Vitamin D Levels and Sperm DNA Fragmentation

Intracytoplasmic sperm injection (ICSI) has revolutionized the treatment of couples with male factor infertility but results remain suboptimal, suggesting the need for further investigation into the molecular biology of spermatozoa. Limitations to traditional semen analysis have brought new methods to the forefront like Sperm Chromatin Structure Assay (SCSA), which uses flow cytometry to measure sperm DNA fragmentation. Increased DNA damage in semen has been correlated with failed IVF cycles and decreased fertilization. Hypovitaminosis D has been associated with abnormal testicular function, including elevated sperm DNA fragmentation in a murine model. The objective of this study was to elucidate the possible corollary relationship between serum vitamin D levels and sperm DNA fragmentation in males seeking infertility treatment.

This study was conducted using a prospective cohort of consenting males seeking infertility treatment at a medium sized Midwest infertility clinic. Serum vitamin D levels and semen samples were collected from each patient. Sperm samples were analyzed by semen analysis according to World Health Organization current guidelines. The SCSA was used to measure acid-induced DNA fragmentation. The relationship between dichotomous variables: alcohol use, tobacco use and BMI were examined using a chi-square test of independence. The relationship between deficient, insufficient and sufficient Vitamin D levels and sperm parameters were analyzed using an analysis of variance.

Serum vitamin D levels were categorized as deficient (less than 20 ng/mL), insufficient (20-30 ng/mL), and sufficient (greater than 30 ng/mL). Of the 111 patients participating, 9 were excluded leaving 102 total patients. The patients were stratified by vitamin D levels: deficient (n=24), insufficient (n=43), and sufficient (n=35). No significant relationship was found between serum vitamin D levels and sperm DNA fragmentation in males seeking infertility treatment. A lack of alcohol consumption was correlated with increased high DNA stainability, a measure of nuclear immaturity (p=0.0042). There was a significant relationship between increased BMI and deficient/insufficient serum vitamin D levels (p=0.0012).

Serum vitamin D levels did not have a statistically significant impact on sperm DNA fragmentation. This study further solidifies the known associations between BMI and serum vitamin D levels. Limitations of the study included number of participants, insufficient power, and time constraints. Further examination of the correlation between seminal and serum vitamin D levels as well as the impact of alcohol on sperm DNA should be explored.