Endocrine Abstracts

Introduction

In Klinefelter syndrome, hypergonadotropic hypogonadism is the most prominent endocrine-metabolic disorder. However, a higher prevalence of cardiovascular risk factors has also been reported.

Objectives

In a sample of individuals with Klinefelter Syndrome (KS): – to document the diagnostic context; – to assess the prevalence of cardiovascular risk factors (CVRF) and compare it with a control group; – to analyse the influence of age at diagnosis and hormone replacement therapy (HRT) on CVRF.

Materials and methods

A sample with KS under 55 years of age and an equal number of age-matched male control subjects were selected.

Results

Study group with 32 KS subjects, mean age 29.5 ± 8.6 years. Diagnosis on average at 17.5 ± 12.3 years of age due to learning/behavioral issues (25.0%), infertility (25.0%), phenotype (21.4%), delayed pubertal development (21.4%) and prenatal diagnosis (7.1%). Karyotype (n = 28): 82.8% 47XXY, 6.9% 46XY/47XXY, 3.4% 48XXXY and 6.9% 49XXXY. All of the subjects had hypergonadotropic hypogonadism, 93.8% decreased testicular volume, 46.2% gyneco/adipomastia and 32.1% cryptorchidism. In those in which it was evaluated (n = 8), the presence of azoospermia was constant. HRT was started in 93.8% at a median age of 15.5 ± 12.0 years. In the last 5 years, these patients had an average of 56.2 ± 37.3% of the total testosterone levels within the reference values, 36.4 ± 35.6% below and 5.9 ± 19.8% above. The vast majority of KS (78.1%) had some CVRF: 15.6% pre-diabetes, 6.3% diabetes, 53.1% dyslipidemia, 46.9% overweight, 18.8% obesity and 6, 3% hypertension. The overall prevalence of CVRF was higher than that of the control group (25 vs 15, P = 0.010), with: higher prevalence of dysglycemia (7 vs 0, P = 0.011) and dyslipidemia (17 vs 8, P = 0.021); more overweight/obese individuals without reaching statistical significance (21 vs 32, P = 0.079); similar prevalence of hypertension (2 vs 3, P = 1, 000). There was no significant correlation between higher number of CVRF and age at diagnosis (P = 0.333), age at HRT initiation (P = 0.281) or the percentage of testosterone assays within reference values (P = 0.753).

Conclusions

This sample is composed mainly of young patients, with a variable context of diagnosis, but in general precocious. Even so, an elevated prevalence of CVRF was registered, higher than that of the control group. Although sample size is a limiting factor, the data does not suggest an influence of early diagnosis and HRT on CVRF.