Ethnic differences in hepatic lipase and HDL in Japanese, black, and white Americans: role of central obesity and LIPC polymorphisms

Abstract

Hepatic lipase activity (HLA) is a determinant of HDL levels, and a polymorphism in the hepatic lipase gene (LIPC) promoter (C-514T) has been hypothesized to account for higher HDL in blacks and Japanese compared with whites. To determine whether the polymorphism contributes to ethnic differences in HDL, we compared LIPC allele frequencies and HLA in Japanese American (JA; n = 84), black American (BA; n = 94), and white American (WA; n = 110) men and women. The LIPC polymorphism was associated with HLA in all cohorts (BA, P = 0.012; JA, P = 0.008; WA, P = 0.009). WA men had 49% and 58% higher HLA than BA and JA men, respectively (both P < 0.05), yet no differences in HLA were found between the women. The higher HLA in the WA men remained after adjustment for the LIPC polymorphism's effect on HLA (P = 0.037) but was erased after adjustment for waist-to-hip-ratio (P = 0.46). Although the WA men had lower HDL and HDL(3) than the JA and BA men (all P < 0.05), there were no differences in HDL(2), implying that variance in HLA may not underlie the ethnic differences in HDL levels. These results suggest that 1) the LIPC promoter polymorphism contributes to variation in HLA and HDL(2) in the three ethnic groups; 2) WA men had higher HLA than BA and JA men, related to ethnic differences in central adiposity but not LIPC allele frequency; and 3) the higher HLA in WA men did not contribute to the ethnic differences in HDL, as the differences in HDL were made up entirely of differences in HDL(3) and not HDL(2).