Features of the circadian rhythm of temperature of the skin at children of 8-9 years and young men and girls

Problem of the present work was studying age features circadian rhythm of temperature of a skin with application of a method "Termochron iButton". Day-night rhythm of a skin temperature at two age-grades was investigated: boys and girls of 8-9 years and young men and girls of 20-22 years. For this purpose monitoring temperature during 48 hours with an interval of registration 10 minutes has been lead. Are revealed authentic chronobiological differences: mesor temperatures above at girls, than at boys, and at young men, above, than at girls. Amplitude of a circadian rhythm is above at boys and at girls. Researches chronobiological parameters in the different terms of day have shown, that an average level of temperature at night below at all examinees. The amplitude at adult people in the different terms of day does not differ, while at children it above in the night term.     

芜湖市284名小学生生长发育的追踪研究

本文报道了1992年10月— 1997年10月对芜湖市284名 6—11岁汉族小学生生长发育的追踪调查结果。调查指标为身高、体重、胸围、脉搏和肺活量。对形态发育指数进行了分析。分析了男女间的差异。并与汉族 1985和1986年均值和日本人数据进行了比较。对当前儿童少年生长发育加速趋势也进行了讨论。     

Prevalence of the fragile X syndrome in four birth cohorts of children of school age

Summary The prevalence of the fragile X syndrome among 12,882 children (6594 boys and 6288 girls) born during the years 1969–1972 in Kuopio province in eastern central Finland has been studied retrospectively. Mentally retarded children were selected from normal schools by using school achievement tests and from registers of mentally retarded individuals. In the present study fragile X syndrome was found in 6/111 mentally retarded children (5.4%), in 4/61 boys and in 2/50 girls, respectively. It was not detected in the control group of 85 healthy children. The corrected prevalence of fragile X syndrome among boys in four successive birth cohorts was estimated to the 1 in 1210 or 0.8/1000, and that among girls, 1 in 2418 or 0.4/1000. The overall prevalence was calculated to be 1 in 1612 or 0.6/1000 children.     

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.     

Cross-sectional comparisons of BMI and waist circumference in British children: mixed public health messages

Research suggests that there has been a leveling off in obesity prevalence occurring in the child population. However, a concern with the evidence base is that all of the studies have relied upon the use of BMI. The purpose of this study was to compare waist circumference (WC), BMI, and waist-to-height ratio (WHtR) data in three different sample of children (total number: 14,697) typically aged 11-12 years. Obesity prevalence defined by BMI did not change significantly between measurement years (2005 boys 20.6%, girls 18.0%; 2006 boys 19.3%, girls 17.3%; 2007 boys 19.8%, girls 16.4%). Obesity prevalence defined by WC was considerably higher especially, in girls (2005 boys 26.3%, girls 35.6%; 2006 boys 20.3%, girls 28.2%; 2007 boys 22.1%, girls 30.1%). The prevalence of children defined as "at risk" according to WHtR (2005 boys 23.3%, girls 21.1%; 2006 boys 16.7%, girls 15.6%; 2007 boys 17.6%, girls 17.2%) was found to be between obesity prevalence, estimated using BMI and WC. This data are the most up to date collection that includes BMI and WC in three large samples of children and clearly demonstrates inconsistencies between different measurements based on current classification systems. There is a need to understand the relationship between BMI and WC, with growth and health risk to establish a consistent public health message that is easily understood by the public.     

Prepubertal Asians have less limb skeletal muscle.

Skeletal muscle mass in prepubertal Asian children has not been examined previously. The aims of this study were to test the hypotheses that 1) prepubertal Asians have less appendicular skeletal muscle (ASM) mass compared with African-Americans and Caucasians, and 2) ASM is less in prepubertal Asian girls compared with Asian boys. ASM was estimated by using dual-energy X-ray absorptiometry in healthy prepubertal girls (n = 170) and boys (n = 166). The results showed that, after adjusting for age, height, and body weight, 1) Asian girls and boys had less amounts of ASM than African-Americans (P < 0.001); 2) Asian girls had less amounts of ASM than Caucasian girls (P = 0.004); 3) there was a trend towards less ASM in Asian compared with Caucasian boys (P = 0.07); 4) and Asian girls had significantly less ASM than Asian boys (P < 0.001). This study indicates that skeletal muscle mass as a fraction of body weight is smaller in Asian compared with African-American and Caucasian children.     

