Substantial differences in diabetes prevalence among countries

The best way to estimate diabetes prevalence is the oral glucose tolerance test (OGTT). OGTT will detect irregularities in sugar metabolism in both individuals with previously diagnosed type 1 and type 2 diabetes, and those who do not know they have the disease. These data are usually collected in special (often regional) surveys and not by routine monitoring. According to this criterion, an estimated 8.6% of the adult (20-79 years) EU-27 population has diabetes, and country estimates range from 4.0% in the United Kingdom to 11.8% in Germany (IDF, 2006b); see Prevalence of diabetes in 2007 and estimates for 2025.

Data presented in Prevalence of diabetes mellitus in some EU countries are standardised according to the standard European population (Doll & Cook, 1967). This enables better comparisons among countries. The age-standardised prevalence of previously diagnosed and newly diagnosed diabetes together for the age group 30-64 years, ranges from 4.9% in Swedish men to 8.7% in English men. For women, it ranges from 4.0% in Italy to 7.2% in Spain. Among people between 65-74 years, the age-standardised prevalence is higher and ranges from 11.4% in Polish men to 22.6% in German men and from 13.1% in English women to 27.7% in Spanish women. The presented data are calculated from data given by the DECODE comparative study and a few additional recent surveys (DECODE Study Group, 2003; Rathmann et al., 2003; Glümer et al., 2003, ERGO-study). The IDF and the DECODE study rely (for the majority) on the same cohort studies. However, the numbers presented are different because different WHO diagnostic criteria were used and because IDF data are standardised according to the standard world population (see remarks under the presented table and figure for further explanation).

The prevalence of diabetes known to general practitioners (GPs) in different European countries shows less variation. For all ages, the prevalence known to GPs ranged from 1.6% in Slovenian men and women, to 3.1% in Belgian men and 3.4% in Belgian women (Fleming et al., 2004). These numbers are lower than the prevalence in the DECODE Study and theIDF database because the percentage of undiagnosed diabetes patients is not included.

Prevalence increases with age

Diabetes prevalence clearly increases with age (see Prevalence of diabetes mellitus in some EU countries). This increase is mainly due to the increase in type 2 diabetes. Of all diabetes patients, 90% have type 2 diabetes (WHO, 2006a; IDF, 2006b). Type 1 diabetes used to be the most frequent type of diabetes among children. However, type 2 diabetes is increasingly seen among children and adolescents as well (WHO, 2006a; IDF, 2006b).

Higher prevalence among lower socio-economic groups

Diabetes shows higher prevalence among lower socio-economic groups (with education as socio-economic indicator) as compared to higher socio-economic groups. The differences in diabetes prevalence between socio-economic groups are larger in women than in men. In men, the majority of countries show only small differences, while in women the association between the socio-economic position and diabetes prevalence is more clear. Both in men and in women differences are more accentuated in Western countries (Dalstra et al., 2005; Eurothine, 2007).

See also: EUphocus: Health inequalities.

No sex differences in diabetes prevalence

There is no clear sex difference in the overall diabetes prevalence. In most of the study cohorts of the DECODE study, the prevalence of previously undiagnosed diabetes, defined by isolated 2 hour post load hyperglycemia was higher in women. In contrast, the prevalence of undiagnosed diabetes defined by isolated fasting hyperglycemia was higher in men. The prevalence of known diabetes did not differ between men and women, except in people older than 80 years (DECODE Study Group, 2003).

Diabetes prevalence is expected to increase

Although increases in diabetes have already occurred globally, they have been especially dramatic in developing countries (WHO, 2003b; Passa, 2002).

The absolute number of people with diabetes in the EU-27 is estimated to rise even further, from approximately 31 million in 2007 to 37 million in 2025. That implies a rise from 8.6% to 10.2% of the total population. These figures are based on current age and gender specific prevalence rates. It is likely that age-specific prevalence rates will rise due to the increasing frequency of obesity (IDF, 2006a). These projections thus probably underestimate the factual 2025 prevalence.

More recent data expected to be available in 2007

By the end of 2007 more recent diabetes prevalence data will become available from the EUCID project. This project will make available national facts of diabetes mellitus and its risk factors from different EU-countries. The indicators for the EUCID project were established by the European Diabetes Indicators Project (EUDIP). Prevalence data will be collected retrospectively for the year 2005.