Association Between Serum 25-Hydroxyvitamin D Concentrations, CDX2 Polymorphism in Promoter Region of Vitamin D Receptor Gene, and Chronic Pain in Rural Japanese Residents.

BACKGROUND

Previous studies examined the association between chronic pain (CP) and serum 25-hydroxyvitamin D (25(OH)D) concentrations; however, the findings obtained were inconsistent. Single nucleotide polymorphisms (SNP) associated with the transcriptional activity of the vitamin D receptor () gene may influence the association of 25(OH)D levels with CP. We aimed to clarify the association between CP, serum 25(OH)D concentration, and SNPs.

METHODS

In the Shika study, we performed a cross-sectional analysis of 551 participants older than 40 years who were asked whether they had been having persistent pain lasting for at least 3 months in any part of the body on a self-administered questionnaire. Serum 25(OH)D concentrations were assessed as a biomarker of the vitamin D status using a radioimmunoassay. rs731236, rs7975232, rs1544410, rs2228570, and rs11568820 were identified using peripheral blood samples, and participants were assigned to those with or without the minor allele for each SNP.

RESULTS

The prevalence of CP was 37.2%. We observed a tendency for lower 25(OH)D levels in participants with CP than in those without CP in the hetero/minor group of rs11568820, which is a polymorphism within the CDX2-binding site in the 1e promoter region of the gene. Furthermore, a logistic regression analysis revealed that lower serum 25(OH)D concentrations were significantly associated with CP in the hetero/minor group, but not in the major group.

CONCLUSION

These results suggest that sufficient serum 25(OH)D concentration reduces the risk of CP in individuals with the minor allele of the CDX2 polymorphism.