Familial aggregation of nutrient intake and physical activity: results from the San Antonio Family Heart Study.
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.
Mitchell
Braxton D
BD
Department of Medicine, University of Maryland School of Medicine, Baltimore 21201, USA. bmitchel@medicine.umaryland.edu
Rainwater
David L
DL
Hsueh
Wen-Chi
WC
Kennedy
Amy J
AJ
Stern
Michael P
MP
Maccluer
Jean W
JW
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