Although the prevalence of Type 2 diabetes (T2DM) in the general population, is approximately 5%, in some areas with significant S Asian communities, it is often 7-8% or often higher due to their increased susceptibility. In fact, by age 80 years, 50% of south Asians have diabetes, with a younger age of onset (10 years earlier) and greater effect on renal and cardiovascular outcomes than European comparators. The reason for this is a combination of genetic and environmental factors. S Asian patients tend to have a higher prevalence of the metabolic syndrome (comprising insulin resistance, hypertension, central obesity and dyslipidaemia).Insulin resistance in this population may appear as early as childhood and supports the concept (at least in part) of a genetic predisposition. This is certainly seen in antenatal clinics where there is a significant preponderance of Asian patients developing gestational diabetes. Fat distribution also differs between white and Asian patients, the latter having an increased level of intra-abdominal (Atherogenic) fat for a given BMI. This has lead to recent NICE guidance on CVD risk in Asian patients. However, it is worth pointing out that the multinational INTERHEART study showed that 80% of CV risk is due to traditional risk factors such as hypertension and an atherogenic lipid profile of low HDL cholesterol and higher triglycerides. . Furthermore, high levels of homocysteine and Lp(a), endothelial dysfunction, and inflammation may also be contributing factors. The other proposed mechanisms include disadvantaged socio-economic status, a ‘proatherogenic’ diet and a relative lack of physical activity.
Whatever the cause, strategies need to be developed to manage the problem. Whilst Metformin remains the tried and trusted first line drug treatment, the more mundane matter of lifestyle modification is likely to be the most successful. Indeed the Indian Diabetes Prevention Programme showed a reduction of >25% in diabetes incidence over 2.5years in those randomised to a lifestyle intervention (with or without Metformin) compared to control. Interestingly, in the lifestyle group no weight loss was noted, the beneficial effects coming from increased exercise. However, the recently published PODOSA study which compared intensive lifestyle (15 dietician visits focussing on diet and exercise) to a control group (4 visits with standard advice) over 3 years in S Asian families showed no change in physical activity between the groups. Of note, although the intervention group lost slightly more weight (-1.64kg), 20% of participants in both groups gained more than 2.5kg. Furthermore, problems with recruitment meant that there was only a hint of a reduced progression to diabetes.
Given the fact that education needs to be the cornerstone of management especially in preventing diabetes, the particular educational needs of S Asian communities need to be addressed. Knowledge of the risks of increasing fatness is poor among many south Asian communities, and it is clear that culturally appropriate interventions are required that involve a whole community. An example of this is “Project Dil” in Leicester, which has undertaken focus groups to identify the south Asian communities’ needs, engaged primary care to set up training programmes for patients and healthcare professionals, and developed peer educators to spread the message.
Healthcare professionals need to understand better the higher risks of coronary heart disease and diabetes and lower thresholds for intervention required in this population. Clinicians must be aware of the very high risk of developing diabetes in people with strong family histories of diabetes, obesity, or cardiovascular disease. As mentioned earlier, this is now incorporated into NICE recommendations.
Clearly a multifactorial approach needs to be taken both to understand the underlying cause of this ‘epidemic’ and to develop a suitable approach to management. Resource, both financial and time will need to be appropriately addressed.
Dr Mark Freeman