Key Findings

This page contains some of the key findings of comparisons of the MRC CFAS and CFAS II studies. To read the results in more detail please click on the finder headings.

A two decade dementia incidence comparison from the Cognitive Function and Ageing Studies I and II – A multicentre population-based study powered to detect changes over time has reported dementia incidence, estimating 209,600 new dementia cases per year.

Prevalence of Dementia in England and Wales – a two decade comparison – This study provides further evidence that a cohort effect exists in dementia prevalence. Later-born populations have a lower risk of prevalent dementia than those born earlier in the past century.

Changing non-participation in epidemiological studies of older people: evidence from the Cognitive Function and Ageing Study I and II – An investigation into the demographic characteristics of respondents and non-respondents in MRC CFAS and CFAS II.

Dementia in western Europe: epidemiological evidence and implications for policy making – A study comparing the incidence and prevalence of dementia across western Europe with studies from Sweden (Stockholm and Gothenburg), the Netherlands (Rotterdam), the UK (England – MRC CFAS and CFAS II), and Spain (Zaragoza). Findings suggest that over the past two to three decades, the occurrence of dementia is stabilising not rising across western Europe.

 

A two decade dementia incidence comparison from the Cognitive Function and Ageing Studies I and II

The Cognitive Function and Ageing Studies has examined dementia in older people aged 65+ for over two decades. Incidence (new cases/population/time) is the best measure for comparing change between populations. CFAS II measured dementia in 3 sites across the UK finding a marked drop in incidence of dementia age for age in the 65+ population, mostly driven by changes in men. There have been major changes in health in people aged 65 and over during this period, with longer life and reductions in risk factors (e.g. smoking), increases in protective factors (e.g. education) and better management of some health conditions. This study is robust because the same methods were used at each time point so the change is not just because of changes in the way that we measure dementia.

Findings

At 2 years CFAS I interviewed 5,156 (76% response) with 5,288 interviewed in CFAS II (74% response). Here we report a 20% drop in incidence (95% CI: 0–40%), driven by a reduction in men across all ages above 65. 

Interpretation

In the UK we estimate 209,600 new dementia cases per year. This study was uniquely designed to test for differences across geography and time. A reduction of age-specific incidence means that the numbers of people estimated to develop dementia in any year has remained relatively stable.

Reference

A two decade dementia incidence comparison from the Cognitive Function and Ageing Studies I and II. Matthews FE, Stephan BCM, Robinson L, Jagger C, Barnes LE, Arthur A, Brayne C, Cognitive Function and Ageing Studies (CFAS) Collaboration. 2016, Nature Communications

 

Prevalence of Dementia in England and Wales – a two decade comparison

The prevalence of dementia is of interest worldwide. Contemporary estimates are needed to plan for future care provision, but much evidence is decades old. We aimed to investigate whether the prevalence of dementia had changed in the past two decades by repeating the same approach and diagnostic methods as used in the Medical Research Council Cognitive Function and Ageing Study (MRC CFAS) in three of the original study areas in England.

Findings

7635 people aged 65 years or older were interviewed in CFAS I (9602 approached, 80% response) in Cambridgeshire, Newcastle, and Nottingham, with 1457 being diagnostically assessed. In the same geographical areas, the CFAS II investigators interviewed 7796 individuals (14 242 approached, 242 with limited frailty information, 56% response). Using CFAS I age and sex specific estimates of prevalence in individuals aged 65 years or older, standardised to the 2011 population, 8·3% (884 000) of this population would be expected to have dementia in 2011. However, CFAS II shows that the prevalence is lower (6·5%; 670 000), a decrease of 1·8% (odds ratio for CFAS II vs CFAS I 0·7, 95% CI 0·6–0·9, p=0·003). Sensitivity analyses suggest that these estimates are robust to the change in response.

Interpretation

This study provides further evidence that a cohort effect exists in dementia prevalence. Later-born populations have a lower risk of prevalent dementia than those born earlier in the past century.

