Journal Article

Effect of Genetically Low 25-Hydroxyvitamin D on Mortality Risk: Mendelian Randomization Analysis in 3 Large European Cohorts

Keppel, Martin, Kiely, Mairead, Løchen, Maja-Lisa, Van Schoor, Natasja M., Gudnason, Vilmundur, Jorde, Rolf, Sempos, Christopher T., Rejnmark, Lars, Škrabáková, Zuzana, Durazo-Arvizu, Ramón A., Schirmer, Henrik, Cotch, Mary Frances, März, Winfried, Dowling, Kirsten G., Aspelund, Thor, Wilsgaard, Tom, Grove-Laugesen, Diana, Swart, Karin M. A., Grübler, Martin R., Eiriksdottir, Gudny, Brouwer, Ingeborg A., Mathiesen, Ellisiv B., Grimnes, Guri, Gudmundsson, Elias F., Lips, Paul, Pilz, Stefan, Kleber, Marcus E., Harris, Tamara B., Cashman, Kevin D., Joakimsen, Ragnar, Njølstad, Inger, Tomaschitz, Andreas, Smith, Albert V.

2019

Overview

The aim of this study was to determine if increased mortality associated with low levels of serum 25-hydroxyvitamin D (25(OH)D) reflects a causal relationship by using a Mendelian randomisation (MR) approach with genetic variants in the vitamin D synthesis pathway. Individual participant data from three European cohorts were harmonized with standardization of 25(OH)D according to the Vitamin D Standardization Program. Most relevant single nucleotide polymorphisms of the genes CYP2R1 (rs12794714, rs10741657) and DHCR7/NADSYN1 (rs12785878, rs11234027), were combined in two allelic scores. Cox proportional hazards regression models were used with the ratio estimator and the delta method for calculating the hazards ratio (HR) and standard error of genetically determined 25(OH)D effect on all-cause mortality. We included 10,501 participants (50.1% females, 67.1±10.1 years) of whom 4003 died during a median follow-up of 10.4 years. The observed adjusted HR for all-cause mortality per decrease in 25(OH)D by 20 nmol/L was 1.20 (95% CI: 1.15–1.25). The HR per 20 nmol/L decrease in genetically determined 25(OH)D was 1.32 (95% CI: 0.80–2.24) and 1.35 (95% CI of 0.81 to 2.37) based on the two scores. In conclusion, the results of this MR study in a combined sample from three European cohort studies provide further support for a causal relationship between vitamin D deficiency and increased all-cause mortality. However, as the current study, even with ~10,000 participants, was underpowered for the study of the effect of the allele score on mortality, larger studies on genetics and mortality are needed to improve the precision.

• Publisher: MDPI AG,MDPI
• Subject: Aged / Aged, 80 and over / alleles / blood serum / Carbon-Nitrogen Ligases with Glutamine as Amide-N-Donor - genetics / Carbon-Nitrogen Ligases with Glutamine as Amide-N-Donor - metabolism / Cardiology / Cholestanetriol 26-Monooxygenase - genetics / Cholestanetriol 26-Monooxygenase - metabolism / Chronic illnesses / Clinical medicine / Cohort Studies / Cytochrome P450 Family 2 - genetics / Cytochrome P450 Family 2 - metabolism / Dietary supplements / Endocrinology / Epidemiology / Europe / Female / females / Gene Expression Regulation / Genes / Genetic Predisposition to Disease / genetic variation / Health sciences / Hospitals / Humans / Internal medicine / Laboratories / Male / Medicine / Mendelian Randomization Analysis / Metabolism / Middle Aged / Mortality / Nutrition research / Oxidoreductases Acting on CH-CH Group Donors - genetics / Oxidoreductases Acting on CH-CH Group Donors - metabolism / Polymorphism, Single Nucleotide / Public health / regression analysis / single nucleotide polymorphism / University colleges / Vitamin D / Vitamin D - analogs & derivatives / Vitamin D - blood / vitamin D deficiency / Vitamin deficiency