title: Variation in the ciliary neurotrophic factor gene and muscle strength in older Caucasian women.
abstract: OBJECTIVE
  To determine whether genetic variants in the ciliary neurotrophic factor (CNTF) gene are associated with muscle strength in older women.
  
  
  METHODS
  Cross-sectional analysis of baseline data from the Women's Health and Aging Studies I (1992) and II (1994), complementary population-based studies.
  
  
  METHODS
  Twelve contiguous ZIP code areas in Baltimore, Maryland.
  
  
  METHODS
  Three hundred sixty-three Caucasian, community-dwelling women aged 70 to 79.
  
  
  METHODS
  Participants were genotyped at the CNTF locus for eight single nucleotide polymorphisms (SNPs), including the null allele rs1800169. The dependent variables were grip strength and the frailty syndrome, identified as presence of three or more of five frailty indicators (weakness, slowness, weight loss, low physical activity, exhaustion). In addition to genotypes, independent variables of body mass index (BMI) and osteoarthritis of the hands were included.
  
  
  RESULTS
  Using multivariate linear regression, single SNP analysis identified five SNPs significantly associated with grip strength (P<.05), after adjusting for age, BMI, and osteoarthritis. Haplotype analysis was performed, and a single haplotype associated with grip strength was identified (P<.01). The rs1800169 null allele fully explained the association between this haplotype and grip strength under a recessive model, with individuals homozygous for the null allele exhibiting a 3.80-kg lower (95% confidence interval=1.01-6.58) grip strength. No association was seen between the CNTF null allele and frailty.
  
  
  CONCLUSIONS
  Individuals homozygous for the CNTF null allele had significantly lower grip strength but did not exhibit overt frailty. Larger prospective studies are needed to confirm this finding and extend it to additional populations.
authors.affiliation: McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, 733 N. Broadway, Baltimore, MD 21205, USA.
authors.forename: Dan E
authors.initials: DE
authors.lastname: Arking
authors.forename: Daniele M
authors.initials: DM
authors.lastname: Fallin
authors.forename: Linda P
authors.initials: LP
authors.lastname: Fried
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.forename: Brock A
authors.initials: BA
authors.lastname: Beamer
authors.forename: Qian Li
authors.initials: QL
authors.lastname: Xue
authors.forename: Aravinda
authors.initials: A
authors.lastname: Chakravarti
authors.forename: Jeremy
authors.initials: J
authors.lastname: Walston
mesh_terms: D000368:Aged; D015992:Body Mass Index; D020934:Ciliary Neurotrophic Factor / Q000235:genetics*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D016330:Frail Elderly; D005838:Genotype; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D044465:White People / Q000235:genetics*
chemical_list: D020934:Ciliary Neurotrophic Factor