Interleukin-6, tumour necrosis factor-alpha and insulin relationships to body composition, metabolism and resting energy expenditure in a migrant Asian Indian population

Objective Systemic inflammation and insulin resistance may play important roles in the pathogenesis of obesity-related diseases for which migrant Asian Indians are at particularly high risk. We examined relationships between markers of insulin resistance and inflammation, resting energy expenditure (REE), and body composition. Design and methods Measurements were made of total and regional body composition, including regional fat mass (FM) and appendicular skeletal muscle mass (ASMM) by dual-energy X-ray absorptiometry (DXA), REE by indirect calorimetry and fasting interleukin (IL)-6, tumour necrosis factor (TNF)-alpha, glucose and insulin, in 79 healthy Asian Indians (38F, 41M; age 30-49 years) from urban Auckland, New Zealand. Beta-cell function (HOMA B%) and insulin sensitivity (HOMA S%) were derived using homeostatic model assessment. Results Men had a more central distribution of body fat than women. REE was strongly correlated with IL-6 concentrations in men but not in women. In both sexes, IL-6 was associated positively with percentage body fat and HOMA B% and inversely with ASMM and HOMA S%. Insulin increased and HOMA S% decreased with increasing waist-to-hip ratio and abdominal-to-thigh fat ratio in men but not in women. TNF-alpha was not significantly associated with any of the variables examined. Conclusion Relationships between body fat distribution and HOMA S% were strongly sex dependent and may indicate a greater propensity for development of the metabolic syndrome among male Asian Indians than females in the age group examined.