The metabolic impact of resting metabolic rate and body fat distribution of obese adolescents, aged 14 to 18 years old
Creators: name: Martino, Pamela Amanda
Publisher: name: Université d'Ottawa / University of Ottawa
Year: 2011
Subjects: subject: Health Sciences, Recreation.
subject: Biology, Physiology.

description: Background: The prevalence of childhood obesity has increased dramatically over the past decade, highlighting the necessity to determine its effects on metabolic profile. Research has shown that abdominal obesity is strongly linked to hyperinsulinemia, dyslipidemia, insulin resistance and type II diabetes, leading to an increased risk for the development of the metabolic syndrome. Currently, little is known about the factors that may predispose individuals to the development of this syndrome. Few studies have looked at the effect of resting metabolic rate on the development of the metabolic syndrome. The effect of body fat distribution on metabolic profile is also an important consideration that warrants further investigation. Objectives: 1) To compare the resting metabolic rate of obese adolescents, in the Healthy Eating, Aerobic and Resistance Training in Youth (HEARTY) trial, with the metabolic syndrome to those without the metabolic syndrome when matched for age, sex and BMI. A secondary objective was to compare the body fat distribution of adolescents with the metabolic syndrome to those with a healthy metabolic profile. 2) To explore the association between adipose tissue distribution (total, visceral, subcutaneous, deep subcutaneous and superficial subcutaneous adipose tissue) and metabolic risk factors (total, LDL-, and HDL- cholesterol, triglycerides, fasting insulin, fasting glucose, 2-hour glucose, HOMA-IR and blood pressure) of obese adolescents in the HEARTY study. Methods: 1) 41 obese adolescents with the metabolic syndrome, as assessed by the International Diabetes Federation criteria, were matched for BMI, age and sex with 41 metabolically healthy obese adolescents. Resting metabolic rate was acquired using indirect calorimetry. Body composition was quantified using Magnetic Resonance Imaging (MRI). 2) 105 participants were included in the analysis. Body composition variables were determined using MRI. Blood pressure, fasting plasma glucose, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, insulin, and 2-hour glucose were measured. Insulin resistance was assessed using the homeostasis model of assessment score (HOMA-IR). Results: 1) Obese adolescents with the metabolic syndrome did not differ in resting metabolic rate compared to those without the syndrome. However, adolescents displaying an unhealthy metabolic profile did have greater visceral adipose tissue compared to those displaying a healthy metabolic profile. 2) Blood pressure, fasting insulin and HOMA-IR were significantly correlated with total adipose tissue, visceral adipose tissue, total subcutaneous adipose tissue and superficial subcutaneous adipose tissue. Triglyceride levels significantly correlated with total adipose tissue and visceral adipose tissue. However, on the multiple regression analysis visceral adipose tissue independently predicted total cholesterol, LDL cholesterol, 2-hour glucose and triglyceride levels, while deep subcutaneous adipose tissue independently predicted blood pressure. Conclusions: 1) Despite having an unhealthy metabolic profile, adolescents with the metabolic syndrome do not have an altered resting metabolic rate. However, the increased amount of visceral adipose tissue may play a part in the development of the syndrome. 2) Although all body fat depots are significantly correlated with metabolic risk factors, visceral adipose tissue remains more predictive of an adverse metabolic profile.