1. Effect of Insulin Resistance on Weight Loss in Overweight Children
Sarah Henes, MS, RD
Kathy Kolasa, Ph.D., RD
Doyle M. Cummings, Pharm.D.
David Collier, M.D., Ph.D.
John Olsson, M.D.

2. Acknowledgements
Rebecca Rawl, Susan Morrissey, Lauren Whetstone, Yancey Crawford;
Brody School of Medicine
Associates of ECU’s Pediatric Healthy Weight Research and Treatment Center
Pitt Memorial Hospital Foundation

3. Background
The prevalence of overweight in children continues to rise at an alarming rate (CDC); >40% Pitt County youth>85th%tile BMI for age
We have recently shown that childhood overweight is associated with hyperinsulinemia and CV risk factors (J Am Dietetic A. 2004;104(3): )
Limited evidence describing effective treatments for pediatric obesity
Summerbell et al Cochrane Systematic Review, May 2003
Numerous preliminary reports describe a variety of dietary initiatives, many of which focus on reduction in carbohydrate intake

4. Background, cont’d
Pittas et al showed in adults that those with higher baseline levels of insulin lost more weight with carbohydrate restriction (Diab Care 2005; 28:2939 – 2941)
Cornier et al showed in adults that insulin resistance (by GTT) modulated the degree of weight loss associated with a low carbohydrate diet (Obesity Research 2005; 13:703 -9)
Similar data were not available in children

5. Study Objective
To examine the relationship between insulin resistance and changes in BMI score in overweight children in association with dietary modification that focused on carbohydrate reduction

6. Methods
Overweight children (> 95th percentile for BMI for age/gender; yr) seen in PHWRTC clinic who have completed at least 3 visits
All received intensive one-on-one dietary counseling including a focus on reducing sweetened beverages (sodas, etc) and other simple carbohydrates
Each child was seen at baseline for intensive counseling and at two subsequent follow-up visits

7. HOMA-IR = (Insulin * Glucose) / 405
Methods
Insulin resistance (IR) estimated at baseline from fasting glucose & insulin using HOMA-IR
HOMA-IR = (Insulin * Glucose) / 405
Children divided into two groups – low IR (≤ 2.0) and high IR (> 2.0) based on HOMA-IR (Cornier et al: Obesity Research 2005; 13:703 -9)
BMI Score = BMI/BMI at 95th percentile for age/gender x 100
Change in BMI score from baseline to 2nd follow-up (mean = 12 weeks) compared in the two groups (low IR and high IR)
Statistics: Pearson CC, t-test, linear regression

8. Results: Patients N = 53 Mean age = 11.2 ± 3 yr 70% female
59% non-white
Mean BMI = 32.5 ± 7

9. Change in sweetened beverage consumption

10. Results
Change in BMI score and HOMA-IR were well correlated (Pearson r = 0.43, p< 0.01)
Those with high IR ( HOMA) had a greater reduction in mean BMI score (- 2) on the reduced CHO diet compared to those with low IR ( HOMA) (+1), (p = 0.05)
There was no significant difference by race or gender

11. Linear Regression
HOMA was significantly (β = 0.4; p < 0.01) associated with change in BMI score at the F/U visit when controlling for age, race, sex, and initial BMI

12. Conclusion
Similar to findings in adults, the decrease in BMI score in children associated with a reduction in sweetened beverage consumption was modestly greater in those with increased insulin resistance
These findings suggest that estimating insulin resistance using HOMA may assist in predicting the BMI response to simple CHO reduction in overweight children