title: Associations of type 2 diabetes with common variants in PPARD and the modifying effect of vitamin D among middle-aged and elderly Chinese.
abstract: BACKGROUND
  Previous studies have identified that variants in peroxisome proliferator-activated receptor PPAR-δ (PPARD), a target gene of vitamin D, were significantly associated with fasting glucose and insulin sensitivity in European populations. This current study sought to determine (1) whether the genetic associations of PPARD variants with type 2 diabetes and its related traits could be replicated in Chinese Han population, and (2) whether the associations would be modified by the effect of vitamin D status.
  
  
  RESULTS
  We genotyped 9 tag single nucleotide polymorphisms (SNPs) that cover the gene of PPARD (rs2267664, rs6902123, rs3798343, rs2267665, rs2267668, rs2016520, rs2299869, rs1053049, and rs9658056) and tested their associations with type 2 diabetes risk and its related traits, including fasting glucose, insulin and HbA1c in 3,210 Chinese Hans. Among the 9 PPARD tag SNPs, rs6902123 was significantly associated with risk of type 2 diabetes (odds ratio 1.75 [95%CI 1.22-2.53]; P = 0.0025) and combined type 2 diabetes and impaired fasting glucose (IFG) (odds ratio 1.47 [95%CI 1.12-1.92]; P = 0.0054). The minor C allele of rs6902123 was associated with increased levels of fasting glucose (P = 0.0316) and HbA1c (P = 0.0180). In addition, we observed that vitamin D modified the effect of rs6902123 on HbA1c (P for interaction = 0.0347).
  
  
  CONCLUSIONS
  Our findings demonstrate that common variants in PPARD contribute to the risk of type 2 diabetes in Chinese Hans, and provided suggestive evidence of interaction between 25(OH)D levels and PPARD-rs6902123 on HbA1c.
authors.affiliation: Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and Graduate School of the Chinese Academy of Sciences, Shanghai, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Lu
authors.forename: Ying
authors.initials: Y
authors.lastname: Wu
authors.forename: Qibin
authors.initials: Q
authors.lastname: Qi
authors.forename: Chen
authors.initials: C
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Gan
authors.forename: Jingwen
authors.initials: J
authors.lastname: Zhu
authors.forename: Huaixing
authors.initials: H
authors.lastname: Li
authors.forename: Xu
authors.initials: X
authors.lastname: Lin
mesh_terms: D000368:Aged; D001786:Blood Glucose / Q000235:genetics / Q000378:metabolism; D002681:China; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics*; D005260:Female; D056726:Genetic Association Studies; D006442:Glycated Hemoglobin / Q000235:genetics; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D047494:PPAR delta / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D014807:Vitamin D / Q000235:genetics / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007328:Insulin; D047494:PPAR delta; D014807:Vitamin D; C517652:hemoglobin A1c protein, human