Diabetes mellitus can be found in almost every population in the world and epidemiological evidence suggests that, without effective prevention and control programmes, diabetes will likely continue to increase globally 1 .
Type 1 diabetes usually accounts for only a minority of the total burden of diabetes in a population but is increasing in incidence in both poor and rich countries. It is the predominant form of the disease in younger age groups in most high-income countries (see Diabetes in the Young).
Type 2 diabetes constitutes about 85 to 95% of all diabetes in high-income countries 1 and may account for an even higher percentage in low- and middle-income countries. Type 2 diabetes is now a common and serious global health problem, which, for most countries, has evolved in association with rapid cultural and social changes, ageing populations, increasing urbanization, dietary changes, reduced physical activity and other unhealthy lifestyle and behavioural patterns 1 .
Gestational diabetes mellitus is common and, like obesity and type 2 diabetes that are related conditions, is increasing in frequency throughout the world. The risk of developing diabetes after GDM is very high. As the prevalence of type 2 diabetes increases within a population so will the prevalence of GDM 2 . The reported prevalence of GDM has varied widely among different populations around the world. Much of the variability is due to differences in diagnostic criteria and detection methods used in different centres. However, it has not been possible to estimate the prevalence of GDM separately as there are very limited population-based studies on GDM. It is recognized that the challenges of GDM have to be addressed and further research is required in this area.
The methods used here to estimate the prevalence of diabetes are conservative and are mostly based on changes in population size and age sturcture. It has not been possible in these projections to take any account of trends in obesity although the projections for LMCs do take into account trends in urbanization. If levels of obesity continue to increase it is possible that the prevalence of diabetes will be even greater than reported here.
It is estimated that approximately 285 million people worldwide, or 6.6%, in the age group 20-79, will have diabetes in 2010, some 70% of whom live in low- and middle-income countries. This number is expected to increase by more than 50% in the next 20 years if preventive programmes are not put in place. By 2030, some 438 million people, or 7.8% of the adult population, are projected to have diabetes. The largest increases will take place in the regions dominated by developing economies (see Figure 2.1)
2: Hunt KJ, Schuller KL. The increasing prevalence of diabetes in pregnancy. Obstet Gynecol Clin North Am 2007; 34 (2): 173-99, vii.