Dementia, disability and frailty in later life – mid-life approaches to delay or prevent onset

Gaps in the evidence

The Public Health Advisory Committee (PHAC) identified a number of gaps in the evidence related to the programmes under examination based on an assessment of the evidence and stakeholder comments. These gaps are set out below.

1. There is a lack of evidence on the relationship between psychosocial risk and protective factors in mid-life and the development of dementia, disability and frailty in later life, including cognitive and social activities. (Source: Expert paper 7; Evidence review 2)

2. There is a lack of evidence on the effectiveness and cost‑effectiveness of interventions for people in mid‑life to address behavioural and psychosocial risk factors and their long‑term impact on the delay or prevention of dementia, disability and frailty. (Source: Evidence review 3)

3. There are a lack of epidemiological studies that relate changes in behavioural risk factors and protective factors designed to detect trends in dementia disease prevalence and incidence. (Source: Evidence review 2)

4. There is a lack of long‑term follow up, retention data and reporting of disease and mortality outcomes and compression of morbidity data from intervention studies. (Source: Evidence review 3)

5. There is a lack of evidence on the clustering of the different physical and psychosocial risk factors, the relationships between the risk factors, compensatory behaviours when a risk factor is changed and which risk factors to address first. (Source: Evidence review 2)

6. There is a lack of evidence on the associations between hearing loss, visual loss and dementia, disability and frailty, the effectiveness and cost‑effectiveness of interventions to prevent and manage hearing and visual loss on the development of dementia, disability and frailty. (Source: Evidence reviews 2 and 3; Expert paper 10)

7. There is a lack of evidence on the associations of sleep disorders and the development of dementia, disability and frailty and the effectiveness and cost‑effectiveness of interventions to improve sleep. (Source: Expert paper 4; Evidence reviews 2 and 3)

8. There is a lack of evidence on the effectiveness and cost‑effectiveness of interventions in mid‑life to prevent falls in later life. (Source: Evidence review 3)

9. There is a lack of evidence on the effectiveness and cost‑effectiveness, and acceptability of different ways of communicating risk to increase the person's understanding of their risk and to motivate them to make changes.

10. There is a lack of evidence on whether dementia can truly be preventable or whether it is only the onset that can be delayed, and on which types of dementia are most influenced by modifiable risk factors. (Source: Evidence review 3)

11. There is a lack of evidence on the effects of the NHS Health Check Programme on delaying or preventing of dementia, disability and frailty. (Source: Expert paper 8)

12. There is a lack of evidence on the effectiveness and cost‑effectiveness of financial and other incentives to change behaviours that increase risk, and their impact on dementia, disability and frailty outcomes. (Source: Evidence review 3).

The Committee made 5 recommendations for research into areas that it believes will be a priority for developing future guidelines. These are listed in recommendations for research.