CrossHow the population was sampled

Random samples of people in their 65th year and above were obtained from Family Health Service Authority lists from each centre. The sample was stratified by age group (65-74 years and 75 years and over) and equal numbers were randomly selected from each age group to produce an overall sample size of approximately 2500 people in each of the areas. The exceptions to this were the centre in Liverpool which aimed to achieve a sample size of 6000, and CFAS Wales , which aimed to interview a representative sample of 3750 people in two areas in Wales (Gwynedd and Swansea). 

The CFAS centres were chosen to represent the national variation with regards to urban-rural, socio-economic levels and in known rates of chronic disease. At both time points all centres had existing researchers with experience in this type of study.

The CFAS I (Between 1989-1993) has six centres across England and Wales: Cambridgeshire, Gwynedd, Newcastle, Nottingham, Oxford, Liverpool. Five of the centres started in 1991 follow an identical study design, while the centre in Liverpool, which was established earlier in 1989, has a different design.

The CFAS II (Between 2008-2011) initially has three centres follow an identical study design across England: Newcastle upon Tyne, Nottingham and Cambridgeshire (consisting of the rural area of East Cambridgeshire and Fenland centered on Ely and surrounding villages), with addition of CFAS wales (Gwynedd and Swansea), funding approved in 2010 later than others in CFAS II with a different sample size.

Timetable of the main CFA Studies

Studies of incidence and natural history require interviews at a minimum of two points in time, sufficiently separated for change in mental/physical function to be identifiable. 


First meeting with the participants in CFAS I (1989-1993)

  • The first interviews established level of cognitive performance and baseline risk factors on all individuals. The interviews were designed to be fully sensitive to dementia.
  • The centre in Liverpool started interviews in 1989.
  • All other 5 centres started interviews in 1991, roughly 3 months later all the participants identified by the first interviews as possible cases of dementia had a more detailed assessment interview. In addition a sample of those participants not suspected of having dementia was also interviewed. In total 20% of the original sample had the assessment interview.

These interviews allowed CFAS to estimate the prevalence of dementia in the population.

Interviews to identify new cases of dementia (1993/94)

  • After 2 years the participants who had not been identified as potential cases of dementia at the first interview were retested
  • Those that were identified as possible new cases of dementia then had a more detailed assessment.

The number of new cases identified allowed CFAS to estimate the incidence of dementia in the population.

Follow-up of Participants

Throughout the study a subgroup of the participants has been seen every year and further interviews of other selected participants took place in 1997, 1999 and 2001.

In 2002/3 all survivors in the Cambridgeshire, Gwynedd, Newcastle, Nottingham and Oxford centres were approached by the study and 3145 were re-interviewed.

 

 

Health and Society

CFA Studies

Aims of the CFA Studies
Design of the CFA Studies
Biological Samples

Summary of Findings

Prevalence of Dementia
Prevalence of Dementia in Institutional Care
Incidence of Dementia
Risk Factors for Dementia
Disability and Healthy Ageing
Costs of Dementia
Healthy Active Life Expectancy
Neuropathology

Supplementary Information From Publications

Operationalisation of Mild Cognitive Impairment