Published online December 1, 2006
PEDIATRICS
Vol. 118
No. 6
December 2006, pp.
2603a-2604
(doi:10.1542/peds.2006-2571)
Low Prevalence of Impaired Fasting Glucose in Obese Adolescents From Southern Europe: In Reply.
Desmond E. Williams, MD
Betsy L. Cadwell, MSPH
Yiling J. Cheng, PhD
Edward W. Gregg, PhD
Linda S. Geiss, MA
Michael M. Engelgau, MD
K. M. Venkat Narayan, MD
Giuseppina Imperatore, MD
Division of Diabetes Translation,
National Center for Chronic Disease Prevention and Health Promotion,
Centers for Disease Control and Prevention,
Atlanta, GA 30341-3724
Catherine C. Cowie, PhD
National Institute of Diabetes and Digestive and Kidney Diseases
National Institutes of Health
Bethesda, MD 20892-2560
We read with interest the letter from Grandone et al and appreciate their sharing recent results from their study of obese adolescents from southern Italy.
There are several possible explanations for the differences between the results of our study1 and those described by Grandone et al. One is that our definitions of impaired fasting glucose (IFG) and overweight may have differed from theirs. We used the American Diabetes Association 2004 definition of IFG (a fasting plasma glucose level of 
100 mg/dL),2 and we used the 2000 CDC growth chart3,4 to identify adolescents who were overweight (those with a BMI 95th percentile for US adolescents, by age and gender).4 The growth charts were constructed by using BMI percentiles from a historic data set containing data from 5 national surveys conducted between 1963 and 1994.4 Grandone et al did not report the definitions they used for IFG and obesity, but their use of either the older definition of IFG (a fasting plasma glucose level of >110 mg/dL) or a different definition of obesity could account for the differences in study results.
A second possible explanation may be the differences in the data sources used by the 2 studies. Our data came from a population-based study of a representative sample of the US population,1 whereas the data for the Italian study seem to have come from a convenience or clinic-based sample of adolescents that is not likely to be representative of the larger Italian adolescent population. Finally, as Grandone et al point out, variations in IFG rates among youth may be attributable to genetic differences as well as differences in physical activity levels, dietary practices, and other environmental factors. Determining the effect of these factors on IFG rates will be important priorities for future research.
Thank you for the opportunity to respond.
REFERENCES
- Williams DE, Cadwell BL, Cheng YJ, et al. Prevalence of impaired fasting glucose and its relationship with cardiovascular disease risk factors in US adolescents, 1999–2000.
Pediatrics. 2005;116:1122–1126[Abstract/Free Full Text]
- American Diabetes Association. Diagnosis and classification of diabetes mellitus.
Diabetes Care. 2004;27(suppl 1):S5–S10
- Himes JH, Dietz WH. Guidelines for overweight in adolescent preventive services: recommendations from an expert committee. The Expert Committee on Clinical Guidelines for Overweight in Adolescent Preventive Services. Am J Clin Nutr. 1994;59:307–316[Abstract/Free Full Text]
- Kuczmarski RJ, Ogden CL, Guo SS, et al. 2000 CDC growth charts for the United States: methods and development. Vital Health Stat 11. 2002;(246):1–190
PEDIATRICS (ISSN 1098-4275). ©2006 by the American Academy of Pediatrics
