Cortical bone loss and measurements of the second metacarpal bone: II. Hypodense bone in postwar Guamanian children

Hand-wrist radiographs from 326 Guamanian children (180 boys and 146 girls) were evaluated for total width, medullary width, length, and combined cortical thickness of the second metacarpal. Bone measurements as well as standing height and weight were compared to similar published data from U.S. mainland black, white, and Mexican-American children. The results demonstrated that the second metacarpal bones of Guamanian boys and girls of all age groups (5–17 years) have a narrower width and shorter length with less combined cortical thickness than any of the other groups. Guamanian children also weighed less and were of shorter stature than their black, white, or Mexican-American counterparts. These results agree closely with those comparisons between Guamanian and U.S. mainland white adults published earlier. It is not possible from the present data to ascertain whether these differences were due to genetic variability or nutritional deficiency.     

Sex matters during adolescence: testosterone-related cortical thickness maturation differs between boys and girls

Age-related changes in cortical thickness have been observed during adolescence, including thinning in frontal and parietal cortices, and thickening in the lateral temporal lobes. Studies have shown sex differences in hormone-related brain maturation when boys and girls are age-matched, however, because girls mature 1-2 years earlier than boys, these sex differences could be confounded by pubertal maturation. To address puberty effects directly, this study assessed sex differences in testosterone-related cortical maturation by studying 85 boys and girls in a narrow age range and matched on sexual maturity. We expected that testosterone-by-sex interactions on cortical thickness would be observed in brain regions known from the animal literature to be high in androgen receptors. We found sex differences in associations between circulating testosterone and thickness in left inferior parietal lobule, middle temporal gyrus, calcarine sulcus, and right lingual gyrus, all regions known to be high in androgen receptors. Visual areas increased with testosterone in boys, but decreased in girls. All other regions were more impacted by testosterone levels in girls than boys. The regional pattern of sex-by-testosterone interactions may have implications for understanding sex differences in behavior and adolescent-onset neuropsychiatric disorders.     

A Longitudinal Study: Changes in Cortical Thickness and Surface Area during Pubertal Maturation

Sex hormones have been shown to contribute to the organization and function of the brain during puberty and adolescence. Moreover, it has been suggested that distinct hormone changes in girls versus boys may contribute to the emergence of sex differences in internalizing and externalizing behavior during adolescence. In the current longitudinal study, the influence of within-subject changes in puberty (physical and hormonal) on cortical thickness and surface area was examined across a 2-year span, while controlling for age. Greater increases in Tanner Stage predicted less superior frontal thinning and decreases in precuneus surface area in both sexes. Significant Tanner Stage and sex interactions were also seen, with less right superior temporal thinning in girls but not boys, as well as greater decreases in the right bank of the superior temporal sulcus surface area in boys compared to girls. In addition, within-subject changes in testosterone over the 2-year follow-up period were found to relate to decreases in middle superior frontal surface area in boys, but increases in surface area in girls. Lastly, larger increases in estradiol in girls predicted greater middle temporal lobe thinning. These results show that within-subject physical and hormonal markers of puberty relate to region and sex-specific changes in cortical development across adolescence.     

大连学生体质发育的研究

为了解大连地区城乡学生生长发育状况及其规律,采用人体测量学方法,调查测量了大连地区7—18岁3834（城市男630,城市女645,乡村男1285,乡村女1274）名汉族学生23项形态指标,并利用以往资料,研讨了大连学生主要形态指标的生长发育规律、生长发育趋势、性差和地区差别。结果表明：1生长发育特点：大连学生测量项目的均值随年龄的增长而增加,生长曲线呈上升趋势并且男女有交叉现象。2性差：大连学生各测量项目均有明显的性差,除女生青春期（10—12岁）外,在其他年龄组均为男生大于女生。3生长的长期变化：大连7—17岁男女学生26年来身高、体重、胸围有较大幅度的增长,其每10年平均增长值分别为2.52cm和1.92cm、4.05kg和2.39kg、1.77cm和1.38cm。4城乡差：大连男女学生身高、体重、胸围仍存在城乡差别。     

