Diabetes: undiagnosed diabetes

Type 2 diabetes is more common in middle-aged and older people. Being overweight greatly increases the risk of type 2 diabetes. People with type 2 diabetes may have few symptoms and as a result many cases are not diagnosed. This section presents the results of an exercise to predict the number of undiagnosed cases of diabetes in Scotland using 2005 data from the Scottish Diabetes Survey together with predictions from the PBS diabetes model.

Predicting numbers of diabetes cases

Statistical models can provide approximate estimates of the number of diabetes cases. The Public Health Observatories/Brent/ScHARR (PBS) model is a prediction model used to estimate the true number of diabetes cases in an area (1). It is based on studies in Coventry, Brent and Clwyd. It takes into account the age, sex and ethnic group make-up of an area, but does not take into account local levels of obesity. The PBS model has been used to estimate the true number of diabetes cases in each NHS Board in Scotland. This can be compared with the number of known cases to estimate the number of undiagnosed cases. These figures are shown in Table 1 and the proportions undiagnosed are shown in Chart 1. More detailed information about the methods used to produce these estimates is available here.

(1) More information on the PBS model is available in a briefing paper (223k) available from the Yorkshire and Humber Public Health Observatory website.

Table 1: Estimated number of undiagnosed cases of diabetes in Scotland by NHS board, 2005

Source: Public Health Observatories/Brent/ScHARR (PBS) model and Scottish Diabetes Survey 2005.

(1) Argyll & Clyde data are for 2004 as figures for 2005 were low because of IT problems.

Click on the chart(s) below to view a full-sized detailed version in a new window

Chart 1