title: Familial resemblance of 7-year changes in body mass and adiposity.
abstract: OBJECTIVE
  To investigate the familial resemblance of 7-year changes in body mass and adiposity among Canadian families.
  
  
  METHODS
  The sample consisted of 655 women and 660 men from 521 families who participated in the Canada Fitness Survey in 1981 and the follow-up Campbell's Survey in 1988. Indicators of baseline and 7-year changes in body mass and adiposity included body mass (kilograms), body mass index (BMI; kilograms per square meter), sum of five skinfolds (SF5; millimeters), and waist circumference (WC; millimeters). The data were adjusted for the effects of age and sex, and the change scores were adjusted for baseline levels. A familial correlation model was used to determine the heritability of each phenotype using maximum likelihood techniques.
  
  
  RESULTS
  Significant familial resemblance was observed at baseline and for 7-year changes in all phenotypes. At baseline, moderate heritabilities were observed [body mass: heritability coefficient (h(2)) = 56%; BMI, h(2) = 39%; SF5, h(2) = 41%; and WC, h(2) = 39%], whereas values were attenuated for each change score except for WC (Deltabody mass, h(2) = 23%; DeltaBMI, h(2) = 14%; DeltaSF5, h(2) = 12%; and DeltaWC, h(2) = 45%).
  
  
  CONCLUSIONS
  Changes in body mass and adiposity significantly aggregate within families over 7 years. However, baseline values are characterized by higher heritability levels except WC. The significant heritabilities observed for change scores suggest that lifestyle, transient environmental factors, and possibly age-related gene effects are important determinants of changes in body mass and adiposity.
authors.affiliation: School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada.
authors.forename: Melanie S
authors.initials: MS
authors.lastname: Hunt
authors.forename: Peter T
authors.initials: PT
authors.lastname: Katzmarzyk
authors.forename: Louis
authors.initials: L
authors.lastname: Pérusse
authors.forename: Treva
authors.initials: T
authors.lastname: Rice
authors.forename: D C
authors.initials: DC
authors.lastname: Rao
authors.forename: Claude
authors.initials: C
authors.lastname: Bouchard
mesh_terms: D000273:Adipose Tissue; D000293:Adolescent; D000328:Adult; D000368:Aged; D001823:Body Composition / Q000235:genetics*; D001824:Body Constitution / Q000235:genetics; D015992:Body Mass Index; D001835:Body Weight / Q000235:genetics*; D002170:Canada; D002648:Child; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000235:genetics; D010641:Phenotype; D010809:Physical Fitness; D012885:Skinfold Thickness