Physicians should not only warn obese children and their families about the long-term consequences of obesity for which they are at risk in adulthood, they should also screen for the many diseases that may already be present.
Objectives
To assess the association of weight loss and insulin sensitivity, glucose tolerance, and metabolic syndrome (MS) in obese adolescents following weight loss treatment, and to determine the threshold amount of weight loss required to observe improvements in these measures.
Study design
A randomized, controlled behavioral weight loss trial was conducted with 113 obese adolescents. Changes in fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), whole body insulin sensitivity index (WBISI), body-mass index (BMI), and MS criteria were assessed at baseline and at month 4.
Results
There was significant improvement in all measures of insulin sensitivity at month 4. Mean fasting insulin dropped to 16.6 from 22.3 μU/mL (p<0.0001). HOMA-IR decreased significantly from 4.9 to 3.7 (p=0.001) and WBISI increased significantly from 2.87 to 3.98 (p<0.0001). An 8% reduction in BMI led to a significant improvement in WBISI (p=0.03) and was the optimal threshold. Fewer individuals met criteria for MS after weight loss (p=0.0038), although there were no significant changes in the individual features of the syndrome.
Conclusions
In this trial, weight loss at month 4 was associated with improved insulin sensitivity in obese adolescents. An approximate decrease in BMI of 8% was the threshold level at which insulin sensitivity improved. As more weight loss programs are designed for obese adolescents, it will be important to have reasonable weight loss goals that will yield improvements in metabolic and cardiovascular disease risk factors.
Context
Insulin-like growth factor (IGF)-I and IGF binding protein (IGFBP)-1 have been linked to cardiovascular disease (CVD) risk and pathophysiology in adults, but there are limited data in youth.
Objective
The aim of the study was to examine the relationship between IGF and IGFBP-1 with traditional and non-traditional CVD risk factors including inflammatory markers and body composition in an obese pediatric cohort.
Design
A cross-sectional study.
Setting
The study was carried out at a university children’s hospital.
Subjects
Sixty-one obese non-diabetic adolescents.
Outcomes
Fasting IGF-I, IGFBP-1, lipoprotein profiles, high-sensitivity C-reactive protein (hsCRP), and total adiponectin as well as insulin sensitivity measures, blood pressure (BP), and anthropometrics.
Results
IGFBP-1 was negatively associated with insulin sensitivity measures, body mass index (BMI), and diastolic BP in males. IGF-I was negatively associated with hsCRP (r = −0.479, p < 0.0005), and IGFBP-1 was positively associated with adiponectin (r = 0.545, p < 0.0005). The IGF-I/CRP and IGFBP-1/adiponectin associations remained significant when controlling for both BMI and insulin sensitivity index (SI). Both IGF-I and IGFBP-1 were negatively associated with waist circumference (r = −0.327 and r = −0.275, respectively) and sagittal abdominal diameter (r = −0.333 and r = −0.371, respectively), while IGFBP-1 was negatively associated with fat mass (r = −0.347, p = 0.01) as well as neck circumference and fat-free mass in males. Controlling for BMI z-score and SI, IGFBP-1 remained negatively associated with diastolic blood pressure (r = 0.706, p = 0.001 and neck circumference (r = −0.548, p = 0.15) in males.
Conclusions
IGF-I and IGFBP-1 associate with CVD risk markers and may add to clinical assessments of cardiometabolic dysfunction in youth.
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