title: Genetic influences on growth traits of BMI: a longitudinal study of adult twins.
abstract: OBJECTIVE
  To investigate the interplay between genetic factors influencing baseline level and changes in BMI in adulthood.
  
  
  METHODS
  A longitudinal twin study of the cohort of Finnish twins (N = 10,556 twin individuals) aged 20-46 years at baseline was conducted and followed up 15 years. Data on weight and height were obtained from mailed surveys in 1975, 1981, and 1990.
  
  
  RESULTS
  Latent growth models revealed a substantial genetic influence on BMI level at baseline in males and females (heritability (h(2)) 80% (95% confidence interval 0.79-0.80) for males and h(2) = 82% (0.81, 0.84) for females) and a moderate-to-high influence on rate of change in BMI (h(2) = 58% (0.50, 0.69) for males and h(2) = 64% (0.58, 0.69) for females). Only very weak evidence for genetic pleiotropy was observed; the genetic correlation between baseline and rate of change in BMI was very modest (-0.070 (-0.13, -0.068) for males and 0.04 (0.00, 0.08) for females.
  
  
  CONCLUSIONS
  Our population-based results provide a basis for identifying genetic variants for change in BMI, in particular weight gain. Furthermore, they demonstrate for the first time that such genetic variants for change in BMI are likely to be different from those affecting level of BMI.
authors.affiliation: Statistics and Epidemiology, Institute of Public Health, University of Southern Denmark, Odense, Denmark. jhjelmborg@health.sdu.dk
authors.forename: Jacob v B
authors.initials: Jv
authors.lastname: Hjelmborg
authors.forename: Corrado
authors.initials: C
authors.lastname: Fagnani
authors.forename: Karri
authors.initials: K
authors.lastname: Silventoinen
authors.forename: Matt
authors.initials: M
authors.lastname: McGue
authors.forename: Maarit
authors.initials: M
authors.lastname: Korkeila
authors.forename: Kaare
authors.initials: K
authors.lastname: Christensen
authors.forename: Aila
authors.initials: A
authors.lastname: Rissanen
authors.forename: Jaakko
authors.initials: J
authors.lastname: Kaprio
mesh_terms: D000328:Adult; D017677:Age Distribution; D001827:Body Height / Q000235:genetics; D015992:Body Mass Index; D001835:Body Weight / Q000235:genetics*; D005260:Female; D005387:Finland / Q000453:epidemiology; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology / Q000235:genetics*; D017678:Sex Distribution