An expanded overview of postmenopausal osteoporosis

Why is the incidence of osteoporotic fracture so much higher in women than in men? The dominant medical view holds that the exaggerated skeletal fragility and fracture risk of postmenopausal women solely reflects the loss of bone following withdrawal of endogenous estrogen. Indeed, an enormous amount of research in this area has attempted to understand the rise in fractures after menopause in terms of the impact of estrogen lack on bone remodeling. Recent insights suggest that this simple view does not offer an adequate explanation for the greater susceptibility of older women to fracture compared to that of men. It seems more reasonable to view bone health as a lifelong process, reflecting the contributions and influences of myriad events occurring throughout life to skeletal acquisition and maintenance. Only recently has the medical community recognized that the amount of bone present at skeletal maturity makes a powerful contribution to lifelong skeletal status. A second area that must be incorporated into discussions of this topic relates to bone size and geometry. Women's bones are inherently smaller than those of men. A bone's strength is determined by its size as well as by its material properties. In boys, pubertal increases in the cortical thickness of long bones are achieved by (testosterone-dependent) periosteal apposition. By contrast, increased cortical thickness in girls reflects bone expansion into the medullary space, with little or no periosteal apposition, suggesting an inhibitory effect of estrogen on the latter process. Consequently, at skeletal maturity, men have wider bones of greater mechanical competence. Although estrogen is generally held to be skeletally protective, this aspect of its actions may actually render women more susceptible to some fractures. In later life, men may lose even more bone from appendicular sites than do women, but men show much greater concomitant increases in periosteal apposition than women, permitting them to maintain a relatively favorable mechanical profile. These several findings are based on cross-sectional observations of relatively few individuals and therefore require confirmation in prospective longitudinal studies. The degree to which gender-related differences in later life skeletal adaptation reflects a bone's mechanical or metabolic environment has been frequently discussed but still awaits experimental confirmation.     

Parent-child correlation for various indices of adiposity in an endogamous Indian population

The study was conducted on 1,042 Punjabi adults and adolescent boys and girls (11-17 years) belonging to middle class families residing in Delhi, India. To study the relative influence of genetic and environmental factors on various fat measures, a set of 7 body measurements namely weight, stature and skinfold thickness at biceps, triceps, subscapular, suprailiac and medial calf measurements was taken on each subject. There was a redistribution of fat away from extremity towards the trunk, a rapid occurring process in males than in females. Increase in body mass index (BMI) with age was more pronounced in females than in males, both at adolescence and adult stage. There was an increase in grand mean thickness (GMT) calculated as mean of all five skinfold thicknesses, in adolescent girls where as in adolescent boys it fluctuated with age. The trunk/extremity ratios reflected a trend in favor of increase in trunk fat, more marked in boys than in girls. The correlations were of low magnitude, however, some skin folds displayed relatively higher value of correlation indicating that these could be determinant of adult obesity.     

The Influence of Sex Steroids on Structural Brain Maturation in Adolescence

Puberty reflects a period of hormonal changes, physical maturation and structural brain reorganization. However, little attention has been paid to what extent sex steroids and pituitary hormones are associated with the refinement of brain maturation across adolescent development. Here we used high-resolution structural MRI scans from 215 typically developing individuals between ages 8–25, to examine the association between cortical thickness, surface area and (sub)cortical brain volumes with luteinizing hormone, testosterone and estradiol, and pubertal stage based on self-reports. Our results indicate sex-specific differences in testosterone related influences on gray matter volumes of the anterior cingulate cortex after controlling for age effects. No significant associations between subcortical structures and sex hormones were found. Pubertal stage was not a stronger predictor than chronological age for brain anatomical differences. Our findings indicate that sex steroids are associated with cerebral gray matter morphology in a sex specific manner. These hormonal and morphological differences may explain in part differences in brain development between boys and girls.     

