Introduction-aim: Non-alcoholic fatty liver disease (NAFLD) is a clinical condition of uncertain etiology, in whose pathogenesis several mechanisms are involved and which is defined by fat vacuoles in more than 5% of hepatic histiocytes in the absence of serious alcohol consumption. It is frequently comorbid with obesity and insulin resistance. However, NAFLD is also seen in non-obese individuals. The purpose of this study was to compare insulin resistance and metabolic parameters in obese and non-obese NAFLD patients.
Materials-method: 50 obese (BMI >=30) and 50 non-obese (BMI <30) presenting to the Bakırköy Dr. Sadi Konuk Education and Research Hospital Endocrinology, Diabetes and Obesity Clinic with hepatic steatosis determined at ultrasonography (USG) and with no causes such as alcohol use, viral diseases or drug use to account for fat deposition and consenting to participate were included in the study. Patients demographic characteristics, biochemical tests and insulin levels were investigated. Insulin resistance was determined using homeostasis model assessment (HOMA-IR), a mathematical technique, with the formula fasting insulin (U/ml) × fasting glucose (md/dl)/405. Insulin resistance was defined as HOMA-IR >2.5.
Results: One hundred patients with NAFLD, 63.3% female, were enrolled in this study. Fifty were obese and 50 were non-obese. Mean age was 44.1±11.1 years. Hepatomegaly accompanied steatosis in 55% of patients. Mean BMI was 37.3±5.63 in the obese group and 28.2±1.35 in the non-obese group. Mean blood sugar values were 99.3±9.78 in the obese group and 103.40±8.3 in the non-obese group, and the difference was not statistically significant (P:0.08). Insulin levels were 10.1±3.3 in the obese subjects and 13.85±12.3 in the non-obese subjects, while HOMA-IR values were 3.48±3.38 in the obese subjects and 2.57±.91 in the non-obese subjects, and the difference was not statistically significant (P>0.05). Insulin resistance was determined in 60% of obese patients and 50% of non-obese patients (in 55% of the entire group). The difference was not significant (P:0.3). When the general characteristics and metabolic parameters of the groups with and without insulin resistance were compared (Table 1), significant differences were observed in terms of BMI, waist circumference, insulin level, HOMA-IR, GGT and indirect bilirubin levels, but none between the other parameters.
|Parameter||With IR||Without IR||P value|
|Sex||F: 52.6%||F: 47.4%||0.098|
|Waist circumference (cm)||103.67±10.72||97.07±10.79||0.022|
Conclusion: We compared metabolic parameters of obese and non-obese patients with NAFLD and insulin resistance. Insulin resistance was present in 55% of the total group. We observed significant differences between insulin levels, HOMA-IR, GGT and indirect bilirubin levels in subjects with insulin resistance. In conclusion, we think that fatty liver disease is by itself a risk factor for insulin resistance independent of obesity, and that GGT and indirect bilirubin levels in particular can show insulin resistance in patients with hepatic steatosis.
Key words: Non-alcoholic fatty liver disease, insulin resistance, GGT
20 May 2017 - 23 May 2017