title: Insulinlike Growth Factor-1 and Its Binding Protein-3 Polymorphisms Predict Circulating IGF-1 Level and Appendicular Skeletal Muscle Mass in Chinese Elderly.
abstract: BACKGROUND
  Previous studies have demonstrated the polymorphisms of insulinlike growth factor-1 (IGF-1) and its binding protein-3 (IGFBP3) genes could affect the circulating IGF-1 level. Moreover, the serum IGF-1 level was correlated with muscle size.
  
  
  OBJECTIVE
  This study aimed to explore the effect of polymorphisms of IGF1, IGFBP3, and IGFBP5 genes on appendicular skeletal muscle mass in Taiwanese older adults in a metropolitan area.
  
  
  METHODS
  A community-based cross-sectional study.
  
  
  METHODS
  A random sample of 472 elders with complete information of dual energy X-ray absorptiometry examination, genotyping analysis, and serum IGF-1 level from Taichung Community Health Study for Elders (TCHS-E) was included.
  
  
  METHODS
  Low appendicular skeletal muscle mass index (ASMI) was defined as 2 SDs below the mean of young adults from our TCHS study (n = 471). Seven polymorphisms of IGF1, IGFBP3, and IGFBP5 were analyzed by using Illumina GoldenGate Genotyping Assay. The χ(2) test, Student t test, and multiple logistic regression were applied for statistical analysis.
  
  
  RESULTS
  The prevalence of low ASMI was 7.1%, 8.8%, and 23.0% in those aged 70 or younger, 71 to 75, and older than 75 years, respectively. We found that serum IGF-1 level (natural logarithmic transformation) was significantly lower in the low ASMI group compared with the normal ASMI group and the SNP rs2854744 near IGFBP3 gene was significantly associated with low ASMI. Moreover, we discovered the SNP rs6214 on the IGF1 gene would significantly affect the serum IGF-1 level. Therefore, the joint effect of rs6214 and rs2854744 was analyzed. Elders with GG genotype of rs6214 and AC or CC genotypes of rs2854744 had a 3.18-fold (95% CI 1.02-9.89) risk of having low ASMI compared with those with the AA and AA genotype, after adjusting for age, gender, smoking, exercise, hyperlipidemia, and albumin level.
  
  
  CONCLUSIONS
  Our results suggest that rs6214 on the IGF1 gene and rs2854744 near the IGFBP3 gene potentially play an important role with ASMI in Taiwanese older adults in a metropolitan area.
authors.affiliation: PhD Program for Aging, College of Medicine, China Medical University, Taichung, Taiwan; Department of Medical Research, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Chuan-Wei
authors.initials: CW
authors.lastname: Yang
authors.affiliation: Graduate Institute of Biostatistics, College of Public Health, China Medical University, Taichung, Taiwan; Department of Healthcare Administration, College of Health Science, Asia University, Taichung, Taiwan.
authors.forename: Tsai-Chung
authors.initials: TC
authors.lastname: Li
authors.affiliation: Department of Medical Research, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Chia-Ing
authors.initials: CI
authors.lastname: Li
authors.affiliation: Department of Medical Research, China Medical University Hospital, Taichung, Taiwan; Department of Family Medicine, China Medical University Hospital, Taichung, Taiwan; School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan.
authors.forename: Chiu-Shong
authors.initials: CS
authors.lastname: Liu
authors.affiliation: Department of Family Medicine, China Medical University Hospital, Taichung, Taiwan; School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan.
authors.forename: Chih-Hsueh
authors.initials: CH
authors.lastname: Lin
authors.affiliation: Department of Family Medicine, China Medical University Hospital, Taichung, Taiwan; School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan.
authors.forename: Wen-Yuan
authors.initials: WY
authors.lastname: Lin
authors.affiliation: PhD Program for Aging, College of Medicine, China Medical University, Taichung, Taiwan; Department of Medical Research, China Medical University Hospital, Taichung, Taiwan; Department of Family Medicine, China Medical University Hospital, Taichung, Taiwan; School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan. Electronic address: cclin@www.cmuh.org.tw.
authors.forename: Cheng-Chieh
authors.initials: CC
authors.lastname: Lin
mesh_terms: D000328:Adult; D044466:Asian People / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood / Q000235:genetics*; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000235:genetics*; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000235:genetics*; D018482:Muscle, Skeletal / Q000502:physiology*; D013624:Taiwan
chemical_list: C515497:IGFBP3 protein, human; D018970:Insulin-Like Growth Factor Binding Protein 1; D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I
keywords: Appendicular skeletal muscle mass; IGF-1; IGFBP3; elderly