Infertility is also associated with poor Vitamin D Binding Protein

Created October 2017

Vitamin D binding protein is lower in infertile patients compared to fertile controls: a case control study

Fertility Research and Practice20173:14, https://doi.org/10.1186/s40738-017-0042-0

Jason Franasiak, Sue Shapses, Wei Sun, Richard Scott and Xiangbing Wang

Premenopausal women (from table 2)

**
Infertile Fertile
25OHD (ng/mL)
standard test, no difference		 30 30
~~#00F:DBP (mg/dL) 40.* 53 ~~
Free 25OHD (pg/mL) 6.3 * 4.3
Bioavailable 25OHD (ng/mL) 3 2
Estradiol (pg/mL) 116* 45 **
  • P < 0.01 = statistically significant
Vitamin D binding protein(GC) and the Vitamin D Receptors (VDR) are two of the genes which restrict how much Vitamin D actually gets to cells . For both gene problems an easy solution (improved fertility in this case) is to just increase the amount of vitamin D consumed. Note: gene problems in the male can also lead to infertility of the couple* Assisted Reproduction – 5 studies concluded vitamin D repletion helps – Review March 2015* Fertility and Sperm category listing has ** items * along with related searchesGenetics category listing contains the following {include}

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Background

The importance of vitamin D in general health as well as in human reproductive success has been an area of focus. A better understanding of vitamin D metabolism, particularly vitamin D binding protein, is important when elucidating this relationship.

Methods

This case control trial seeks to characterize vitamin D metabolism in infertile patients undergoing natural cycle IVF as compared to normally cycling premenopausal women with proven fertility matched for age and body mass index (BMI). A total of 68 subjects were examined; 39 were infertile premenopausal women and 29 were regularly cycling fertile controls. Their 25-hydroxy vitamin D (25OHD), vitamin D binding protein (DBP), and albumin were measured and free and bioavailable 25OHD calculated. Between group comparisons were conducted with an unpaired t-test. A stepwise regression using age, BMI, 25OHD, estradiol & albumin in the model were used to determine predictors of DBP.

Results

Age, BMI, and total 25OHD did not differ between the two groups. However, vitamin D binding protein, free and bioavailable vitamin D were significantly different in the infertile patients as compared to the regularly cycling fertile controls (p < 0.01). Stepwise Regression using age, BMI, 25OHD, estradiol & albumin in the model showed that only albumin was a predictor of DBP (β-coefficient − 0.310; p = 0.01).

Conclusion

The implications of lower vitamin D binding protein associated with infertility is not clear from this pilot study, and requires further study.

Tags: Fertility and sperm Vit D Binding Protein