title: Social differences in insulin-like growth factor-1: findings from a British birth cohort.
abstract: OBJECTIVE
  Insulin-like growth factor-1 (IGF-1) is related to factors that are socially patterned and may play a role in social differences in the development of morbidities including disability. Our aim is to examine whether there are social differences in IGF-1 in a cohort of participants between 44 and 45 years of age.
  
  
  METHODS
  We examine the association of IGF-1 with social position measured by father's or own occupational class at three time points in childhood and adulthood, in a cohort of individuals born in one month in 1958 (N = 3,374 men and 3,302 women).
  
  
  RESULTS
  Lower IGF-1 levels were associated with lower social position measured with father's occupational class at birth (p < 0.0001) and own occupational class aged 42 years (p < 0.001). Adult social position was associated with IGF-1 independently of social position at birth (p < 0.001) or any covariates examined.
  
  
  CONCLUSIONS
  IGF-1 secretion is associated with social position such that low social position is associated with lower levels of IGF-1. This biomarker may play a role in the development of social differences in morbidities associated with aging, such as the development of disability.
authors.affiliation: International Institute for Society and Health, University College London, London, UK. M.kumari@ucl.ac.uk
authors.forename: Meena
authors.initials: M
authors.lastname: Kumari
authors.forename: Faiza
authors.initials: F
authors.lastname: Tabassum
authors.forename: Charlotte
authors.initials: C
authors.lastname: Clark
authors.forename: David
authors.initials: D
authors.lastname: Strachan
authors.forename: Stephen
authors.initials: S
authors.lastname: Stansfeld
authors.forename: Chris
authors.initials: C
authors.lastname: Power
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D015331:Cohort Studies; D005220:Fathers; D005260:Female; D015438:Health Behavior; D054624:Health Status Disparities; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009790:Occupations; D012307:Risk Factors; D012737:Sex Factors; D012923:Social Class; D006113:United Kingdom; D049629:Waist-Hip Ratio
chemical_list: D015415:Biomarkers; D007334:Insulin-Like Growth Factor I