About Twenty-07: Who takes part in the Study?
The Study was originally located in the Central Clydeside Conurbation (CCC), a socially mixed and mainly urban area which includes the City of Glasgow and, in 1986 had a population of around 1.7 million.
In the beginning, the Study comprised two distinct but connected samples:
The Regional Sample is the core of the Study and participants in each cohort are representative of the general population living within the Study area.
In order to select suitable volunteers, every local government district in the Central Clydeside Conurbation area was listed according to its level of employment and socio-economic group, using data from the 1981 Census. Fifty-two postcode sectors were then chosen from this list, and individuals were then selected from these postcode sectors within each age cohort. The same postcode sectors were chosen for all three age cohorts, and if two individuals were selected from the same household, one was replaced.
The aim of the Locality Sample is to focus more intensively on the relationship between an individual’s circumstances and their health and the environment in which they live. The two localities in the Study are the North West and South West areas of the city of Glasgow. These were chosen deliberately to capture different socio-economic experiences and environments. When the Study began, the North West area of the city was more middle class while the south west area was more working class. Both areas, however, contained a lot of variation in the population.
By having two localities within the study, we can build up a much more detailed picture of local social, economic and physical environments, and then assess the impact of these on health alongside an individual’s own characteristics.
While participants originally lived in the Study area in 1986, many have subsequently moved. We try to stay in touch with all study members wherever they move to, and interview all those living in the UK.