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Vitamin D and mortality: a Mendelian randomization study.

Olivia Trummer¹, Stefan Pilz, Michael M Hoffmann

¹Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria.

Clinical Chemistry

|January 16, 2013

Summary

This summary is machine-generated.

Low vitamin D levels are linked to higher mortality but are unlikely to be the cause. This Mendelian randomization study found no causal link between vitamin D genetic variants and death rates.

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Area of Science:

Genetics
Epidemiology
Endocrinology

Background:

Decreased 25-hydroxy-vitamin D (25-OH-vitamin D) concentrations are associated with increased mortality.
The causal relationship between low vitamin D levels and mortality remains unclear.

Purpose of the Study:

To investigate whether common genetic variants associated with 25-OH-vitamin D concentrations are causally linked to mortality rates.
Utilizing Mendelian randomization to assess causality.

Main Methods:

A prospective cohort study of 3316 participants undergoing coronary angiography.
Genotyping of single-nucleotide polymorphisms (SNPs) in GC, DHCR7, and CYP2R1 genes.
Measurement of 25-OH-vitamin D concentrations and tracking of all-cause, cardiovascular, and noncardiovascular deaths over a median of 9.9 years.

Main Results:

GC and DHCR7 genotypes significantly predicted 25-OH-vitamin D concentrations (P < 0.001).
Despite a significant number of deaths (955 total, 619 cardiovascular), the studied genetic variants were not associated with any mortality outcomes after adjusting for risk factors.
The analyzed genotypes explained 17.5% of the variation in vitamin D levels.

Conclusions:

Genetic variants influencing 25-OH-vitamin D levels do not appear to be causal factors for mortality.
The observed association between low vitamin D and mortality is likely observational rather than causal.