Pressure-flow studies: an evaluation of within-testing reproducibility--validity of the measured parameters

Growth and maturation during adolescence has not been well described in rural African populations, although it may represent the missing link between high levels of preschool stunting and nearly 'normal' adult heights. In 1995 the homes of subjects aged 10.3-17.5 years, living in a rural area of Senegal, were visited, and all adolescents present, 1527 boys and 1126 girls, were included in the analysis. A number of girls were absent because they worked in the capital city Dakar. Resident girls (n = 705) had significantly higher means than boys for all anthropometric variables (weight, body mass index, arm circumference and muscle arm circumference, triceps and subscapular skinfolds), except for height and head circumference. Girls who had just returned from seasonal migration to Dakar (n = 415) were, on average, 2 kg heavier, but not taller, than resident girls (p < 0.0001). The girls fell off in height from 11 to 13 years compared to the NCHS reference and then 'caught up' until the age of 17, while boys fell off during the entire age span. Mean age at menarche was estimated at 16.1 years (95% fiducial CI: 15.8-16.4) from status quo data by probit analysis. No significant difference was found between residents and migrants. Postmenarcheal girls had better nutritional status than premenarcheal girls in terms of height, weight, body mass index, percentage body fat and arm muscle circumference (p < 0.0001). In conclusion, puberty, as assessed by age at menarche, is delayed by about 3 years in this population, probably due to malnutrition.     

Relation of race, age, and sex hormone differences to serum leptin concentrations in children and adolescents

We explored the effects of race, age, and sex hormones on the serum leptin concentrations in 203 white and 88 black children and adolescents (ages 9.3-20.5 years). A significant sex by race interaction on serum leptin levels (p = 0.0301) was observed with lower serum leptin concentrations, adjusted for subscapular thickness and age, in black boys than in white boys. Girls had serum leptin levels that were on average 2.15 times those of boys (p < 0.0001). There was an age by sex interaction (p < 0.0001) with serum leptin concentrations decreasing in boys but not in girls with age. A strongly inverse relationship of serum testosterone levels with serum leptin levels in boys (p = 0.0067) appeared to explain this effect of age. In conclusion, the serum leptin concentration is slightly lower in black boys. A higher testosterone level in boys appears to account for an age-related decline in serum leptin in boys and the overall lower levels in boys than in girls.     

Changes in haemoglobin and haematocrit values in children aged 6 to 13 1/2 years in Mexico City

Levels of haemoglobin (Hb), haematocrit (Ht) and mean corpuscular haemoglobin concentration (MCHC) were determined in 523 boys and 350 girls, clinically healthy, ages 6-0 to 13-5 years, middle socio-economic class living in Mexico City. In girls no significant differences according to age were observed in Hb or MCHC; however, Ht was significantly greater at 10-5 than at 10-0 years, without subsequent modifications. In boys, Hb and Ht had a first increase between 10-5 and 11-0 years and a second rise from 12-5 years on: MCHC remained unchanged. Boys were six to twelve months behind girls in regard to Ht increase; however, Ht increased when boys and girls reached similar mean weights (34 kg), heights (138 cm) and surface areas (1-15 m2); concomitantly, they had progressed to stage 2 of sexual development. Clear sex differences began to appear at age 11-5 when boys had higher Hb and Ht values than girls. These data suggest that Hb and Ht changes in these children are not related to chronological age but can be better interpreted if compared to weight, height, surface area or stage of sexual development.     

Tumor-related arthrodesis. Reconstruction of the shoulder contour using a free TRAM (Transverse Rectus Abdominis Musculocutaneous) flap]

We evaluated growth hormone binding protein (GHBP) activity in a group of obese children (12 boys and 12 girls, age 3.1-14.7 years, BMI 21.1-33.3, 11 prepubertal and 13 early pubertal) and in 26 age-matched normal weight children (14 boys and 12 girls, age 2.1-16.0 years, BMI 14.2-21.4, 18 prepubertal and 8 early pubertal). All children were of normal stature. GHBP activity was significantly higher in the obese (39.1 +/- 1.1%) than in the control children (28.3 +/- 1.0%, p < 0.0001). Mean serum GHBP was not different between boys and girls or between prepubertal and pubertal subjects. A positive correlation was found between BMI and GHBP levels only in the normal weight children (r = 0.425, p < 0.05). Baseline insulin concentrations in the obese children were 97.6 +/- 7.9 pmol/l (normal values, 45.0 +/- 18.6 pmol/l), and the mean insulin AUC following OGTT in the obese was 811.3 +/- 160.7 pmol/l (normal values, 373.1 +/- 150.1 pmol/l). Serum GHBP activity in the obese was not correlated with baseline serum insulin concentrations or with the insulin AUC following OGTT. In conclusion, we found that obese children have elevated GHBP activity, and speculate that this phenomenon may serve to compensate for their reduced GH secretion and accelerated GH clearance.     

