This study tested the hypothesis that mid-life intellectual, physical and social activities contribute to cognitive reserve (CR). Two hundred and five individuals (196 with MRI) aged 66-88 from the Cambridge Centre for Ageing and Neuroscience (www.cam-can.com) were studied, with cognitive ability and structural brain health measured as fluid IQ and total grey matter volume, respectively. Mid-life activities were measured using the Lifetime of Experiences Questionnaire. Multivariable linear regression found that mid-life activities (MA) made a unique contribution to late-life cognitive ability independent of education, occupation and late-life activities. Crucially, MA moderated the relationship between late-life cognitive ability and brain health, with the cognitive ability of people with higher MA less dependent on their brain structure, consistent with the concept of CR.

In conclusion, mid-life activities contribute uniquely to CR. The modifiability of these activities has implications for public health initiatives aimed at dementia prevention.