Insulin Sensitivity and β-Cell Function in Women With Polycystic Ovary Syndrome
- Jana Vrbíková, MD,
- Bela Bendlová, PHD,
- Martin Hill, PHD,
- Markéta Vanková, MS,
- Karel Vondra, MD and
- Luboslav Stárka, MD DSC
Abstract
OBJECTIVE—To evaluate insulin sensitivity (IS) and β-cell function (βF) in lean and obese women with polycystic ovary syndrome (PCOS), either separately or by using a disposition index (DI).
RESEARCH DESIGN AND METHODS—A total of 64 women with PCOS and 20 healthy women were examined by anthropometry, oral glucose tolerance tests (OGTTs), and insulin tolerance tests. Statistical analysis used one-way ANOVA, Kruskal-Wallis, and Mann-Whitney U tests, as appropriate.
RESULTS—A significantly higher waist-to-hip ratio (P < 0.0001) was found in both lean and obese women with PCOS. Higher basal blood glucose (P < 0.004) and blood glucose values at 3 h of OGTT (P < 0.008) were found in lean and obese PCOS subjects in comparison with control subjects. Insulin resistance by homeostasis model assessment (P < 0.007) was significantly higher in obese PCOS than in control or lean PCOS subjects. Early-phase insulin secretion (insulinogenic index [ΔI/ΔG30–0, where I is insulin and G is glucose]; P < 0.0007) was significantly higher in both lean and obese PCOS subjects than in healthy women. All tested combinations of parameters of IS and βF (DIs) followed a physiological hyperbolic relationship. Significantly lower values of the fasting state–derived DIs were found (all P < 0.05) in obese PCOS subjects. Significantly higher values of all of these indexes derived from nonfasting values were found in lean PCOS as compared with control and obese PCOS subjects (all P < 10–3).
CONCLUSIONS—Increased βF was found even in lean individuals with PCOS. Insulin hypersecretion is thus probably connected to the pathogenesis of PCOS.
- AUC, area under the curve
- βF, β-cell function
- Cp, C-peptide
- DHEA, dehydroepiandrosterone
- DHEAS, DHEA sulfate
- DI, disposition index
- FGIR, fasting glucose-to-insulin ratio
- HOMA, homeostasis model assessment
- IGT, impaired glucose tolerance
- IR, insulin resistance
- IS, insulin sensitivity
- ITT, insulin tolerance test
- KITT, rate of glucose disappearance
- OGTT, oral glucose tolerance test
- PCOS, polycystic ovary syndrome
- SHBG, sex hormone–binding hormone
- WHR, waist-to-hip ratio.
Footnotes
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Address correspondence and reprint requests to Jana Vrbíková, MD, Institute of Endocrinology, Národní 8, 116 94 Prague 1, Czech Republic. E-mail: jvrbikova{at}endo.cz.
Received for publication 23 November 2001 and accepted in revised form 11 April 2002.
A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
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