Hyperinsulinemia in pre- and post-pubertal children born small for gestational age

BACKGROUND: Reduced fetal growth is a potential risk factor for development of metabolic abnormalities in later life. The relationship between low birthweight and impaired glucose tolerance, type 2 diabetes and insulin resistance in adulthood has been well documented. PURPOSE: Assuming that fetal undernutrition is associated with insulin resistance in middle age, we elected to study whether this process may already be present in young adults and adolescents born small for gestational age (SGA). SUBJECTS AND METHODS: Children born in Vall d'Hebron Hospital Infantil, Barcelona, between 1986 and 1989 and between 1978 and 1983 with birthweights below the third centile for the local standard values, were invited to participate in the present study. Of those, 51 (22 girls and 29 boys) were pre-pubertal with 9.4 +/- 0.2 years of age and 49 (29 girls and 20 boys ) were post-pubertal, with 17.3 +/- 0.3 years of age. All patients underwent a standard, 2-hour oral glucose tolerance test. Insulin and glucose responses were compared with our previously published data in control children with normal birthweight. RESULTS: The insulin response at 30 min after glucose load was significantly higher (p < 0.001) in pre- and post-pubertal girls and boys formerly SGA than in controls. In addition, the girls also had a higher insulin response at 60 and 120 min. Mean serum insulin (MSI), the area under the insulin curve during the glucose challenge, was statistically increased in pre- and post-pubertal boys and girls born SGA when compared to controls. CONCLUSION: The presence of high insulin levels after an oral glucose challenge in children and adolescents born SGA might be considered as an early marker of subsequent insulin resistance in adulthood. Furthermore, our population offers the opportunity to study the natural course of hyperinsulinemia and its outcome. Follow-up of this cohort may be helpful in distinguishing a subset of young children and adolescents in whom therapeutic intervention could be done.     

游泳训练对儿童最大有氧活动能力的影响

本文利用步行机对９１名８－１１岁男女儿童进行最大有氧活动能力的测试,其中训练组４２人选自北京市海滨区业余游泳队的儿童,对照组４９人（男２４人,女２５人）选自与训练组儿童条件相近的普通学校学生。观察９个月的游泳训练对儿童有氧活动能力的影响。研究结果表明,训练组儿童的身高,体重,瘦体重和肺活量在观察前及观察后的两次测试中均高于对照组。观察期间形态指标的增长值和两组值在两组间大都无明显差别,表明两组儿童     

Validation of two running tests as estimates of maximal aerobic power in children

In order to validate the "Maximal Multistage 20 Meter Shuttle Run Test" by Leger and Lambert (1982) (20-MST) as an estimate of maximal aerobic power (VO2max) and to compare the results of this test with the results of a 6 min endurance run, 82 subjects (41 boys and 41 girls) aged 12-14 performed the 20-MST and the 6 min endurance run, and had their VO2max directly measured during maximal treadmill running. The 20-MST is a maximal running test starting at a running speed of 8.0 km X h-1, which is increased every minute and in which the pace is set by an audio signal. Performing the test, one runs a 20-meter course back and forth. The test result is expressed as "palier" (one palier is approximately one minute). The mean results of the 20-MST were, for boys, 8.0 palier (+/- 1.7) and for girls, 6.4 palier (+/- 1.5). The mean results of the 6 min endurance run were for boys, 1264.4 meters (+/- 160.8), and for girls, 1103.9 meters (+/- 144.7). The mean VO2max for boys was 53.2 ml X kg-1 X min-1 (+/- 5.4) and for girls, 44.1 (+/- 4.8) ml X kg-1 X min-1. The correlation coefficient between VO2max and the 20-MST was found to be 0.68 (+/- 3.9) for boys, 0.69 (+/- 3.4) for girls and 0.76 (+/- 4.4) for both sexes, and that of VO2max with the 6 min endurance run was 0.51 (+/- 4.6) for boys, 0.45 (+/- 4.3) for girls and 0.63 (+/- 5.3) for both sexes. The conclusion is that the 20-MST is a suitable tool for the evaluation of maximal aerobic power. Although the differences in validity between the 20-MST and the 6 minutes endurance run were statistically not significant (p greater than 0.05), for reasons of practicability the 20-MST should be preferred to the 6 minutes endurance run when used in physical education classes.     

