Background: The prevalence of obesity in children has been shown to be plateauing or decreasing in some countries. However, the burden of severe obesity is often not assessed. Children with severe obesity may be at an increased risk for cardiovascular disease and diabetes. The objective is to determine the prevalence of severe obesity in young children and to examine the association with cardiometabolic risk factors.
Methods: A longitudinal study was conducted through The Applied Research Group for Kids! (TARGet Kids!), a practice-based research network in Toronto, Canada. Healthy children from birth to 6 years of age were recruited and followed through middle childhood. The main outcomes of the study were as follows: total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and non-HDL cholesterol, triglycerides, glucose, systolic blood pressure (SBP), and diastolic blood pressure (DBP). BMI was age and sex standardized based on the WHO growth standards. A BMI z-score >3 was used to define obesity for children <5 years of age, and severe obesity for children ≥5 years of age.
Results: Among 5738 children <5 years, 0.8% had a zBMI >3. In 626 children who were 5 and 6 years old, 2.1% had a zBMI >3. In the multivariable analysis adjusted for age, sex, maternal ethnicity, and family history, using repeated measures, children with a zBMI >3 had significantly higher odds of having abnormal SBP [odds ratio (OR) 6.4, 95% confidence interval (CI) 1.5-27.9; p = 0.01] and DBP (OR, 3.6 95% CI 1.2-10.6; p = 0.02), respectively, as compared with healthy-weight children. Trends demonstrating an association between a zBMI >3 and abnormal lipid levels were also identified.
Conclusion: Young children with a zBMI >3 have significantly higher blood pressure measures and trends toward worse lipid profiles than children at lower zBMIs.
Keywords: BMI; cardiometabolic risk; children; severe obesity.