Received on April 19, 2005
Accepted on June 27, 2005

Endocrinology and Metabolism

Serum Parathyroid Hormone Concentrations Are Increased in Women with Polycystic Ovary Syndrome

¹ Division of Endocrinology and Human Reproduction, Second Department of Obstetrics and Gynecology, Aristotle University of Thessaloniki, Thessaloniki, Greece
² Laboratory of Nuclear Medicine, AHEPA University Hospital of Thessaloniki, Thessaloniki, Greece
³ Endocrine Section of the First Department of Internal Medicine, Athens University School of Medicine, Athens, Greece

^* To whom correspondence should be addressed. E-mail: argic{at}med.auth.gr.

Background: The present study was designed to investigate the effects of polycystic ovary syndrome (PCOS) and of obesity on serum parathyroid hormone (PTH), 25-hydroxyvitamin D (25-OH-vitamin D), and 1,25-dihydroxyvitamin D [1,25-(OH)₂-vitamin D] concentrations and the possible associations of the above calciotropic hormones with the hormonal and metabolic characteristics of the syndrome.

Methods: We studied 58 obese [body mass index (BMI) >30 kg/m²] women with PCOS, 64 overweight (BMI, 25-30 kg/m²) women with the syndrome, 169 normal-weight (BMI <25 kg/m²) women with PCOS, 29 obese controls (ovulatory women without clinical or biochemical hyperandrogenemia), 14 overweight controls, and 70 normal-weight controls. Blood samples were collected (at 0900 after an overnight fast) between the 3rd and 6th days of a menstrual cycle in the control groups and during a spontaneous bleeding episode in the PCOS groups. Circulating concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin (PRL), testosterone, ⁴-androstenedione, 17-hydroxyprogesterone, sex-hormone-binding globulin (SHBG), insulin, glucose, PTH, 25-OH-vitamin D, and 1,25-(OH)₂-vitamin D were measured.

Results: Both PCOS and increased body weight had a significant positive effect on serum PTH values. PTH concentrations were significantly correlated with age, BMI, glucose, PRL, SHBG, and testosterone. Only the correlations with testosterone and PRL were BMI-independent. The effect of PCOS on PTH concentrations remained significant after adjustment for BMI, but not after adjustment for testosterone concentration. Increased body weight also had a significant negative effect on 25-OH- and 1,25-(OH)₂-vitamin D concentrations, but no association with the syndrome was observed.

Conclusions: The results of the present study are in agreement with previous data supporting an association of increased PTH and decreased vitamin D metabolite concentrations with obesity. Moreover, the present findings indicate, for the first time, that PTH probably is also linked to PCOS-associated hyperandrogenism.