Increased fibrinogen levels among South Asians versus Whites in the United Kingdom are not explained by common polymorphisms

Abstract

Determinants of fibrinogen level among South Asians are not established. In 1997-1999, plasma fibrinogen levels and prevalences of the fibrinogen polymorphisms A alpha Thr312Ala, beta-445G/A, and B beta Arg448Lys and correlates were compared among 100 apparently healthy United Kingdom South Asians and 100 age- and sex-matched Whites. Mean fibrinogen levels were higher in South Asians (3.33 g/liter, 95% confidence interval (CI): 3.16, 3.51) than in Whites (2.84 g/liter, 95% CI: 2.72, 2.96) (p < 0.0001), but genotype distributions were similar. B beta Arg448Lys was related to fibrinogen in South Asians (RR (n = 67): 3.22 g/liter, 95% CI: 3.03, 3.43; RK (n = 26): 3.72 g/liter, 95% CI: 3.65, 4.11; KK (n = 7): 3.07 g/liter, 95% CI: 2.53, 3.72) (p = 0.04) and Whites (p = 0.06). beta-455G/A was related to fibrinogen in Whites (GG (n = 56): 2.68 g/liter, 95% CI: 2.56, 2.86; GA (n = 37): 2.97 g/liter, 95% CI: 2.79, 3.17; AA (n = 5): 3.22 g/liter, 95% CI: 2.85, 3.65) (p = 0.02) and South Asians (p = 0.07). After adjustment for age, gender, body mass index, hypertension, cholesterol, triglycerides, smoking, A alpha Thr312Ala, and beta-455G/A, fibrinogen levels remained significantly higher in South Asians (3.56 g/liter, 95% CI: 3.35, 3.77) than in Whites (3.03 g/liter, 95% CI: 2.85, 3.22) (p < 0.0001). These findings suggest that increased fibrinogen levels among South Asians versus Whites are not due to differences in the prevalence of genetic polymorphisms that encode for fibrinogen.