Background and aims: The prevalence of type 2 diabetes (T2DM) is increasing at an alarming rate worldwide. The prevalence of T2DM in Iceland has been comparatively low. The aim of this study is to estimate the prevalence of T2DM in Iceland from 1967-2002 using American Diabetic Association (ADA) '97 criteria and to assess the effect of employing three different diagnostic criteria: World Health Organization (WHO) '85, ADA'97, WHO'99.
Materials and methods: This study is based on data from the Icelandic Heart Association (IHA), mostly from a representative random sample of the Icelandic population (The Reykjavik Study). The total population of this survey is 16393, 7852 males and 8541 females, aged 45-64. The study period was divided into five equal size cross-sectional periods, each about 6 years. The prevalence of T2DM was computed for every period.
Results: The age-standardized prevalence (95% CI) of T2DM in males, computed according to ADA'97 criteria has in a 30 year period risen from 3.3% (2.6-4.0) to 4.9% (3.5-5.3) which is an increase of 48%. In females the prevalence rose from 1.9% (1.4-2.4) to 2.9% (1.9-3.9) in the same period, a 53% increase. The Ratio of unknown T2DM is 0.66. Prevalence of T2DM in obese males and females is 10.6% (95% CI: 8.6-12.6) and 7.1% (95% CI: 5.5-8.7) respectively.
Conclusion: The prevalence of T2DM is now increasing in Iceland as in the rest of the world although the increase has taken place somewhat later than elsewhere. The prevalence of T2DM is however still relatively low when compared to other western countries. Early detection of T2DM is of importance and screening should be used according to clinical guidelines. The current increase in T2DM is most likely due to increasing obesity.