Background: Parathyroid hormone (PTH) plays a crucial role in calcium metabolism and skeletal development, to some extent via altering vitamin D level, and hypersecretion of PTH is implicated in the aetiology of osteoporosis. In this study we analysed association between variants of promoter region of PTH gene and circulating 25-hydroxy-vitamin D (25(OH)D) level.
Methods: Circulating level of 25(OH)D and genotypes of PTH SNPs rs1459015, rs10500783 and rs10500784 were determined in healthy adults (N=386) of different nationalities living in Riyadh. Association between the different PTH genetic variants and corresponding mean serum 25(OH)D levels were statistically analysed.
Results: We observed high prevalence of vitamin D deficiency (<50 nmol/l) among all nationals living in Riyadh and the extent of deficiency ranged from 59% of Indians to 82% of Yemeni. Comparison of the means of 25(OH)D levels corresponding to different genotypes of PTH SNPs indicated that the T allele of SNP rs1459015 was significantly associated with higher level of 25(OH)D in the Sudanese (p=0.03), while the T allele of SNP rs10500783 was associated with higher level of 25(OH)D in Saudis (p=0.03). Analysis of different genotypes of the PTH SNPs indicated that carriers of the CC genotype of SNP rs1459015 had a higher risk of suffering from vitamin D deficiency in the Sudanese (p=0.02).
Conclusions: Specific variants of PTH SNPs were associated with altered levels of 25(OH)D and different degrees of vitamin D deficiency. Replication of these results in future studies may elucidate of the role of PTH in the regulation of vitamin D absorption and metabolism.
Disclosure: The authors declared no competing interests. This study was funded by the Prince Mutaib Chair for Biomarkers of Osteoporosis at King Saud University, Riyadh, Saudi Arabia.