title: A multi-cohort study of polymorphisms in the GH/IGF axis and physical capability: the HALCyon programme.
abstract: BACKGROUND
  Low muscle mass and function have been associated with poorer indicators of physical capability in older people, which are in-turn associated with increased mortality rates. The growth hormone/insulin-like growth factor (GH/IGF) axis is involved in muscle function and genetic variants in genes in the axis may influence measures of physical capability.
  
  
  METHODS
  As part of the Healthy Ageing across the Life Course (HALCyon) programme, men and women from seven UK cohorts aged between 52 and 90 years old were genotyped for six polymorphisms: rs35767 (IGF1), rs7127900 (IGF2), rs2854744 (IGFBP3), rs2943641 (IRS1), rs2665802 (GH1) and the exon-3 deletion of GHR. The polymorphisms have previously been robustly associated with age-related traits or are potentially functional. Meta-analysis was used to pool within-study genotypic effects of the associations between the polymorphisms and four measures of physical capability: grip strength, timed walk or get up and go, chair rises and standing balance.
  
  
  RESULTS
  Few important associations were observed among the several tests. We found evidence that rs2665802 in GH1 was associated with inability to balance for 5 s (pooled odds ratio per minor allele = 0.90, 95% CI: 0.82-0.98, p-value = 0.01, n = 10,748), after adjusting for age and sex. We found no evidence for other associations between the polymorphisms and physical capability traits.
  
  
  CONCLUSIONS
  Our findings do not provide evidence for a substantial influence of these common polymorphisms in the GH/IGF axis on objectively measured physical capability levels in older adults.
authors.affiliation: School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom. tamuno.alfred@bristol.ac.uk
authors.forename: Tamuno
authors.initials: T
authors.lastname: Alfred
authors.forename: Yoav
authors.initials: Y
authors.lastname: Ben-Shlomo
authors.forename: Rachel
authors.initials: R
authors.lastname: Cooper
authors.forename: Rebecca
authors.initials: R
authors.lastname: Hardy
authors.forename: Cyrus
authors.initials: C
authors.lastname: Cooper
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Deary
authors.forename: Tom R
authors.initials: TR
authors.lastname: Gaunt
authors.forename: David
authors.initials: D
authors.lastname: Gunnell
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Harris
authors.forename: Meena
authors.initials: M
authors.lastname: Kumari
authors.forename: Richard M
authors.initials: RM
authors.lastname: Martin
authors.forename: Avan Aihie
authors.initials: AA
authors.lastname: Sayer
authors.forename: John M
authors.initials: JM
authors.lastname: Starr
authors.forename: Diana
authors.initials: D
authors.lastname: Kuh
authors.forename: Ian N M
authors.initials: IN
authors.lastname: Day
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000235:genetics*; D000886:Anthropometry; D015331:Cohort Studies; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D056726:Genetic Association Studies; D060005:Genotyping Techniques; D018737:Hand Strength / Q000502:physiology; D006262:Health; D019382:Human Growth Hormone / Q000235:genetics*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D004856:Postural Balance / Q000502:physiology; D012727:Sex Characteristics; D015398:Signal Transduction / Q000235:genetics*; D006113:United Kingdom
chemical_list: C035170:IGF2 protein, human; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II