The Influence of Intelligence in Young Adulthood on Quality of Life in Midlife: a Danish Cohort Study of 893 Men

Intelligence has been associated with a wide range of important life outcomes, including quality of life (QoL). However, previous studies have mainly focused on the association between current intelligence and QoL instead of investigating whether intelligence can predict later QoL. The purpose of the present cohort study was to investigate the influence of intelligence in young adulthood on three distinct aspects of QoL in midlife. The study population consisted of all male members of the Copenhagen Perinatal Cohort (CPC, 1959–1961) who have appeared before a Danish draft board and participated in a midlife follow-up examination in 2009–2011 (N = 893). Intelligence was measured by the intelligence test Børge Priens Prøve at the mandatory draft board examination. QoL was measured at the follow-up by the participants’ scores on three QoL self-report measures: The Satisfaction With Life Scale, the Vitality Scale of the Medical Outcomes Study 36-Item Short-Form Health Survey, and a single-item QoL measure based on the question: “How is your quality of life at the moment?”. General linear regression and binary logistic regression were used to estimate the association between intelligence and QoL. The results showed curvilinear associations of intelligence with life satisfaction, vitality, and the single-item QoL measure, suggesting that individuals with low intelligence in young adulthood had a higher risk of low satisfaction with life, low vitality, and low QoL in midlife. In conclusion, the study findings suggest that intelligence in young adulthood exerts a lasting influence on distinct, but complementary aspects of QoL in midlife.