Reference

A two-decade comparison of prevalence of dementia in individuals aged 65 years and older from three geographical areas of England: results of the Cognitive Function and Ageing Study I and II – Fiona E Matthews, Antony Arthur, Linda E Barnes, John Bond, Carol Jagger, Louise Robinson, Carol Brayne, on behalf of the Medical Research Council Cognitive Function and Ageing Collaboration.  Lancet, 2013, Matthews FE 

 

Changing non-participation in epidemiological studies of older people: evidence from the Cognitive Function and Ageing Study I and II

As non-participation in epidemiological studies can threaten the generalisability of the findings, this investigation aimed to explore the change in non-participation between CFAS I and CFAS II. Comparisons of the demographic factors associated with non-participation were observed across the two studies.

Findings

Non-participation was found to be higher in CFAS II (45.3%) than in CFAS I (18.3%). After adjustments were made for counfounders, in both CFAS I and CFAS II, women were more likely to decline to take part (CFAS I: odds ratio (OR) 1.3 95% confidence interval (CI) 1.3 to 1.4; CFAS II: 1.1 95% CI 1.1 to 1.2). Deprivation was associated with non-participation in both studies (highest versus lowest Townsend deprivation quintile, CFAS I: OR 1.4 95% CI 1.2 to 1.6; CFAS II: 2.0 95% CI 1.8 to 2.2). Age was not associated with non-participation in either study (CFAS I, p=0.21; CFAS II,  p=0.47).

Interpretation

Non-participation in epidemiological studies of older people has increased substantially in the past two decades and public willingness to take part in studies of this kind would appear to be declining. As communities become more diverse and older people have increasing commitments on their time, new ways to engage prospective participants are urgently needed.

Reference

Changing non-participation in epidemiological studies of older people: evidence from the Cognitive Function and Ageing Study I and II – Lu Gao, Emma Green, Linda E Barnes, Carol Brayne, Fiona E Matthews, Louise Robinson, Antony Arthur, on behalf of the Medical Research Council Cognitive Function and Ageing Collaboration. Age Ageing, 2015, Gao L

 

Dementia in western Europe: epidemiological evidence and implications for policy making

Dementia is receiving increasing attention from governments and politicians. Epidemiological research based on western European populations done 20 years ago provided key initial evidence for dementia policy making, but these estimates are now out of date because of changes in life expectancy, living conditions, and health profiles. To assess whether dementia occurrence has changed during the past 20- 30 years, investigators of five different studies done in western Europe (Sweden [Stockholm and Gothenburg], the Netherlands [Rotterdam], the UK [England], and Spain [Zaragoza]) have compared dementia occurrence using consistent research methods between two timepoints in welldefined geographical areas. 

Findings

Findings from four of the five studies showed non-significant changes in overall dementia occurrence. The only significant reduction in overall prevalence was found in the study done in the UK, powered and designed explicitly from its outset to detect change across generations (decrease in prevalence of 22%; p=0·003). Findings from the study done in Zaragoza (Spain) showed a significant reduction in dementia prevalence in men (43%; p=0·0002). The studies estimating incidence done in Stockholm and Rotterdam reported non-significant reductions. Such reductions could be the outcomes from earlier population-level investments such as improved education and living conditions, and better prevention and treatment of vascular and chronic conditions. 

Interpretation

This evidence suggests that attention to optimum health early in life might benefit cognitive health late in life. Policy planning and future research should be balanced across primary (policies reducing risk and increasing cognitive reserve), secondary (early detection and screening), and tertiary (once dementia is present) prevention. Each has their place, but upstream primary prevention has the largest effect on reduction of later dementia occurrence and disability.

Reference

Dementia in western Europe: epidemiological evidence and implications for policy making – Yu-Tzu Wu, Laura Fratiglioni, Fiona E Matthews, Antonio Lobo, Monique M B Breteler, Ingmar Skoog, Carol Brayne. Lancet, 2015, Wu YT