BACKGROUND: We examine the influence of social circumstances early in life on changes in cognitive function from young adulthood to middle age, and we explore the impact of birth characteristics, childhood activities, education and adult social class on the expected relationship. METHODS: A cohort of 11 532 men born in Copenhagen, Denmark in 1953-7906, 10 246 and 2483 participants-had completed assessments of cognitive function at ages 12, 18 and 57 years, respectively. Linear regression was used to investigate the association of early-life characteristics with cognitive test scores at these ages and with score changes from early to mid-adulthood. RESULTS: The cognitive scores at age 57 years had high correlations with scores at ages 12 (r = 0.67) and 18 years (r = 0.70), and these two scores also showed bivariate correlation (r = 0.69). Having a father from the working class at birth was associated with lower cognitive function at ages 12, 18 and 57 years. The latter relation was attenuated when educational status at age 18 years and adult social class were adjusted for, while birth characteristics and childhood activities had minor influence. Having an unskilled father at birth, low education, few intellectual and many social activities in childhood as well as low adult social class were associated with decline in cognitive function. CONCLUSION: Adverse social circumstances early in life were associated with lower cognitive function at ages 12, 18 and 57 years, as well as with a decline between these ages. Educational status at age 18 years and adult social class seemed to account for most of the associations, whereas childhood activities were independent predictors that did not explain the social inequality.
European Journal of Public Health, 2013, Vol 23, Issue 6, p. 974-980