Gender differentiations of cognitive-motor functioning in prepubertal and pubertal children

The aim of this study was to determine cognitive and motor status factors in female and male children aged 10-14, as well as developmental and/or integration functions according to gender. The study included 162 girls and 134 boys aged 10-14, divided into four groups: 84 girls aged 10-12 (mean age 11.26, SD 0.68), 84 boys aged 10-12 (mean age 11.41, SD 0.50), 78 girls aged 13-14 (mean age 13.52, SD 0.63) and 50 boys aged 13-14 (mean age 13.21, SD 0.53). The significance of quantitative differences between boys and girls in the overall system of variables was defined based on the results of canonic discriminant analysis of variance, and within each variable based on the results on univariate analysis of variance (ANOVA). In the younger age group (10-12 years), girls were superior to boys in a test assessing flexibility (Seated straddle stretch), whereas, compared to girls, boys had greater strength of the trunk (Crossed-arm sit-ups), greater explosive strength ofjump and sprint type (Standing broad jump and 20 m dash), and coordination (Obstacle course backwards and Steps laterally). In the older age group (13-14 years) differences in flexibility were even more prominent in favor of girls, whereas the differences in explosive strength increased in favor of boys, especially of the throwing type with better agility (Steps laterally), balance (Board balance) and greater static strength of arms and shoulders (Bent-arm hang). In order to determine qualitative differences between pubertal and prepubertal girls and boys, the matrix of variable inter-correlations was factorized by the procedure of principal components procedure, that were then transformed to promax solution. The results showed that cognitive functioning had a significant role in the motor efficacy of girls and boys aged 10 to 14. In the age group of 10-12 years, in females, cognitive functioning is related to the motor system which integrates the regulation of muscle tone with agility/coordination, whereas in males there is a relation between cognitive abilities and the regulator of speed of upper extremities movement frequency. In the age group of 13-14 years, in females, cognitive functioning is involved in forming the factors for regulation of coordination and the intensity of energy mobilization in lower extremities, and to some degree, in the factor for regulation of intensity of energy mobilization in upper extremities and strength of the trunk, whereas in males the integration of synergetic regulation of movement in terms of balance and agility in terms of speed of direction change is carried out with significant involvement of cognitive abilities.     

Activity pattern, smoking habits, and somatometric variables of the Czechoslovakian population

A total of 3762 subjects of both sexes, natives of Czechoslovakia, ranging in age from 12--55 years, were examined. Both anamnestic data and selected anthropometric variables were evaluated. The proportion of non-smokers for adult males was 47--56%, and for adult females was 54--74% of the population. The proportion of subjects not engaged in any type of physical activity decreases in boys between 12 and 18 years from 28 to 16%, in girls between 12 and 15 years from 25 to 22%; from then on the trend reverses and the percentages rises up to 42% in men and 65% in women. The number of subjects participating in competitive sporting activity reaches its peak at 18 years, when 46% of boys annd 43% of girls compete, but then decreases quickly. 12 year old girls are taller and heavier than boys but at 15 years the relationship is reversed. The LBM at the age of 12 is equal in boys and girls, but from then till 18 years the increase is larger in boys. The LBM weight in adults remains steady, women attaining 77% of the value found in men. The skinfold increases with age similarly in both sexes, except for an interval between 12 and 18 years, when girls show a steeper increase. Adult women attain 121--160% of the values characteristic for men. The grip strength of the right hand equals about 50 kp in adult men and 30 kp in adult women. Within the age range followed, it remains unaffected by age.     

Growth charts for Croatian school children and secular trends in past twenty years

The aim of this study was to construct new Croatian growth charts for body height and weight of boys and girls aged 6.5 to 18.5 years and to investigate differences between our and pre-existing studies. Analysis was based on a multistage stratified sample representative for school children aged 6.5 to 18.5, 6046 boys and 5656 girls. Growth reference was constructed using LMS method. Present results demonstrated an increment of body height and weight during the last two decades. Highest increase of body height is in boys aged 13-14 years 6.5 cm, in girls aged 12 years is 5.0 cm. Highest increase of body weight is in 16 year age group of boys 8.7 kg and in 11-12 year age group of girls 5.2 kg. In conclusion, regarding presence of secular trend because previously used growth charts in Croatia are obsolete.     

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.     

