METformin and FINGER Intervention to Prevent Cognitive Impairment and Disability in Older Adults at Risk for Dementia

Dementia is the main cause of disability in older adults, currently affecting about 50 million people world-wide with this number estimated to triple in the next 30 years. In MET-FINGER, we aim to understand whether the FINGER 2.0 multidomain intervention, combining healthy lifestyle changes and a drug for diabetes (metformin), may help reduce the risk of dementia and improve health and independence among older adults.

The study primary objective is to test the effect of the intervention, compared to healthy lifestyle advice, on the change in cognition, measured as a composite score including 14 of neuropsychological/cognitive tests. The secondary objective is to test the intervention effect on change in individual cognitive domains, functioning level, and risk factors for dementia (e.g., lifestyle, medical, and psychosocial). To this aim, a range of personal/health-related data and blood samples, will be collected. Potential interactions between metformin and lifestyle changes; potential disease-modifying effects; and feasibility of the metformin + lifestyle combination will be explored.

600 older people with risk factors for dementia, but without dementia/substantial cognitive impairment, will be recruited in the United Kingdom, Finland, and Sweden (at least 50% with higher genetic risk of Alzheimer's Disease/dementia based on the Apolipoprotein E (APOE) gene). Participants will be randomly assigned 1:1 to either a self-guided multidomain lifestyle intervention or to the FINGER 2.0 multidomain lifestyle-based intervention. Outcome assessors will be blinded to group allocation. Within the FINGER 2.0 intervention group, participants at increased risk of diabetes, will be randomly assigned 1:1:1 to either the metformin 2000mg/day, metformin 1000mg/day, or placebo group (double blinded). The intervention duration is 24 months.

The lifestyle intervention includes four main components: physical exercise, diet, brain training and health checks. In the self-guided group, participants will create their own program, based on health advice and recommendations which will be provided during the study. In the FINGER 2.0 intervention group, participants will receive intensive lifestyle guidance, and participate in structured activities, which will be as tailored as possible on each person's daily habits and needs.

Over the 2-year study period, all participants will attend four assessment visits: baseline, 6-, 12-, and 24-months.

After being identified and pre-screened in relevant registers, potential participants will undergo a screening assessment (after providing informed consent for the screening procedures) where inclusion criteria related to both cognition and cardiovascular/lifestyle risk factors will be checked. Participants meeting the inclusion criteria will undergo the exclusion criteria assessment with the study physician.

Eligible participants will be invited to the baseline visit where informed consent for the full study will be signed, baseline assessment will be conducted, and participants will be randomized to either the FINGER 2.0 multidomain lifestyle-based intervention or self-guided multidomain lifestyle intervention group. Based on the results of the baseline assessment, the eligibility to the metformin/placebo treatment will be assessed in all participants randomized to the FINGER 2.0 intervention group. Eligible participants will be further randomized to one of the three metformin treatment groups (metformin 2000mg/day, metformin 1000mg/day, or placebo). Non eligible participants will continue the study by following the structured lifestyle intervention alone.

In the self-guided intervention group, participants will build their own healthy lifestyle program based on standard healthy lifestyle advice that they will receive at individual consultations with the study physician/nurse as part of the visits.

Within the FINGER 2.0 intervention group, participants will be invited to attend individual consultations and group meeting sessions in relation to the four intervention components (diet, physical activity, cognitive training, and cardiovascular/metabolic risk monitoring). As part of the physical activity component, group training sessions with a physiotherapist/professional trainer will be organized both at a gym as well as online. Within the cognitive training component, participants will have access to an online cognitive training program for independent training sessions. Individually tailored recommendations and plans will be provided to each participant.

Metformin and placebo will be dispensed every 3 months, both administered orally. The active drug is Glucophage® XR 500. All participants randomized to the metformin/placebo groups will receive 4 identical tablets per day as follows:

* 2000mg/day: 4x500mg metformin
* 1000mg/day: 2x500mg metformin + 2x500mg placebo
* Placebo: 4x500mg placebo.

Metformin will be titrated weekly from 500mg/day up to 2000mg/day over 4 weeks. Participants who do not tolerate the treatment will be allowed to remain in the study either in a lower dose treatment group, or receiving the structured lifestyle intervention only.

Participants will not be actively told to what lifestyle intervention group they have been assigned and assessors for primary and secondary outcomes will be blinded to the lifestyle group allocation. The metformin/placebo treatment will be conducted in double blind.

Eligibility Criteria:
Inclusion Criteria:

* Main inclusion criteria (all participants)

  1. Age 60-79 years.
  2. Cardiovascular Risk Factors, Aging and Dementia (CAIDE) Risk Score ≥6 points.
  3. Cognitive performance at the mean level or slightly lower than expected for age according to local population norms based on the Montreal Cognitive Assessment (MoCA) test and the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) verbal learning test.
  4. Proficiency in the local language (English, Finnish or Swedish)
* Inclusion criteria for metformin/placebo treatment (only for participants in the FINGER 2.0 multimodal lifestyle-based intervention arm)

  1. No diagnosed diabetes or known contraindications to metformin treatment.
  2. Elevated adiposity (BMI≥25 kg/m2 OR waist circumference \> 102 cm in men and \> 88 cm in women) OR mildly impaired fasting glucose (6.1-6.9 mmol/l).

Exclusion Criteria:

* Main exclusion criteria (all participants)

  1. Dementia or substantial cognitive impairment (e.g., memory clinic referral needed as judged by the study physician).
  2. Current or past use of medications for Alzheimer's Disease or related diseases (e.g., cholinesterase inhibitors, memantine, aducanumab).
  3. Diminished decision-making capacity, not capable of consenting or completing study assessments, based on clinical judgement.
  4. Other known significant neurologic disease (including e.g., Parkinson's disease, Huntington's disease, normal pressure hydrocephalus, brain tumour, progressive, supranuclear palsy, seizure disorder, subdural hematoma, multiple sclerosis, or history of significant head trauma with persistent neurologic sequelae or known structural brain abnormalities).
  5. Any other condition affecting safe engagement in the intervention (e.g., malignant disease, major depression, symptomatic cardiovascular disease, revascularisation within the previous year).
  6. Severe loss of vision, hearing, or communicative ability; conditions preventing cooperation.
  7. Coincident participation in the active phase of another intervention trial.
  8. A member of the household already enrolled in the MET-FINGER trial
* Exclusion criteria for metformin/placebo treatment (only for participants in the FINGER 2.0 multimodal lifestyle-based intervention group)

  1. Use of metformin for any indication.
  2. History of intolerance to metformin used for any indication.
  3. Diabetes diagnosed or suspected at baseline (e.g., HbA1c≥6.5%, fasting glucose ≥7 mmol/l, or 2HPG≥11.1 mmol/l).
  4. Metformin contraindications, e.g., history/presence of known renal or liver disease, congestive heart failure, alcohol abuse, calculated Glomerular Filtration Rate\<60 ml/min.