Autonomic Regulation of Heart Rate and Distinctive Features of Oculomotor Activity in Eight- to Nine-Year-Old Boys and Girls during the Reading of Texts of Different Complexities

Distinctive features of autonomic regulation of the heart rate and spatiotemporal parameters of eye movements during the reading of texts of different complexities levels from a computer screen have been analyzed in girls and boys eight to nine years of age. Sex-related differences in heart rate variability (HRV) pattern were already observed in the resting state, since parasympathetic effects were stronger in boys than in girls. Parasympathetic activity decreased in boys who were reading texts of different complexities. The most pronounced decrease was observed during the reading of the first (simple) text. The changes in girls were mostly due to an increase in sympathetic activity and were less pronounced than in boys. Oculomotor activity analysis revealed differences in reading process strategy: reading was more fragmented (discrete) in the girls and more integrated in the boys. However, reading skills were not fully developed in children of eight to nine years of age, since “syllabized” reading was observed in girls and boys alike.     

Growth attainments of well-off chandigarh children: A mixed longitudinal study

Distance and velocity pattern of growth for body weight and height of 134 well-off Chandigarh boys aged 9–17 years, and 109 girls aged 9 to 16 years were studied following a mixedlongitudinal growth study design. For both body weight and height pattern-wise, Chandigarh boys showed close similarity with their American counterparts up to about 13 years of age, while girls did so till 12 years. Where after, Chandigarh children remained lighter and shorter than those of American origin and this differential may be explained on racial grounds rather than nutritional ones since all children included in this study remained free from dietary and other health related constraints. Marginally, higher height growth attainments noticed in Chandigarh children in contrast to their other Indian counterparts during initial years of adolescence shows that Chandigarh children are in process of expressing their genetic growth potential to its full which has not yet been fully achieved. The rate (velocity) of weight and height growth in Chandigarh children remained substatially lower than their sex-matched British counterparts throught the period of study. PHV in boys measured 6.4 cm/yr. and 5.4 cm/yr. in girls. It was attained at the age of 11.5 years in girls and 12.5 years in boys. Peak weight velocity in boys averaged 3.7 kg/yr., while it measured 4.6 kg/yr. in girls. In girls (11.5 yr.), PWV too was attained earlier than boys (13.5 yr.) by two years. The shorter height and lighter weight growth attainments noticed in Chandigarh children in contrast to their Western counterparts may be attributed to slower and lesser magnitude peak growth velocities recorded in Chandigarh children. The use of values presented has been recommended to monitor and assess growth attainments of Indian children residing in the Union Territory of Chandigarh.     

Diagnostic utility of a low-dose gonadotropin-releasing hormone test in the context of puberty disorders

OBJECTIVES: The 10-microg gonadotropin-releasing hormone (GnRH) test assesses pituitary gonadotroph responsiveness, whereas the 100-microg dose assesses maximal secretory capacity. Our aims were to establish normative data for the low-dose test in children and to evaluate the test in diagnosing common pubertal disorders. METHODS: We retrospectively classified 107 children who underwent 10-microg GnRH tests into normal prepubertal (20 boys, 10 girls), normal early pubertal (10 boys, 16 girls), constitutional delay of puberty (CDP, 13 prepubertal boys >12 years), hypogonadotropic hypogonadism (HH, 5 prepubertal boys >12 years), central precocious puberty (CPP, 19 girls) or premature thelarche/variant (13 girls). RESULTS: Peak LH response was higher in prepubertal boys >12 years compared with younger boys (p < 0.01) but showed no further change in early puberty. CDP boys had LH responses similar to prepubertal boys >12 years. HH boys showed an absent LH response which diagnosed HH with 100% sensitivity and 96% specificity. Thelarche girls had LH:FSH peak ratios lower than normal prepubertal (p = 0.001), pubertal (p < 0.05) or CPP (p = 0.001) girls. CONCLUSIONS: We have established normative values for the low-dose GnRH test in children. The test successfully differentiated HH from CDP in boys, and contributed to the differential diagnosis of CPP and premature thelarche in girls.     

