title: Birth weight, weight at 1 y of age, and body composition in older men: findings from the Hertfordshire Cohort Study.
abstract: BACKGROUND
  Size in early life is related to adult body mass index, and early environmental influences have been proposed to have lifelong consequences for obesity. However, body mass index also reflects fat-free mass, and few studies have examined the relation between size in early life and direct measures of body composition in older people.
  
  
  OBJECTIVE
  We investigated the associations of birth weight and weight at 1 y of age with body composition in older men.
  
  
  METHODS
  We carried out a retrospective cohort study in Hertfordshire, United Kingdom. Men who were born between 1931 and 1939 and for whom there were records of birth weight and weight at 1 y of age (n = 737) participated in the study. The main outcome measures were adult body mass index, fat-free mass, and fat mass.
  
  
  RESULTS
  Birth weight was significantly and consistently positively associated with adult body mass index and fat-free mass but not with measures of adult fat mass. In contrast, weight at 1 y of age was associated with adult body mass index, fat-free mass, and fat mass.
  
  
  CONCLUSIONS
  The consistently reported positive relation between birth weight and adult body mass index may reflect prenatal and maternal influences on fat-free mass rather than on fat mass in older people. The postnatal environment may be more influential than prenatal factors in the development of obesity in later life.
authors.affiliation: Medical Research Council Environmental Epidemiology Unit, University of Southampton, Southamption, United Kingdom. aas@mrc.soton.ac.uk
authors.forename: Avan Aihie
authors.initials: AA
authors.lastname: Sayer
authors.forename: Holly E
authors.initials: HE
authors.lastname: Syddall
authors.forename: Elaine M
authors.initials: EM
authors.lastname: Dennison
authors.forename: Helen J
authors.initials: HJ
authors.lastname: Gilbody
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Duggleby
authors.forename: Cyrus
authors.initials: C
authors.lastname: Cooper
authors.forename: David J
authors.initials: DJ
authors.lastname: Barker
authors.forename: David I
authors.initials: DI
authors.lastname: Phillips
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D001724:Birth Weight; D001823:Body Composition; D015992:Body Mass Index; D001835:Body Weight; D015331:Cohort Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology / Q000209:etiology*; D012189:Retrospective Studies; D006113:United Kingdom