Analysis reveals extent of undiagnosed type 2 diabetes

Analysis of data by the Office for National Statistics (ONS) has provided new insights into the risk factors for prediabetes and undiagnosed type 2 diabetes. The analysis made use of data collected by the Health Survey for England (HSE).

The HSE annually surveys a representative sample of the population living in private households in England. Its process includes an interview with participants to provide demographic information and the collection of blood samples for testing. The total sample size of 26,751 was achieved by combining data from 2013 to 2019.

The analysis found that:

• Around 7% of adults showed evidence of type 2 diabetes (HbA_1c ≥48 mmol/mol), and that 30% of these – approximately 1 million adults – were undiagnosed.
• Older adults were more likely to have type 2 diabetes, but younger adults were more likely to be undiagnosed – 50% of those aged 16–44 years with type 2 diabetes were undiagnosed compared with 27% of those aged ≥75 years.
• Those in better general health and women with a lower BMI, lower waist circumference or who were not prescribed antidepressants were more likely to be undiagnosed. 
• Around 12% had prediabetes (HbA_1c 42–47 mmol/mol), equating to approximately 5.1 million adults. 
• Those most at risk of having prediabetes had known risk factors for type 2 diabetes, such as older age or being overweight or obese. There was, however, considerable prevalence in those typically considered to be at low risk – 4% of those aged 16–44 years and 8% of those who were not overweight had prediabetes.
• Black and Asian ethnic groups had a higher prevalence of prediabetes compared with White, Mixed and Other ethnic groups (22% vs 10%) and of undiagnosed type 2 diabetes (5% vs 2%).

The high number of people who are unaware of their diabetes or prediabetes is of great concern, as they are not receiving the treatment and support that they require to reduce the risk of developing health complications. The ONS analysis provides a greater understanding of this population, which may enable resources to be better directed to the areas where they are most needed.

The data is available here.