Causes of precocious puberty in children referred for evaluation in hospital conditions

INTRODUCTION: Symptoms of precocious puberty (PP) in children always arouse anxiety in their parents. Many children with PP are being hospitalized for the detailed diagnostic work-up. The aim of our study was to analyze the frequency of the variants of PP in children referred to our department. MATERIAL: Retrospective analysis of 119 children (103 girls and 16 boys) referred for hospitalization in the years 2003-2005 due to signs of precocious puberty was performed. RESULTS: Premature thelarche, benign variant of puberty, was diagnosed in 62 (53%) girls, in the mean age of 3.39 (+/- 2.33) years. Their mean height was within 0.7 +/- 1.1 SD. Premature pubarche was diagnosed 30 (25%) children--22 girls and 8 boys in the mean age was 7.24 (+/- 0.81) years. Their mean height was 1.3 +/- 1.0 SD and was significantly higher than normal (p < 0.0001). Premature menarche was diagnosed in 8 (7%) girls in the mean age 4.81 +/-2.26 years. Mean height in this group was normal for age (0.9+/-0.8 SD). PP was diagnosed in 19 (16%) children (11 girls and 8 boys) in the mean age 5.91 +/- 1.63 years. Mean height in this group was 1.6 +/- 0.7 SD, and was significantly higher than the mean for age (p<0.0005). GnRH-dependent type was present in 15 children, diagnosed as idiopathic in 9 girls and 1 boy. In 5 children (4 boys and 1 girl) pathology of central nervous system was found. In 4 children GnRH-independent precocious puberty was diagnosed--in 3 caused by congenital adrenal hyperplasia and in 1 boy by tumour of testis (leydigioma). CONCLUSIONS: Girls with precocious thelarche without growth acceleration present the benign variant of puberty and need clinical follow up only. Boys with clinical signs of precocious puberty should be carefully evaluated to rule out the organic cause.     

Changes in BMI and the prevalence of overweight and obesity in children and adolescents in Cracow, Poland, 1971-2000.

The aim of this study is to examine changes in prevalence of overweight and obesity, using International Obesity Task Force criteria, in three cohorts of children and youth living in Cracow, Poland, in 1971, 1983 and 2000. Rates of overweight and obesity doubled among boys and girls, from 7.5% and 6.5% in 1971, to 15.2% and 11.8% in the year 2000. The greatest increases in prevalence occurred in the youngest age groups (7-12 years for boys and 7-10 years for girls), increases being less extensive among adolescents, and lowest of all in the oldest age groups (16-18 years in boys and 14-18 years in girls). The absence of a positive secular trend in BMI among adolescent females relative to males may be due to sociocultural pressures associated with transition to a free market economy in Poland. The extent to which girls attempt to achieve the ideal body, as portrayed by media and society more generally, increases across adolescence.     

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.     

A factor analysis of cranial base and vault dimensions in children

Lengths within the cranial base and vault were measured in cephalometric radiographs of 220 boys and 177 girls ranging in age from 0 to 15 years; all these children are participants in The Fels Longitudinal Growth Study. The present study is based on mixed longitudinal data derived from 1640 radiographs for boys and 1260 radiographs for girls. Factor analysis was applied separately for boys and girls for each age group; i.e., 0–3, 4–6, 7–9, 10–12, and 13–15 years. For the 0–3 year age group, two factors were extracted in each sex, whereas four factors were extracted in the rest of the age groups. The factor structures are similar in the three older age groups of boys (7–9, 10–12, and 13–15 years). The first four factors for these groups are labelled, respectively: cranial vault size, posterior cranial base length, presphenoid length, and basisphenoid length. The order of the third and fourth factors is reversed in the 7–9 year olds. For girls, the factors extracted were also the same in both the 7–9 and 10–12 year age groups, even though the order of factors was different between age groups; i.e., anterior cranial base length, cranial vault size, basisphenoid length, and basioccipital length. Differential growth rates among cranial base dimensions probably cause changes in factor patterns. Obliteration of the spheno-occipital synchondrosis is suggested as the mechanism responsible for the change of factor pattern in the girls. Closure of this synchondrosis would have occurred too late to affect the patterns in boys.     

