Ask the Experts - Geographic Prevalence of Diabetes and Resulting...
Ask the Experts - Geographic Prevalence of Diabetes and Resulting...
With the varying prevalence of diabetes around the world, does the long-term prognosis from this disease and its complications also vary internationally? What is the trend in mortality from diabetes and its complications in South Africa? Can you suggest any articles on this topic?
Philip Smalley, MD, FRCPC
With increasing longevity, changes in demographic age distributions, rising urbanization, and further modernization, we have estimated that the present population of approximately 110 million people with diabetes in the world will reach around 220 million by the year 2010, the majority of them having type-2 diabetes. Clearly, type-2 diabetes will be a major public health problem in every region of the world, but its greatest impact likely will be felt in newly industrialized and developing nations and minority groups in developed countries. The corresponding burden of complications and premature mortality resulting from diabetes will constitute a major public health problem for most countries.
Numerous published reports of epidemiologic studies highlight the spectacularly high susceptibility of Micronesian, Polynesian, and certain Melanesian Pacific Islanders, Australian Aborigines, North American Indians, African American and other black populations, Hispanics, migrant Asian Indians, and Chinese to type-2 diabetes. On the other hand, there is little information about the morbidity and mortality from diabetes in these groups.
Certain ethnic groups seem to have a higher prevalence of complications, suggesting that there may be an underlying genetic component. For example, certain native American populations have a high frequency of renal disease. On the other hand, most studies have shown that the occurrence of microvascular complications relates predominantly to the duration of diabetes and the degree of metabolic control, irrespective of ethnic background. As far as the association between macrovascular disease and diabetes is concerned, there are differences in patterns between countries that reflect the general pattern of atherosclerosis in nondiabetic subjects. For example, until recently, macrovascular disease was relatively uncommon in Asian and Pacific Island populations compared with Europeans. On the other hand, in association with changes in lifestyle, some of the highest rates of cardiovascular disease are now seen in countries such as Singapore and Mauritius.
Although the worldwide prevalence of diabetes varies, the natural history and long-term outcomes basically are very similar. However, with the new knowledge from the Diabetes Control and Complications Trial (DCCT), the United Kingdom Prospective Diabetes Study (UKPDS), and a number of other trials, it is clear that the degree of metabolic control influences the development of complications, particularly microvascular complications. Thus, the long-term prognosis in each country and for individuals is very much dependent on the standard of medical care and availability of appropriate therapies in any given country. The foregoing comments apply predominantly to type-2 diabetes, and the situation for type-1 diabetes is probably even more likely to be influenced by the availability of not only insulin but adequate diabetes-specific clinical and educational services.
Although type-2 diabetes mellitus in Europids is usually characterized by onset after the age of 50 years, in Native Americans, Indian Ocean and Pacific Islanders, and other high-prevalence groups, onset in the 20- to 30-year-old group, and even in children and adolescents, is increasing. This phenomenon has enormous personal, social, and economic costs as these groups face 50 years or more of diabetes therapy. Thus, the socioeconomic and public health impact of type-2 diabetes on individuals and society is much greater and is mediated by its effects on the work force, extended diabetes therapy, premature morbidity and mortality, and the negative consequences on fertility and reproduction. These aspects are a particular problem for the healthcare sector in developing countries and for services directed at minority groups in developed countries.
What is the trend for mortality from diabetes in South Africa? Although there have been several excellent reports on the epidemiology of diabetes from South Africa, reports on morbidity and mortality have been sparse. The current and future picture in South Africa is compounded by the current AIDS epidemic, as Panz and Joffe pointed out in 1999 in an article in the British Medical Journal. As a result of AIDS, our own predictions for the diabetes epidemic in Africa are muted by the fact that there is such a high mortality rate in young adults from AIDS. The impact of AIDS is likely to profoundly change the patterns of morbidity and mortality from diabetes, not only in South Africa, but in many nations of the African continent.
With the varying prevalence of diabetes around the world, does the long-term prognosis from this disease and its complications also vary internationally? What is the trend in mortality from diabetes and its complications in South Africa? Can you suggest any articles on this topic?
Philip Smalley, MD, FRCPC
With increasing longevity, changes in demographic age distributions, rising urbanization, and further modernization, we have estimated that the present population of approximately 110 million people with diabetes in the world will reach around 220 million by the year 2010, the majority of them having type-2 diabetes. Clearly, type-2 diabetes will be a major public health problem in every region of the world, but its greatest impact likely will be felt in newly industrialized and developing nations and minority groups in developed countries. The corresponding burden of complications and premature mortality resulting from diabetes will constitute a major public health problem for most countries.
Numerous published reports of epidemiologic studies highlight the spectacularly high susceptibility of Micronesian, Polynesian, and certain Melanesian Pacific Islanders, Australian Aborigines, North American Indians, African American and other black populations, Hispanics, migrant Asian Indians, and Chinese to type-2 diabetes. On the other hand, there is little information about the morbidity and mortality from diabetes in these groups.
Certain ethnic groups seem to have a higher prevalence of complications, suggesting that there may be an underlying genetic component. For example, certain native American populations have a high frequency of renal disease. On the other hand, most studies have shown that the occurrence of microvascular complications relates predominantly to the duration of diabetes and the degree of metabolic control, irrespective of ethnic background. As far as the association between macrovascular disease and diabetes is concerned, there are differences in patterns between countries that reflect the general pattern of atherosclerosis in nondiabetic subjects. For example, until recently, macrovascular disease was relatively uncommon in Asian and Pacific Island populations compared with Europeans. On the other hand, in association with changes in lifestyle, some of the highest rates of cardiovascular disease are now seen in countries such as Singapore and Mauritius.
Although the worldwide prevalence of diabetes varies, the natural history and long-term outcomes basically are very similar. However, with the new knowledge from the Diabetes Control and Complications Trial (DCCT), the United Kingdom Prospective Diabetes Study (UKPDS), and a number of other trials, it is clear that the degree of metabolic control influences the development of complications, particularly microvascular complications. Thus, the long-term prognosis in each country and for individuals is very much dependent on the standard of medical care and availability of appropriate therapies in any given country. The foregoing comments apply predominantly to type-2 diabetes, and the situation for type-1 diabetes is probably even more likely to be influenced by the availability of not only insulin but adequate diabetes-specific clinical and educational services.
Although type-2 diabetes mellitus in Europids is usually characterized by onset after the age of 50 years, in Native Americans, Indian Ocean and Pacific Islanders, and other high-prevalence groups, onset in the 20- to 30-year-old group, and even in children and adolescents, is increasing. This phenomenon has enormous personal, social, and economic costs as these groups face 50 years or more of diabetes therapy. Thus, the socioeconomic and public health impact of type-2 diabetes on individuals and society is much greater and is mediated by its effects on the work force, extended diabetes therapy, premature morbidity and mortality, and the negative consequences on fertility and reproduction. These aspects are a particular problem for the healthcare sector in developing countries and for services directed at minority groups in developed countries.
What is the trend for mortality from diabetes in South Africa? Although there have been several excellent reports on the epidemiology of diabetes from South Africa, reports on morbidity and mortality have been sparse. The current and future picture in South Africa is compounded by the current AIDS epidemic, as Panz and Joffe pointed out in 1999 in an article in the British Medical Journal. As a result of AIDS, our own predictions for the diabetes epidemic in Africa are muted by the fact that there is such a high mortality rate in young adults from AIDS. The impact of AIDS is likely to profoundly change the patterns of morbidity and mortality from diabetes, not only in South Africa, but in many nations of the African continent.
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