Polycystic Ovary Syndrome
Also still at an early stage of understanding is the relationship of calcium intake to polycystic ovary syndrome (PCO). PCO is one of the most common causes of infertility today and is generally considered to be a condition of abnormal oocyte differentiation of uncertain etiology. The calcium-PTH-vitamin D axis has not previously been evaluated in PCO. Recently, Thys-Jacobs and colleagues reported a series of 13 patients with PCO who had high serum PTH levels and very low serum 25(OH)D ..
Although this represented a new finding, interesting in its own right, what is more impressive is the fact that treatment with calcium and vitamin D reversed not only the abnormal indices of the calcium economy, but produced a remission in the syndrome, with two of the patients becoming pregnant. There are, as yet, no randomized trials of calcium in this disorder, and so the results, however provocative, must be considered tentative. Nor is there yet an experimental basis to explain the effect. The various meiotic and mitotic divisions through which the oocyte goes during its maturation are known to be triggered by rises in cytosolic [Ca2+], so there is at least a plausible area in which to look for an effect of high circulating levels of PTH. But whether such an effect can explain the findings in this syndrome is still only speculative.
Nevertheless, the dramatic effect on the disease process produced by lowering serum PTH and raising serum 25(OH)D implicates these substances in the pathogenesis of the disorder (and with them, of course, calcium intake), even if the details of the mechanism must, for now, remain unclear.
