Serum alanine aminotransferase activity in obese children

Abstract

To confirm the significance of the serum alanine aminotransferase (ALT) test for the diagnosis of fatty liver and to clarify the relationship between serum ALT activity and the duration of obesity, we analysed 310 obese young school children (195M, 115F), who were classified into three duration groups (1-3 y, 4-6 y, 7 + y), three age groups (6-7 y, 8-9 y, 10-11 y), and four obesity groups (weight excess: mild, 20-29%; moderate, 30-39%; severe, 40-49%; very severe, 50%). Seventy-seven patients with abnormal ALT test, > 30 IU/l, and 27 patients with normal ALT test were examined by ultrasound study to identify the fatty-fibrotic pattern of the liver. Abnormal results of the serum ALT test were found in 24% of all patients. The fatty-fibrotic pattern was identified in 64/77 (83%) patients with abnormal ALT test and in 5/27 (18%) patients with normal ALT test. The serum ALT test has a sensitivity of 0.92 for detecting the fatty-fibrotic pattern proven by ultrasound study. Frequencies of cases with abnormal serum ALT levels increased with the duration of obesity. In the shortest duration group, however, the frequencies of abnormal results in serum ALT test did not increase with advanced ages or the grades of obesity. In conclusion, the present study confirmed the usefulness of the serum ALT test for screening fatty liver, and showed that a longer duration of obesity is generally associated with the occurrence of fatty liver in a paediatric obese population. In young patients with mild obesity or a short duration of obesity, however, fatty liver or fatty fibrosis may develop. Early intervention should be made in the case of obese children.

Liver steatosis in juvenile obesity: correlations with lipid profile, hepatic biochemical parameters and glycemic and insulinemic responses to an oral glucose tolerance test

“…The present data show a direct although weak correlation between the degree of obesity and that of steatosis, according with several observations, 8,21,23,24,36,37 but opposite results are reported, 6,38 possibly related to the minor severity of weight excess of the subjects. On the other hand, as far as the Table 3 The biochemical parameters in the subjects, grouped according to the pubertal stage and to the presence (S) or not (N) of steatosis (* P`0.001 vs stages II ± III; **P`0.001 vs stages IV ± V; {P`0.05, {P`0.01, §P`0.001, N vs S) Liver steatosis in juvenile obesity G Guzzaloni et al duration of obesity is concerned, which we have not considered for the lack of reliable data, there are many concerns in the literature: in fact it has been suggested that both a long, 19,20,23,24,36,38 and a shorter duration 22 could be independent cofactors for determining steatosis, and also that no correlation exists with the duration as such, at least in adults. 8,37 The distribution of adipose tissue, evaluated by WHR, would in¯uence the degree of steatosis only at the end of the pubertal development, a fact that is consistent with the poor reliability of this index in childhood and puberty.…”

“…41 Increased serum levels of transaminases have proved to be correlated with steatosis, both before and after puberty, but ALT only tended to be higher during the whole period of pubertal development when steatosis occurred, as previously reported. 23 However, we con®rm that the prevalence of steatosis may be underestimated when an increase of ALT beyond the upper limit of normal is considered as a diagnostic criterion, as slight steatosis often does not involve enzymatic modi®cations; 38 on the other hand, the serum levels of transaminase correlate positively with the degree of steatosis, according to some observations, 42 but in disagreement with others. 14,19,20 From the present study, gGT appears to be useless for evaluating fatty liver in juvenile obesity, while it may be considered a marker of steatosis and hepatic insulin resistance in adults.…”

Prevalence of Elevated Alanine Aminotransferase Among US Adolescents and Associated Factors: NHANES 1999–2004

“…12 This threshold had a sensitivity of 0•92 for detecting the fatty-fibrotic pattern proven by ultrasound among obese children. 29 We conducted a secondary analysis using 40 U/L as a threshold defining elevated ALT for the sake of comparison, as this and similar thresholds have been previously used in studies in adolescents 13, 30 , and to indicate NAFLD in adults 15, 18, 31 . In addition, linear regression was used to assess associations of characteristics with ALT as a continuous variable as in general population studies of adults, associations of liver enzymes with BMI and components of the metabolic syndrome are linear and do not demonstrate threshold effects.…”

Strategies for the prevention and control of obesity in the school setting: systematic review and meta-analysis

“…The physical health of obese children is compromised in a manner similar to adults. Childhood obesity is associated with an increased risk of hyperinsulinemia, 3 insulinresistance, 4 type 2 diabetes, 5,6 hypertension, 7,8 hypercholesterolemia, 3 chronic inflammation, 9 abnormalities in endothelial function, 10 hyperandrogenemia, 4 gallstones, 11 hepatitis, 12,13 asthma, cancer 14 and orthopedic problems. 10 Obesity has also been shown to diminish children's quality of life severely 14 and is associated with decreased selfesteem 15,16 and depressive symptoms.…”