Hum. Reprod. Advance Access originally published online on October 12, 2007
Human Reproduction 2007 22(12):3264; doi:10.1093/humrep/dem330
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Letters to the Editor |
Calcium homeostasis and anovulatory infertility
Divison of Endocrinology and Human Reproduction, 2nd Department of Obstetrics and Gynecology, Aristotle University of Thessaloniki, Greece
1 Correspondence address. E-mail: protoekptotos{at}yahoo.com
We have read with great interest the well-designed study by Chavarro et al. (2007)
and we would like to comment on the potential relationship between calcium homeostasis and anovulatory infertility.
Chavarro et al. reported a negative association between calcium, as well as vitamin intake and infertility, which, nonetheless, was not significant after adjustment for multiple factors, including body mass index (BMI). We agree with the authors that these findings alone cannot totally exclude the possibility that calcium and vitamin D intake could have some effect on ovulation and female fertility. It should be noted that increased BMI is itself strongly associated with relatively low levels of bioavailable vitamin D (Panidis et al., 2005).
In a recent study, involving women with the polycystic ovary syndrome (PCOS), the most common cause of anovulatory infertility, obesity or overweight and PCOS were independently associated with increased parathyroid hormone (PTH) levels (Panidis et al., 2005). Moreover, a BMI-independent positive correlation between PTH and testosterone was observed. It is well known that increased calcium and vitamin D intake suppress PTH production and, could, therefore, possibly, improve PCOS-associated hyperandrogenemia and anovulation. Indeed, in a previous report, PCOS-associated signs of hyperandrogenism were alleviated, after administration of high doses of vitamin D (Thys-Jacobs et al., 1999). The sample size, however, was too small to allow any firm conclusions. Given the above evidence, we believe that the possible interplay between calcium homeostasis and PCOS-associated reproductive morbidity should be specifically addressed in future large-scale studies.
References
Chavarro JE, Rich-Edwards JW, Rosner B, Willett WC. A prospective study of dairy foods intake and anovulatory infertility. Hum Reprod (2007) 22:1340–1347.
Panidis D, Balaris C, Farmakiotis D, Rousso D, Kourtis A, Balaris V, Katsikis I, Zournatzi V, Dimanti-Kandarakis E. Serum parathyroid hormone levels are increased in women with the polycystic ovary syndrome. Clin Chem (2005) 51:1691–1697.
Thys-Jacobs S, Donovan D, Papadopoulos A, Sarrel P, Bilezikian JP. Vitamin D and calcium dysregulation in the polycystic ovarian syndrome. Steroids (1999) 6:430–435.[CrossRef]
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