title: Familial aggregation of nutrient intake and physical activity: results from the San Antonio Family Heart Study.
abstract: OBJECTIVE
  To evaluate the extent to which levels of physical activity and nutrient intake aggregate in families, and secondarily, to assess the repeatability of these behavioral measures over a 5-year period.
  
  
  METHODS
  Measurements were obtained in a population-based sample consisting of 1364 members of 42 large Mexican American families. Nutrient intake was assessed by a food frequency questionnaire validated for use in this population. Usual level of physical activity was estimated using a 7-day recall questionnaire.
  
  
  RESULTS
  Correlations between baseline (obtained 1992-1995) and follow-up (obtained 1996 to 2000) measures of all behaviors were highly significant (p < 0.001), ranging from 0.24 for % of calories derived from fat to 0.44 for % of calories derived from alcohol. Familial effects, estimated using variance component methods, were stronger when modeled as a genetic heritability than as a shared household effect; as a heritability they accounted for a significant portion of the total variation of all traits (9% for physical activity levels, p < 0.05; and 13-26% for nutrient intake, p < 0.001 for all).
  
  
  CONCLUSIONS
  Measurements of physical activity and dietary behaviors in this population tracked over 5 years, and there was a significant degree of aggregation of these behaviors within families. Understanding the sources of these family effects may facilitate efforts to improve cardiovascular health.
authors.affiliation: Department of Medicine, University of Maryland School of Medicine, Baltimore 21201, USA. bmitchel@medicine.umaryland.edu
authors.forename: Braxton D
authors.initials: BD
authors.lastname: Mitchell
authors.forename: David L
authors.initials: DL
authors.lastname: Rainwater
authors.forename: Wen-Chi
authors.initials: WC
authors.lastname: Hsueh
authors.forename: Amy J
authors.initials: AJ
authors.lastname: Kennedy
authors.forename: Michael P
authors.initials: MP
authors.lastname: Stern
authors.forename: Jean W
authors.initials: JW
authors.lastname: Maccluer
mesh_terms: D000328:Adult; D015519:Bone Density; D004032:Diet; D015444:Exercise; D005192:Family Health; D005260:Female; D015438:Health Behavior; D006801:Humans; D008297:Male; D017058:Mexican Americans; D008875:Middle Aged; D011795:Surveys and Questionnaires; D013781:Texas / Q000453:epidemiology