Stature and body weight growth patterns from longitudinal data of Japanese children born during World War II

Stature and body weight data of 100 boys and 100 girls from 7 to 17 years of age in Shimodate City who were born during World War II were longitudinally analyzed. The children were significantly smaller and lighter throughout their growth period than those born 11 years after the end of the war. The correlation coefficient between statures at each age and at age 17 showed a gradual increase with increasing age, while that between statures at each age and at age 7 decreased with age. However, a drop in the correlation coefficient was found during puberty, at age 11 for girls and at age 13 for boys. Comparing the normalized distance from mean values of stature and body weight at age 7, at puberty, and at age 17, only 51% of the children continued to be in the same relative position for both height and weight, 6% of boys and 4% of girls showing a decreasing pattern for both and 4% of boys and 7% of girls showing an increasing pattern for both. Thus, about 60% of the children of either sex presented parallel stature and body weight growth patterns for ages from 7 to 17.     

Hand dominance and bilateral asymmetry in the structure of the second metacarpal

Bilateral asymmetry in the structure of the second metacarpal was examined in relation to functional hand dominance in a large, clinically nonselected, healthy population sample from the Baltimore Longitudinal Study of Aging. Bilateral bone measurements were made from anteroposterior hand radiographs of a total of 992 individuals, 609 males and 383 females, with an age range of 19–94 years. Hand dominance was determined on the basis of personal impression. Total width and medullary width at the midshaft of the second metacarpal were measured to 0.05 mm using a Helios caliper. These two measurements were used to derive cortical thickness, cortical bone area, periosteal (total) area, medullary area, percent cortical area, and the second moment of area in the mediolateral plane. In both right and left-handed individuals, statistically significant side differences were found in the calculated bone areas and the second moment of area, with the dominant hand being larger. Cortical thickness did not show significant side-related differences for either handedness. These results show that functional handedness leads to periosteal and endosteal expansion of the second metacarpal cortex on the dominant side, increasing bone strength without increasing cortical thickness. This is the first time this pattern of asymmetry has been reported in left-handers as well as right-handers. Our results argue for the primacy of environmental (mechanical) effects in determining bilateral asymmetry of limb bone structural properties. © 1994 Wiley-Liss, Inc.     

Intelligence in Taiwan: Progressive Matrices means and sex differences in means and variances for 6- to 17-year-olds

Data for Raven's Progressive Matrices are reported for a sample of 6290 6- to 17-year-olds in Taiwan. The Taiwanese obtained a mean IQ of 109.5, in relation to a British mean of 100. There was no difference in mean scores of boys and girls at age 7 years. At age 10 years girls obtained significantly higher scores than boys, and at ages 13 and 16 years boys obtained significantly higher scores than girls. There was no sex difference in variance at age 7 years. At ages 10, 13 and 16 years variance was significantly greater in boys.     

Effect of ethnicity and sex on the growth of the axial and appendicular skeleton of children living in a developing country

Bones in the axial and appendicular skeletons exhibit heterogeneous growth patterns between different ethnic and sex groups. However, the influence of this differential growth on the expression of bone mineral content is not yet established. The aims of the present study were to investigate: 1) whether there are ethnic and sex differences in axial and appendicular dimensions of South African children; and 2) whether regional segment length is a better predictor of bone mass than stature. Anthropometric measurements of stature, weight, sitting height, and limb lengths were taken on 368 black and white, male and female 9-year-old children. DXA (dual-energy x-ray absorptiometry) scans of the distal ulna, distal radius, and hip and lumbar spine were also obtained. Analyses of covariance were performed to assess differences in limb lengths, adjusted for differences in stature. Multiple regression analyses were used to assess significant predictors of site-specific bone mass. Stature-adjusted means of limb lengths show that black boys have longer legs and humeri but shorter trunks than white boys. In addition, black children have longer forearms than white children, and girls have longer thighs than boys. The regression analysis demonstrated that site-specific bone mass was more strongly associated with regional segment length than stature, but this had little effect on the overall pattern of ethnic and sex differences. In conclusion, there is a differential effect of ethnicity and sex on the growth of the axial and appendicular skeletons, and regional segment length is a better predictor of site-specific bone mass than stature.     

