Gender Differences in Healthy Ranges for Serum Alanine Aminotransferase Levels in Adolescence

Abstract

Background & AimsThere is a worldwide epidemic of obesity among adolescents who subsequently are at increased risk for the development of non alcoholic fatty liver disease (NAFLD). The serum alanine aminotransferase (ALT) is the most frequently used test for screening these individuals, but no age and gender-specific upper limits of normal (ULN) based on healthy population data in children are available. The objective of the present study was to define ULN for ALT in healthy children in order to use this as a tool for case finding.MethodsA total of 975 school children (aged 7–18 years) were included in the study cohort. Highly significant correlations (all p<0.001) were noted between ALT values and measures of BMI, systolic and diastolic blood pressure, insulin levels, HOMA-IR, total cholesterol and triglyceride concentrations. In order to define the population with no risk factors, we excluded subjects having abnormal values for factors that correlated with ALT. This population comprised 186 boys and 185 girls.ResultsIn boys, median serum ALT levels were 16 IU/L and 9, 11, 18, and 30 IU/L for the 5th, 25th, 75th, and 95th percentiles. In girls, median serum ALT was 13, and 7, 9, 16, and 21 IU/L for the 5th, 25th, 75th, and 95th percentiles, respectively. The ULNs for ALT were 30 IU/L and 21 IU/L for boys and girls respectively. We found a linear relationship between age and ALT in females (p<0.001) but not in males. By multiple logistic regression, independent predictors of an elevated ALT included the BMI, waist hip ratio and levels of serum total cholesterol. In females, age was an additional inverse predictor.ConclusionsIn children and adolescents, these normal limits for ALT should be applied. Those with persistent elevations should be investigated further.

First National Report on Aminotransaminases` Percentiles in Children of the Middle East and North Africa (MENA): the CASPIAN-III Study

“…Some studiesindicated this ALT cutoff level as moderate sensitivity for the pediatric age group; it is proposed that lower levels of ALT may be considered for children and adolescents rather than for adults (9-11). The limited studies that established the normal values of liver function tests in the pediatric age group proposed that the liver enzymes levels are different according to age and gender (12-14). …”

Elevated alanine aminotransferase activity is not associated with dyslipidemias, but related to insulin resistance and higher disease grades in non-diabetic non-alcoholic fatty liver disease

“…It is also associated with a large amount of heath care cost [4] . NAFLD represents the most frequent chronic liver disease in the general population and is anticipated to become even more prevalent with time, due to the elevating proportion of people of both younger and older age, obesity and diabetes [5][6][7][8][9] . Putting together, NAFLD is emerging as a serious and global health problem which needs to be more precisely and critically addressed.…”

Methodological and Statistical Comments on CASPIAN-III Study

“…However, sampling method is more important than sample size for generalizability. Authors claimed that difference in their findings with previous study in Tehran, which has revealed lower limit for upper normal limits for ALT and AST (3), can be due to sampling, which is only from one city and not whole country and this difference may be also due to lower sample size. They have mentioned that the population studied in Tehran was less than one-fourth of the current nationwide study.…”

“…You should not compare your total sample size with the number of studied people in one province. Their results seems more representative to Tehran due to your mentioned limitations specifically when Poustchi et al (3) have excluded subjects having abnormal values for factors that correlated with ALT in their study. In different parts of the paper (2), authors have expressed that there are linear associations.…”