Objective: To observe the relationship of liver fat content to insulin resistance and metabolic syndrome (MS) in nonalcoholic fatty liver disease (NAFLD) patients without known diabetes mellitus (DM).
Methods: 106 patients diagnosed as with fatty liver by ultrasonography, 61 males and 45 females, aged 47 +/- 14, underwent anthropometric examination and laboratory tests including lipid profile, fasting and 2 hour serum glucose and insulin after 75 g glucose load. CT scanning was used to determine the fat content in liver. Homeostasis model assessment insulin resistance (HOMA-IR) was calculated. Metabolic syndrome was defined based on the ATP III criteria.
Results: The liver fat content in all subjects was distributed from 0 to 34.7% [median (quartile) 6.34% (3.11%-10.82%)]. Forty-five of the 106 patients (42.45%) were diagnosed as with MS. When the liver fat increased by quartile order [< 3.11% (n = 26), 3.11%-6.34% (n = 27), 6.34%-10.82% (n = 27), and > or = 10.82% (n = 26)], the percentages of MS were 19.2% (n = 5), 29.6% (n = 8), 48.1% (n = 13), and 73.1% (n = 19) respectively (P < 0.05). Stepwise Logistic regression analysis (forcing liver fat in the model) showed that being female, liver fat content, fasting glucose, systolic blood pressure, BMI, and history of hypertension were significant risk factors of MS, and HDL-C and fasting insulin were significant protection factors of MS. The standard partial regression coefficient of liver fat content was higher than those of fasting blood glucose, systolic blood pressure, and BMI. Stepwise multiple linear regression analysis demonstrated that liver fat content was a significant risk factor of HOMA-IR while BMI and waist circumference were not.
Conclusion: Compared with BMI and waist circumference, liver fat content is a stronger risk factor of IR and MS.