Two centuries of growth among Czech children and youth

The trend of increasing height can be interpreted as a reflection of the unfolding progress of civilization. Height changes among children and adolescents are good markers of this trend. We analyze the secular trend in the heights of children and adolescents in the Czech Republic on the basis of data from anthropological surveys. The earliest height data pertain to Czech youths who attended the Military Schools in Austria in 1800-1809. Data also exist for 1895 and continue in 1951 and at 10-year intervals thereafter. Growth curves were obtained for separate age groups by fitting mean values via third-order polynomial smoothing splines. Between 1951 and 2001, the mean heights of boys and girls aged 2.5 years increased by 2.7 and 3 cm, respectively. Since 1895, the mean height of 13-year-old boys has increased by 19.4 cm, and the mean height of girls has increased by 18.3 cm.     

Stature variation in the British American Colonies: French and Indian War records, 1755-1763

Personnel records kept by military units of American colonials during the French and Indian War (1755-1763) are analyzed for relationships between environmental factors and stature. A robust American economy and direct access to high-quality food were apparently critical to tallness of this white American male sample. American-born men were taller at all ages than those who had migrated from Europe. January temperatures, rural versus urban birth, and ethnicity also showed stature relationships within the American-born group; thermal effects were by far the strongest of the non-nutritional factors.     

Femur/stature ratio and estimates of stature in children.

The present study examines the relationship between femur length and stature in children between the ages of 8 and 18 years. In previous investigations, my colleagues and I reported the surprising finding that femur length bears a nearly constant relationship to stature in adult humans regardless of ethnicity or gender. This earlier study revealed that the femur/stature ratio averages 26.74% in adult humans, and that using the ratio to predict stature from femur length yields remarkably accurate estimates. The current study shows that femur/stature ratios of children between the ages of 8 and 11 differ significantly from their older counterparts. Between the ages of 12 and 18, there are no significant differences due to age in the femur/stature ratio; however, there are significant differences in this age group attributable to gender. This study also shows that the worldwide average adult femur/stature ratio does not adequately describe children in this age range. This study strongly documents the adolescent growth spurt in the femur/stature ratios of both males and females at the precise time one would expect to see the spurt occur (10-12 in females; 12-14 in males). This growth follows a nearly identical trajectory in both genders, with relative femur growth dominating before the peak years of the growth spurt, and relative stature growth dominating afterward. This accounts for the ratio's rise to maximum values just before peak growth, and its decline toward the adult ratio thereafter. These findings require us to use separate adolescent femur/stature ratios of 27.16 (females) and 27.44 (males) to estimate the stature of children between the ages of 12 and 18. Preliminary testing shows these ratios to be more accurate in estimating stature than the properly selected Trotter and Gleser adult regression equation. Use of the adolescent male ratio with the Homo erectus juvenile WT 15000 results in a lower stature estimate (157.4 cm) than previously reported. It is suggested that continued testing of the ratio occur, but that the values herein derived may be useful in routine forensic cases involving children in this age range, and with subadult paleontological specimens.     

Birth Weight and Its Relationship to Size Attained and Relative Fat Distribution at 7 to 12 Years of Age

The relationship between birth weight and relative subcutaneous fat distribution at school age was considered in 131 boys and 106 girls 7 to 12 years of age. Relative fat distribution at school age was estimated with the ratio of the subscapular to triceps skinfolds (S/T) for the total sample, and with the ratio of the sum of two trunk (subscapular, midaxillary) to the sum of two extremity (triceps, medial calf) skinfolds (T/E) for subsamples of 102 boys and 63 girls. There were no sex differences in the S/T ratio (mm/mm), boys 0.62 ± 0.15, girls 0.63 ± 0.18; T/E ratio (mm/mm), boys 0.58 ± 0.13, girls 0.59 ± 0.16; and BMI (kg/m²), boys 17.1 ± 2.4, girls 16.9 ± 2.2. Second order partial correlations, controlling for age and the BMI or age and sum of skinfolds, between birth weight and the skinfold ratios are, respectively, ?0.22 and ?0.20 (p<0.01) for S/T and ?0.29 and ?032 (p<0.01) for T/E in girls, and ?0.18 and ?0.17 (p<0.05) for S/T and ?0.06 and ?0.6 for T/E in boys. Though low, the correlations suggest that as birth weight decreases proportionally more subcutaneous fat is accumulated on the trunk than on the extremities, more so in females than in males. Results of stepwise multiple regression analyses indicate that birth weight accounts for from 2% to 8% of the variance in relative subcutaneous fat distribution at school age.     

Morphological changes in the central sulcus of children with isolated growth hormone deficiency versus idiopathic short stature

In this study, the morphological changes in the central sulcus between children with isolated growth hormone deficiency (IGHD) and those with idiopathic short stature (ISS) were analyzed. Thirty children with IGHD (peak growth hormone < 5 µg/L) and 30 children with ISS (peak growth hormone > 10.0 µg/L) were included. Morphological measurements of the central sulcus were obtained from T1‐weighted MRIs using BrainVISA, including the average sulcal width, maximum depth, average depth, top length, bottom length, and depth position‐based profiles (DPPs). The bilateral average width of the central sulci was significantly wider, while the left maximum depth and right average depth of the central sulcus were significantly smaller, in children with IGHD than in children with ISS. There were no significant differences in the right maximum depth, left average depth, or bilateral top length and bottom length of the central sulcus between groups. The DPPs of the middle part of both central sulci (corresponding to the hand motor activation area) and the inferior part of the right central sulcus (corresponding to the oral movement area) near the Sylvian fissure were significantly smaller in children with IGHD than in controls before false discovery rate (FDR) correction. However, all the above significant DPP sites disappeared after FDR correction. There were significant morphological changes in the three‐dimensional structure of the central sulcus in children with IGHD, which were the outcome of other more essential cortical or subcortical changes, resulting in their relatively slower development in motor, cognitive, and linguistic functional performance.     

