Childhood socio-economic circumstances and dementia: prospective register-based cohort study of adulthood socio-economic and cardiovascular health mediators

Abstract

Background: This study analysed the association between childhood socio-economic circumstances and the risk of dementia, and investigated the mediating role of potentially modifiable risk factors including adulthood socio-economic position and cardiovascular health. Methods: We used a 10% sample of the 1950 Finnish population census linked with subsequent population and health registers (n ¼ 95 381). Information of socio-economic characteristics, family structure and housing conditions at the age of 0–15 years was obtained from the 1950 census. We identified cohort members who developed dementia in 2000–2018 using national hospital, medication and death registers. Discrete time survival analysis using logistic regression and mediation analysis applying the Karlson–Holm–Breen (KHB) method were employed. Results: An excess risk of dementia was observed for household crowding [odds ratio (OR) ¼ 1.10; 95% CI 1.02–1.18 for 3 to <4 persons per heated room; OR ¼ 1.19; 95% CI 1.11–1.27 for ≥4 persons], single-father family (OR ¼ 1.27; 95% CI 1.07–1.51) and eastern and northern region of residence (OR ¼ 1.19; 95% CI 1.10–1.28). The effects of single-father family and region of residence were mostly direct with adulthood characteristics mediating 14% and 29% of the total effect, respectively. The largest indirect effect was observed for household crowding mediated through adulthood socio-economic position (47–65%). Conclusions: The study shows that childhood socio-economic circumstances are associated with dementia, and that the underlying mechanisms only partly relate to adulthood socio-economic position and cardiovascular health. Socio-economic and health interventions targeted at families with children may carry long-term benefits by contributing to a lower dementia risk in later life.