Age- and gender-related development of stretch shortening cycle during a sub-maximal hopping task

The aim of this study was to analyse the effects of age and gender (and their interaction) on a stretch shortening cycle solicited during a hopping task. For this aim, 147 girls and 148 boys aged 11 to 20 years, who were enrolled in middle school or secondary school with no experience in sport activity, or training less than three times per week, performed 3×5 hops in place. Leg-stiffness, jump-height and reactive-strength indices were assessed using an accelerometer (Myotest). The participants were selected in order to form five age groups: 11 12, 13-14, 15-16, 17-18 and 19-20 years. Regression analysis between force and centre of mass displacement revealed spring-mass behaviour for all groups (r²=.73-.89), meaning that beginning at the age of 11 years, children are able to perform complex inter-muscular coordination of the lower limbs, revealing efficient neural control early in childhood. Leg stiffness increased from 24.7 ± 10.6 kN · m⁻¹ at 11-12 years to 44.1 ± 14 kN · m⁻¹ in boys, with a small increase until 16 years (+17%) and a large increase between 17 and 20 years (+32.7%). In girls, leg stiffness increased from 26.6 ± 9 kN · m⁻¹ at 11-12 years to 39.4 ± 10.9 kN · m⁻¹ at 19-20 years, with a curious decrease in leg stiffness at 17-18 years, probably due to an increase in the percentage of fat at this age (25%). While no gender effect was found, the reactive-strength index revealed that, from 15-16 years onward, boys were better able to produce high levels of force in a shorter time than girls. The age of 15-16 years is a threshold of maturity and gender differentiation, where the boys investigated are more efficient in the stretch shortening cycle.     

Gender-specific growth patterns of transversal body dimensions in Croatian children and youth (2 to 18 years of age)

In a cross-sectional study of growth, 5,260 healthy children of both sexes from Zagreb (Croatia) aged 2 to 18 years were measured. Six transversal body dimensions were studied: biacromial, transverse chest, antero-posterior chest, biiliocristal, bicondylar humerus and bicondylar femur diamters. A significant increase in body diameters has been observed until the age of 14 to 15 in girls and until the age of 16 in boys, showing that girls have a 1 to 2 years shorter period of growth. Compared to boys of the same age, they achieved larger amounts of final transversal bone size throughout the whole growth period. The most pronounced example was the knee diameter that in girls attained 95% of adult size as early as the age of 10. In both genders, the adult size is achieved earlier in widths of the extremities than in those of the trunk. The studied transversal body segments showed different growth dynamics, which is gender-specific. While sexual dimorphism in pelvic and shoulder diameters emerged with pubertal spurt, gender differences in chest and extremities' diameters started early in life. In all ages, boys had larger chest, elbow and knee diameters. In pubertal age boys gained a significantly larger biacromial diameter (from the age of 13 onwards), while girls exceeded them in biiliocristal diameter (from 10 to 14 years). The findings of gender differences were compared to those reported for other European populations and their growth patters were discussed comparing viewpoints.     

Thyroid autoimmunity in children and adolescents with type 1 diabetes mellitus. Effect of age, gender and HLA type

Type 1 diabetes is often associated with additional autoimmune phenomena. However, data reported on the frequency of thyroid autoimmunity differ vastly. Therefore, the prevalence of thyroid autoantibodies was evaluated at a large pediatric diabetes center in Southern Germany. 2,305 determinations (TPO and TG, ELISA) were performed in 495 patients with type 1 diabetes (234 boys, 261 girls; age at last measurement: 15.4 +/- 0.3 years, duration of diabetes 7. 5 +/- 0.2 years). The prevalence of elevated thyroid antibodies increased dramatically with age: from 3.7% in patients less than 5 years of age up to 25.3% in the age group 15-20 years (p < 0.0001). For children older than 10 years, girls were significantly more affected than boys (p < 0.0001). Thyroid autoimmunity tended to be more prevalent in the subgroup of patients with the HLA type DR3/DR4 compared to patients with other HLA types (p = 0.08). In children older than 10 years, basal TSH concentrations were significantly elevated in antibody-positive patients (p < 0.05). In conclusion, thyroid autoimmunity is prevalent in children and adolescents with type 1 diabetes. Adolescent girls and young women are especially affected. Yearly routine determinations of thyroid antibodies are therefore recommended.     

