Study design
Background
Many previous observational cohort studies have identified modifiable risk factors for development of dementia, e.g. hypertension, hypercholesterolemia, diabetes, and obesity. Also protective factors, e.g. higher education, more frequent physical activity, healthy diet, and active lifestyle have been found.
The aim of the FINGER study was to investigate, if modification of these risk-and protective factors can influence cognitive performance among older adults, who have elevated risk for developing dementia.
Primary aim of the study was the change in cognitive function in two years. Secondary aims included analyses of physical functioning, activities of daily living, quality of life, depression, utilization of health resources, lifestyles, and risk factor levels.
Goal of the lifestyle intervention was to improve several lifestyles simultaneously, aiming for a sustainable and long-lasting lifestyle improvement. The effect of the intervention on longer-term outcomes like dementia are investigated by arranging follow-up measurements several years after the intervention.
Participants
The study recruited 1260 Finnish at-risk elderly persons from the general population aged 60-77 years at the beginning of the study. Participants were selected using a validated midlife dementia risk score and they needed to have at least some modifiable risk factors. The recruitment was done in six study centers in Finland (Helsinki, Kuopio, Oulu, Seinäjoki, Turku, Vantaa) among participants of previous nationally representative risk factor surveys (FINRISK and FIN-D2D).
Interventions
Participants were randomly assigned to either a multi-domain intervention or control group (1:1). The multi-domain intervention had 4 main components: nutrition; exercise; cognitive training (including a computer-based training program) and social activity; and monitoring of metabolic/vascular risk. The control group received regular health advice.
In the intensive intervention, dietary guidance was based on national recommendations, and it was executed as a combination of individual and group counselling. Special emphasis was given to fish, fruits and vegetables, and whole grain.
Exercise intervention consisted of strength training conducted at the gym combined with aerobic training and balance exercises, and was based on international guidelines. Intensity of training increased throughout the intervention period.
Cognitive training comprised group meetings and individual training with a computer-based program, which was developed based on previous studies. Training focused on episodic memory, executive function, processing speed, and working memory; domains that are typically first to decline with aging.
Management of metabolic and vascular risk factors was based on national evidence-based guidelines (Käypä hoito -recommendations, Current Care Guidelines), and it included additional meetings with the study nurse and the study physician for measurements and counselling and motivational discussion for lifestyle management.
Outcomes
All participants underwent cognitive evaluation at the beginning of the trial, and at the 1st and the 2nd year (primary outcome). They also meet the study nurse annually for measuring anthropometrics and collecting blood samples, which are used to analyse metabolic and vascular risk factors and genetic factors. In addition, several self-reported questionnaires are completed by the participants on e.g. lifestyles and quality of life. Data from national registries is also utilized, for example data for health care use (HILMO).
