Which Amount of BMI-SDS Reduction Is Necessary to Improve Cardiovascular Risk Factors in Overweight Children?

CONTEXT: Knowing the changes of cardiovascular risk factors (CRFs) in relation to weight loss would be helpful to advise overweight children and their parents and to decide whether drugs should be prescribed in addition to lifestyle intervention.

OBJECTIVE: The objective of the study was to determine the body mass index (BMI)-SD score (SDS) reduction to improve CRFs in overweight children.

DESIGN: This was a prospective observation study.

SETTING: The study was conducted at a specialized outpatient obesity clinic.

PATIENTS: A total of 1388 overweight children (mean BMI 27.9 ± 0.1 kg/m(2), mean age 11.4 ± 0.1 y, 43.8% male, 45.5% prepubertal) participated in the study.

INTERVENTION: The study included a 1-year lifestyle intervention.

MAIN OUTCOME MEASURES: We studied changes of blood pressure (BP), fasting high-density lipoprotein- and low-density lipoprotein-cholesterol, triglycerides, glucose, and homeostasis model assessment (HOMA) of insulin resistance index. Change of weight status was determined by δBMI-SDS based on the recommended percentiles of the International Task Force of Obesity.

RESULTS: BMI-SDS change was associated with a significant improvement of all CRFs except fasting glucose and low-density lipoprotein-cholesterol after adjusting for multiple confounders such as baseline CRFs, age, gender, BMI, pubertal stage, and its changes. BMI-SDS reduction of 0.25-0.5 was related to a decrease of systolic blood pressure (BP) (-3.2 ± 1.4 mm Hg), diastolic BP (-2.2 ± 1.1 mm Hg), triglycerides (-6.9 ± 5.8 mg/dL), HOMA (-0.5 ± 0.3), and triglyceride/high-density lipoprotein)-cholesterol (-0.3 ± 0.2), whereas high-density lipoprotein (HDL)-cholesterol increased (+1.3 ± 1.2 mg/dL). A reduction of greater than 0.5 BMI-SDS led to more pronounced improvement (systolic BP -6.0± 1.3 mm Hg, diastolic BP -5.1 ± 1.3 mm Hg, triglycerides -16.4 ± 7.1 mg/dL, HDL-cholesterol +1.6 ± 1.5 mg/dL, HOMA -0.9 ± 0.3). Per 0.1 BMI-SDS reduction in systolic BP (-1.0 mm Hg), diastolic BP (-0.8 mm Hg), triglycerides (-2.3 mg/dL), HOMA (-0.2), and triglyceride/HDL-cholesterol (-0.5) decreased significantly, whereas HDL-cholesterol (0.2 mg/dL) increased significantly in linear regression analyses and accounted for multiple confounders.

CONCLUSIONS: A BMI-SDS reduction of 0.25 or greater significantly improved hypertension, hypertriglyceridemia, and low HDL-cholesterol, whereas a BMI-SDS greater than 0.5 doubled the effect.