Habitual level of physical activity and cardiorespiratory endurance capacity in children

A total of 257 healthy children (140 boys, 117 girls) varying in age from 5.7 to 18.5 years underwent graded exercise tests on a treadmill. Cardiorespiratory endurance capacity was assessed by determination of the ventilatory threshold, which was defined as the highest exercise intensity before a disproportionate increase occurred in pulmonary ventilation (VE) relative to oxygen uptake (VO2). The purpose of the present study was to investigate the relationship between the habitual level of physical activity (HLPA) and the cardiorespiratory endurance capacity in children. The HLPA was assessed by a standardized questionnaire. In boys and girls HLPA increased gradually with advancing age. For the group as a whole, the boys reached the highest values for HLPA. The most active boys reached the highest value for ventilatory threshold and the lowest value was found in the less active ones, except for the age span of 12-16 years. It is concluded that more active boys showed a higher cardiorespiratory endurance capacity, as assessed by the ventilatory threshold, compared to less active ones, except during puberty. It can be postulated that during puberty this effect may be overruled by the influence of other more dominant growth-related factors. In girls, because HLPA was rather low, there was no discriminative effect of HLPA on exercise performance, as would be expected.     

Plasma dehydroepiandrosterone, its sulfate, testosterone and FSH during puberty of African children in Gabon

Plasma levels of dehydroepiandrosterone (DHEA), its sulfate (DHEAS), testosterone (T) and follicle stimulating hormone (FSH) were measured by radioimmunoassay in 111 schoolboys and 95 schoolgirls from 7 to 18 years. 68 male and 55 female adults aged from 19 to 25 were also investigated. Results are expressed as the mean +/- SD, DHEA was the first hormone to vary showing a significant mean increase between the 10 and 11 year age groups of both boys and girls. Higher levels were observed in the age 12 group (boys 164.70 +/- 60.74; girls 256.60 +/- 145.40 ng/dl) but were followed by a significant decrease in both 13 year old groups. Similar increases followed by decreases were also noted for DHEAS, although the increase started between 11 and 12 years and reached a maximum at 13. An abrupt increase in FSH levels between 11 and 12 years followed by a plateau through 15-18 years, was observed for boys and girls. As expected, T levels increasing significantly in boys with the initial rise between 11 and 12 and a climb through to the 15-18 age group. Our results suggest a late plasma DHEAS secretion with adult levels attained after age 19. Menarche was also found to be late.     

Ethnic and secular influences on the size and maturity of seven year old children living in Guatemala City

Three groups of children, those of European parentage, those of Guatemalan parentage, and those of mixed European-Guatemalan parentage were measured for height, weight, and skeletal maturity. The children were born between 1945 and 1965, they were all of high socioeconomic status, and they all attended the same private school in Guatemala City. At 7 years, the boys of the European group were significantly taller than boys of the Guatemalan group. European and mixed European-Guatemalan girls were significantly taller than Guatemalan girls. These results are maturity independent. The influence of skeletal age was removed statistically by analysis of covariance. Girls of the mixed group were significantly heavier than girls of European and Guatemalan groups. Mixed group girls also had more significantly advanced skeletal ages than European girls. When the patterns of size and maturity status are analyzed by sex, there is evidence for a relatively greater environmental influence on the boys and a relatively greater genetic influence on the girls. Dividing the data into two birth year cohorts, 1945 to 1955, and 1956 to 1965, does not provide evidence for secular trends in growth or maturation. These results are similar to those from studies in developed nations that report an end to the secular trend for the “well off” population of those countries.     

The influence of incompetent lip seal on the growth and development of craniofacial complex

Abnormal orofacial functions in the period of growth and development can cause morphological anomalies of the craniofacial complex. The aim of this study was to determine the correlation between open mouth posture and morphology of craniofacial complex. The shape, size and relationships of skeletal parts of craniofacial complex were determined by analysis of lateral cephalograms in the sample of 84 children--45 girls and 39 boys (aged 8.96 +/- 0.66 years). The sample was divided into two groups--lip competence and lip incompetence group. Differences in cephalometric values between observed groups were found. The values of inclination of lower central incisors (angle ILi/NB), interbasal angle (NL/NSL), angle between occlusal and mandibular plane and anterior lower facial height were significantly higher in the group with open mouth posture. It can be concluded that lip incompetence plays an important role in growth and development of craniofacial complex.     

Gender-specific growth patterns for stature,sitting height and limbs length in Croatian children and youth (3 to 18 years of age)

In a cross-sectional study of growth, 5,155 children (2,591 females, 2,564 males) from the town of Zagreb (Croatia) were measured. Four traits of linear dimensionality (stature, sitting height, arm and leg lengths) were studied in the age span of 3 to 18 years. A significant average annual increase of all four anthropometric parameters were observed up to 14 and 15 years of age in girls and 16 years of age in boys, showing that girls had a shorter growing period. In the prepubertal period until 9 years of age, gender differences were negligible. At the age of 10, boys were overgrown by girls in all parameters due to the earlier onset of puberty in girls. The growth gains for girls, when compared with those for boys, show a different pattern across variables. The female growth advantage remained in a two years period for the limbs length, but in a three year period for stature and the longest, for 4 years, for sitting height. The male predominance in size had an onset at the age of 13 for the limbs and in the age of 14 for stature and sitting height. The patterns of sexual dimorphism in stature and sitting height during growing years are similar to those observed in other populations of Europe. Growth of Croatian children and youth is very similar to that of the tallest European populations.     

