The Cambridge City over-75s Cohort Study (CC75C) is a long-term follow-up study of a representative population-based sample of older people which started in 1985 from a survey of over 2,600 men and women aged 75 and above.
Professor Carol Brayne, Dr Tom R Dening, Dr Jane Fleming, Professor Felicia A Huppert, Professor Eugene S Paykel.
For further information contact:
Professor Carol Brayne
Department of Public Health and Primary Care
Institute of Public Health
University Forvie Site
Cambridge CB2 0SR
Tel: (44) 1223 330334
Fax: (44) 1223 330330
The older people who have taken part – and those still taking part – in this study make up a unique group: the Cambridge City over-75s Cohort (CC75C). Through a series of interviews and assessments spanning over 20 years they have contributed to one of the largest and longest-running longitudinal observational studies of ageing into older old age.
The study’s origins lie in a survey of dementia prevalence, the Hughes Hall Project for Later Life (D.W. O'Connor, P. Pollitt), which began in 1985 and its first follow-up dementia incidence study, the Cambridge Project for Later Life (C. Brayne, F.A. Huppert, E.S. Paykel). The initial study targeted all men and women aged 75 or older who were registered with a selection of geographically and socially representative general practices in Cambridge, and achieved a 95% response rate in six of the seven practices. From this original survey of 2610 people, 2166 individuals form the baseline sample for the longitudinal cohort. This excluded participants enrolled through one of the practices because of differential recruitment and also a sub-group involved in a concurrent intervention study. It is the survivors from this group – now known as the Cambridge City over-75s Cohort – who have been followed up on at least six further occasions, with sub-groups assessed more often. Those still alive now continue to be followed up, all of them at least in their late 90s, some now centenarians.
Each follow-up survey has included the Cambridge Cognitive Examination (CAMCOG), a detailed cognitive assessment that includes the Mini-Mental State Examination (MMSE). Sub-samples have had detailed psychiatric assessment using the Cambridge Diagnostic Examination for the Elderly (CAMDEX) interview, detailed neuropsychological assessment and additional tests. Longitudinal data are also available on socio-demographic variables (e.g. change of residence, household structure, change in marital status, social contact), activities of daily living, use of health and social services, health problems and medication, self-rated health and subjective well-being. Biological resources collected include blood and saliva samples, whilst the brain donation programme has made it possible to undertake neuropathological and molecular biological analyses on tissue from a representative sample of elderly people. Functional performance testing and heel ultrasound measurements of bone fragility were introduced in the sixth interview wave, which also included a year's prospective falls data collection. The focus of the latest survey was on quality of life issues at the end of life for which we have been interviewing relatives or carers of surviving members of the cohort all aged 95 or more, as well as these study participants themselves. Currently follow-up is still on-going with collaborative interviews to highlight the contribution to research of those who intend to donate brain tissue. CC75C is one of only six studies worldwide with population-based brain donor collections and this resource is now part of the EclipSE collaboration (The Epidemiological Clinicopathological Studies in Europe http://www.eclipsestudy.eu/).
Secure funding for longitudinal studies in the UK is difficult to achieve, but over the course of the study we have been successful in raising grants from numerous sources and attracting a high calibre of scientific collaborators, including students and visitors, to join the study personnel. To date, there have been more than a hundred publications arising from the study.