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Robert M. Malina

Publications and source records attributed to Robert M. Malina.

6 recordsLinked to original sources
PubMed2000

Familial resemblance in fatness and fat distribution.

The purpose of the study was to estimate the degree of familial resemblance in anthropometric indicators of fatness and fat distribution. The sample consisted of 327 Caucasian participants from 102 nuclear families. Indicators of fatness included the body mass index (BMI), the sum of six skinfolds (SF6: triceps + biceps + medial calf + subscapular + suprailiac + abdominal), and waist circumference (WAIST), while indicators of fat distribution included WAIST adjusted for BMI (WAIST(ADJ)), the trunk-to-extremity skinfold ratio, adjusted for SF6 (TER(ADJ)), and the first principal component of skinfolds, adjusted for the mean skinfold of the individual (PC1). A general familial correlation model was fit to the data, and a series of nested reduced models were also fit so as to test hypotheses about familial resemblance. The hypothesis of no familial resemblance (all familial correlations are zero) was rejected for all phenotypes, indicating that fatness and fat distribution aggregate within families. For the three indicators of fatness (BMI, SF6, and WAIST), the sibling and parent-offspring correlations were significant. Further, there were no sex or generation differences in the familial correlations. For the three indicators of fat distribution (TER(ADJ), WAIST(ADJ), and PC1), there was no parent-offspring resemblance; sibling resemblance was significant for TER(ADJ) and PC1. Further, spouse resemblance was not significant for WAIST(ADJ), but was for TER(ADJ) and PC1. For both WAIST(ADJ) and PC1 there were significant sex differences in the familial correlations. A combination of models including no sex or generation differences and no spouse resemblance was the most parsimonious model for BMI, SF6, and TER(ADJ). The environmental model (all correlations equal) was the most parsimonious for WAIST, the model of no sibling resemblance was the most parsimonious for WAIST(ADJ), and the model of no spousal resemblance was the most parsimonious for PC1. Estimates of maximal heritability range from 46-60% for fatness and from 29-48% for fat distribution, independent of overall fatness, suggesting that in this sample the heritability of fatness is greater than that for fat distribution. Further, the pattern of correlations, which generally includes no spousal resemblance but significant parent-offspring and sibling correlations, suggests the role of genes in explaining at least part of the heritability. Am. J. Hum. Biol. 12:395-404, 2000. Copyright 2000 Wiley-Liss, Inc.

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PubMed1999

Variation in subcutaneous adipose tissue distribution associated with age, sex, and maturation.

Age-, sex-, and maturity-associated variation in subcutaneous adipose tissue (SAT) distribution is reviewed and then considered longitudinally in a sample of Polish youth. Current study of adipose tissue distribution places considerable emphasis on abdominal adiposity, specifically intra-abdominal or visceral adipose tissue (VAT). Most studies of children and adolescents do not include an abdominal skinfold, and when it is available, the skinfold is grouped with others as a sum of skinfolds. Correlations between abdominal VAT and SAT based on computerized tomography in non-obese children are moderate to high, and those between the suprailiac and abdominal skinfolds and abdominal VAT are moderately high. Changes in three individual skinfolds (triceps, subscapular, abdominal) and ratios of the skinfolds were considered by chronological age and relative to the timing of peak height velocity (PHV), and in children of contrasting maturity status in participants of the Wroclaw Growth Study, 193 boys and 197 girls, who were followed longitudinally from 8 to 18 years of age. Individual skinfolds behave differently during childhood and adolescence, and the changes are influenced by the timing of the adolescent growth spurt. Sex differences in estimated velocities are negligible up to about 2 years before PHV; then velocities tend to be higher in girls. The velocity of the triceps skinfold is negative in boys just before and after PHV; estimated velocities for the trunk skinfolds are positive through the growth spurt in both sexes, and are somewhat greater after PHV, especially in girls. The individuality of changes in individual skinfolds during the adolescent spurt contributes to changes in the relative distribution of SAT at this time. The timing of the adolescent growth spurt is an important factor influencing the distribution of SAT both in the total sample and in youth classified as early and late maturing. Am. J. Hum. Biol. 11:189-200, 1999. Copyright 1999 Wiley-Liss, Inc.

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PubMed1999

Adolescent spurts in body dimensions: Average and modal sequences.

The sequence of growth spurts in 11 body dimensions was examined in 101 Polish adolescents, 52 males and 49 females, followed longitudinally from 11-18 years. The dimensions included weight; stature; symphyseal height; biacromial and bicristal breadths; and arm, forearm, chest, thigh and calf circumferences. Upper segment length was estimated as stature minus symphyseal height. Measurements were taken quarterly from 11-14 years, and annually or less frequently thereafter. Growth curves were fitted to individual longitudinal observations using kernel regression to derive estimates of ages at peak velocity (PV) and peak velocities. Within each sex, mean ages at PV were used to define the average sequence, while the most frequently observed sequence of PVs in individuals was used to define the modal sequence. Average and modal sequences differed, the latter probably reflecting individual variability in timing. The spurt in the estimate of leg length (symphyseal height) occurred prior to that for stature in males (first in the sequence) and was nearly coincident with that for stature in females (second in the sequence by 0.01 years). The timing of spurts in other dimensions within each sex was more variable in both average and modal sequences. Am. J. Hum. Biol. 11:287-295, 1999. Copyright 1999 Wiley-Liss, Inc.

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PubMed1999

Relation between birth weight at term and growth rate, skeletal age, and cortical bone at 6-11 years.

There is an apparent link between fetal and childhood growth and puberty and risk for several degenerative diseases in adulthood. It is also important to consider associations between birth weight and indicators of growth and biological maturation during childhood and adolescence as potential explanations for associations between fetal growth and adult risk for disease. The present study examines the association between birth weight and (1) size attained and rate of growth in body size and cortical bone area of the second metacarpal (M II), and (2) skeletal age and rate of skeletal maturation in children 6-11 years of age. The sample included 127 boys and 105 girls of European ancestry, divided into two age groups, 6-8 years and 9-11 years. The relationship between birth weight and attained size (stature, mass, and the BMI), M II cortical area and skeletal age (SA, Tanner-Whitehouse method) during childhood was examined with correlational analyses. Observations on children measured on two occasions were converted to annual velocities, and correlations between birth weight and annual velocities were also calculated. Birth weight is significantly associated with stature and mass in boys and only with stature in girls 6-11 years of age, but is not related to the BMI, M II cortical area, or skeletal maturity. Birth weight is not significantly related to annual velocities of growth in stature, mass, the BMI and M II cortical area; to the annual increment in SA; and to weight gain from birth to the time of measurement (intervals of 6 to 11 years). The results emphasize a role of other influences than birth weight on growth rate, cortical area of M II, and skeletal maturation during childhood. Am. J. Hum. Biol. 11:505-511, 1999. Copyright 1999 Wiley-Liss, Inc.

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