Prevalence of overweight and obesity among the affluent adolescent school children of Amritsar, Punjab

In the present study, an attempt has been made to assess the prevalence of overweight and obesity in adolescent children (between 10-15 years of age) of the affluent families of Amritsar district of Punjab, a state in rapid economic and epidemiological transition. A total of 640 children (323 boys and 317girls) were measured for height and weight. Overweight and obesity were assessed using age and sex-specific body mass index (BMI) cut-off points. 9.91% boys and 11.99% girls were overweight, and 4.95% boys and 6.31% girls were obese. The prevalence of overweight and obesity among the affluent children in Amritsar was as high or higher as in some industrialized countries.     

Spatial Synchronization of Brain Bioelectric Potentials Differs in Boys and Girls Aged 12–13 Years Reading Narrative Texts

The contribution of each cortical zone to the organization of spatial synchronization of brain bioelectric potential s (SSBP) was estimated using cross-correlation matrices of 20-channell EEG during reading in boys and girls aged 12–13 years. Differences in the topical distribution of the SSBP levels in young boys and girls were revealed both in the resting state and during reading. In boys, the SSBP level in the left temporal lobe was lower than that in girls, and in the right parietal lobe it was higher than that in girls in all the states studied. A decrease of SSBP in central cortex zones was revealed, indicating the activation of motor cortical areas in all subjects during reading. Enhancement of SSBP in the parietal regions of the left hemisphere and the occipital zones of both hemispheres is observed in boys during reading, while in girls SSBP is increased bilaterally in the frontotemporal areas with the involvement of the left frontal lobe. Moreover, during reading intrahemispheric correlations between EEGs of the central and temporoparietal regions with emphasis on the right hemisphere were more pronounced in boys, while both intra- and interhemispheric correlations of the left temporal regions were pronounced in girls.     

Gender differences in nutritional behavior and weight status during early and late adolescence

The current study aimed to determine gender differences in nutritional habits, eating behaviour, weight status, body image and weight control practices during early and late adolescence. 677 Viennese pupils (253 boys and 424 girls) between the ages 10 and 18 years (x = 14.1 yrs; +/- 2.2) were enrolled in the study. Weight status was determined by means of body mass index percentiles. To assess eating behavior, food preferences, body image and weight control practices, a 48 item questionnaire was developed. Significant gender differences in weight status were observable during late adolescence only. Girls are significantly less satisfied with their body weight. Furthermore, girls practice dieting and weight control to avoid any weight gain more frequently than boys. Gender differences in eating behavior intensified from early to late adolescence. From early to late adolescence, meal size decreased among girls, while it remains stabile or increased among boys. Boys eat generally more than girls. Furthermore, boys preferred meat and fast food while girls consumed fruits, vegetables and healthy food significantly more frequently. These gender differences are explained by gender specific energetic demands and culture typical beauty ideals.     

Understanding the Influence of Race/Ethnicity,Gender, and Class on Inequalities in Academic and Non-Academic Outcomes among Eighth-Grade Students: Findings from an Intersectionality Approach

