Study About The Risk Factors Of Non-alcoholic Fatty Liver Disease, Especially The Effects Of The Single Nucleotide Polymorphism Of SIRT1 And GCKR

ObjectiveOur present study aimed to investigate the potential risk factors for nonalcoholic fatty liver disease (NAFLD) among subjects aged over 40 years old, and the relationship between the SNP of GCKR (rs3817588, rs780094), SIRT1 rs12778366 and the susceptibility of NAFLD was also explored, which could give hint to the prevention and treatment of NAFLD.MethodsA total of 5786 subjects were selected into our study, which were divided into normal control group (4086 subjects) and NAFLD group (1699 subjects) according to the ultrasound diagnosis and physical examination. Basic information of the subjects and medical history were collected by the doctor. Fasting blood were obtained from an antecubital vein, and triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), alanine aminotransferase (ALT), aspartate aminotransferase (AST), urine acid, and fasting plasma glucose (FPG) were determined. Whole blood DNA (from 132 NAFLD patients and 252 healthy controls) was extracted by using business kit (Biomiga), polymerase chain reaction (PCR) and Sequenom MassARRAY SNP array were used to analyze the genotype of SIRT1 and GCKR. Statistical analyses were conducted using the SPSS software. Continuous variables are presented as the mean and standard deviation (SD).The Student’s t-test for normally distributed traits, Wilcoxon rank sum test for non-normally distributed continuous variables or ordinal variables, and a chi squared test for dichotomous variables(the percentage data), Stepwise multiple regression analysis was employed to evaluate the risk factors for NAFLD. P<0.05 (2-tailed test) was considered statistically significant. The Hardy-weinbeurg law used to assess the representation of two groups genotype. The relationship between gene mutation and the susceptibility of NAFLD was analyzed by unconditional Logistic regression.Results1. Comparing with the control group, subjects in NAFLD group had significantly higher levels of body mass index (BMI), alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), triglyceride (TG), fasting blood glucose (FPG), uric acid (UA), systolic blood pressure (SBP), diastolic blood pressure (DBP), and obviously decreased level of high density lipoprotein cholesterol (HDL-C) (P<0.05), and there had no significant difference in gender and age between case and control group. Results of Logistic regression analysis showed that BMI1 (OR=4.30), TG (OR=1.94), FPG1(OR=1.86)、DBP (OR=1.02), LDL-C (OR=1.27), ALT(OR=1.02), were independent risk factors of NAFLD, and HDL-C(OR=0.61) was protective factor (P<0.05).2. Content of serum androgen and estrogen had significant difference between the control and case group. The mean content of male androgen between cases and controls was 3.75 ± 1.08 and 4.44 ± 1.04, while the female estrogen was 12.46 ± 6.03 and 10.68 ±5.71. There had obvious negative correlation between the content of serum androgens and the risk of NAFLD for female (OR=0.50,95% CI:0.32-0.76), while the content of serum estrogens was positively related to the risk of NAFLD for female (OR=1.05, 95% CI:1.07-1.102).3. There had no significant differences in the frequencies of GCKR rs3817588 genotype within case and control groups (P>0.05), but the allele frequency (T:59.8% vs 53.6%, C:40.2% vs 46.4%) had statistical significance (P<0.05). Carriers with C mutation allele had lower uric acid level. Comparing with the most common T allele, C mutation allele as a protective factor decreased the susceptibility of NAFLD, with the OR= 0.703 (95% CI 0.50～0.98). GCKR rs780094 and SIRT1 rsl2778366 genotypes and allele frequency had no significant difference between the NAFLD cases and the controls (P>0.05). There had no significant effects of the variants of the SNP of SIRT1 and GCKR on the risk of NAFLD or the biochemical parameters, such as TG, FPG、 HDL-C, LDL-C, ALT and AST/ALT. The adjusted odds ratios had no significant changes.Conclusions1. Based on our present data, NAFLD patients commonly showed the characteristics of obesity, hypertension, glycol-lipids abnormal (high levels of FPG、 TC%TG and LDL-C, low level of HDL-C), hyperuricemia and elevated liver enzymes. BMI、FPG、TG、LDL-C、DBP、ALT were the independent risk factors of NAFLD, and HDL-C was protective factor.2. There had significant difference in the serum level of androgen and estrogen between the cases and controls. The elevated level of androgen decreased the risk of NAFLD for male, which suggested its protective effect of the risk of NAFLD, while the serum estrogen showed the reverse effects on the risk of NAFLD for female.3. Results of the SNP suggested that SIRT1 rsl2778366 and GCKRrs780094 polymorphisms were not associated with the susceptibility of NAFLD, while GCKR rs3817588 C alleles was associated with the low serum uric acid level and decreased the risk of NAFLD.