Circulating 25-Hydroxy Vitamin D Relative to Vitamin D Receptor Polymorphism after Vitamin D3 Supplementation in Breast Cancer Women: A Randomized, Double-Blind Controlled Clinical Trial

Abstract

<span style="font-family: TimesNewRomanPS-BoldMT; font-size: small;"><span style="font-family: TimesNewRomanPS-BoldMT; font-size: small;"><strong>Objective: </strong></span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;" lang="JA"><span style="font-family: TimesNewRomanPSMT; font-size: small;" lang="JA">The influence of vitamin D receptor (VDR) genetic variation on serum 25-hydroxyvitamin D levels</span></span><br /> [25(OH)D] after vitamin D3 supplementation remains unclear. We aimed to investigate changes of 25(OH)D in a<br /> randomized, double-blind, placebo-controlled clinical trial, according to VDR genotype, after provision of vitamin D3 to<br /> <span style="font-family: TimesNewRomanPSMT; font-size: small;" lang="JA"><span style="font-family: TimesNewRomanPSMT; font-size: small;" lang="JA">breast cancer cases for a 2-month period. </span></span><strong><span style="font-family: TimesNewRomanPS-BoldMT; font-size: small;"><span style="font-family: TimesNewRomanPS-BoldMT; font-size: small;">Methods: </span></span></strong><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;">Participants were assigned to two treatment arms: placebo (n = 28) </span></span>and vitamin D3 supplementation (n =28). The supplementation group received 50,000 IU of vitamin D every week for 2 months. Blood samples were collected at baseline and after intervention to measure serum 25(OH) D3. Genotypes were<br /> <span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;">assessed for FokI, BsmI, ApaI, and TaqI polymorphisms. </span></span><strong><span style="font-family: TimesNewRomanPS-BoldMT; font-size: small;"><span style="font-family: TimesNewRomanPS-BoldMT; font-size: small;">Results: </span></span></strong><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;">After eight weeks supplementation, the rvention</span></span><br /> group showed a significant increase in the serum concentration of 25(OH) D3 (28±2.6 to 39±3.5; p=0.004). Subjects<br /> were then classified into twelve subgroups according to different VDR genotypes. Subjects with ff/Ff, TT/Tt, and Bb<br /> genotypes had significantly higher increases in serum 25(OH)D compared to those with FF, tt, and BB/bb genotypes<br /> post-intervention. Serum vitamin D3 levels with the AA genotype were lower than with aa/ Aa. No differences were<br /> <span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;">found among other subgroups. </span></span><strong><span style="font-family: TimesNewRomanPS-BoldMT; font-size: small;"><span style="font-family: TimesNewRomanPS-BoldMT; font-size: small;">Conclusion: </span></span></strong><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;">Vitamin D3 supplementation increases serum 25(OH)D in women with</span></span><br /> breast cancer. Serum vitamin D3 in TT/Tt, ff/Ff, and Bb carriers was more responsive to vitamin D supplementation<br /> than in those with FF/ff and tt genotypes. Other subgroups might gain less from vitamin D3 supplementation.