It is this very population approach which epidemiologist Jaakko Tuomilehto will pursue in tomorrow’s Geoffrey Rose lecture. His case is that lifestyle measures encouraged at the population level for the prevention of type 2 diabetes will have far greater benefits than in diabetes alone.
“We know that lifestyle interventions are the most effective means of preventing type 2 diabetes,” he says, “but it’s also clear that these same lifestyle measures have benefits in the prevention of cardiovascular diseases, cancers and Alzheimer’s disease. Of course, high risk individuals will benefit from medical interventions, but the bigger impact will come at the population level from the prevention of just a few common risk factors.”
The evidence in support of preventing type 2 diabetes through lifestyle measures is, says Tuomilehto, as strong as that linking tobacco to lung cancer, and it’s now quite clear that these same lifestyle risk factors - excess weight, physical inactivity, high blood pressure, smoking, poor diet - when reduced in the prevention of diabetes will also have benefits in a range of other chronic diseases.
Indeed, this was a theme of a recent WHO report on the global status of non-communicable diseases. The recommended “best buys” of the report at the population level were restrictions on smoking, raised taxes on tobacco and alcohol, reduced salt in foods, the replacement of trans-fats with polyunsaturated fat, and public awareness about diet and physical activity. The report also noted that the culprit risk factors are now the “pervasive aspects of economic transition, rapid urbanization and 21st-century life”.
And shortly after the conclusion of this year’s ESC Congress the United Nations will host a summit meeting in New York on the control of non-communicable diseases with a view to adopting an action plan to which member states will subscribe. The meeting, says the UN, “presents a unique opportunity for the international community to take action against the epidemic”.
Such a perspective was also behind the ESC’s founding membership of the Chronic Disease Alliance, an association of ten science-based European organisations, which has also declared its objective of reversing the rise in chronic non-communicable diseases through political action against tobacco use, poor nutrition, lack of physical activity and alcohol.
Jaakko Tuomilehto, from the Department of Public Health at the University of Helsinki, Finland, and Danube University Krems in Austria, was a member of the ESC (and EASD) Task Force for the 2007 guidelines on diabetes, pre-diabetes, and cardiovascular diseases. He too recognises that “changing society” will not be done without major political interventions (as has been seen in some anti-smoking campaigns, for example), even though the public rewards are huge. Indeed, studies show that the number needed to treat to prevent one case of type 2 diabetes with lifestyle intervention in people with impaired glucose tolerance is dramatically low.
The Finnish Diabetes Prevention Study, led by Tuomilehto, found that a reduction in body weight achieved through an intensive diet and exercise programme was associated with a 58% reduction in risk of developing type 2 diabetes. The lifestyle goals in this study were a 5% reduction in body weight, a reduction of all fat intake to less than 30% of energy consumption, an increase in fibre intake, and programme of moderate exercise for 30 minutes a day or more. Even after one year of the study those following the plan had achieved a significantly greater reduction in body weight than the control group and favourable changes in glucose levels. Most importantly, fewer subjects in the lifestyle intervention group developed type 2 diabetes than in the control group, with the reduction in risk directly related to the magnitude of the changes in lifestyle. Similar results have been found in several other diabetes prevention studies in many different populations.
“So the evidence for lifestyle intervention is compelling,” says Tuomilehto, “the problem lies with its universal application.” But what the epidemiology of diabetes makes clear is that the implementation of a healthier lifestyle policy, with an increase in physical activity, the uptake of a healthier diet and a reduction of body weight, is the basis for preventing type 2 diabetes, and that this same principle will yield commensurate benefits in the prevention of the world’s other principal non-communicable diseases. And as for “prevention without borders”, Tuomilehto insists that disease prevention through healthy lifestyle “does not recognise borders between different non-communicable diseases”, but provides universally beneficial effects for multiple areas of health.