childhood SES partially mediated the intelligence–health relationship.

Abstract

Background

The link between intelligence in youth and all-cause mortality in later-life is well established. To better understand this relationship, the current study examines the links between pre-morbid intelligence and a number of specific health outcomes at age 50 using the NLSY-1979 cohort.

Methods

Participants were the 5793 participants in the NLSY-79 who responded to questions about health outcomes at age 50. Sixteen health outcomes were examined: two were summary measures (physical health and functional limitation), 9 were diagnosed illness conditions, 4 were self-reported conditions, and one was a measure of general health status. Linear and logistic regressions were used, as appropriate, to examine the relationship between intelligence in youth and the health outcomes. Age, sex and both childhood and adult SES, and its sub-components – income, education, & occupational prestige – are all adjusted for separately.

Results & conclusion

Higher pre-morbid intelligence is linked with better physical health at age 50, and a lower risk for a number of chronic health conditions. For example, a 1 SD higher score in IQ was significantly associated with increased odds of having good, very good, or excellent health, with an odds ratio of 1.70 (C.I. 1.55–1.86). Thirteen of the illness outcomes were significantly and negatively associated with IQ in youth; the odds ratios ranged from 0.85 for diabetes/high blood sugar to 0.65 for stroke, per one standard deviation higher score in IQ. Adjustment for childhood SES led to little attenuation but adult SES partially mediated the relationship for a number of conditions. Mediation by adult SES was not consistently explained by any one of its components—income, education, and occupation status. The current findings contribute to our understanding of lower intelligence as a risk factor for poor health and how this may contribute to health inequalities.

Keywords

Cognitive epidemiology
Intelligence
IQ
Health
Chronic disease
SES
Age 50
AFQT
NLSY-79

Cited by (0)