medwireNews: Cardiometabolic abnormalities, including non-alcoholic fatty liver disease (NAFLD), are already present in many overweight or obese children aged between 2 and 6 years, report researchers.
“Our results suggest that the risk for metabolic abnormalities related to obesity begins to manifest early in the natural history of weight gain”, say Melania Manco (Bambino Gesù Children’s Hospital, Rome, Italy) and colleagues.
They add that their findings “emphasize the need to start screening for cardiometabolic abnormalities using multidisciplinary strategies at an earlier age than is now recommended.”
The study involved 5729 healthy children, among whom rates of overweight according to the International Obesity Task Force definition ranged from 7.0% at age 2.0 years to 16.9% at age 5.8 years, with corresponding obesity rates of 1.1% and 2.9%. A total of 219 of these 597 overweight or obese children underwent further testing.
The most common cardiometabolic abnormalities were insulin resistance, in 35.2% of the children, NAFLD in 31.1%, and dyslipidaemia in 25.1%. Although all the children studied were overweight, those with cardiometabolic abnormalities had a significantly higher average body mass index and subcutaneous adipose tissue thickness than those without abnormalities.
On multivariate analysis, insulin resistance was related to subcutaneous and visceral adipose tissue thickness, triglyceride levels and diastolic blood pressure, with these explaining 35.7% of the variability in the children’s Homeostatic Assessment Model Algorithm–Insulin Resistance (HOMA-IR).
The researchers say these relationships are as expected, because the combination of insulin resistance and increased adipose deposits is associated with increased lipolysis. This results in increased free fatty acid delivery to the liver, which, if unable to accommodate the increase, develops hepatic steatosis.
Writing in JAMA Pediatrics, Manco et al highlight that although one in three overweight children had NAFLD, their HOMA-IR was not significantly different from that of unaffected children, and only 22% had increased levels of liver enzymes. Ultrasonography, as used in this study, may therefore be the preferred means of detecting NAFLD, they say.
NAFLD was significantly associated with greater visceral and subcutaneous adipose thickness, however, which the team says “reinforces the concept of enlarged abdominal adiposity as a pivotal risk factor for NAFLD.”
By Eleanor McDermid, Senior medwireNews Reporter
JAMA Pediatr 2014; Advance online publication