Life Events and Incident Dementia: A Prospective Study of 493,787 Individuals Over 16 Years

ObjectivesLife events can be stressful and have a detrimental impact on health, but evidence is inconclusive regarding life events and dementia risk. The present study tests whether life events are associated with incident dementia, whether experiencing multiple events has cumulative effects, and whether the associations vary across age, sex, race/ethnicity, socioeconomic status, and genetic vulnerability.MethodsUK Biobank participants (N = 493,787) reported on 6 life events that occurred within the past 2 years: serious illness, injury, assault to yourself or close relative, death of a spouse/partner or close relative, marital separation/divorce, and financial problems. Incident all-cause dementia was ascertained through health records from the UK National Health Service over a 16-year follow-up.ResultsSerious illness, injury, or assault to yourself, marital separation/divorce, and financial difficulties were associated with a higher risk of dementia; serious illness, injury, or assault of a close relative was associated with a lower risk of dementia. When combined, experiencing 3–4 events was associated with a more than 2-fold increase in dementia risk. The association for marital separation/divorce was stronger within the first 5 years of follow-up (consistent with reverse causality). Death of a spouse/partner or close relative was mostly unrelated to dementia risk. With few exceptions, the associations were similar across age, sex, race/ethnicity, socioeconomic status, and apolipoprotein E e4 status groups.DiscussionSevere illness, injury, or personal assault, marital separation or divorce, and financial hardships may raise risk of dementia, particularly when these events occur together.