Glucose metabolism in patients with Klinefelter's syndrome

Objective To evaluate the characteristics of glucose metabolism and the possible mechanisms of glucose metabolism disorder in patients with Klinefelter's syndrome (KS). Methods This was a retrospective clinical research. The following data were collected and analyzed: the general condition, gonadotropic and gonadal hormone levels, lipid and glucose profiles, glucose and insulin levels after a 75 g oral glucose tolerance test, and homeostasis model assessment of insulin resistance (HOMA-IR) in 19 patients with KS alone, 9 patients with both KS and DM, 18 DM patients without KS; all were hospitalized in PLA General Hospital since 1990. Independent sample t test was used for comparison betneen two groups. Results (1) The incidence of DM in KS patients was 32.1% (9/28); in patients with 47, XXY karyotype and 48, XXYY karyotype the incidence were 30.7% (8/26) and 50% (1/2), respectively; (2) Compared with simple KS patients, patients with both KS and DM was significantly older, while the testosterone (T) level was significantly lower[ (28±8) vs (22±4) year, (2.0±1.3) vs (5.4±4.3) nmol/L, t=3.044, -2.249; all P<0.05]; Although they had similiar fasting insulin level and area under the curve of insulin, KS patients complicated with DM presented a much higher insulin resistance index (6.5±3.4 vs 1.2±2.1, t=3.234, P<0.05) ; (3) KS patients complicated with DM were much higher and heavier than simple DM patients[(178±12)vs(170±6) cm, (91±23)vs(80±14)kg, t=0.750, 3.866; P<0.05]. The low-density lipoprotein concentration in patients with both KS and DM were lower than that of the patients with KS alone [(2.13±0.93)vs(2.85±0.50) mmol/L, t=-2.681; P<0.05], but their glucose and insulin levels during an oral glucose load were not different between two groups; (4) The estradiol-to-testosterone ratio of KS patients complicated with DM was significantly higher than that of simple KS patients as well as simple DM patients (t=2.302, 2.748; P<0.05) . Conclusions (1) KS patients tend to develop late-onset DM; (2) The possible risk factors of glucose metabolism disorder in KS patients are age, testosterone level, insulin resistance, high estradiol-to-testosterone ratio and abnormalities of X chromosome. Key words: Insulin resistance; Diabetes mellitus; Klinefelter's syndrome; X-chromosome; Testosterone