Association among obesity-related anthropometric phenotypes: analyzing genetic and environmental contribution

Obesity has become a public-health and policy problem in many parts of the world. Epidemiological and population studies in this field are usually based on different anthropometric measures; however, common genetic and environmental factors between these phenotypes have been scarcely studied. The objective of this article is to assess the strength of these factors on the covariation among a large set of obesity-related traits. The subject group consisted of 533 nuclear families living in the Greater Bilbao (Spain), and included 1,702 individuals aged 2-61 years. Detailed anthropometric measurements (stature, breadths, circumferences and skinfolds) were carried out in each subject. Bivariate quantitative genetic analyses were performed using a variance-components procedure implemented in the software SOLAR. The results revealed that the majority of these traits is affected by common genetic and environmental factors. All correlations were significantly different from 1 and varied from non-significant to very high (>0.90, P < 0.0001), with clearly lower pleiotropic effects among pairs including fat-distribution traits. Despite the strong common genetic effects detected among phenotypes determining the amount of body fat and mass, there is a residual genetic influence on the local fatness measures that cannot be explained exclusively by the genetic influence on overall fatness. Moreover, the observed relationships confirm a partially different genetic control of truncal and peripheral fat. In conclusion, our findings highlight the relevance of considering different types of traits in the prevention and treatment of obesity, as well as in the search for genes involved in its development

Genetic Contribution to Variation in Body Configuration in Belgian Nuclear Families: A Closer Look at Body Lengths and Circumferences

The purpose of the current study was to evaluate the contribution of genetic factors on body configuration related phenotypes. The sample consisted of 119 Belgian nuclear families including 231 males and 229 females. Factor analysis with varimax rotation was carried out to analyse 13 length and circumference measures and the resulting two synthetic traits (LF and CF; linear and circumference factors, respectively) were used as summary variables. Univariate quantitative genetic analysis indicated that variation in anthropometric as well as in synthetic traits was significantly dependent on additive genetic effects, with heritabilities ranging from 0.55 to 0.88. Narrow sense heritability estimates were higher for measurements principally characterizing skeletal mass than in variables that also involve soft-tissues. Sex, age and their interactions explained 11–67% of the total phenotypic variance. This report also examined the covariations between pairs of anthropometric and synthetic traits (length measurements and LF vs. height; circumference measures and CF vs. weight and BMI; LF vs. CF). Significant genetic correlations among all the studied traits (except for middle finger length vs. height) confirmed the influence of pleiotropy on genetic determination of these phenotypes. Bivariate analysis showed that pleiotropic effects had a great influence in determining body traits variation within body length measurements, as well as between body circumferences and weight or BMI. In relation to the two synthetic traits, even the variation of body lengths and circumferences was highly determined by genetic factors, shared genetic influences were unlikely to explain much of the observed variation between LF and CF. The results of the present study allow us to conclude that in this population body configuration related traits are subject to a strong genetic control and that shared genes also contribute to this genetic structure

Association of maternal menarcheal age with anthropometric dimensions and blood pressure in children from Greater Bilbao

Background: Earlier menarche has been related to shorter height and greater obesity-related anthropometric dimensions and blood pressure in women. Boys and girls with earlier maternal menarcheal age (MMA) have shown greater height and body mass index (BMI) in childhood. Aim: To analyse associations of menarcheal age with their own and their children's anthropometric dimensions and blood pressure. Subjects and methods: The sample consisted of 493 women and their children (aged 2-19 years) from Greater Bilbao (Basque Country, Spain). For both generations there is information on 19 anthropometric dimensions, blood pressure and socio-demographic characteristics. Linear regressions adjusted for different covariates were used to analyse the associations. Results: Menarcheal age in women showed the greatest positive associations with iliospinal height and ectomorphy and negative associations with BMI, sum of six skin-folds, endomorphy and mesomorphy. Boys with earlier MMA had greater body heights and breadths, particularly iliospinal height and biacromial breadth (0.10z-score/year; p Conclusion: Children with earlier MMA tend to have greater anthropometric dimensions. Adolescent growth spurt might affect these relationships, at least in girls.Peer reviewe

Genetic and environmental effects on body mass index from infancy to the onset of adulthood: an individual-based pooled analysis of 45 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) study

Background: Both genetic and environmental factors are known to affect body mass index (BMI), but detailed understanding of how their effects differ during childhood and adolescence is lacking

A statistical investigation into the sharing of common genetic factors between blood pressure and obesity phenotypes in nuclear families from the Greater Bilbao (Spain)

