title: Familial aggregation of seven-year changes in blood pressure in Canada.
abstract: OBJECTIVE
  To determine the familial resemblance for baseline and seven-year changes in blood pressure in the Canadian population.
  
  
  METHODS
  The study participants were 857 people from 348 families in the 1988 Campbell's Survey, which was a seven-year follow-up of the Canada Fitness Survey. Systolic and diastolic blood pressures were measured at baseline and at follow-up, and were adjusted for age and body mass index by using regression analysis. Familial correlation models were fit to the data by using path analysis, and maximal heritabilities were calculated from the most parsimonious models.
  
  
  RESULTS
  There was significant familial resemblance for baseline blood pressure and changes in blood pressure. In general, all classes of familial correlations (spousal, parent-offspring and sibling) were significant and were of comparable magnitude. The maximal heritabilities, which are influenced to an unknown degree by genes and shared environmental factors, were 50% and 70% for diastolic and systolic blood pressures, respectively, and 66% and 41% for seven-year changes in diastolic and systolic blood pressures, respectively.
  
  
  CONCLUSIONS
  There is significant familial aggregation for blood pressure and for natural changes in blood pressure in the Canadian population. Genes may be important in explaining the familial resemblance for blood pressure; however, the presence of significant spousal correlations suggests that shared lifestyle and family environments are also important factors in the familial aggregation.
authors.affiliation: School of Kinesiology and Health Science, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada. katzmarz@yorku.ca
authors.forename: P T
authors.initials: PT
authors.lastname: Katzmarzyk
authors.forename: L
authors.initials: L
authors.lastname: Pérusse
authors.forename: T
authors.initials: T
authors.lastname: Rice
authors.forename: D C
authors.initials: DC
authors.lastname: Rao
authors.forename: C
authors.initials: C
authors.lastname: Bouchard
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D001794:Blood Pressure / Q000235:genetics*; D001795:Blood Pressure Determination; D015992:Body Mass Index; D002170:Canada / Q000453:epidemiology; D002648:Child; D003430:Cross-Sectional Studies; D003625:Data Collection; D003971:Diastole / Q000235:genetics; D005191:Family Characteristics; D005192:Family Health; D014644:Genetic Variation; D006801:Humans; D006973:Hypertension / Q000453:epidemiology* / Q000235:genetics*; D008137:Longitudinal Studies; D008957:Models, Genetic; D017678:Sex Distribution; D013223:Statistics as Topic; D013599:Systole / Q000235:genetics