Non-alcoholic Fatty Liver Disease and Glucose Metabolism in Obese Children

Background

Type 2 diabetes mellitus (T2DM) accounts for the majority of diabetes over widespread ages from childhood to adulthood. Those affected have similar characteristics, such as excessive abdominal body fat, extreme insulin resistance (decreased responsiveness to insulin), and problems with beta-cell function, which are the cells that produce insulin. Another risk factor of obesity is non-alcoholic fatty liver disease (NAFLD), which is on the rise with the increase in prevalence of obesity. Glucose intolerance may be correlated with NAFLD in at-risk populations. Evaluating glucose levels in children can be an early indicator for diabetes, and testing can help prevent the health complications.

Purpose

The researchers evaluated a large group of children to see if a correlation between glucose tolerance, beta-cell function, insulin resistance, and NAFLD exists.

Population

A group of 571 children and adolescent obese Caucasians between the ages of 8 and 18, and in the 95th percentile for body mass index (BMI) for their gender and age.

 Procedure

The children had a clinical examination to determine one of 5 pubertal stages of development. BMI was calculated as weight/height. The children’s alcohol consumption was determined in an interview. A laboratory assessment was used to test for the hepatitis B and C viruses, and total cholesterol. Glucose and insulin levels were measured with a 2-hour oral glucose tolerance test (OGTT). A liver ultrasonography was used to estimate fatty liver in the children.

Results

In 234 (41%) of the children tested, non-alcoholic fatty liver disease (NAFLD) was found from the tests, which was most prevalent in males. Children with NAFLD were found to have a higher body mass index, fasting glucose and insulin levels, and higher 2 hr oral glucose tolerance test levels compared to children without NAFLD. Fasting glucose alone detected only five children with NAFLD with impaired fasting glucose, but the OGTT determined 55 NAFLD children with impaired glucose tolerance.

Limitations

The researchers obtained insulin and beta-cell function indirectly from OGTT instead of from methods commonly used for children, like C-peptide. Another limitation was with the ultrasonography, because it is known to underestimate the prevalence of fatty liver and could not detect the presence of liver fibrosis. Finally, the researchers used waist circumference as an estimate of visceral fat, and this is a limitation compared to a direct measurement.

Conclusion

Higher insulin resistance was associated with the presence of NAFLD. In obese children with NAFLD, the abnormal glucose levels is better detected by 2 hr OGTT than fasting glucose, and may be a risk factor for the development of T2DM later in life.

 

The full title of the report is “Relationship between fatty liver and glucose metabolism: a cross-sectional study in 571 obese children.” It can be found in Nutrition, Metabolism & Cardiovascular Diseases 22:120-126, 2012. The authors are Bedogni G., Gastaldelli A., Manco M., De Col A., Agosti F., Trirbelli C., Sartorio A.

 

Written by Jordanne Swieck and Kayla Pinzone,
Dept. Nutritional Sciences, Rutgers University-NewBrunswick
Edited by faculty of the NJ Obesity Group