Insulin Resistance, Inflammation, and Nonalcoholic Fatty Liver Disease in Non-obese Adults Without Metabolic Syndrome Components

Purpose: The purpose of the present study was to examine the association of insulin resistance and inflammation with nonalcoholic fatty liver disease (NAFLD) in non-obese adults without metabolic syndrome components.

Methods: This was a cross-sectional study of 759 subjects aged 50 years and older. Diagnosis of NAFLD was based on sonographic evidence of fatty liver without significant alcohol consumption and another cause of chronic liver disease. Subjects without metabolic syndrome components were defined as having none of the following: high blood pressure (≥130/85 mmHg), elevated fasting glucose (≥100 mg/dl), hypertriglyceridemia (≥150 mg/dl), low high-density lipoprotein-cholesterol (men <40 mg/dl; women <50 mg/dl), and abdominal obesity measured by waist circumference ≥90 cm for men and ≥80 cm for women. The subjects were divided into quartile groups according to levels of high-sensitivity C-reactive protein (hs-CRP), homeostasis model assessment of insulin resistance (HOMA-IR), and uric acid. Odds ratios (ORs) were computed for each quartile relative to the lowest quartile group.

Results: After adjustment for age, sex, smoking status, regular exercise, hs-CRP, HOMA-IR, and uric acid, a significant association was found between NAFLD and higher levels of hs-CRP, HOMA-IR, and uric acid. After adjustment for age, sex, smoking status, regular exercise, hs-CRP, HOMA-IR, and uric acid, the Ors (95 % confidence interval) of NAFLD with the highest quartile of hs-CRP, HOMA-IR, and uric acid compared with the lowest quartile were 2.58 (1.03-6.50), 2.55 (1.08-6.05), and 5.15 (1.78-14.89), respectively.

Conclusions: Insulin resistance and inflammation are independently associated with NAFLD in non-obese adults without metabolic syndrome components.