Diagnosing Insulin Resistance in the General Population
- Kirsten A. McAuley, MBCHB1,
- Sheila M. Williams, BSC(HONS)2,
- Jim I. Mann, DM, PHD, FRACP1,
- Robert J. Walker, MD, FRACP3,
- Nick J. Lewis-Barned, FRACP4,
- Lara A. Temple, BSC1 and
- Ashley W. Duncan, BSC, NZCS1
- 1Department of Human Nutrition
- 2Department of Preventive and Social Medicine, and
- 3Department of Medicine, Otago University, Dunedin, New Zealand
- 4Department of Diabetes and Endocrinology, Gloucestershire Royal Hospital, Gloucester, U.K.
Abstract
OBJECTIVE—Difficulties in measuring insulin sensitivity prevent the identification of insulin-resistant individuals in the general population. Therefore, we compared fasting insulin, homeostasis model assessment (HOMA), insulin-to-glucose ratio, Bennett index, and a score based on weighted combinations of fasting insulin, BMI, and fasting triglycerides with the euglycemic insulin clamp to determine the most appropriate method for assessing insulin resistance in the general population.
RESEARCH DESIGN AND METHODS—Family history of diabetes, BMI, blood pressure, waist and hip circumference, fasting lipids, glucose, insulin, liver enzymes, and insulin sensitivity index (ISI) using the euglycemic insulin clamp were obtained for 178 normoglycemic individuals aged 25–68 years. Product-moment correlations were used to examine the association between ISI and various surrogate measurements of insulin sensitivity. Regression models were used to devise weights for each variable and to identify cutoff points for individual components of the score. A bootstrap procedure was used to identify the most useful predictors of ISI.
RESULTS—Correlation coefficients between ISI and fasting insulin, HOMA, insulin-to-glucose ratio, and the Bennett index were similar
in magnitude. The variables that best predicted insulin sensitivity were fasting insulin and fasting triglycerides. The use
of a score based on
rather than the use of fasting insulin alone resulted in a higher sensitivity and a maintained specificity when predicting
insulin sensitivity.
CONCLUSIONS—A weighted combination of two routine laboratory measurements, i.e., fasting insulin and triglycerides, provides a simple means of screening for insulin resistance in the general population.
- AST, aspartate aminotransferase
- BP, blood pressure
- HOMA, homeostasis model assessment
- IGT, impaired glucose tolerance
- ISI, insulin sensitivity index
- IVGTT, intravenous glucose tolerance test
- M, glucose disposal rate
- Mbw/I, ISI corrected for total body weight divided by average insulin
- Mffm/I, ISI corrected for fat-free mass divided by average insulin
- PSEP, prognostic separation index
- TAG, triglycerides
- WHR, waist-to-hip ratio
Footnotes
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Address correspondence and reprint requests to Dr. Kirsten McAuley, Department of Human Nutrition, Otago University, P.O. Box 56, Dunedin, New Zealand. E-mail: kirsten.mcauley{at}stonebow.otago.ac.nz.
Received for publication 25 July 2000 and accepted in revised form 9 November 2000.
N.J.L.-B. has received grants from the National Heart Foundation of New Zealand and the Laurensen Trust (Otago Medical Foundation).
A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
