Occupational complexity and neuroimaging measures of structural MRI and PET‐amyloid in a randomized controlled trial: FINGER

Background Higher occupational complexity has been associated with better cognition in late life, but associations with brain changes remain unclear. We assessedwhether occupational complexity was associated with baseline brain structural MRI measures and PIB‐PET amyloid burden in the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER). Method FINGER is a two‐year, population‐based, multicenter, multidomain randomized controlled trial. Inclusion criteria included age 60‐77 years; Cardiovascular Risk Factors, Aging and Dementia Risk Score of at least 6; cognition at a mean level or slightly lower than expected for age. Participants (n=1260) were randomly assigned in a 1:1 ratio to a multidomain intervention group (diet, exercise, cognitive training, vascular risk management) or a group receiving general health advice. Primary outcome was change in cognition (Neuropsychological Test Battery). Occupational complexity with data, people, and substantive complexity were classified through the Dictionary of Occupational Titles. The MRI analyses included a subgroup of 126 participants from three different FINGER study sites and the PiB‐PET measures included 42 participants from one study site. MRI regional cortical thickness and volumes were measured using the Freesurfer image analysis suite (version 5.0.3). Linear, logistic, and ordinal logistic regression models were used to assess the association between occupational complexity and neuroimaging measures, adjusting for age, sex, education, intracranial volume, and study site. Neuroimaging assessments included hippocampal and total gray matter volume, Alzheimer´s disease signature thickness, visually rated medial temporal atrophy (MTA), and amyloid accumulation. Result There was no association between occupational complexity and brain cortical thickness, volume measures, or PiB‐PET measures. Conclusion No association between occupational complexity and brain structure and amyloid burden was found in older adults at increased risk of dementia. These findings should be verified in larger cohorts.