Genetic and environmental determination of tracking in subcutaneous fat distribution during adolescence.
BACKGROUND
The distribution of fat and adipose tissue is an important predictor of disease risk. Variation in fat distribution during adolescence is correlated with fat distribution in adulthood.


OBJECTIVE
The objective was to gain insight into the relative contribution of genes and environment to the stability of subcutaneous fat distribution from early adolescence into young adulthood.


METHODS
Ratio of trunk to extremity skinfold thickness (TER) data from the Leuven Longitudinal Twin Study (n = 105 Belgian twin pairs followed from 10 to 18 y of age) was entered into a longitudinal path analysis.


RESULTS
The best-fitting model included additive genetic sources of variance and nonshared environment. Heritabilities ranged between 84.3% (95% CI: 63.9-92.3%) and 88.6% (95% CI: 76.5-94.1%) in boys and between 78.4% (95% CI: 59.3-88.3%) and 88.3% (95% CI: 77.0-93.8%) in girls. The majority of the phenotypic tracking (boys: 0.40-0.78; girls: 0.38-0.72) could be attributed to the moderate-to-high genetic correlations (rG) (between 0.27-0.84 and 0.38-0.80 for the various age intervals in boys and girls, respectively). This rG could be attributed to both genetic sources of variance, which are the same throughout adolescence, as well as genetic sources of variance that are "switched-on" at a certain age, the effect of which is then transmitted to subsequent observations. Environmental correlations (rE) in boys ranged between 0.51 and 0.70 but contributed relatively little to phenotypic tracking because the amount of variance explained by the environment was low (11.4-15.7%). In girls rE was low to moderate at best (0.09-0.48).


CONCLUSIONS
Phenotypic tracking in subcutaneous fat distribution during adolescence is predominantly explained by additive genetic sources of variance.
Peeters
Maarten W
MW
Department of Biomedical Kinesiology, Faculty of Kinesiology and Rehabilitation Sciences Epidemiology Unit, Strangeways Research Laboratory, Cambridge, United Kingdom. maarten.peeters@faber.kuleuven.be
Beunen
Gaston P
GP
Maes
Hermine H
HH
Loos
Ruth J F
RJ
Claessens
Albrecht L
AL
Vlietinck
Robert
R
Thomis
Martine A
MA
D000273:Adipose Tissue / Q000254:growth & development*; D000293:Adolescent; D041923:Adolescent Development / Q000502:physiology*; D001823:Body Composition / Q000235:genetics* / Q000502:physiology; D001824:Body Constitution / Q000235:genetics* / Q000502:physiology; D050218:Body Fat Distribution; D002648:Child; D004777:Environment; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008957:Models, Genetic; D010641:Phenotype; D011446:Prospective Studies; D012885:Skinfold Thickness