Twin study of genetic and environmental influences on adult body size, shape, and composition.
OBJECTIVE
To investigate the genetic and environmental influences on adult body size, shape, and composition in women and men, and to assess the impact of age.


METHODS
In this cross-sectional study of 325 female and 299 male like-sex healthy twin pairs, on average 38 y old (18-67 y), we determined zygosity by DNA similarity, and performed anthropometry and bioelectrical impedance analysis of body composition. The contribution to the total phenotypic variance of genetic, common environment, and individual environment was estimated in multivariate analysis using the FISHER program. Further, these variance components were analysed as linear functions of age.


RESULTS
In both women and men genetic contributions were significant for all phenotypes. Heritability for body mass index was 0.58 and 0.63; for body fat%, 0.59 and 0.63; for total skinfolds, 0.61 and 0.65; for extremity skinfolds 0.65 and 0.62; for truncal skinfolds, 0.50 and 0.69; for suprailiac skinfolds, 0.49 and 0.48; for waist circumference, 0.48 and 0.61; for hip, 0.52 and 0.58; for lean body mass/height2, 0.61 and 0.56; and for height, 0.81 and 0.69, respectively. There was no strong evidence of common environmental effects under the assumptions of no nonadditive effect. The pattern of age trends was inconsistent. However, when significant there was a decrease in heritability with advancing age.


CONCLUSIONS
These findings suggest that adult body size, shape, and composition are highly heritable in both women and men, although a decreasing tendency is seen with advancing age.
Schousboe
K
K
The Danish Twin Registry, Epidemiology, Institute of Public Health, University of Southern Denmark, Denmark. kschousboe@health.sdu.dk
Visscher
P M
PM
Erbas
B
B
Kyvik
K O
KO
Hopper
J L
JL
Henriksen
J E
JE
Heitmann
B L
BL
Sørensen
T I A
TI
D000273:Adipose Tissue / Q000033:anatomy & histology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001823:Body Composition / Q000235:genetics / Q000502:physiology*; D001824:Body Constitution / Q000235:genetics / Q000502:physiology*; D001827:Body Height / Q000235:genetics / Q000502:physiology; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D004247:DNA / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012885:Skinfold Thickness
D004247:DNA