Sex differences in body composition early in life

Background: Early development of the percentage of fat and muscle is rarely considered, but is important because excessive fat is related to the development of diabetes and other morbidities later in life. In pediatric medicine, there are few to no data comparing sex differences in body composition in the first months of life despite the fact that males are typically longer and weigh more than girls at birth.Objective: The purpose of this study was to determine whether observed sex differences in body composition at birth persist through the first 6 months of life.Methods: Participants were healthy, full-term, male and female newborns. Children throughout the Oklahoma City, Oklahoma, metropolitan area were enrolled. The inclusion criteria were: mothers aged 18 to 45 years at the time of delivery; a term pregnancy lasting ≥37 weeks of gestation (determined by mother's physician); weight adequate for gestational age; and a hospital stay for the infant of <3 days following delivery. The exclusion criteria were: maternal tobacco use or alcohol consumption (>1 drink per week) during pregnancy; gestational diabetes; preeclampsia; and infants with presumed or known congenital birth defects. Baseline assessment at birth included length and weight. Newborns had their body composition (percent fat [%fat], total fat, and fat-free mass) determined at ~1 month of age using whole body plethysmography. Mothers were invited to have their children take part in a 5-month extension that conducted additional body composition measurements at 3 and 6 months of age.Results: Sixty-four girls (mean [SD] age at time of testing, 20.9 [7.9] days; birth weight, 3500 [388] g; birth length, 49.9 [2.4] cm; white race, 73.4%) and 53 boys (mean age at time of testing, 20.2 [7.3] days; birth weight, 3353 [413] g; birth length, 51.0 [2.4] cm; white race, 69.8%) were assessed and included in the study. At birth, girls were significantly shorter and weighed more than boys (both, P < 0.05). At ~1 month of age, body composition revealed that girls had significantly greater %fat (15.1% vs 12.7%; P < 0.05) and less fat-free mass (3182 [303] vs 3454 [361] g; P < 0.001) than did boys. At 3 months of age, girls continued to have significantly less fat-free mass (4379 [347] vs 4787 [310] g; P < 0.01) than did boys; however, by 6 months of age, no significant sex difference was observed in any body composition variable studied.Conclusion: In this small sample of healthy, full-term newborns, at ~1 month of age, statistically significant differences in %fat and fat-free mass existed between girls and boys; however, by 6 months of age, these differences no longer existed.     

Heights and weights of Da-an boys: did sisters really make a difference?

This study further examined the negative association between boys' growth and the presence of sisters within a relatively affluent community in Taipei, Taiwan. Among 596 boys born in 1976-77, differences in height and log-transformed weight were judged using analysis of covariance (ANCOVA) with measurement age as a covariate, and parental education level (four levels), number of sisters (0, 1, 2 or 3+) and number of brothers (0, 1, 2+) as predictors. The relative importance of birth order and sibling sex was examined among the near majority of boys with one sibling (47%, 278/596). The sibling composition variable was defined using mutually exclusive categories representing individuals with one sibling: either one older or younger brother or sister. All boys contributed information before leaving middle school at a mean age of 14.9 +/- 0.4 years SD. The results were compared with similar analyses of data for 154 of these same boys for whom measurements were available from primary school entry at a mean age of 64 +/- 0.3 years SD onward. Results were also compared with data for a cohort of 153 boys who entered primary school later in 1986. Results confirm that boys from the Da-an area born in the mid-1970s who did not have sisters were significantly taller (2.2-2.5 cm, p < or = 0.008) and heavier (3.0-3.9 kg, p < or = 0.016) than those with one or two sisters. However, the 26 boys with three or more sisters, most of whom were last-born, were somewhat taller than those with one or two sisters. The same curvilinear relationships in height and weight appeared both among boys as they prepared to leave middle school and among the subset also measured just after entering primary school. When numbers of sisters were statistically controlled, the presence of two or more brothers was also significantly negatively associated with mean stature, but not weight, among middle school boys. Analyses among boys with one sibling revealed that birth order was associated with mean stature, but only if the sibling was female; an older sister was associated with a greater deficit in mean stature than a younger sister. Evidence of rising educational expectations, continued declines in family size with fewer gender-related differences in numbers of siblings, and a clear secular increase in body size in this community among children entering primary school from 1982 to 1986 suggest a possible explanatory model.     

