Metabolic Syndrome: Prevention and Treatment
Excerpt from Obesity -The Tip of the Iceberg?
Metabolic Syndrome, also known as Syndrome X, or the insulin resistance syndrome, represents a cluster of health risk factors present at one time in an individual. The definition varies between countries and organisations, but it generally involves raised levels of plasma lipids (cholesterol and triglycerides), glucose, blood pressure risk factors and abdominal obesity. The International Diabetes Federation has just proposed a new definition, namely if someone has abdominal obesity (94cm for Australians, 90cm for Asians) as well as two of the following: pre-diabetes or diabetes, high blood pressure and high cholesterol.
This clustering of multiple interrelated risk factors dramatically raises overall risk for an individual to develop conditions such as diabetes, cardiovascular disease or even premature death. As such, it is much more clinically meaningful than obesity, particularly as it appears to be the waist circumference, rather than BMI, that poses the greater health risk.
Alarmingly, it is estimated that 25% to 30% of Australians have Metabolic Syndrome. The most sensible approach to reversing Metabolic Syndrome is weight reduction, exercise and sensible nutrition (especially reductions in saturated fat and high-GI carbohydrates). Evidence of the success of this approach is provided by the Diabetes Prevention Program (DPP), a large randomised controlled trial designed to study the impact of lifestyle and pharmacological intervention (the drug Metformin) on the prevention of diabetes among subjects with impaired glucose tolerance (4). Interestingly, 53% of the subjects actually met the criteria for Metabolic Syndrome and therefore this study also served as a data source for the impact of lifestyle and drug intervention on Metabolic Syndrome.
The most sensible approach to reversing Metabolic Syndrome is weight reduction, exercise and sensible nutrition (especially reductions in saturated fat and high-GI carbohydrates).
After 3.2 years of follow-up, the lifestyle intervention (which consisted of an intensive lifestyle regimen designed to induce 7% weight loss and 150 minutes of exercise per week) was effective at preventing or delaying the onset of diabetes for 58% of the subjects, compared with 31% among those subjects who were treated with Metformin. The prevalence of Metabolic Syndrome was also significantly reduced from 51% to 43% in the intensive lifestyle intervention group.
This result is all the more impressive as, during the course of the study, the prevalence actually increased among the control subjects from 55% to 61%. In the drug treatment group, the results remained unchanged. The change in prevalence among members of the lifestyle intervention group amounts to a 41% reduction relative to the control group and a 29% reduction compared with the Metformin group. Hence, the impact of a moderate amount of weight loss and an increase in physical activity is not only effective in reducing the incidence in diabetes, but also is more effective in reducing other components of the Metabolic Syndrome.
It is clear that the best strategy in combating Metabolic Syndrome is to try to reduce all the risk factors, and aggressive lifestyle intervention is appropriate for most people. Unfortunately, some people may need medication to control diabetes, cholesterol and blood pressure, in addition to measures to reduce weight. Some hope for those with higher levels of risk may be offered by a new drug called Rimonabant, as recent reports in The Lancet suggest that this may substantially reduce all the risk factors associated with the Metabolic Syndrome. However, it should be remembered that every drug has side-effects, whereas lifestyle changes do not. Finally, for those of us who are complacent, remember that prevention is better than cure!