Association between serum 25-hydroxyvitamin D and prostate-specific antigen: a retrospective study in men without prostate pathology.

Objectives: Recently, vitamin D status has been associated with prostate cancer risk. However, some studies argue that there is no association of vitamin D with prostate cancer risk and serum prostate-specific antigen (PSA) concentrations. No clear conclusions can be drawn from the studies found in the literature. Our aim was to assess the relationship between PSA and 25-hydroxyvitamin D [25(OH)D]. Methods: We selected 415 individuals without prostate pathologies and subgroups were generated according to age and 25(OH)D. Statistical analyses were performed using Shapiro-Wilk test, Student's t and ANOVA tests, and Pearson's correlation. Besides, the minimum sample size needed to obtain statistically significant results between groups according to 25(OH)D concentration was calculated and a Student's t-test for paired samples was performed to study individuals with two PSA measurements over time, where 25(OH)D concentration increased or decreased more than 25 %. Results: We observed a slight correlation between age and PSA concentration (r=0.379, p<0.001). However, we found no significant differences when we compared PSA concentrations between groups according to 25(OH)D concentrations (p=0.891): 1.25 ± 1.32 µg/L (group with 25(OH)D<50 nmol/L) and 1.17 ± 0.90 (group with 25(OH)D≥50 nmol/L). Pearson's correlation coefficient was close to 0. The minimum samples size to obtain statistically significant results was 815,346 men, and we observed no differences in PSA concentrations in individuals with two measurements. Conclusions: Our findings show no association in men without prostate pathologies, based on 25(OH)D levels.