Gastrointestinal Lay summaries

2015

Adolescents with non-alcoholic fatty liver disease have more body fat from three years of age

Keywords: anthropometry, body mass index, non-alcoholic fatty liver disease, skinfold thickness

What is already known about this subject:

  • Non-alcoholic fatty liver disease is an obesity-related disease (unrelated to alcohol intake) in which fat builds up in the liver. It can lead to liver damage and is also associated with heart disease and type 2 diabetes.
  • Treating obesity and its related conditions (including non-alcoholic fatty liver disease) is difficult. The most effective form of treatment may be to identify those at risk of disease before it occurs.
  • The environment a child is exposed to is important in determining their risk of disease as an adult. Understanding the growth patterns that occur in children who go on to develop non-alcoholic fatty liver disease may help us understand the early life factors that contribute to this disease, and may also help in identifying individuals most at risk.

What this Raine study adds:

  • Liver ultrasound and questionnaire data at 17 years of age, together with height, weight and skinfold thickness data from birth, childhood and adolescence in Raine participants revealed that 15% of adolescents had non-alcoholic fatty liver disease.
  • Adolescents who had non-alcoholic fatty liver disease had more body fat from three years of age.
  • Size at birth was not related to non-alcoholic fatty liver disease at 17 years of age.
  • Risk of non-alcoholic fatty liver disease begins within the first few years of life. Preventative measures for non-alcoholic fatty liver disease should begin during childhood.

Ayonrinde, O. T., et al. (2015). “Childhood Adiposity Trajectories and Risk of Nonalcoholic Fatty Liver Disease in Adolescents.” Journal of Gastroenterology and Hepatology 30(1): 163-171. [publink]

2013

Identification of genetic risk factors for non-alcoholic fatty liver disease

Keywords: adolescent, fatty liver, genetics

What is already known about this subject:

  • Diabetes and obesity are two major risk factors for non-alcoholic fatty liver disease, a condition in which fat builds up in the liver (and is unrelated to alcohol intake).
  • There are numerous genes that predispose to diabetes and obesity, and a small number of genes have been identified that are related to non-alcoholic fatty liver disease in adults.
  • Adolescence may be a useful time to study the genetic inheritance of non-alcoholic fatty liver disease, as adolescents are likely to be in the earliest stages of disease, with the least impact by external factors such as alcohol, diabetes and other co-occurring illnesses.

What this Raine study adds:

  •  13% of Raine participants had non-alcoholic fatty liver disease at 17 years of age.
  • Four gene variants were associated with non-alcoholic fatty liver disease in DNA samples from Raine participants, and two of these genes were important in the liver. Testing in adults with non-alcoholic fatty liver disease showed that these two genes were also important in adult disease.
  • Identifying genetic risk factors associated with early onset non-alcoholic fatty liver disease may help to identify those at greatest risk of future disease and offer insight into the causes of this condition.

Adams, Leon A, Scott W White, Julie A Marsh, Stephen J Lye, Kristin L Connor, Richard Maganga, Oyekoya T Ayonrinde, et al. 2013. “Association between Liver-Specific Gene Polymorphisms and Their Expression Levels with Nonalcoholic Fatty Liver Disease.” Hepatology (Baltimore, Md.) 57 (2) (February): 590-600. doi:10.1002/hep.26184. [publink]

2012

Genetic causes of fatty liver disease in non-obese girls

Keywords: body fat, adolescent, genetics, fatty liver, gender

What is already known about this subject:

  • Fatty liver disease is a condition in which fat accumulates in the liver. Fatty liver disease often occurs in people who are obese, and excessive calorie intake and lack of physical activity are important predisposing factors.
  • Genetics are also an important cause of fatty liver disease, and gene variations causing imbalances in fat metabolism may predispose individuals to fatty liver disease. To date, one gene involved in fat metabolism within the liver has been shown to increase the risk of fatty liver disease, but more remain to be discovered.

What this Raine study adds:

  • Data from Raine participants, including measures of body fat, liver ultrasound and blood tests collected at 17 years of age and DNA samples collected at 14 and 17 years of age, revealed that 11% of boys and 21% of girls had fatty liver disease. Adolescents with fatty liver disease had more body fat than those without the disease.
  • Of the seven fat metabolism genes tested, variants in one gene were found to increase the risk of fatty liver disease. Two of the gene variants increased the risk of fatty liver disease in girls, but not in boys. In girls with these gene variants, fatty liver disease was not associated with obesity.
  • Variations in this gene may explain a large proportion of cases of fatty liver disease in girls who are not obese. Understanding different pathways leading to fatty liver disease will help in the diagnosis and treatment of this disease.

Adams, L. A., Marsh, J. A., Ayonrinde, O. T., Olynyk, J. K., Ang, W. Q., Beilin, L. J., Mori, T., Palmer, L. J., Oddy, W. W., Lye, S. J., Pennell, C. E. (2012). Cholesteryl ester transfer protein gene polymorphisms increase the risk of fatty liver in females independent of adiposity. Journal of Gastroenterology and Hepatology, 27(9), 1520-7. doi:10.1111/j.1440-1746.2012.07120.x [publink]

2011

Body fat distribution and severity of fatty liver disease differ between adolescent boys and girls

Keywords: metabolism, adolescent, fatty liver disease, obesity, abdominal fat, subcutaneous fat, skinfold thickness

What is already known about this subject:

  • Non-alcoholic fatty liver disease is a condition in which fat accumulates in the liver unrelated to alcohol intake. It can lead to serious liver and metabolic disease, including scarring of the liver, type 2 diabetes and cardiovascular disease in some people.
  • Children and adolescents can develop non-alcoholic fatty liver disease, but it is generally thought of as an adult disorder.
  • Early life factors are likely to be important in the development of non-alcoholic fatty liver disease, but little is known about the progression of this disease in children and adolescents.

What this Raine study adds:

  • Data from physical assessments (height, weight, skin fold thickness), abdominal ultrasound and blood tests revealed that 13% of Raine Study adolescent participants had non-alcoholic fatty liver disease at 17 years of age. These adolescents were representative of Western Australian adolescents at the time of the study. Non-alcoholic fatty liver disease was more common in girls (16%) than in boys ( 10%).
  • The best indicator of non-alcoholic fatty liver disease in Raine adolescents was the amount of subcutaneous fat (fat under the skin), but the severity of liver disease was related to the amount of visceral fat (fat around the internal abdominal organs).
  • Although boys were less likely to have non-alcoholic fatty liver disease, when they did it was associated with more severe metabolic features and more severe liver disease.
  • Features of non-alcoholic fatty liver disease represent important risk factors for long term liver disease, type 2 diabetes and cardiovascular disease. Further research should focus on identifying treatable or reversible risk factors.

Ayonrinde,  Oyekoya T, John K Olynyk, Lawrence J Beilin, Trevor A Mori, Craig E Pennell, Nicholas de Klerk, Wendy H Oddy, Peter Shipman, and Leon A Adams. 2011. “Gender-Specific Differences in Adipose Distribution and Adipocytokines Influence Adolescent Nonalcoholic Fatty Liver Disease.” Hepatology (Baltimore, Md.) 53 (3) (March): 800-9. doi:10.1002/hep.24097. [publink]