Hyperinsulinaemia and hyperleptinaemia are BMI independent features of morbid obesity in a Qatari, compared to a Caucasian, population: Effect of surgical weight loss.

Abstract

Background: Recent trends suggest that the sharpest increases in the prevalence of obesity are in countries of the Middle East, especially in Qatar. Early and rapid onset of the disease in this population, along with a primarily abdominal omental deposition of adipose tissue, is closely associated with insulin resistance, whilst longer duration of obesity in Caucasians is associated with maintenance of insulin sensitivity, independently of BMI. The impact of more aggressive treatments for obesity, such as surgery, on the metabolic health of the Qataris is not known. Objectives: To test the hypothesis that inherent differences between the Qataris and Caucasians in adipose tissue secretory function and sensitivity to insulin determines their response to interventions that reduce their adipose tissue mass. Methods: Non-diabetic morbidly obese subjects were recruited from Qatari and Caucasian patients awaiting weight reduction surgery (Al-Emadi Hospital, Doha, Qatar and Whittington Hospital, London, UK). Anthropometric measures were recorded. Blood samples were obtained before, and in a sub-set after weight loss for determination of lipids, glucose, insulin and adipokines. Insulin resistance was measured by HOMA. Results: The Qataris were significantly younger (p=0.005), despite having comparable BMI (Qatari 47.7±7.0; Caucasian 48.4±7.6 kg/m-2, p=0.70). They also had lower diastolic blood pressure and a better lipid profile. However, the Qataris had significantly higher insulin and HOMA index of insulin resistance, and higher leptin and interleukin-6. Also, in Qataris, leptin was negatively correlated with a number of risk factors for metabolic syndrome, independent of BMI. However, these correlations seem to be BMI-dependent in Caucasians. Further, weight loss in Caucasians did not significantly change insulin sensitivity but did reduce dyslipidemia. While in Qataris, characterized by high insulin resistance, weight loss causes sharp reduction in insulin resistance but not in dyslipidemia. Conclusion: Obesity in Qatari subjects was accompanied by a higher degree of hyperinsulinaemia and hyperleptinaemia compared to Caucasians. The nature of obesity and high insulin resistance in Qataris makes it amenable to aggressive weight loss treatment, whereas in Caucasians other less aggressive treatments for obesity may be applicable.