Decreased β-Cell Function in Overweight Latino Children With Impaired Fasting Glucose
- Marc J. Weigensberg, MD1,
- Geoff D.C. Ball, PHD2,
- Gabriel Q. Shaibi, BA2,
- Martha L. Cruz, PHD2 and
- Michael I. Goran, PHD23
- 1Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, California
- 2Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
- 3Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California
- Address correspondence and reprint requests to Michael I. Goran, PhD, 1540 Alcazar St., Room 208-D, Department of Preventive Medicine, University of Southern California, Los Angeles, California 90033. E-mail: goran{at}usc.edu
Abstract
OBJECTIVE—To determine whether overweight Latino children with impaired fasting glucose (IFG) (≥100 mg/dl) have increased insulin resistance or decreased β-cell function compared with those with normal fasting glucose (NFG).
RESEARCH DESIGN AND METHODS—We studied 207 healthy overweight Latino children, aged 8–13 years, with a family history of type 2 diabetes. Fasting and 2-h glucose and insulin were assessed by oral glucose tolerance test. Insulin sensitivity (Si), the acute insulin response to glucose (AIRg), and the disposition index (DI; an index of β-cell function) were determined using the insulin-modified intravenous glucose tolerance test and minimal modeling. Body composition was determined by dual-energy X-ray absorptiometry.
RESULTS—There were no differences in body composition between NFG (n = 182) and IFG (n = 25) children. Compared with children with NFG, children with IFG had higher fasting and 2-h glucose values and higher fasting insulin. After adjusting for covariates, children with IFG had no difference in Si but 15% lower DI than NFG children (2,224 ± 210 vs. 2,613 ± 76, P < 0.05). Multivariate linear regression showed that AIRg and DI, but not Si, were significant predictors of fasting blood glucose.
CONCLUSIONS—In overweight Latino adolescents with a family history of type 2 diabetes, IFG is associated with impaired β-cell function and therefore may identify children likely to be at risk for progression to type 2 diabetes. The actual risk of progression of IFG to type 2 diabetes remains to be determined by prospective longitudinal studies.
- ADA, American Diabetes Association
- AIRg, acute insulin response to glucose
- DI, disposition index
- HOMA-IR, homeostasis model assessment of insulin resistance
- IFG, impaired fasting glucose
- IGT, impaired glucose tolerance
- NFG, normal fasting glucose
- USC, University of Southern California
Footnotes
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A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
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- Accepted July 7, 2005.
- Received April 13, 2005.
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