Introduction to the special issue on cognitive epidemiology

This is an introduction to a special issue of the journal Intelligence on cognitive epidemiology. Cognitive epidemiology is a new field of study, which examines the associations between intelligence—usually from early in life—and later morbidity (physical and mental) and mortality. In addition to exploring and establishing associations, studies within cognitive epidemiology attempt to explain them, by testing possible confounders and mediators, and complex pathways, of intelligence–health associations. Popular among mediators are health behaviours and education, and the well-known risk factors for chronic illnesses such as cardiovascular disease. In this special issue, readers will find advances in all of these matters. Thirteen new empirical studies, all involving large cohorts of humans, provide novel associations between intelligence and mortality, morbidity, and health behaviours and risk factors. New hypotheses of these associations are tested. This is the largest collection of cognitive epidemiology studies to date. Together, they will take the field forward by a quantum jump. This is a feast of cognitive epidemiology, establishing that, beside education and occupation, health outcomes contribute to the impressive predictive validity of intelligence differences.