E. Rebato

EVIDENCE OF PHENOTYPIC AND SOCIAL ASSORTATIVE MATING FOR ANTHROPOMETRIC AND PHYSIOLOGICAL TRAITS IN COUPLES FROM THE BASQUE COUNTRY (SPAIN)

This study examined 28 anthropometrical and physiological traits in 107 married couples living in the province of Biscay (Basque Country, Spain). The aim was to verify the existence of a phenotypic and/or social preference when choosing a mate. For this, correlations between pairs of spouses were estimated by maximum likelihood, and a model of familial transmission (path analysis) was applied in order to test if social homogamy between mates existed. The results provide significant evidence of phenotypic as well as social homogamy in several of the studied traits. Even if an assortment existed when choosing a mate for bony traits such as height, the effect of cohabitation cannot be discounted as the main causal factor for the high phenotypic resemblance observed between spouses for body composition traits. In addition, with the social homogeneity of the studied sample, significant evidence of the existence of social homogamy between mates was only found for 20% of the studied variables.

Body mass index and energy intake in Venezuelan University students

Abstract The object of the present study was to examine the relationship between Body Mass Index (BMI) and levels of energy intake (EI) in a sample of 1054 young adult students (746 females and 308 males), between 16 and 29 years of age, who were attending the Central University of Venezuela. BMI values were obtained by measuring the weight and height of individuals, whereas EI was calculated on the basis of consumption surveys carried out over a 48 hour period. BMI and EI were found to be higher in males than in females and both variables were positively correlated within the male and the female sub-groups under consideration (Pearson correlation coefficient r = 0.73 for male group; r=0.75 for female group). The BMI distribution percentage was found to be similar for both sexes, with most subjects falling within categories of acceptable ranges. BMI was found to be highly influenced by caloric intake in the analyzed sample, independent of sex. Comparison with other population references indicates that nutritional stress did not occur during the growth years of students in the analyzed group.

Heritability variations of morphometric traits in West Bengal (India) children aged 4-19 years: a mixed-longitudinal growth study.

Background: Longitudinal and semi-longitudinal growth studies on siblings reflecting heritability changes during growth are very scarce. Moreover, studies of variables other than height, weight and BMI are virtually non-existent. Aim: The study compared changes in the heritability of six body lengths, four body breadths, and three indices between ages 4 and 19 years on the basis of a mixed-longitudinal sample of siblings, and examined whether heritability estimates change during the growth period. The data consisted of 238 brothers and 214 sisters from 134 middle-class nuclear families living in Kolkata (India). The analysis of sibling correlation was performed by maximum likelihood. The age-related patterns of heritabilities of the various traits were described by a cubic spline. Results: The heritability was very high and significant in most traits, and at all considered ages. Mean heritability in the 10 morphometric traits was 69.3%, which was higher than the heritability values for the three indices. Conclusions: These results confirmed the existence of age-related trends in heritability of the considered morphometric traits. The sharp decline of the heritabilities at adolescence in most of the morphometric traits, and the acromio-iliac index in particular, may be due to the large inter-individual variation in the age at which the adolescent growth spurt is reached in both sexes.

Multifactorial analysis of a mixed-longitudinal sample of Indian siblings: Age and sex effects on heritability

The aim of the present study was to examine the heritability of 11 traits in a mixed-longitudinal sample of Indian siblings, and to determine whether heritability estimates vary during the growth period and whether they are influenced by sex. The sample consisted of 245 brothers and 213 sisters from 138 nuclear families living in a semi-urban area in Kolkata, India. The age ranged between 5 and 19 years. The traits were standardised for age and sex using standard deviation scores (SDS) produced by the LMS method (Cole, T.J., 1988. Fitting smoothed centile curves to reference data. J. R. Stat. Soc. A 151, 385-418). The standard deviation scores were analysed by PCA. The two factors with eigenvalues above 1 explained 77.3% of the variance; they showed a high level of pleiotropism present among the studied traits and represented body lengths (PC1) and body weight and breadths (PC2). The heritability between all types of siblings (irrespective of sex) for the PC1 and PC2 was estimated. The heritability between various pairs of siblings showed variations along the whole ontogenetic period studied. During the childhood and pre-pubertal period, heritability between brothers, brother-sister pairs and any sibling pairs was mostly constant, with small and non-significant variations. All the pairs showed the lowest degree of heritability during puberty for PC1 but not for PC2, with significant changes of heritability estimates between adolescence and adulthood, in most of the analysed sibling pairs and in both PC factors. The highest heritability was generally observed at the end of the examined growth period in all pairs. A significant effect of sex on heritability was only detected for PC2 at 11 years of age.

Genetic and environmental sources on familial transmission in Biscayan families. III. The dynamometric strength.

The present research analyses a cross-sectional sample of 284 individuals (86 fathers, 86 mothers, 54 sons and 58 daughters) in 86 nuclear families living in the province of Biscay (Basque Country, Spain), with the aim of estimating both transmissible and non-transmissible components acting on familial resemblance for the maximum dynamometric strength of both hands, by means of a path analysis. Standardised data of each generation and sex were adjusted to a BETA model of path analysis independent of sex effects, allowing nevertheless the possibility to differentiate between transmissible (genetic and cultural) and non-transmissible (environmental) components acting on the observed phenotypic variance in Biscayan offspring. The results supported the full model of familial transmission for the two variables, in addition to other reduced models that gave rise to transmission effects regardless of any influence from the siblings shared environment on the environmental transmitted component from their parents (b = 0), and without social homogamy between mates (u = 0). The most parsimonious model created, based on the previous ones, was accepted for both traits. The total transmissible variance (t2) explained between 21% (right hand) and 44% (left hand) of the observed phenotypic variation. These values are close to those from the literature (t2 = 37%). However, we should take into account that these kinds of estimations are specific for each group or population.