Comparison of the prevalence of type A behavior in boys and girls from two contrasting socioeconomic status groups

The prevalence of Type A behavior in children from lower-class rural and upper-class urban backgrounds was compared using the Hunter-Wolf A-B Self-Rating Scale (H-W A-B). Analyses of variance were performed for two levels of socioeconomic status (SES), two levels of race (black and white), two levels of gender, and two levels of age (9-11 and 13-14). A significant difference for SES was found in the predicted direction with a greater prevalence of Type A being found among upper-urban children (p less than .001). There was also a significant effect for race (p less than .0001). Although there was a significant effect for gender with boys scoring higher (p less than .001), there was no difference between boys and girls within either SES group, and both boys and girls in the upper-urban group were more Type A than boys and girls in the lower-rural group (p less than .001). The possibility that the lack of sex differences within groups may reflect changing lifestyles for young women is discussed as a topic worthy of further epidemiological investigation.     

Sex Differences and Activity of the Left and Right Brain Hemispheres

The problem is reviewed of sex differences and the brain organization of the visual-spatial and verbal-cognitive functions both in adults and in the 5–15-year old children. Characteristic of men are the integral strategy of the face image recognition, specialization of the right hemisphere for visual-spatial functions, and the tonic inhibitory effect of the right hemisphere on the left one. Typical of women are the fragmented type of the image recognition, the equality of the brain hemispheres functions at the unfamiliar face recognition, and predominance of the left hemisphere by accuracy of the object localization in the visual field. It is possible that the general strategy of the recognition in women is not realized due to the right hemisphere submitted to the interfering effect of the left hemisphere. Analysis of sex differences in distribution of verbal functions shows that the capability for the verbal learning at the age of 5 years and older is higher in girls than in boys. Such capability seems to be accounted for by the superiority of the left hemisphere in girls in this type of its activity and by its earlier development and maturation. The phenomenon of semantic paralexia appearing more often in boys is accounted for by inclusion of lexical-semantic fields of the right hemisphere symmetric areas in the verbal-cognitive activity There are reasons to believe that the higher capability in girls for the verbal learning is mainly due to processes of the auditory-verbal integration within the limits of the left hemisphere, whereas this verbal ability in boys depends on the relative predominance of the interhemispheric connections.     

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.     

Maxillary volume growth in childhood

Nasomaxillary abnormalities in form, position, and development in children are often prominent features of craniosynostosis, and in particular, craniofacial dysostosis. While attempting to quantitatively assess the volumetric maxillary deficiency in these patients, it became apparent that there was no "normal" reference range for maxillary volumes throughout childhood that could be used for comparison. The aim of this study was to generate a model for measuring maxillary volume and subsequent changes throughout childhood. The technique of segmentation was applied to magnetic resonance images obtained in 55 healthy children (30 boys, 25 girls), aged 1 month to 184 months (15.33 years). Maxillary volumes were plotted against age for boys and girls to create a model for normal maxillary growth during the first 15 years of life. Maxillary volumes were larger in boys at all ages. However, the pattern of maxillary growth in boys and girls was similar and could be divided into three periods, each lasting approximately 5 years. During the first 5 years of life, there is a steady increase in maxillary volume, at the end of which the maxilla has reached 53 percent of the volume recorded at 15 years. There is an accelerated rate of growth between 5 and 11 years, which corresponds to the development and eruption of the permanent dentition. Thereafter, until the age of 15 years, the rate of growth of the maxilla plateaus. Maxillary volume in the first 12 months of life is, on average, 29 cm3 in boys and 25 cm3 in girls. By 15 years of age, it has increased to an average of 73.0 cm3 in boys and 59.4 cm3 in girls (an increase by a factor of 2.5 in boys and 2.4 in girls). The difference between the two sexes is statistically significant for the entire series (boys: mean maxillary volume = 56.55 cm3, SD = 24.61; girls: mean maxillary volume = 40.68, SD = 17.69, p = 0.009, one-way analysis of variance).