Meet-the-Professor Session
Diabetes and obesity worldwide: epidemics in full flight
Paul Zimmet
International Diabetes Institute, Melbourne, Australia
Coca-colonization
’Globalization’ and ’Coca-colonization’ are having profound
effects on health worldwide. We face a huge public health challenge from
both Type 2 diabetes and obesity, from childhood through to old age.
Obesity has reached epidemic proportions globally. The situation is
worsening. In Europe, USA and Australia, the prevalence is high and
increasing. Over 60% of the adult population of the USA and Australia is
either overweight (BMI 25–29.9) or obese (BMI > 30). Over 20% of
adults fall into this latter category. In some developing countries as
well as among disadvantaged groups in developed countries, e.g.
Mexican-Americans, Afro-Americans, Native Canadians and Australian
Aborigines, an even more extreme situation exists. Generalized and
abdominal adiposity, and physical inactivity are independent risk
factors for Type 2 diabetes and impaired glucose tolerance.
Epidemic obesity
Epidemic obesity with some of the highest prevalence in the world
exists in these populations, e.g. 70% of Samoans have a BMI in excess of
30. In both Samoa and Mauritius, two populations where longitudinal data
are available, there have been dramatic increases in prevalence over
relatively short time periods (Figure 1). Similar trends have been noted
in American Pima Indians, Australian Aborigines, migrant Asian Indians
and Mexican-Americans.
Coincident with the high rates of obesity, the prevalence of Type 2
diabetes is also escalating. This increase is expected to continue, and
recent projections show that there are currently 120 million people
worldwide with Type 2 diabetes, and by the year 2010, this figure is
expected to climb to well over 230 million. This represents an epidemic
of major proportions. The majority of the new cases will be those with
Type 2 diabetes and the majority of these will be in China, the Indian
subcontinent and Africa. We estimate that from 65 million cases of Type
2 diabetes in Asia and Oceania in 1995, the number will double to 135
million by 2010. Some of the highest recorded rates of Type 2 diabetes
are found in the Pacific Islands with 1 in 3 adults affected in a number
of countries. A major concern here is the growing socio-economic burden
of cardiovascular disease, blindness, renal failure and amputations
resulting from the diabetes epidemic. Obesity and Type 2 diabetes
represent just two constituents of the Metabolic Syndrome, a cluster of
cardiovascular disease risk factors also described as ‘The New World
Syndrome’. Sooner, rather than later, serious morbidity and mortality
from cardiovascular disease is inevitable.
Type 2 in the young
Another issue of major concern is that Type 2 diabetes has generally
been believed to be rare in children, adolescents and young adults. Not
so any longer! An important and alarming feature of the diabetes
epidemic is that Type 2 diabetes is increasing in these younger age
groups. This poses significant problems as the safety of therapies used
in Type 2 diabetes, apart from insulin, has not been tested in this age
group. Obesity has been implicated in this trend in Afro- and
Mexican-Americans and Pacific Islanders.
