Leptin Receptor Gene Polymorphisms and the Risk of Non-Alcoholic Fatty Liver Disease and Coronary Atherosclerosis in the Chinese Han Population

BACKGROUND Leptin receptor (LEPR) polymorphisms have been reported to be associated with lipid metabolism and insulin resistance in various populations. However, whether LEPR polymorphisms are associated with the risks of non-alcoholic fatty liver disease (NAFLD) and coronary atherosclerosis in the Chinese Han population remains unknown. OBJECTIVES To investigate the association of LEPR polymorphisms at Q223R and K109R with the risks of NAFLD and coronary atherosclerosis in the Chinese Han population. PATIENTS AND METHODS Genotypes of LEPR Q223R and K109R were determined by polymerase chain reaction followed by sequencing in patients with NAFLD (n = 554), coronary atherosclerosis (n = 421), and healthy controls (n = 550). Serum lipid profiles were determined using biochemical methods. Pearson's χ(2) test was used to check for Hardy-Weinberg equilibrium and to analyze the distributions of genotypes' alleles between groups. Baseline characteristics were analyzed using student's t-test, paired-samples t-test, or the χ(2) test where appropriate. RESULTS The LEPR Q223R A allele significantly reduced the risks of both NAFLD and coronary atherosclerosis (OR = 0.683, 95% CI: 0.527 - 0.884, P = 0.004 and OR = 0.724, 95% CI: 0.548 - 0.955, P = 0.022, respectively). Compared to controls, no significant differences in the genotype and allele frequencies of K109R were found in the NAFLD and coronary atherosclerosis populations, respectively. However, there was a significantly increased risk of coronary atherosclerosis in NAFLD patients who carried the K109R A allele (OR = 2.283, 95% CI: 1.556 - 3.348, P < 0.001). CONCLUSIONS LEPR Q223R polymorphisms may confer a significant risk of NAFLD and coronary atherosclerosis. The A allele in the K109R polymorphism might be considered an independent risk factor for coronary atherosclerosis in NAFLD patients.