About the research
The researchers investigated the associations between childhood intelligence and several biomarkers that indicate adult cardiovascular disease (CVD) in an effort to further understand the causal mechanisms between cognition and vascular health outcomes. They did this by adjusting for several potential confounding and mediating variables including socioeconomic status, birth factors and smoking. Secondly, the researchers investigated the associations between CVD biomarkers at age 45 and cognitive ability at age 50 to discover any reverse causation. They did this by controlling for performance on a general intelligence assessment at age 11. The findings indicate that childhood intelligence was predictive of inflammatory and/or hemostatic biomarker status at midlife. Early life factors accounted for 24 to 44 percent of these associations, whereas further adjustment for adult indicators of health behaviour largely attenuated the effects (82 to 100 percent). The inverse associations between age 45 biomarkers and age 50 cognition were largely accounted for by childhood intelligence. These findings highlight the need to consider cognitive ability as a potential influential factor on inflammatory (and hemostatic) status in midlife. Only by taking this in to account can the true extent to which increases in such biomarkers adversely affect later cognitive performance be determined.
Methodology
The researchers used a multiple regression analysis to test all longitudinal associations, which were adjusted for gender and included an attrition weighting. Data were added to the models as continuous variables, including:
- a general intelligence test score at age 11
- cognitive performance test scores at age 50, including attention and memory
- log-transformed inflammatory and hemostatic biomarker levels at age 46
- confounding variables at birth, including parental socioeconomic status, gestational age and birth weight
- potential mediating factors at middle age, including body mass index, waist-to-hip ratio, blood pressure, smoking and adult socioeconomic status
Publications
This research was published as Childhood intelligence and midlife inflammatory and hemostatic biomarkers: The National Child Development Study (1958) cohort, Health Psychology, 23 May 2011.