Total and regional fat distribution is strongly influenced by genetic factors in young and elderly twins.
OBJECTIVE
Indirect estimates of obesity such as BMI seem to be strongly influenced by genetic factors in twins. Precise measurements of total and regional fat as determined by direct techniques such as DXA scan have only been applied in a few twin studies. The aim of the present study was to estimate the heritability (h(2)) of total and regional fat distribution in young and elderly Danish twins.


METHODS
Monozygotic (108) and dizygotic (88) twins in two age groups (25 to 32 and 58 to 66 years) underwent anthropometric measurements and DXA scans. Intraclass correlations and etiologic components of variance were estimated for total and regional fat percentages using biometric modeling.


RESULTS
The intraclass correlations demonstrated higher correlations for all fat percentages among monozygotic twins as compared with dizygotic twins. The biometric modeling revealed a major genetic component (h(2)) of total (h(2)(young) = 0.83, h(2)(elderly) = 0.86) and regional fat percentages (trunk, h(2)(young) = 0.82, h(2)(elderly) = 0.85; lower body, h(2)(young) = 0.83, h(2)(elderly) = 0.81; and trunk/lower body, h(2)(young) = 0.83, h(2)(elderly) = 0.71) in both the young and elderly twins.


CONCLUSIONS
The h(2) estimates emphasize that body fat and distribution as determined by DXA scan are under extensive genetic control.
Malis
Charlotte
C
Steno Diabetes Center, Gentofte, Denmark.
Rasmussen
Eva L
EL
Poulsen
Pernille
P
Petersen
Inge
I
Christensen
Kaare
K
Beck-Nielsen
Henning
H
Astrup
Arne
A
Vaag
Allan A
AA
D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000033:anatomy & histology*; D000328:Adult; D000367:Age Factors; D000368:Aged; D000886:Anthropometry; D001699:Biometry; D001823:Body Composition; D050218:Body Fat Distribution; D006801:Humans; D008875:Middle Aged; D009765:Obesity / Q000235:genetics*; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic