Estimating the number of people with Down’s syndrome in Scotland and the cohort at elevated risk of early onset dementia

Abstract

Purpose The purpose of this paper is to estimate the size of the population of people with Down’s syndrome in Scotland in order to provide a basis for estimating likely numbers of people with dementia in Down’s syndrome at a range of ages. Design/methodology/approach Recorded data were requested from all general practitioner (GP) services in Scotland on people with an identified READ code denoting Down’s syndrome. A statistical weighting model was then applied to account for non-response bias. Findings There were 3,261 people with Down’s syndrome estimated by the application of a statistical weighting model. Of these, 1,118 people (34 percent) were aged between 40 and 59. This age banding includes the age groups reported as having the highest incidence of early onset dementia in Down’s syndrome. Research limitations/implications It is not possible to apply a benchmark to the percentage of observed data which gives an indication of how accurate the estimates produced are. Rather, the quality of the estimates depends on the response rate itself and the extent to which response is correlated with the outcome variable. In short, the quality of the final weighted estimates depends on the extent to which the biasing effect is mitigated by the weighting. As a result, a different response rate to this survey would have resulted in variations in the weighting model and therefore provided a different set of estimates. Social implications Adults with Down’s syndrome have an elevated risk of developing dementia significantly earlier than the general population and require specific age appropriate supports and services to meet their needs both pre and post-diagnosis. The reality of this is currently not fully realized in either standard practice or national policy concerning the issue. Originality/value This is the first set of data collected from GP services in Scotland to examine this issue and attempt to identify the population of people with Down’s syndrome in Scotland as a whole.