Several routinely assessed blood tests in children may be significantly affected by obesity, particularly those that measure liver enzymes, inflammatory markers, and lipids and lipoproteins, according to study results published in The Journal of Clinical Endocrinology & Metabolism.
While biochemical markers may be used to assess risk for comorbidities associated with obesity, adiposity may alter the results of routine laboratory tests. The goal of the current study was to compare serum concentrations of biochemical markers between children and adolescents with normal weight, overweight, and obesity, as well as to investigate the associations between each biochemical marker and 3 measures of obesity: body mass index (BMI), waist circumference, and waist-to-hip ratio z scores.
The researchers studied 1332 apparently healthy children and teens (aged 5.1 to <19.0 years) with BMI between 13.4 and 65.0 kg/m2, from the Greater Toronto Area and Hamilton, Ontario, Canada. Serum samples were analyzed on the Abbott Architect c8000 system for 35 biochemical markers. Reference intervals were established for all analytes before and after accounting for patients with overweight/obesity.
Overall, 13 of the 35 biochemical markers were significantly different between children with normal weight, overweight, and/or obesity, including alanine aminotransferase, apolipoprotein B, complement components 3 and 4, cholinesterase, high-sensitivity C-reactive protein, gamma-glutamyl transferase, haptoglobin, high-density lipoprotein cholesterol, iron, transferrin, triglycerides, and uric acid.
The researchers found that 24 routine blood tests were affected by obesity after adjusting age and sex, including liver function tests, inflammatory markers, lipids, and iron. A total of 20 biochemical markers were significantly associated with BMI z score, 16 with waist circumference z score, and 18 with waist-to-hip ratio z score.
Of the routine chemistry markers, the most pronounced change between BMI categories was evident for uric acid, with a significant stepwise increase between children with normal weight, overweight, and obesity.
“While it is unknown whether altered levels of biochemical markers in subjects with excess adiposity reflect health or indolent disease, it is important that altered analyte concentrations in subjects with overweight and/or obese are not normalized and that clinicians are aware of the effect of weight status on several laboratory tests,” concluded the researchers.
Higgins V, Omidi A, Tahmasebi H, et al. Marked influence of adiposity on laboratory biomarkers in a healthy cohort of children and adolescents [published online December 17, 2019]. J Clin Endocrinol Metab. doi:10.1210/clinem/dgz161