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The incidence of type 2 diabetes in the United Kingdom from 1991 to 2010

Authors


Correspondence to: Prof. Craig J. Currie, Professor of Applied Pharmacoepidemiology, School of Medicine, Cardiff University, The Pharma Research Centre, Cardiff MediCentre, Cardiff CF14 4UJ, UK. E-mail: currie@cardiff.ac.uk

Abstract

Aims

To characterize the incidence of type 2 diabetes in the UK over the previous 20 years; and determine if there has been an increase in people aged 40 years or less at diagnosis.

Methods

For this retrospective cohort study, patients newly diagnosed with type 2 diabetes between 1991 and 2010 were identified from the UK Clinical Practice Research Datalink (CPRD). Patient data were grouped into 5-year intervals by year of diagnosis and age at diagnosis. A standardized incidence ratio (SIR) was determined (1991–1995 = 100). The percentage of newly diagnosed patients for each age group and aged ≤40 years was calculated for each 5-year calendar period. The incidence rate by age and 5-year calendar period was also determined.

Results

In 2010, the crude incidence rate of type 2 diabetes was 515 per 100,000 population. The overall SIR increased to 158 (95% CI 157–160, p < 0.001), 237 (235–238, p < 0.001) and 275 (273–276, p < 0.001) for 1996–2000, 2001–2005 and 2006–2010, respectively. For those ≤40, the respective values were 217 (209–226, p < 0.001), 327 (320–335, p < 0.001) and 598 (589–608, p < 0.001). An increase in incidence occurred with increasing 5-year calendar period. The incidence of type 2 diabetes was higher for males after the age of 40 and higher for females aged ≤40. The percentage of patients aged ≤40 years at diagnosis increased with each increasing 5-year calendar period (5.9, 8.4, 8.5 and 12.4%, respectively).

Conclusions

There was a significant increase in the incidence of diagnosed type 2 diabetes between 1991 and 2010 and the proportion of people diagnosed at a relatively early age has increased markedly.

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