Abstract and Introduction
Background: The prevalence of non-alcoholic fatty liver disease (NAFLD) in children is 8% in the general population, and 34% in the context of obesity. There is a paucity of data on the prevalence of hepatic steatosis in healthy children in Ontario.
Aims: To determine the prevalence of hepatic steatosis using abdominal computed tomography (CT) scans in a cohort of previously healthy children across the paediatric age spectrum in Ontario, Canada, and to determine any association between measures of abdominal adiposity and hepatic steatosis.
Methods: Retrospective review of the SickKids Trauma Database from 2004–2015. Previously healthy children ages 1–17 years having undergone an abdominal CT scan as a part of routine trauma assessment were included, and those with an intra-abdominal injury excluded. Steatosis was defined as a difference between liver and spleen attenuation ≤-25HU. The percentage of the total area occupied by abdominal subcutaneous adipose and visceral adipose tissue was measured. Anthropometrics and baseline demographics were collected.
Results: A total of 503 (51% male) children with mean (±SD) age 9.5 ± 4.5 years and weight z-score of 0.37 ± 1.05 were studied. Seventy-seven (15%, 95% CI [12%–18%]) had hepatic steatosis; no differences found between sexes or across age quartiles. The abdominal subcutaneous adipose tissue area was greater in those with hepatic steatosis compared to those without (32% [22–42] vs 24% [17–36], P = 0.003). The visceral adipose tissue area was significantly greater in older children ≥9.8 years with hepatic steatosis (7.7% [5.1–10] vs 6.6% (4.9–8.5), P = 0.04).
Conclusion: Hepatic steatosis was highly prevalent in previously healthy children in Ontario, including children of pre-school age. We found an association between hepatic steatosis and abdominal subcutaneous adipose tissue, and in older children with visceral adipose tissue.
Non-alcoholic fatty liver disease (NAFLD) is the most common cause of liver disease in both adults and children in the developed world and is being diagnosed at an increasingly younger age.[1,2] It is a major population health concern, as it is the second most common indication for liver transplantation in adulthood and it has been shown to be associated with decreased patient survival. The natural history of paediatric NAFLD has not been well described; however, data derived from the placebo arms of randomized control trials suggest that only a minority of children improve with lifestyle interventions over a span of 1–2 years.[5,6] Taken together, these data are significant considering that pooled mean prevalence of NAFLD in the general paediatric population is 7.6%, and in obese children reaches 34.3%. Little is known of the prevalence of NAFLD in young children (pre-school age) and, in addition, the prevalence of paediatric NAFLD in Canada has not been well described.
The pathogenesis of non-alcoholic fatty liver disease is thought to be multifactorial. Host (eg obesity, genetics, ethnicity, insulin resistance, etc.) and environmental factors (eg dietary intake, microbiome, etc.) predispose patients to the development of hepatic steatosis, which is often accompanied by inflammation and/or fibrosis. Of these, abdominal (or central) obesity is the stronger risk factor,[8–10] including in lean individuals with NAFLD whose body mass index (BMI) is not indicative of an overweight/obese state. In clinical practice, abdominal adiposity can be assessed using waist circumference measurements. Waist circumference is superior to body mass index in determining the presence of excess adiposity; however, it is not often obtained and it does not differentiate between abdominal visceral and subcutaneous adipose tissue. Because pro-inflammatory cytokines that contribute to metabolic dysregulation and inflammation are predominantly released from the visceral adipose tissue, it is thought that visceral adiposity contributes to non-alcoholic fatty liver disease.[13,14] This has not been extensively studied in children with non-alcoholic fatty liver disease; however, emerging studies are reporting on imaging-based estimates of abdominal adiposity and its relation to hepatic steatosis severity.
The objective of this study was to determine the prevalence of hepatic steatosis in a cohort of previously healthy children across the paediatric age spectrum in Ontario, Canada. Our aims were to determine the presence of hepatic steatosis using abdominal computed tomography (CT) scans performed in previously healthy trauma victims and to determine association between measures of abdominal adiposity and hepatic steatosis.
Aliment Pharmacol Ther. 2018;48(5):556-563. © 2018 Blackwell Publishing