Trajectory of multimorbidity before dementia: A 24‐year follow‐up study.

INTRODUCTION: Although the multimorbidity–dementia association has been widely addressed, little is known on the long‐term trajectory of multimorbidity (TOM) in preclinical dementia. METHODS: Based on the Health and Retirement Study, burden of multimorbidity was quantified with the total number of eight long‐term conditions (LTC). Patterns of TOM before dementia diagnosis were investigated with mixed‐effects models. RESULTS: In 1752 dementia cases and 5256 matched controls, cases showed higher and faster increasing predicted number of LTC than controls, with a significant case–control difference from 20 years prior to dementia diagnosis. Larger increases in number of LTC during preclinical phase of dementia were found in White participants, females, those whose age at dementia onset was younger, and those who were less educated. DISCUSSION: Our findings emphasize the faster accumulation of multimorbidity in prodromal dementia than in natural aging, as well as effect modifications by age and sex. Highlights: TOM increased faster in prodromal dementia than in natural ageing.Patterns of TOM by dementia status diverged at 20 years before dementia diagnosis.Patterns of TOM were modified by age and sex. [ABSTRACT FROM AUTHOR]