Circulating Serum 25-Hydroxyvitamin D Levels and Bone Mineral Density: Mendelian Randomization Study.

Area of Science:

• Endocrinology
• Genetics
• Bone Metabolism

Background:

• Serum 25-hydroxyvitamin D (S-25OHD) is linked to bone health, but its long-term impact on bone mineral density (BMD) is debated.
• Understanding the causal relationship between elevated S-25OHD and BMD is crucial for public health recommendations.

Purpose of the Study:

• To investigate the causal association between genetically predicted higher S-25OHD concentrations and BMD using a Mendelian randomization design.
• To clarify whether long-term elevated S-25OHD levels positively influence bone density.

Main Methods:

• Employed a Mendelian randomization approach utilizing five single-nucleotide polymorphisms (SNPs) as instrumental variables for S-25OHD.
• Analyzed associations between S-25OHD-associated SNPs and BMD (femoral neck, lumbar spine, heel) using data from the GEFOS Consortium and UK Biobank.

Main Results:

• No significant causal association was found between genetically predicted S-25OHD and femoral neck or lumbar spine BMD.
• A suggestive association was noted between a SNP near CYP24A1 and femoral neck BMD (p=0.01), but did not reach Bonferroni significance.
• Genetically predicted S-25OHD was not causally linked to higher BMD in the general population.

Conclusions:

• This study does not support a causal relationship between long-term elevated S-25OHD concentrations and increased BMD in healthy individuals.
• Findings advocate for prioritizing evidence-based cut-off points for vitamin D inadequacy over general recommendations for S-25OHD elevation.