title: Vitamin D and C-Reactive Protein: A Mendelian Randomization Study.
abstract: Vitamin D deficiency is widely prevalent and has been associated with many diseases. It has been suggested that vitamin D has effects on the immune system and inhibits inflammation. The aim of our study was to investigate whether vitamin D has an inhibitory effect on systemic inflammation by assessing the association between serum levels of vitamin D and C-reactive protein. We studied the association between serum 25-hydroxyvitamin D and C-reactive protein through linear regression in 9,649 participants of the Rotterdam Study, an observational, prospective population-based cohort study. We used genetic variants related to vitamin D and CRP to compute a genetic risk score and perform bi-directional Mendelian randomization analysis. In linear regression adjusted for age, sex, cohort and other confounders, natural log-transformed CRP decreased with 0.06 (95% CI: -0.08, -0.03) unit per standard deviation increase in 25-hydroxyvitamin D. Bi-directional Mendelian randomization analyses showed no association between the vitamin D genetic risk score and lnCRP (Beta per SD = -0.018; p = 0.082) or the CRP genetic risk score and 25-hydroxyvitamin D (Beta per SD = 0.001; p = 0.998). In conclusion, higher levels of Vitamin D are associated with lower levels of C-reactive protein. In this study we did not find evidence for this to be the result of a causal relationship.
authors.affiliation: Department of Epidemiology, Erasmus University Medical Center, Rotterdam, the Netherlands; Netherlands Institute for Health Sciences, Rotterdam, the Netherlands.
authors.forename: Marte C
authors.initials: MC
authors.lastname: Liefaard
authors.affiliation: Department of Epidemiology, Erasmus University Medical Center, Rotterdam, the Netherlands.
authors.forename: Symen
authors.initials: S
authors.lastname: Ligthart
authors.affiliation: Department of Epidemiology, Erasmus University Medical Center, Rotterdam, the Netherlands.
authors.forename: Anna
authors.initials: A
authors.lastname: Vitezova
authors.affiliation: Department of Epidemiology, Erasmus University Medical Center, Rotterdam, the Netherlands.
authors.forename: Albert
authors.initials: A
authors.lastname: Hofman
authors.affiliation: Department of Epidemiology, Erasmus University Medical Center, Rotterdam, the Netherlands; Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, the Netherlands.
authors.forename: André G
authors.initials: AG
authors.lastname: Uitterlinden
authors.affiliation: Department of Epidemiology, Erasmus University Medical Center, Rotterdam, the Netherlands.
authors.forename: Jessica C
authors.initials: JC
authors.lastname: Kiefte-de Jong
authors.affiliation: Department of Epidemiology, Erasmus University Medical Center, Rotterdam, the Netherlands.
authors.forename: Oscar H
authors.initials: OH
authors.lastname: Franco
authors.affiliation: Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, the Netherlands.
authors.forename: M Carola
authors.initials: MC
authors.lastname: Zillikens
authors.affiliation: Department of Epidemiology, Erasmus University Medical Center, Rotterdam, the Netherlands.
authors.forename: Abbas
authors.initials: A
authors.lastname: Dehghan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002097:C-Reactive Protein / Q000378:metabolism*; D015331:Cohort Studies; D005260:Female; D005838:Genotype; D006801:Humans; D016014:Linear Models; D008297:Male; D057182:Mendelian Randomization Analysis; D008875:Middle Aged; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood* / Q000235:genetics
chemical_list: D014807:Vitamin D; D002097:C-Reactive Protein