男性青少年脂肪组织分布与相对骨龄的关系——Fels追踪研究

本文对Fels追踪研究中8—17岁男性青少年的相对骨龄与脂肪分布类型之间的关系做了分析。按体重/身高~2调整后,如用每个年龄的三种皮褶厚度(ST)指数的均值表示脂肪分布类型的话,8—12岁时,脂肪分布类型呈外周型分布,但13岁后开始朝向心型发展呈全身性分布。如用肩胛下ST/(肩胛下ST+肱三头肌区ST)的比例表示的话,那么14—17岁时,相对骨龄早者(简称早组)与相对骨龄晚者(简称晚组)相比,前者有较明显的向心型分布倾向。13—14岁时,早组的上述比值的年增长明显大于晚组。但是,按脂肪分布类型指数等级的基线和体重/身高~2调整之后,7、11或14岁时的相对骨龄不能预测17岁时的脂肪分布类型指数的等级。所以,我们可以得出这样的结论:如按本文的比例指数加以定量的话,脂肪分布类型与男性青少年的相对骨龄只有微弱的关系。他们的脂肪分布类型可能与其它成熟指征(如男性青春期的第二性征)有明显的关系。     

Inbreeding effects on the growth in stature among Telaga boys and girls of Kharagpur, West Bengal, India

The present study is an attempt to understand the genetical effects of inbreeding on the process of growth. The inbred and non-inbred subjects were selected on the basis of extensive pedigrees of five generations in the Telaga, an endogamous population of Kharagpur, India. Preference was given to cousins belonging to the same kindreds while selecting control sample so that environmental variation was minimized. Altogether 633 boys and 614 girls of different inbreeding levels aged five to twenty years were measured for stature. Analysis has been done in different levels of inbreeding in each age and sex on mean annual increments and variances of increments. The results revealed that comparison of annual increment for each age between boys and girls with different degrees of inbreeding and application of the one-tailed t-test of significance does not provide any evidence of inbreeding effect on mean increment for stature studied in either sex. This might indicate the absence of marked dominant/recessive effects of genes determining annual increments in body size rather than the absence of genetical control of increments due to growth. Moreover, it is noteworthy that the variance of annual increment due to growth (which is estimated indirectly) consistently increases with increase of inbreeding level with only a few exceptions. The exceptions occur more often in girls than in boys, which can be explained by greater environmental stress and selection pressure and variation in X-linked inbreeding among girls. This would be worthwhile to verify in longitudinal growth data in future. Increased variances of annual increment with inbreeding, in the absence of change of mean increment on inbreeding, would indicate the influence of additive autosomal genes for the process of physical growth in children in either sex. A close scrutiny of the annual increments for the measurements in all the four levels of inbreeding in either sex fails to bring out any consistent trend of change in the age of adolescent spurt with inbreeding. This might suggest an underlying homozygosity of several genes with inbreeding in the population.     

Roentgenographic and direct measurement of femoral cortical involution in a prehistoric Mississippian population

Recent roentgenographic studies suggest that periosteal apposition adds femoral cortical bone faster than it is lost by endosteal involution, so that cortical bone area increases with age. A comparison was made of direct and roentgenographic measurements of femoral cortical bone using femora from 23 females and 20 males of a prehistoric Mississippian population dated at A.D. 1540–1700. The comparison revealed that significant errors existed in the technique of radiographic measurement (p<0.000001), in estimating male and female cortical thickness (p<0.000001), and the changes in thickness with age (p<0.000001). There was no significant interaction of the variables: age, sex, and method. The errors arose partly from the inability of the roentgenograph to reveal clearly endosteal porosity, and partly in the assumption that the medial and lateral cortical wall thickness would be representative of the mean cortical thickness. The reduction in cortical thickness (11.3% males and 29.3% females) with age as measured directly is comparable with loss in modern populations.     

