The Concept of CMR

The influence of ethnicity on metabolic complications

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Ethnic differences do seem to influence adipose tissue distribution. It has been suggested that Asian, Hispanic, and Caucasian populations are particularly prone to intra-abdominal obesity and its associated health risks.

Compared to Whites, Blacks generally have a better lipoprotein-lipid profile, including lower fasting triglyceride and apolipoprotein B levels as well as higher HDL cholesterol concentrations (6-8). Després et al. (6) have found that intra-abdominal adipose tissue accumulation was a critical correlate of plasma triglycerides, apolipoprotein B, and HDL cholesterol, suggesting that the more favourable metabolic profile of black individuals could be due to the fact that they are less prone to intra-abdominal fat deposition than white individuals. Black subjects also have significantly higher postheparin hepatic lipase  and lower hepatic lipase activity than white subjects, both in men and women (6). The low hepatic lipase activities in Blacks may have a genetic basis and contribute to their higher plasma HDL cholesterol concentrations when compared to Whites (13).

Though they have less intra-abdominal adipose tissue accumulation, black women are especially prone to insulin resistance. This finding holds up even after matching them with white women for age, degree of obesity, and waist-to-hip ratio as a relative index of abdominal obesity (8). Among women, upper body obesity independent of total body fatness has been shown to be less detrimental to black women than to white women with regard to the risk of developing diabetes and CVD (14). This could be explained by the fact that black women are more likely than white women to store their excess trunk fat subcutaneously.

Reference

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6. Després JP, Couillard C, Gagnon J, et al. Race, visceral adipose tissue, plasma lipids, and lipoprotein lipase activity in men and women: the Health, Risk Factors, Exercise Training, and Genetics (HERITAGE) family study. Arterioscler Thromb Vasc Biol 2000; 20: 1932-8.

7. Albu JB, Murphy L, Frager DH, et al. Visceral fat and race-dependent health risks in obese nondiabetic premenopausal women. Diabetes 1997; 46: 456-62.

8. Lovejoy JC, de la Bretonne JA, Klemperer M, et al. Abdominal fat distribution and metabolic risk factors: effects of race. Metabolism 1996; 45: 1119-24.

13. Vega GL, Clark LT, Tang A, et al. Hepatic lipase activity is lower in African American men than in white American men: effects of 5' flanking polymorphism in the hepatic lipase gene (LIPC). J Lipid Res 1998; 39: 228-32.

14. Dowling HJ and Pi-Sunyer FX. Race-dependent health risks of upper body obesity. Diabetes 1993; 42: 537-43.

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