Association between childhood infection, serum inflammatory markers and intelligence: findings from a population-based prospective birth cohort study

Epidemiol Infect. 2018 Jan;146(2):256-264. doi: 10.1017/S0950268817002710. Epub 2017 Dec 4.

Abstract

A link between infection, inflammation, neurodevelopment and adult illnesses has been proposed. The objective of this study was to examine the association between infection burden during childhood - a critical period of development for the immune and nervous systems - and subsequent systemic inflammatory markers and general intelligence. In the Avon Longitudinal Study of Parents and Children, a prospective birth cohort in England, we examined the association of exposure to infections during childhood, assessed at seven follow-ups between age 1·5 and 7·5 years, with subsequent: (1) serum interleukin 6 and C-reactive protein (CRP) levels at age 9; (2) intelligence quotient (IQ) at age 8. We also examined the relationship between inflammatory markers and IQ. Very high infection burden (90+ percentile) was associated with higher CRP levels, but this relationship was explained by body mass index (adjusted odds ratio (OR) 1·19; 95% confidence interval (CI) 0·95-1·50), maternal occupation (adjusted OR 1·23; 95% CI 0·98-1·55) and atopic disorders (adjusted OR 1·24; 95% CI 0·98-1·55). Higher CRP levels were associated with lower IQ; adjusted β = -0·79 (95% CI -1·31 to -0·27); P = 0·003. There was no strong evidence for an association between infection and IQ. The findings indicate that childhood infections do not have an independent, lasting effect on circulating inflammatory marker levels subsequently in childhood; however, elevated inflammatory markers may be harmful for intellectual development/function.

Keywords: Birth cohort study; C-reactive protein; infection; inflammatory markers; intelligence quotient; interleukin 6.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • C-Reactive Protein / immunology*
  • Child
  • Child, Preschool
  • Cohort Studies
  • England / epidemiology
  • Female
  • Humans
  • Infant
  • Infections / epidemiology
  • Infections / immunology*
  • Infections / psychology
  • Inflammation / immunology*
  • Inflammation / psychology
  • Intelligence Tests
  • Intelligence*
  • Interleukin-6 / immunology*
  • Longitudinal Studies
  • Male
  • Odds Ratio
  • Prospective Studies

Substances

  • IL6 protein, human
  • Interleukin-6
  • C-Reactive Protein