Early evidence of ethnic differences in cardiovascular risk: cross sectional comparison of British South Asian and white children

Abstract

Objectives: To examine whether British South Asian children differ in insulin resistance, adiposity, and cardiovascular risk profile from white children. Design: Cross sectional study. Setting: Primary schools in 10 British towns. Participants: British children aged 8 to 11 years (227 South Asian and 3415 white); 73 South Asian and 1287 white children aged 10 and 11 years provided blood samples (half fasting, half after glucose load). Main outcome measures: Insulin concentrations, anthropometric measures, established cardiovascular risk factors. Results: Mean ponderal index was lower in South Asian children than in white children (mean difference −0.43 kg/m³, 95% confidence interval −0.13 kg/m³ to −0.73 kg/m³). Mean waist circumferences and waist:hip ratios were similar. Mean insulin concentrations were higher in South Asian children (percentage difference was 53%, 14% to 106%, after fasting and 54%, 19% to 99%, after glucose load), though glucose concentrations were similar. Mean heart rate and triglyceride and fibrinogen concentrations were higher among South Asian children; serum total, low density lipoprotein, and high density lipoprotein cholesterol concentrations were similar in the two groups. Differences in insulin concentrations remained after adjustment for adiposity and other potential confounders. However, the relations between adiposity and insulin concentrations (particularly fasting insulin) were much stronger among South Asian children than among white children. Conclusions: The tendency to insulin resistance observed in British South Asian adults is apparent in children, in whom it may reflect an increased sensitivity to adiposity. Action to prevent non-insulin dependent diabetes in South Asian adults may need to begin during childhood. What is already known on this topic Compared with white people British South Asians are at increased risk of coronary heart disease, stroke, and non-insulin dependent diabetes There is evidence that these conditions originate in early life What this study adds British South Asian children show higher average levels of insulin and insulin resistance than white children These ethnic differences in insulin resistance in childhood are not associated with corresponding differences in adiposity, particularly central adiposity Insulin metabolism seems to be more sensitive to a given degree of adiposity among the South Asian children compared with white children The prevention of insulin resistance and its consequences may need to begin during childhood, particularly in South Asians