T. Rice et al., CROSS-TRAIT FAMILIAL RESEMBLANCE FOR BODY-FAT AND BLOOD-PRESSURE - FAMILIAL CORRELATIONS IN THE QUEBEC FAMILY STUDY, American journal of human genetics, 55(5), 1994, pp. 1019-1029
Cross-trait resemblance between body fat and blood pressure (BP) was e
xamined among families in the Quebec Family Study by using a bivariate
familial correlation model assessing both intraindividual (e.g., comp
arison of father's body fat with his own BP) and interindividual (e.g.
, comparison of father's body fat with son's BP) cross-trait correlati
ons. Each of six body-fat measures-(i) percent body fat, (ii) body-mas
s index, (iii) the sum of six skinfolds, (iv) the ratio of the sum of
six skinfolds to total fat mass, (v) the ratio of the trunk skinfold s
um to the extremity skinfold sum, and (vi) the regression of the trunk
-extremity skinfold ratio on the sum of six skinfolds-was analyzed sep
arately with systolic BP and with diastolic BP. Results showed that (1
) upper-body fat was the strongest interindividual correlate of BP (es
pecially the correlation of trunk-extremity ratio with diastolic BP),
suggesting shared pleiotropic genetic and/or common familial environme
ntal effects; (2) summary body-fat measures either were inconsistent (
in the case of both percent body fat and sum of six skinfolds) or gave
no evidence of interindividual cross-trait resemblance skinfolds and
BP largely vanished once the skinfold sum was adjusted for fat mass, s
uggesting that the intraindividual association may be mediated largely
by the absolute amount of subcutaneous fat rather than by the subcuta
neous proportion. Finally, the magnitude of the spouse resemblance for
the trunk-extremity ratio with diastolic BP suggests that a significa
nt proportion of the resemblance may be due to environmental influence
s, In summary, our investigation confirms a heritable link between BP
and truncal-abdominal fat as predicted by the metabolic-syndrome hypot
hesis. That this result is obtained in primarily normotensive, nonobes
e families, suggests the connection involves normal metabolic paths.