Interpreting skeletal growth in the past from a functional and physiological perspective

The study of juvenile skeletal remains can yield important insights into the health, behavior, and biological relationships of past populations. However, most studies of past skeletal growth have been limited to relatively simple metrics. Considering additional skeletal parameters and taking a broader physiological perspective can provide a more complete assessment of growth patterns and environmental and genetic effects on those patterns. We review here some alternative approaches to ontogenetic studies of archaeological and paleontological skeletal material, including analyses of body size (stature and body mass) and cortical bone structure of long bone diaphyses and the mandibular corpus. Together such analyses can shed new light on both systemic and localized influences on bone growth, and the metabolic and mechanical factors underlying variation in growth. Am J Phys Anthropol, 2013. © 2012 Wiley Periodicals, Inc.     

Big‐sized trees overrule remaining trees' attributes and species richness as determinants of aboveground biomass in tropical forests

Large‐diameter, tall‐stature, and big‐crown trees are the main stand structures of forests, generally contributing a large fraction of aboveground biomass, and hence play an important role in climate change mitigation strategies. Here, we hypothesized that the effects of large‐diameter, tall‐stature, and big‐crown trees overrule the effects of species richness and remaining trees attributes on aboveground biomass in tropical forests (i.e., we term the “big‐sized trees hypothesis”). Specifically, we assessed the importance of: (a) the “top 1% big‐sized trees effect” relative to species richness; (b) the “99% remaining trees effect” relative to species richness; and (c) the “top 1% big‐sized trees effect” relative to the “99% remaining trees effect” and species richness on aboveground biomass. Using environmental factor and forest inventory datasets from 712 tropical forest plots in Hainan Island of southern China, we tested several structural equation models for disentangling the relative effects of big‐sized trees, remaining trees attributes, and species richness on aboveground biomass, while considering for the full (indirect effects only) and partial (direct and indirect effects) mediation effects of climatic and soil conditions, as well as interactions between species richness and trees attributes. We found that top 1% big‐sized trees attributes strongly increased aboveground biomass (i.e., explained 55%–70% of the accounted variation) compared to species richness (2%–18%) and 99% remaining trees attributes (6%–10%). In addition, species richness increased aboveground biomass indirectly via increasing big‐sized trees but via decreasing remaining trees. Hence, we show that the “big‐sized trees effect” overrides the effects of remaining trees attributes and species richness on aboveground biomass in tropical forests. This study also indicates that big‐sized trees may be more susceptible to atmospheric drought. We argue that the effects of big‐sized trees on species richness and aboveground biomass should be tested for better understanding of the ecological mechanisms underlying forest functioning.     

Stature of sub-arctic birch in relation to growth rate, lifespan and tree form

BACKGROUND AND AIMS: Sub-arctic mountain birch Betula pubescens var. pumila communities in the North Atlantic region are of variable stature, ranging from prostrate scrubs to forests with trees up to 12 m high. Four hypotheses were tested, relating growth and population characteristics of sub-arctic birch woodland and scrub to tree stature; i.e. the variable stature of birch woods is due to differences in (1) the mean growth rate; (2) the age-related patterns of growth rate; (3) the life expectancy of stems; or (4) the tree form. Methods: A stratified random sample of 300 birch trees was drawn from the total population of indigenous birch woodlands and scrub in Iceland, yielding 286 valid sample genets. The population was divided into three sub-populations with dominant trees 0-2, 2-4 and 4-12 m tall, referred to as birch scrub, birch scrub-woodland and birch forest, respectively. KEY RESULTS: Trees in the scrub population were of more contorted growth form than birch in the scrub-woodland and forest populations. Mean growth rates, mean age and median life expectancies increased significantly with sub-population of greater tree stature. At the population level, annual increment and longevity of birch stems was apparently interrelated as the stems in vigorously growing birch sub-populations had a longer life expectancy than those of slower growth. However, no difference was observed between sub-populations in age-related patterns of extension growth rate. CONCLUSIONS: The results were consistent with hypotheses (1), (3) and (4), but hypothesis (2) was rejected. Hence, mountain birch of more vigorous growth attains a greater stature than birch of lesser increment due to faster extension growth rate and a longer lifespan. In addition, the more contorted stem form of scrub populations contributes to their low stature.     

Variation in ancient Egyptian stature and body proportions

Stature and the pattern of body proportions were investigated in a series of six time-successive Egyptian populations in order to investigate the biological effects on human growth of the development and intensification of agriculture, and the formation of state-level social organization. Univariate analyses of variance were performed to assess differences between the sexes and among various time periods. Significant differences were found both in stature and in raw long bone length measurements between the early semipastoral population and the later intensive agricultural population. The size differences were greater in males than in females. This disparity is suggested to be due to greater male response to poor nutrition in the earlier populations, and with the increasing development of social hierarchy, males were being provisioned preferentially over females. Little change in body shape was found through time, suggesting that all body segments were varying in size in response to environmental and social conditions. The change found in body plan is suggested to be the result of the later groups having a more tropical (Nilotic) form than the preceding populations.