Table 1.

Measurement instruments.

Instrument or assessment	Outcome
Background and Health Survey	Detailed demographic, health, and lifestyle characteristics
Intervention engagement	System reports of course enrolment and progression and newsletter engagement; self-report intervention and community activity engagement data
Knowledge of Dementia Risk Reduction Survey	Knowledge of dementia risk; recall and recognition of modifiable and nonmodifiable dementia risk factors
Motivation to Change Lifestyle and Health Behaviours for Dementia Risk Reduction Scale [40]	Beliefs and attitudes toward lifestyle and behavioral changes for dementia risk reduction
All Aspects of Health Literacy Scalea [43]	Functional, communicative, and critical health literacy
New General Self-Efficacy Scalea [42]	Perceived ability to achieve a range of different types of task.
Dementia Risk Profile	Behaviors affecting dementia risk factors: diagnosis, regular checks and management of cardiometabolic health; BMI; physical and cognitive activity; diet, alcohol consumption, and smoking
Hospital Anxiety and Depression Scale [48]	Symptom severity for 2 dimensions (anxiety and depression); pooled score indicates psychological distress
Perceived Stress Scalea [44]	Extent to which daily life is perceived as stressful
Lubben Social Network Scale [49]	Extent of social networks; 3 dimensions (family, neighbors and friends)
Assessment of Quality of Life [50]	Multiattribute utility instrument that generates psychometric and Quality of Life Years scores based on 8 dimensions of health-related quality of life: physical health (independent living, pain, and senses) and psychosocial health (mental health, happiness, coping, relationships, and self-worth)
Written reflection task [51]	Cognitive performance: idea density, grammar, and sentence construction
Talk2Me Online [23]	Cognitive performance: image naming, picture description, and audio files providing approximately 2000 lexicosyntactic, acoustic, and semantic features for analysis
Cambridge Neuropsychological Test Automated Battery Online [45]	Cognitive performance: Paired Associates Learning captures learning and recall of visual information over successive trials and is sensitive to cognitive decline in early Alzheimer disease and mild cognitive impairment [52] Spatial Working Memory assesses executive function, retention, and manipulation of visuospatial information
TAS Test [47]	Motor and cognitive performance using keyboard tapping, visuomotor reaction tests, and visuospatial working memory tests providing approximately 1000 motor-cognitive features for analysis
Blood samples	Biomarker levels indicative of dementia pathology (eg, beta-amyloid, phosphorylated tau, and neurofilament light) measured in plasma or serum using enzyme-linked immunoassay, SIMOA,b and mass spectrometry
Genetics	Candidate gene markers related to Alzheimer disease such as apolipoprotein epsilon-E and the brain-derived neurotrophic factor polymorphism measured via blood samples

^aInstruments only administered to some participants.

^bSIMOA: Single Molecule Array.