The association between adverse experiences throughout the life-course and risk of dementia in the English Longitudinal Study of Ageing.

Introduction: Studies investigating the association between adverse experiences across the life-course and dementia consider a narrow range of experiences and use sum scores, assuming each experience has the same impact on dementia risk. We considered the timing, type and cumulation of adverse experiences. Methods: The English Longitudinal Study of Ageing measured adverse experiences in a retrospective interview. Cox proportional hazard models were used to investigate associations between dementia and sum adversity scores, individual experiences, and broad categories adapted from existing frameworks. Results: Number of adult, but not total or childhood, adverse experiences was associated with dementia. Child abuse and adult economic hardship were associated with a 74% and 32% higher hazard of dementia respectively. Discussion: Adulthood adverse experiences associate with dementia in a cumulative risk manner. In childhood, only abuse was associated with dementia. Use of sum scores to summarise adverse experiences throughout the life-course may oversimplify associations with dementia.