Tl. Nelson et al., Genetic and environmental influences on waist-to-hip ratio and waist circumference in an older Swedish twin population, INT J OBES, 23(5), 1999, pp. 449-455
OBJECTIVE: To investigate the genetic and environmental influences on waist
-to-hip ratio (WHR) and waist circumference (WC) measurements in males and
females.
DESIGN: Measurements taken from 1989 - 1991 as part of The Swedish Adoption
/Twin Study of Aging (SATSA) were used for analysis. The SATSA sample conta
ins both twins reared together as well as twins reared apart.
SUBJECTS: 322 pairs of twins (50 identical, 82 fraternal male pairs and 67
identical, 123 fraternal female pairs); age range: 45 - 85 y (average age,
65 y).
MEASUREMENTS: Waist-to-hip ratio (WHR), waist circumference (WC) and body m
ass index (BMI).
RESULTS: In males, additive genetic effects were found to account for 28% o
f the variance in WHR and 46% of the variance in WC. In females, additive g
enetic effects were found to account for 48% of the variance in WHR and 66%
of the variance in WC. The remaining variance in males was attributed to u
nique environmental effects (WHR, 72%; WC, 54%) and in females the remainin
g variance was attributed to unique environmental effects (WHR, 46%; WC, 34
%) and age (WHR, 6%). When BMI was added into these models it accounted for
a portion of the genetic and environmental variance in WHR, and over half
of the genetic and environmental variance in WC.
CONCLUSION: There are both genetic and environmental influences on WHR and
WC, independent of BMI in both males and females, and the differences betwe
en the sexes are significantly different.