Objectives: Several obesity phenotypes (e.g. body mass and fat, fat distribution) have been suggested to be a risk for elevated blood pressure. This study was undertaken to determine the heritability of four blood pressure phenotypes: SBP, DBP, pulse pressure (PP) and mean arterial pressure (MAP) and to assess the strength of genetic and environmental correlations among these phenotypes, and also between blood pressure and the different obesity-related traits. Methods: The studied sample consisted of 429 nuclear families living in the Greater Bilbao (Spain) and included 1302 individuals aged 4-61 years. Univariate and bivariate quantitative genetic analyses were performed using a variance components procedure implemented in Sequential Oligogenic Linkage Analysis Routines software. Results: SBP, DBP, PP and MAP were significantly influenced by genetic factors with heritability estimates of 0.25, 0.28, 0.14 and 0.31, respectively, and presented high genetic and environmental correlations between them (except DBP-PP). On the contrary, whereas SBP, DBP and MAP showed common environmental factors with almost all body mass and fat-related traits, pleiotropic effects were only detected for some pairs, especially for those phenotypes that included skinfolds. In contrast, PP did not exhibit common genetic or environmental factors with obesity phenotypes in the studied population Conclusion: Blood pressure and obesity phenotypes do not share, in general, a substantial influence of common genetic and environmental effects. Finally, the results obtained revealed the importance of the amount of adipose tissue in the genetic correlations with SBP, DBP and MAP, at least, during the growth period

The Association Between Puberty Timing and Body Mass Index in a Longitudinal Setting : The Contribution of Genetic Factors

We analyzed the contribution of genetic factors on the association between puberty timing and body mass index (BMI) using longitudinal data and two approaches: (i) genetic twin design and (ii) polygenic scores (PGS) of obesity indices. Our data were derived from Finnish cohorts: 9080 twins had information on puberty timing and BMI and 2468 twins also had genetic data. Early puberty timing was moderately associated with higher BMI in childhood in both boys and girls; in adulthood these correlations were weaker and largely disappeared after adjusting for childhood BMI. The largest proportion of these correlations was attributable to genetic factors. The higher PGSs of BMI and waist circumference were associated with earlier timing of puberty in girls, whereas weaker associations were found in boys. Early puberty is not an independent risk factor for adult obesity but rather reflects the association between puberty timing and childhood BMI contributed by genetic predisposition.Peer reviewe

Association of Birth Order with Cardiovascular Disease Risk Factors in Young Adulthood: A Study of One Million Swedish Men

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Genetics of somatotype and physical fitness in children and adolescents

Objectives To analyze the influence of genetic and environmental factors on the variation in somatotype, physical fitness, and their mutual associations. Methods Twins from 214 pairs (87 monozygotic) of the Autonomous Region of Madeira, Portugal, from 3 to 18 years of age (51% girls) were assessed in anthropometry and physical fitness tests. We estimated endomorphy, mesomorphy, and ectomorphy based on anthropometric measures and physical fitness using the Eurofit test battery. Two age categories were analyzed: children (3-11 years) and adolescents (12-18 years). Genetic and environmental variations were estimated using quantitative genetic twin modeling. Results No genetic sex differences were found, thus boys and girls were pooled in all genetic analyses. Heritability estimates were high for somatotype (a(2)= 0.80-0.93), physical fitness traits (a(2)= 0.67-0.83), and largely similar in children and adolescents. Positive correlations were found for ectomorphy with motor ability and cardiorespiratory endurance as well as for endomorphy and mesomorphy with muscular strength (r= 0.25-0.37). In contrast, negative associations were found for ectomorphy with muscular strength, as well as for endomorphy and mesomorphy with motor ability and cardiorespiratory endurance (-0.46 to -0.26). Twin modeling indicated that these associations were explained mostly by genetic factors in common to the two associated traits (84% or more). Conclusions Associations between somatotype and physical fitness tests are mainly explained by common genetic background in children and adolescents. Therefore, interventions in youth should consider that a child's performance in physical fitness tests partly reflects their inherited physique.Peer reviewe

Association of height and pubertal timing with lipoprotein subclass profile: exploring the role of genetic and environmental effects

Objectives: Little is known about the relationship between growth and lipoprotein profile. We aimed to analyze common genetic and environmental factors in the association of height from late childhood to adulthood and pubertal timing with serum lipid and lipoprotein subclass profile. Methods: A longitudinal cohort of Finnish twin pairs (FinnTwin12) was analysed using self-reported height at 11-12, 14, 17 years and measured stature at adult age (21-24 years). Data were available for 719 individual twins including 298 complete pairs. Serum lipids and lipoprotein subclasses were measured by proton nuclear magnetic resonance spectroscopy. Multivariate variance component models for twin data were fitted. Cholesky decomposition was used to partition the phenotypic covariation among traits into additive genetic and unique environmental correlations. Results: In men, the strongest associations for both adult height and puberty were observed with total cholesterol, low-density lipoprotein cholesterol, intermediate-density lipoprotein cholesterol and low-density lipoprotein particle subclasses (max. r = -0.19). In women, the magnitude of the correlations was weaker (max. r = -0.13). Few associations were detected between height during adolescence and adult lipid profile. Early onset of puberty was related to an adverse lipid profile, but delayed pubertal development in girls was associated with an unfavorable profile, as well. All associations were mediated mainly by additive genetic factors, but unique environmental effects cannot be disregarded. Conclusions: Early puberty and shorter adult height relate to higher concentrations of atherogenic lipids and lipoprotein particles in early adulthood. Common genetic effects behind these phenotypes substantially contribute to the observed associations