Concordance of vitamin D peripheral levels in infertile couples' partners.

A large number of evidence supports the role of vitamin D insufficiency in both women and men infertility. However, no studies have evaluated the rate of concordance of vitamin D status between the partners. This finding might open new scenarios in the interpretation of the available data linking vitamin D insufficiency and infertility. In the present cross-sectional study, 103 consecutive infertile couples were recruited between April and May 2014. Both partners concomitantly provided a serum sample for the assessment of 25-hydroxy-vitamin D [25-(OH)-D]. Vitamin D insufficiency was defined as serum 25-(OH)-D <20 ng/ml. One hundred-fifty subjects (73 women and 77 males) were 25-(OH)-D insufficient, corresponding to a rate of 73%. Overall, concordance was observed in 73 couples (71%), thus higher than the expected 61% (0.732 + 0.272) based on chance (p = 0.007). The Pearson coefficient of correlation R2 between the partners of the couples was 0.52 (p < 0.001). No statistically significant differences emerged when evaluating the rate of 25-(OH)-D insufficiency according to the causes of infertility. Serum 25-(OH)-D correlates within the partners of infertile couples. Further evidence is warranted to determine the clinical relevance and possible clinical applications of this finding.