Calciotropic hormones, insulin resistance, and the polycystic ovary syndrome.

OBJECTIVE To investigate whether abnormalities in serum concentrations of 1,25-dihydroxyvitamin D [1,25(OH)(2)D], 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), calcium, and phosphorus were associated with risk of polycystic ovary syndrome (PCOS) and obesity. The possible correlations of the calciotropic hormones with insulin resistance were also examined. DESIGN Case-control study. SETTING Department of Genetics, Royan Institute. PATIENT(S) Eighty-five women with PCOS and 115 control women were recruited. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Serum levels of glucose, insulin, total calcium, phosphorus, PTH, 25(OH)D, and 1,25(OH)(2)D were measured in all 200 subjects. RESULT(S) The presence of PCOS had age- and body mass index (BMI)-independent positive effects on serum phosphorus, PTH, 25(OH)D, and insulin concentrations as well as on insulin resistance. Furthermore, overweight/obese (BMI > or =25 kg/m(2)) women with PCOS had significantly decreased levels of 1,25(OH)(2)D and glucose compared with normal-weight (BMI <25 kg/m(2)) women with PCOS. In women with PCOS, phosphorus was correlated negatively with insulin and insulin resistance and positively with 1,25(OH)(2) D. In addition, in normal-weight patients, PTH correlated positively with insulin and insulin resistance. CONCLUSION(S) It is possible that elevated levels of phosphorus and PTH in women with PCOS, at least in part, through their effects on insulin levels and insulin resistance, are involved in pathogenesis of the syndrome.