Sex differences in the cross-sectional areas of psoas major and thigh muscles in high school track and field athletes and nonathletes

The present study aimed to examine the sex differences in the cross-sectional areas of the psoas major, quadriceps femoris, hamstrings, and adductors in high school track and field athletes and nonathletes. The cross-sectional areas of the psoas major at L4-L5 and three thigh muscles at the mid-thigh were determined in the right side of the body using magnetic resonance imaging in 61 sprinters (29 boys and 32 girls), 50 jumpers (28 boys and 22 girls), 33 throwers (18 boys and 15 girls), and 40 nonathletes (20 boys and 20 girls), aged from 16 to 18 yrs. On the whole, the cross-sectional area for every muscle group was greater in the athletes than in the nonathletes and in the boys than in the girls. The average value of the cross-sectional area for the girls as a percentage of that for the boys in every subject group was lower in the psoas major (57.6-64.7%) than in the thigh muscles (67.8-82.9%). Among the thigh muscles, the muscle group which showed significant sex differences in the ratio of cross-sectional area to the two-third power of lean body mass was limited to the quadriceps femoris in the sprinters and nonathletes and hamstrings in the throwers. However, the ratio for the psoas major was significantly higher in the boys than in the girls in all subject groups. The current results indicate that, although regular participation in sports training during adolescence promotes hypertrophy in the psoas major and thigh muscles in not only boys but also girls, a greater sex difference exists in the muscularity of the psoas major than of the thigh muscles, in athletes and nonathletes.     

Standards of arm muscle by stature for the assessment of nutritional status of children

This study is based on a sample of 9,134 children ranging in age from 2 to 17 years from which the excessively lean and fat children by skinfold thickness were excluded. This sample was derived from the combined data sets of the first and second National Health and Nutrition Examination Surveys (NHANES I and II) of 1971-1974 and 1976-1980. Means and percentiles of upper arm muscle area were calculated for 3 cm increments in stature from 84 to 184 cm for boys and from 84 to 176 cm for girls. Based on means, Z-score units, and percentile ranges of upper arm muscle area by stature, five operational categories of nutritional status have been established. It is recommended that these standards and this classification system be used to supplement current standards of weight for age and weight for height in order to obtain a more complete assessment of body composition and nutritional status.     

Bone growth and mineralisation in children aged 4 to 10 years

The relationships between bone width and mineral content and age, sex, height and weight were studied in 420 children aged 4–10 years living in Cambridge using single photon absorptiometry. The relationship of bone width with bone mineral content was significantly different between the sexes after adjusting for differences in body size. In addition, bone width in boys was found to be greater for a given height and weight; changes in weight had a greater effect on bone width in boys than in girls. Prediction equations for bone width and mineral content based on height and weight are given, which should enhance the application of single photon absorptiometry in clinical practice.     

Physical fitness of children aged 5 and 6 years

Maximal oxygen uptake (Vo2 max) of 85 healthy kindergarten children, 46 boys and 39 girls, aged 5 and 6 years, was determined by means of track running. Their physique, skinfold thickness, grip and back muscle strength, and performances of 25 m-run, 50 m-run, standing broad jump, and 5 min-endurance run were also measured. Skinfold thickness of girls was significantly larger than that of boys. Boys were significantly superior to girls in all the motor performances. The Vo2 max per unit of body weight was 49.46 ml/kg/min for boys and 46.30 ml/kg/min for girls, the sex difference being significant at the 0.001 level. The correlation coefficient between Vo2 max per kg body weight and 5 min-endurance run performance was 0.417 for boys and 0.049 for girls, while that between absolute Vo2 max and body weight was 0.899 for boys and 0.563 for girls. The regression equation of the absolute value of Vo2 max (liter/min) on body weight (kg) was: Y=0.051X-0.025 for boys and Y=0.024 + 0.408 for girls, the regression coefficient of boys being twice as large as that of girls. It appears that at ages 5-6 sex differences are exhibited ont only in muscle strength and agility but also in endurance run and aerobic work capacity.