South Asian population on iHealth-T2D
• Sri Lanka
• Migrant population in United Kingdom
The International Diabetes Federation reports that the number of people with Type-2 diabetes (T2D) will rise from 382 million to 592 million between 2013 and 2035. Type-2 diabetes is the fifth leading cause of death worldwide, and a major contributor to development of coronary heart disease, stroke, peripheral vascular disease and end-stage renal failure.
South Asians, who represent one-quarter of the world’s population, are at high risk of type-2 diabetes. India alone has ~56 million people with T2D, the second highest number in the world. Conservative estimates based on population growth, ageing and rates of urbanisation show that T2D cases in India will increase to ~100 million by 2030. T2D prevalence is currently ~9% in rural India, ~18% in urban India, and ~22% amongst Indians living in Europe (compared to ~6% among Europeans). Similar patterns are observed among South Asians in Pakistan, Bangladesh, and Sri Lanka.
Diabetes represents a major and growing threat to health and well-being among South Asians, as they migrate from rural to urban areas, and in regional settings around the world. Though diabetes among South Asians is more prevalent among the affluent, recent data show that diabetes rates are rapidly rising among low and middle income South Asians, who are also more susceptible to diabetes complications due to reduced access to quality healthcare in these settings.
An additional health burden is the earlier age of onset of T2D among South Asians. Diabetes prevalence is ~14 times higher in South Asian than in European children, substantially increasing lifetime burden of disease and its complications. Diabetes poses a massive clinical, economic and social burden among South Asians.
The economic disparities within India, Pakistan, Bangladesh, and Sri Lanka, combined with scarcity of adequate healthcare and low education status in large numbers of the population, continue to present a major obstacle in reducing the burden of diabetes in South Asian countries. It is estimated that low income groups in these countries spend at least one fourth of their income on diabetes care. Furthermore, cost of care increases substantially with complications of T2D, or when admission to hospital or insulin are needed. T2D also places a heavy burden in the health expenditures of European countries to which South Asians have emigrated in large numbers, notably UK, France, Germany, Netherlands and Sweden.
The London Life Sciences Population (LOLIPOP) study
To investigate new strategies for prediction of future T2D amongst South Asians, we have established the LOLIPOP study. LOLIPOP is a prospective, population based cohort of 18,606 South Asians and 9,766 European white men and women, aged 35-75 years recruited from the lists of 58 general practitioners in West London (2003-8).
LOLIPOP provides a well powered, prospective evaluation of risk factors and predictors of incident T2D amongst South Asians. Our results identify HbA1c as highly discriminatory biochemical tool for identification of high-risk South Asians. HbA1c achieves better discrimination for T2D than fasting glucose, and other single-sample measures of glucose metabolism. In addition HbA1c has the additional advantages of being a non-fasting assay, which is simpler and cheaper to administer than an oral glucose tolerance test. These make HbA1c well suited for community wide and opportunistic screening.
Amongst anthropometric and non-invasive measures, we find that waist circumference is the best predictor of incident T2D in South Asians. Waist circumference achieves better discrimination than body mass index or waist hip ratio as quantified by AUC. Waist also performs superiorly to the only composite non-invasive risk scores developed for identification of T2D in South Asians (the Indian Diabetes Risk Score). Waist circumference≥100cm identifies ~50% of South Asian men and women in the UK who will develop T2D.
These observations provide a strong, evidence-based rationale for iHealth-T2D study in which we will determine the clinical utility and cost-effectiveness of HbA1c and waist circumference for identification of South Asians at high risk of T2D, to enhance scalable implementation of lifestyle modification and improve health.
Please visit the LOLIPOP website to learn more about the study.