Socioeconomic, racial/ethnic, and gender inequalities in academic achievement have been widely reported in the US, but how these three axes of inequality intersect to determine academic and non-academic outcomes among school-aged children is not well understood. Using data from the US Early Childhood Longitudinal Study—Kindergarten (ECLS-K; N = 10,115), we apply an intersectionality approach to examine inequalities across eighth-grade outcomes at the intersection of six racial/ethnic and gender groups (Latino girls and boys, Black girls and boys, and White girls and boys) and four classes of socioeconomic advantage/disadvantage. Results of mixture models show large inequalities in socioemotional outcomes (internalizing behavior, locus of control, and self-concept) across classes of advantage/disadvantage. Within classes of advantage/disadvantage, racial/ethnic and gender inequalities are predominantly found in the most advantaged class, where Black boys and girls, and Latina girls, underperform White boys in academic assessments, but not in socioemotional outcomes. In these latter outcomes, Black boys and girls perform better than White boys. Latino boys show small differences as compared to White boys, mainly in science assessments. The contrasting outcomes between racial/ethnic and gender minorities in self-assessment and socioemotional outcomes, as compared to standardized assessments, highlight the detrimental effect that intersecting racial/ethnic and gender discrimination have in patterning academic outcomes that predict success in adult life. Interventions to eliminate achievement gaps cannot fully succeed as long as social stratification caused by gender and racial discrimination is not addressed.     

Age-dependent heart rate variability in preschool children living under the conditions of the European Arctic region

The results of analysis of specific characteristics of the heart rate variability (HRV) regulation in preschool children living under the Arctic high-latitude conditions are presented. The principal ageand gender-specific differences in the HRV regulation have been inferred from the intergroup evaluations of the HRV indicators in boys and girls. A functional developmental delay has been shown in 2.5-year-old girls compared with boys of the same age group. The applied orthostatic test has shown lower reserve capacities in children of the senior group compared with the junior group. It has been shown that the mechanisms of the regulation of cardiac rhythm in girls experience higher strain during orthostasis as compared with boys. The division of children into age groups with an age difference of one year has allowed the detection of the tendency towards basically different responses to functional loads during orthostasis. The mean HRV values characteristic of four- to six-year-old children living in the Arctic are presented. It has been shown that the children living at middle latitudes have a higher adaptive potential compared with the children living in high-latitude Arctic areas.     

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.     

Scaling peak VO2 to body mass in young male and female distance runners.

This study examined age- and sex-associated variation in peak oxygen consumption (VO2) of young male and female distance runners from an allometric scaling perspective. Subjects were from two separate studies of 9- to 19-yr-old distance runners from the mid-Michigan area, one conducted between 1982 and 1986 (Young Runners Study I, YRS I) and the other in 1999-2000 (Young Runners Study II, YRS II). Data from 27 boys and 27 girls from YRS I and 48 boys and 22 girls from the YRS II were included, and a total of 139 and 108 measurements of body size and peak VO2 in boys and girls, respectively, were available. Subjects were divided into whole year age groups. A 2 x 9 (sex x age group) ANOVA was used to examine differences in peak VO2. Intraindividual ontogenetic allometric scaling was determined in 20 boys and 17 girls measured annually for 3-5 yr. Allometric scaling factors were calculated using linear regression of log-transformed data. Results indicated that 1) absolute peak VO2 increases with age in boys and girls, 2) relative peak VO2 (ml x kg(-1) x min(-1)) remains relatively stable in boys and in girls, 3) relative peak VO2 (ml x kg(-0.75) x min(-1)) increases throughout the age range in boys and increases in girls until age 15 yr, and 4) peak VO2 adjusted for body mass (ml/min) increases with age in boys and girls. The overall mean cross-sectional scaling factor was 1.01 +/- 0.03 (SE) in boys and 0.85 +/- 0.05 (SE) in girls. Significant age x sex interactions and significant scaling factors between sexes identify the progressive divergence of peak VO2 between adolescent male and female distance runners. Mean ontogenetic allometric scaling factors were 0.81 [0.71-0.92, 95% confidence interval (CI)] and 0.61 (0.50-0.72, 95% CI) in boys and girls, respectively (P = 0.002). There was considerable variation in individual scaling factors (0.51-1.31 and 0.28-0.90 in boys and girls, respectively). The results suggest that the interpretation of growth-related changes in peak VO2 of young distance runners is dependent upon the manner of expressing peak VO2 relative to body size and/or the statistical technique employed.