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Familial aggregation on trunkal fat of Portuguese nuclear families. A
quantitative genetic study.
M. Souza, R. Chaves, D. Santos, R. Garganta, A. Seabra, J. Maia
CIFI2D, Department of Kinanthropometry and Applied Statistics, Faculty of Sport, University of Porto,
Portugal.
An android fat pattern induces significant risks in the manifestation of cardiovascular disease
(CVD) and metabolic disorders [1-3]. There is evidence that some individuals are more
susceptible to changes in trunkal fat (TF), suggesting that genetic factors play important roles
in the etiology of this multifactorial and polygenic phenotype [3-4]. There is a lack of studies
in Genetic Epidemiology in Portugal aiming at verifying familiar aggregation (FA) and
predicting the influence of the genetic factors in TF.
The aims of this study were to (1) identify the presence of indirect transmission of genetic
factors between parents and children in two phenotypes of TF, and (2) to estimate the
contribution of genetic and environmental factors responsible for phenotypic variation on
relative trunkal fat (TFrel) and absolute trunkal fat (TFabs).
The sample consisted of 422 individuals from 107 Portuguese nuclear families. TFrel and TFabs
were measured with a bioelectric impedance device, Tanita ® model BC-418MA. Family
structure and quantitative genetic analysis of the two phenotypes between different family
members were verified in PEDSTATS. Familiar correlations were computed in the FCOR
module of SAGE 5.3. Heritability estimates (h 2 ) estimated using a maximum likelihood
method implemented in SOLAR 4.0.
Correlation coefficients (intraclass between same-sex members and interclass between
opposite-sex pairs) were low-to-moderate: TFrel (0.205 < r < 0.738) and TFabs (0.199 < r <
0.782). Genetic factors explained 50 and 47% of the variation in phenotypes of TFrel and TFabs,
respectively.
These results (1) showed a strong familial aggregation on trunkal fat of Portuguese nuclear
families; (2) a moderate-to-high genetic influence in their distribution at the population level;
(3) contribute to promote the need for further studies in Genetic Epidemiology (4) and suggest
the need for physical activity and nutritional interventions directed to all family members to
reduce this risk factor – high levels of trunkal fat.
References:
[1] Katzmarzyk PT, Bouchard C. (2005), Genetic Influences on Human Body Composition, In:
Heymsfield SB, Lohman TG, Wang Z, B. GS, “Human Body Composition”. Second Edition ed: Human
Kinetics.
[2] Rice TK, Borecki IB. (2001), Familial Resemblance. In: Rao DC, Province MA, “Genetic
Dissection of Complex Traits”, Academic Press.
[3] Bell CG, Walley AJ, Froguel P.(2005), The genetics of human obesity. Nat Rev Genet, 6 (3), 221-
34.
[4] Rankinen T, Zuberi A, Chagnon YC, Weisnagel SJ, Argyropoulos G, Walts B, et al. (2006), The
human obesity gene map: the 2005 update. Obesity (Silver Spring), 14 (4), 529-644.
320 3 rd meeting of young researchers at UP