Objective physical activity in people with young onset dementia, late onset dementia, and without dementia: A UK Biobank study

Background: Current physical activity literature does not distinguish between young (dementia diagnosed before 65) and late onset dementia despite differences between these groups such as age, being known to influence physical activity levels. Objective: The primary aim was to compare objective physical activity levels between people with young onset dementia, late onset dementia, and age-matched control participants without dementia. Methods: This cross-sectional analysis included four groups (young onset dementia [n = 23]; young onset control [n = 782]; late onset dementia [n = 30]; late onset control [n = 918]) of participants aged 49 to 76 (56% male) from the UK Biobank. Objective light intensity physical activity, moderate-vigorous intensity physical activity, sedentary behavior, and sleep were measured using 7-day wrist-worn accelerometry. Results: People with young onset dementia did more light and moderate-vigorous intensity physical activity than those with late onset dementia, with these differences becoming nonsignificant when controlling for age. There were no significant differences between people with young onset dementia and the young onset control group. Comparatively, people with late onset dementia did less light intensity physical activity and spent more time sedentary and sleeping than the late onset control group. Conclusions: This study highlights the distinct physical activity levels of people with young onset and late onset dementia. Future physical activity research should distinguish between young onset and late onset dementia. Such an approach will be important for producing findings that are more applicable for individuals diagnosed with dementia at all stages of life.