Epidemiology and costs of diabetes.

The prevalence of diabetes is increasing worldwide, particularly in developing countries. In the next decades, India and China are expected to provide the greatest numbers of affected people, mainly owing to the increasing incidence of this disease in those countries. Regarding developed countries, such as in Europe and the United States, the increasing trend is mainly due to the prolonged survival of both the general and the diabetic populations. From an epidemiologic point of view, the first relevant point is that almost 80% of diabetes cases could be prevented just by avoiding overweight and obesity. The estimated attributable risk of excess body weight is extremely high; no other modifiable effect has such an impact on the health of the general population. The second relevant point is that the global trend of the disease shows a tendency to onset at a younger age. The third point is that in developed countries the prevalence of diabetes is increasing mainly among the elderly, who are responsible for the highest consumption of health care resources in absolute terms. Regarding type 1 diabetes, which represents one-tenth of affected individuals, both large geographic and temporal variations in disease incidence have been found, supporting the hypothesis of as yet unknown environmental determinants. The incidence is increasing in linear fashion, not supporting the hypothesis of younger age at onset as the main explanation for this trend. Because the prevalences of both type 1 and type 2 diabetes are increasing worldwide, they will produce a profound impact on overall health care costs.