Is Intra-Abdominal Obesity a Unique Risk Factor for Metabolic Syndrome in Non-Diabetics? (Commentary) (Report‪)‬

Excess body fat imparts risk for metabolic syndrome, diabetes and cardiovascular disease. A question that has engendered interest is whether the risk imparted by obesity results from excess visceral or subcutaneous adiposity. Regardless of the controversy, excess abdominal fat is viewed as a risk factor for diabetes and cardiovascular disease. In fact, waist girth is now part of the assessment tools for metabolic syndrome as recommended by the Adult Treatment Panel (ATP) III guidelines (1). In recent years the definition has been revised for non-Europeans because body mass index (BMI) and waist girth definitions of overweight and obesity for persons of European ancestry do not always apply to non-Europeans (2). Of late, guidelines for South Asians at risk for metabolic syndrome also have been introduced in India (3). An underlying assumption in all of these guidelines is that a clustering of metabolic risk factors predisposing to diabetes mellitus and/ or cardiovascular disease is associated with central obesity. Whether the central obesity paradigm holds in the future depends on new developments in the research on adipose tissue function. In recent years, the study of the impact of obesity on health in various populations has proven very instructive as well. One population of interest is South Asians who have the highest risk for type 2 diabetes mellitus and/or cardiovascular disease (4). In rural areas, the prevalence of diabetes is ~2 per cent while in urban India it is ~11 per cent and for South Asians living in South Africa, United Kingdom or the United States it is as high as 15 per cent. Coronary artery disease is also prevalent in urban Indian areas and much higher in migrant South Asians compared to those of European ancestry. Of interest, the high prevalence of type 2 diabetes mellitus in South Asians has not been entirely attributed to obesity (5,6). South Asians also have a high prevalence of insulin resistance beyond that expected for a given BMI (6-10). It has been suggested that insulin resistance per se is the underlying cause of metabolic risk leading to type 2 diabetes and/or cardiovascular disease (7,11-16).