Changes of liver fat content and transaminases in obese children after 12-mo nutritional intervention

AIM:To assess a relationship between longitudinal changes in liver fat content and biochemical parameters in obese children after 1-year nutritional intervention.METHODS:Forty-six obese children, 21 males and 25females, aged 6-14 years, underwent metabolic measurements, liver ultrasonography(US) and chemicalshift magnetic resonance imaging(MRI) examinations at baseline and after 1-year nutritional intervention. A child was defined obese if her/his body mass index(BMI)was above the age- and sex-adjusted BMI Cole’s curve passing through the cut-off of 30 kg/m2 at 18 years.BMI Z scores were calculated and adjusted for age and gender by using the Cole’s LMS-method and Italian reference data. Biochemistry included serum alanine aminotransferase(ALT) and aspartate aminotransferase(AST). Abdominal US and chemical-shift MRI were performed according to a randomized sequence.The same radiologist performed US by a GE Logiq 9(General Electric Healthcare Medical Systems, Milwaukee, WI, United States) using a 3.5-MHz convex array transducer. Liver echogenicity was evaluated independently on videotape by 3 radiologists unaware of the child and MRI outcomes, and a consensus was established. Another experienced radiologist, unaware of the child and US data, performed the abdominal chemicalshift MRI with a 1-t system NT-Intera(Philips Medical Systems, Best, The Netherlands) and a phased-array coil. Liver fat fraction(FF) on MRI was judged elevated when greater than 9%. A FF>18% was considered expressing more severe cases of fatty liver according to Fishbein. A nutritional-behavioral intervention was recommended to promote a normocaloric balanced diet and active lifestyle based on the Italian guidelines for treatment of childhood obesity.RESULTS:Compared to baseline, at the end of intervention children showed lower intakes of energy(mean± SD:2549±1238 Kcal vs 1770±622 Kcal, P<0.0001), total fat(90±47 g vs 52± 23g, P<0.0001),carbohydrates(356±174g vs 241±111 g, P=0.001),and protein(99±48g vs 75±23g, P=0.006) intakes. Prevalence of FF≥9% declined from 34.8%to 8.7%(P<0.01), with a mean reduction of 7.8%(95%CI:5.0-10.6). At baseline, FF was associated with liver biochemical parameters(maximum P<0.001). At the end of the intervention association was found with AST(P=0.017). Change of FF was associated with change in AST(P =0.027) and ALT(P=0.024). Rate of increased liver echogenicity declined from 45.6% to21.7%(P<0.0001). Liver echogenicity was associated with A