Preventing cognitive decline – should interventions be multidimensional?
Research has associated several vascular (heart and blood vessels) and lifestyle-related risk factors with cognitive impairment in later life and Alzheimer’s disease. Indeed, an estimated third of Alzheimer’s disease cases worldwide have been reported to be attributable to seven modifiable factors (low education, hypertension, obesity, diabetes, physical inactivity, smoking and depression), providing prevention opportunities.
Cognitive impairment, dementia and Alzheimer’s disease are complex, multifactorial disorders and so multi-domain interventions targeting several risk factors and disease mechanisms simultaneously could be needed for optimum prevention effects.
Dementia is a multifactorial disorder, so does it need a multifactorial solution?
Such a multidimensional programme has been used in a new study published this week in The Lancet. The Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER), assessed the effects on brain function of a comprehensive intervention aimed at addressing some of the most important risk factors for age-related dementia, such as high body-mass index and heart health.
The study targeted ‘at risk’, older individuals, rather than patients in a clinical setting. Around 1200 people from across Finland, aged 60–77 years, deemed to be at risk of dementia, based on standardised test scores, were randomised to an intervention or control group.
Healthy eating, physical activity, brain training and medical management may help maintain cognitive function
The intervention included healthy eating guidance, incorporating similar dietary guidelines to the UK; 25-35% energy from fat, less than 10% energy from saturated fat, 25-35g fibre, less than 5g salt per day and less than 5% daily energy from alcohol. The main difference with current UK healthy eating advice was a higher fibre (25-35g vs 23g) and lower salt (5 vs 6g) recommendation. The intervention also involved individually tailored strength and aerobic activities, brain training exercise, and management of some dementia risk factors. The control group received standard health advice only.
After two years, study participants’ mental function was scored using a standard test, the Neuropsychological Test Battery (NTB), where a higher score corresponds to better mental functioning. Overall test scores in the intervention group were 25% higher than in the control group. For some parts of the test, the difference between groups was even more striking—for executive functioning (the brain’s ability to organise and regulate thought processes) scores were 83% higher in the intervention group, and processing speed was 150% higher. However, the intervention appeared to have no effect on patients’ memory.
Interventions in dementia may be more useful at pre-dementia or at risk stages
In light of the negative results in many nutrition or lifestyle trials in people with dementia, the focus of intervention may be more useful at pre-dementia or at-risk stages when intervention might not be too late. The study finding, suggesting a multidomain intervention can improve or maintain cognitive function among older at risk individuals, is perhaps most appropriately interpreted in a public health context, where small long-term lifestyle changes may have a potentially large impact.
The study participants will now be followed for at least seven years to determine whether the diminished cognitive decline seen in this trial is followed by reduced levels of dementia and Alzheimer’s diagnoses.
Watch this space!
*All information is correct at the time of publishing