title: Interaction effect of serum 25-hydroxyvitamin D levels and CYP1A1, CYP1B1 polymorphisms on blood pressure in an elderly population.
abstract: OBJECTIVE
  Hypertension and vitamin D deficiency are prevalent worldwide, especially in the elderly. Considering the possibility of gene-environment contributions to disease development, we evaluated the influence of certain cytochrome P450 polymorphisms and vitamin D levels on blood pressure (BP).
  
  
  METHODS
  We measured serum 25-hydroxyvitamin D levels [25(OH)D] and BP in 535 individuals over 60 years old and identified single-nucleotide polymorphisms (SNPs) of CYP1A1 and CYP1B1 in lymphocyte DNA. Repeated measure analyses were used to determine the statistical association.
  
  
  RESULTS
  The relationship between 25(OH)D and SBP or DBP was inversely significant, and influence of several CYP1A1 and CYP1B1 SNPs on BP was found across different genotypes. Estimated effect of 25(OH)D levels on BP in the group with higher risky genotype scores of selected SNPs (rs4646421, rs2551188, and rs1056836) was greater (β = -2.841, P = 0.004 for SBP; β = -2.035, P = 0.001 for DBP) than the group with lower genotype score (β = -0.878, P = 0.347 for SBP; β = 0.037, P = 0.947 for DBP), and synergistic interaction between vitamin D levels and genotype variations was observed (P-interaction = 0.081 for SBP and 0.008 for DBP). When stratified by the hypertension medication status, interaction effect was found only in individuals taking medication (P-interaction = 0.004 for SBP and 0.001 for DBP).
  
  
  CONCLUSIONS
  Genetic variations in CYP1A1 and CYP1B1 and the serum levels of 25(OH)D showed synergistic effect on BP, especially in individuals currently in treatment for hypertension.
authors.affiliation: aDepartment of Preventive Medicine, Seoul National University College of Medicine bDepartment of Environmental Health, Graduate School of Public Health, Seoul National University cEnvironmental Health Center, Seoul National University College of Medicine, Seoul dDepartment of Biochemistry eDepartment of Internal Medicine, School of Medicine, Kyungpook National University, Daegu fInstitute of Environmental Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.
authors.forename: Hye Y
authors.initials: HY
authors.lastname: Park
authors.forename: Jin H
authors.initials: JH
authors.lastname: Kim
authors.forename: Sanghyuk
authors.initials: S
authors.lastname: Bae
authors.forename: Yi Y
authors.initials: YY
authors.lastname: Choi
authors.forename: Jae Y
authors.initials: JY
authors.lastname: Park
authors.forename: Yun-Chul
authors.initials: YC
authors.lastname: Hong
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000235:genetics*; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics*; D065633:Cytochrome P-450 CYP1B1 / Q000235:genetics*; D005260:Female; D059647:Gene-Environment Interaction; D005838:Genotype; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000188:drug therapy / Q000235:genetics*; D015810:Linkage Disequilibrium; D008297:Male; D020641:Polymorphism, Single Nucleotide; D056910:Republic of Korea; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D; C569463:CYP1A1 protein, human; C585496:CYP1B1 protein, human; D019363:Cytochrome P-450 CYP1A1; D065633:Cytochrome P-450 CYP1B1