Ian N. Scobie - Diabetes Mellitus

National data demonstrate an alarming increase in the prevalence of diabetes mellitus in the developed world. The 2011 National Diabetes Fact Sheet in the USA tells us that the prevalence of diabetes is 8.3% in the US population, varying from 7.1% in non-Hispanic whites to 12.6% in non-Hispanic blacks (with even higher rates in Mexican Americans). This equates to 18.8 million people with diabetes (and 7.0 million with undiagnosed diabetes). Data from the UK Quality and Outcomes Framework reveal that 4.26% of the UK population has diabetes, equating to 2.8 million people. The number of people with diabetes worldwide projected for 2025 is more than 300 million.

With increasing urbanization in India there has been an explosive increase in the prevalence of diabetes, which has now reached 8.0%, with 50 million people with type 2 diabetes. In China, diabetes has become a major public health problem, with an estimated prevalence of 9.7%. Although the incidence of new cases of type 1 diabetes is increasing in many countries, the increase in new cases of type 2 diabetes is of near-epidemic proportions. Societal factors seem to be the likely culprits behind this massive increase in diabetes prevalence in both developed and developing countries. Such factors include the adoption of a westernized diet and lifestyle and a decline in physical activity leading to ever-rising rates of obesity. In the developing world, population movements from rural agricultural areas to urban areas are associated with the acquisition of type 2 diabetes.

Cardiovascular disease remains a significant cause of death in both type 1 and type 2 diabetes. Preventive strategies are needed to minimize cardiovascular risk and improve outcome. However, these should not be at the expense of the pursuit of good blood glucose control, as this closely correlates with the development of those specific microvascular complications of diabetes that so clearly define this ubiquitous condition.

In parallel with the increase in diabetes prevalence, diabetes research continues to flourish; from basic science through to randomized prospective clinical trials, there is a great endeavor to determine the exact pathogenesis of type 1 diabetes, type 2 diabetes and other forms of diabetes and their complications, and to understand how best to prevent and treat them. One particular feature has been the recent advent of new pharmaceutical products to treat type 2 diabetes, albeit associated with problems along the way. Research continues into the development of a possible vaccine to prevent type 1 diabetes.

The aim of this fourth edition of Fast Facts: Diabetes Mellitus is to provide readers with an up-to-date picture of our understanding of diabetes mellitus and its various causes, its clinical manifestations and the treatment strategies that can be used to reduce the burden of its metabolic consequences.

1 Epidemiology

The prevalence of diabetes around the world is increasing rapidly (see the .

Figure 1.1 Comparative prevalence of diabetes: the scale shows the percentage of the adult population affected by diabetes. IDF Diabetes Atlas, fifth edition. International Diabetes Federation, 2011.

It is clear some nations have substantially higher rates of diabetes. Data from 2011 in the Diabetes Atlas of the IDF show the highest national prevalence of diabetes in adults from Kiribati, the Marshall islands, Nauru, Lebanon and other Middle Eastern nations ().

TABLE 1.1 Countries with the highest comparative prevalence of diabetes in adults aged 2079 years

Country	Prevalence (%)
Kiribati	25.7
Marshall islands	22.2
Kuwait	21.1
Nauru	20.7
Lebanon	20.2
Qatar	20.2
Saudi Arabia	20.0
Bahrain	19.9
Tuvalu	19.5
United Arab Emirates	19.2
Data from IDF Diabetes Atlas, fifth edition. International Diabetes Federation, 2011.

Mortality

Diabetes caused 4.6 million deaths globally in 2011 approximately 6% of the total world mortality. Even more people have died from cardiovascular disease, the risk of which is increased by diabetes-related comorbidities such as hyperlipidemia, hypertension and renal disease. Data for deaths attributable to diabetes according to world regions are shown in .