A nationwide Swedish study of age at retirement and dementia risk

Objectives The aim of this nationwide study was to examine the association between age at retirement and dementia risk, with a follow-up period of up to 24 years. Methods/design This cohort study comprised Swedish citizens born in 1930 who were alive in the year 1990 (n = 63 505). The cohort was followed for incidents of dementia through data provided by the Swedish National Patient Register and the Cause of Death Register. Age at retirement and socioeconomic variables were retrieved from Statistics Sweden. Results During the follow-up, 5181 individuals received a dementia diagnosis. Competing risk regression models, adjusted for sex, education, marital status, occupation, and previous history of cardiovascular diseases, showed that later-than-average retirement age was associated with decreased dementia risk. Conclusions The present results support the idea that individuals who retired at an older age have a decrease risk of dementia. However, as this was an observation study, unmeasured factors, such as premorbid cognitive level and genetic predisposition, may have influenced our findings and remains to be elucidated in future studies.