title: A four-stage model explaining the higher risk of Type 2 diabetes mellitus in South Asians compared with European populations.
abstract: With approximately 1.5 billion people at risk, the staggeringly high risk of Type 2 diabetes in South Asians comprises a global problem. The causes of this high risk are complex, with 23 major risk factors identified in a Lancet seminar. This paper proposes a four-stage explanatory model: (1) the birth of a small, adipose, lowlean mass South Asian baby--the phenotype tracking through life; (2) in childhood and early adulthood, the deposition of any excess energy intake preferentially in upper body and ectopic fat stores rather than in the lower body or superficial subcutaneous fat stores; (3) as a consequence of points 1 and 2, and exacerbated by an environment of low physical activity and excess calories, the accelerated appearance of high levels of plasma insulin, triglycerides and glucose, and the fatty-liver vicious cycle; (4) β-cell failure as a result of fewer β-cells at birth, exposure to apoptotic triggers such as fat in the pancreas, and high demand from insulin resistance, which causes diabetes. Other risk factors--especially energy-dense hyperglycaemic diet and low physical activity--play into this pathway. The recommended behavioural changes fit with this model, which brings clarity to guide future research, policy, practice and health promotion.
authors.affiliation: Edinburgh Ethnicity and Health Research Group, Centre for Population Health Sciences, University of Edinburgh, Edinburgh, UK. raj.bhopal@ed.ac.uk
authors.forename: R S
authors.initials: RS
authors.lastname: Bhopal
mesh_terms: D001211:Asia, Western / Q000208:ethnology; D001835:Body Weight; D003924:Diabetes Mellitus, Type 2 / Q000208:ethnology*; D005060:Europe / Q000208:ethnology; D006803:Human Development / Q000502:physiology; D006801:Humans; D008019:Life Style; D010641:Phenotype; D015995:Prevalence; D012307:Risk Factors; D014504:Urban Health