Exposures and conditions prior to age 16 are associated with incidence of dementia status among adults in the United States Health and Retirement Study

Background: Dementia and cognitive impairment are prevalent conditions, and susceptibility likely begins years before symptoms. Early life has not been comprehensively tested for potential risk factors for dementia. Objective: To explore the associations between childhood conditions and exposures and cognitive impairment in adulthood. Methods: In the US Health and Retirement Study (normal baseline cognition; n = 16,509; 2008–2018 waves), 31 exposures before age 16 were retrospectively assessed with ten-year incident cognitive status (dementia, impaired, normal). Using parallel modified Poisson models, each exposure was tested with incident cognition, adjusting for sex, baseline age, follow-up, race/ethnicity, personal/parental education. Results: Among the analytic sample, participants were mean 61 years of age at baseline and all had normal cognition. During up to 10 years of follow-up, 14.5% developed cognitive impairment and 5.3% developed dementia. Participants with depression during childhood had 1.49 (95%CI:1.2,1.84) times higher risk of incident impairment, relative to normal cognition. Participants with headaches/migraines during childhood had 1.43 (95%CI:1.14,1.79) times higher risk of incidence of dementia. Participants with learning problems during childhood had 1.71 (95%CI:1.44,2.03) times higher risk of incident impairment. Childhood self-rated health of fair (1.59, 95%CI:1.2,2.1) and poor (2.42, 95%CI:1.62,3.61) had higher risk of incidence of dementia, relative to excellent self-rated health. Associations between additional exposures and either incident impairment or dementia did not reach the multiple testing threshold (false discovery rate < 0.01). Conclusions: Conditions and exposures during the early life period may be important for later life cognitive impairment or dementia. These findings support extending the relevant dementia risk window to evaluate childhood.