Bright liver, body composition and insulin resistance changes with nutritional intervention: a follow-up study

Background: Nonalcoholic fatty liver disease (NAFLD) because of its association with obesity, diabetes and insulin resistance (IR), is the hepatic expression of metabolic syndrome. Exercise and nutritional intervention can improve and prevent these inter-related conditions; the relationships between the degree of IR and ultrasound (US) morphological post-interventional changes are not defined. Aims: The aim of our study was to assess the relationship, if any, in NAFLD patients, among IR, BMI and degree of bright liver, before and after 6 months of a moderately hypocaloric/balanced dietary/lifestyle treatment. Fifty outpatients with a clinical and US diagnosis of NAFLD were studied. Methods: Liver echogenicity [Bright Liver Score (BLS)] was scored on a four-graded scale. IR was assessed by homoeostasis model-insulin resistance (HOMA-IR). Body composition was assessed by bioimpedance assessment and skinfold measurements. Results: A significant decrease of BLS was observed, with a concurrent decrease of body weight, body mass index (BMI) and HOMA-IR. Bright liver decrease has a trend parallel to IR, much less steep than the trend of bright liver reduction against US liver dimensions, body weight and BMI decrease. HOMA-IR is the only baseline variable that enters significantly in the multiple regression and, alone, explains 21.4% of variance in predicting bright liver degree. After dietary interventions, both HOMA-IR and BMI are significantly involved in the multiple regression and explain, together, 42.3% of variance in predicting bright liver degree; variation in BLS can be predicted by variation of body weight and of US longitudinal measurement of the liver. Conclusions: Liver US BLS appears to be a useful tool, both alone and along with other US measurements and body weight changes, for the assessment of clinical-metabolic amelioration in patients treated with dietetic interventions. The clinical-diagnostic role, if any, of other assessed laboratory analyses, in the subset of NAFLD, does not appear to be definite.