FokI Polymorphism of the VDR Gene Is Associated with Vitamin D Insufficiency in Elite Male Power Athletes of Kazakhstan

<b>Background/Objectives</b>: We aimed to investigate the association between <i>VDR</i> gene variants and vitamin D levels in elite male power athletes of Kazakhstan. <b>Methods</b>: We recruited 92 elite male power athletes of Kazakhstan. Concentrations of serum 25(OH)D were measured with the Access 25(OH) Vitamin D Total Assay on the Unicel Dxl 800 Access Immunoassay System. Gene polymorphisms were determined by a real-time polymerase chain reaction (RT-PCR) allelic discrimination assay using TaqMan™ probes. <b>Results</b>: Vitamin D insufficiency was registered in 63% of athletes. Age (χ² = 6.83, <i>p</i> < 0.01), BMI (χ² = 6.83, <i>p</i> < 0.01), and sport experience (χ² = 4.44, <i>p</i> < 0.04) showed a statistically significant association with vitamin D insufficiency and deficiency (age, χ² = 7.93, <i>p</i> < 0.01; BMI, χ² = 5.11, <i>p</i> < 0.03; sport experience, χ² = 6.19, <i>p</i> = 0.01). The A/A genotype of the <i>VDR</i> FokI polymorphism (rs2228570) showed a strong correlation with vitamin D insufficiency (G/G-G/A vs. A/A, OR = 9.25, 95% CI = 2.01-42.51, <i>p</i> < 0.01) but not deficiency. <b>Conclusions</b>: Our study reveals a significant prevalence of vitamin D insufficiency and deficiency among elite male power athletes of Kazakhstan. Age, BMI, and sport experience are essential factors in developing personalized strategies to address vitamin D insufficiency. The A/A genotype of the <i>VDR</i> FokI polymorphism can be used as a potential biomarker for vitamin D inadequacy in elite male power athletes of Kazakhstan.