Muscle strength and hormonal levels in adolescents: gender related differences

The purpose of the present investigation was to study muscle strength in adolescents and its relationship to serum levels of testosterone and growth hormone in both genders. Thirty active adolescents (15 boys; age range 11 -12 y/o) participated in the first study. Isokinetic muscle strength of the dominant knee extensors (KE) was determined at 0, 12, 20, 30, 120, 180 and 240 deg/sec using a Cybex 340 dynamometer. The assessment of pubertal status was accomplished using the criteria of Tanner. Serum levels of total testosterone (T) and growth hormone (GH) were determined using radioimmunoassay techniques. Boys had higher (p< 0.001) T levels but no differences in muscle strength were detected between genders. Fifty-seven additional subjects representing three age groups (11-12 y/o, n=18; 13-14, n=21; 17-18, n=18) participated in the second study. A significant increase in peak torque (absolute and corrected for body weight) with age was observed in both genders. There were no significant gender differences in strength for the two youngest age groups, but boys were stronger than girls in the oldest age group (group 3). Testosterone and GH levels increased with age in boys but not in girls. Gender related differences in T were found in groups 2 and 3. A positive correlation (r=0,64 boys; r=0.46 girls) between testosterone levels and absolute muscle strength was seen in both genders. Our results suggest that increases in anabolic hormones precede muscle strength gains in adolescent males. In addition, gender related differences in muscle strength during adolescents cannot be explained solely on the basis of difference in body size or T levels.     

Development of sex-differentiated preferences during late childhood and adolescence.

Examined factors influencing sex-differentiated responses to selected interests and interpersonal traits by young people in 3 age groups: 516 in late childhood (Grades 4–6), 398 in early adolescence (Grades 7–9), and 337 in late adolescence (Grades 10–12). There was limited evidence for same-sex bias during late childhood, varying by sex and race in its pervasiveness or clarity. Interpersonal traits were not generally sex stereotyped. Several interests were sex stereotyped during adolescence, but not those most directly related to academic learning. In general, interests were more strongly sex stereotyped by boys than by girls. Greater cognitive maturity generally attenuated sex stereotyping of interests. Certain developmental trends differed by sex and/or by race, and socioeconomic background (parents" education) influenced developmental trends among Blacks but not among Whites. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Growth charts, growth velocity and bone development in childhood obesity

OBJECTIVE: To compare the growth charts of obese subjects (4-18 years) with the Tanner's growth curves and to analyze the growth velocities and bone age of obese children in prepuberty and adolescence. Moreover to compare the relationship between the serum insulinemic and glycemic levels and height standard deviation score (HSDS). DESIGN: Growth charts: this study included 1250 obese subjects (669 males, 581 females) observed between 1981 and 1993 and divided into seven age categories (4-6, 7-8, 9-10, 11-12, 13-14, 15-16, 17-18 years). Growth velocities: yearly growth velocities of 579 obese subjects (325 males, 254 females) were compared to growth velocities of 473 controlled children of the same sex, chronological age and pubertal stage. Bone age (BA) of 846 obese subjects (470 males, 376 females) was estimated. Blood analysis: insulin secretion of 70 obese children was considered and compared to 70 lean controls of equal chronological age and sex. MEASUREMENTS: Growth rate, standardized height and other physical characteristics of the children were measured by trained examiners. All subjects were evaluated singularly for at least 4 years with a follow-up every 6 months. BA was estimated by radiograph of the left hand and wrist using the Tanner-Whitehouse II system by a single observer. For the insulin secretion study and glycemic levels oral glucose tolerance test (OGTT) was performed using a glucose load of 1.75 g/kg per body weight. Plasma insulin was assessed by a double antibody radioimmunoassay. RESULTS: In adipose children the growth charts, referred to 97th centile, 50th centile and 3rd centile, were superior to those of the normal population up to the age of 13 and 12.5 years for male and for female respectively; growth decreases at the above age in both sexes. The obese subjects were equal in height to the non obese subjects as they reached their 18th birthday. The growth velocity (cm/yr) of the obese child, in the age range considered here, does not show differences when compared with the lean child in the prepubertal status (P not significant) but decreases during Tanner's stage II, III IV in boys and girls (P < 0.0001). BA is more advanced over chronological age (delta BA-CA) in both sexes. The increase of BA over CA does not show a remarkable difference during pubertal maturation in boys (P not significant); whereas in girls the delta BA-CA decreases with advancing sexual maturation (P < 0.0001). Our obese subjects have significantly higher plasma insulinemic levels compared with the lean controls (P < 0.0001). Moreover there is a positive correlation between plasma insulinemic levels and HSDS (r = 0.881, P < 0.0001). We did not observe a correlation between serum glycemic levels and HSDS. CONCLUSION: Our data demonstrate that the growth increase in an obese child starts in the first years of life. The statural advantage acquired in the first years of life would be exploited and maintained up to the beginning of puberty and with a growth velocity equal to that of the lean subject. Skeletal maturation is strongly increased in both sexes. Bone age remained advanced during the entire period of pubertal development. During puberty obese subjects demonstrate a less notable growth spurt when compared with lean subjects. The growth advantage gradually decreases and final adult height of obese and normal subjects is equal.     

Intima-media thickness and diameter of carotid and femoral arteries in children, adolescents and adults from the Stanislas cohort: effect of age, sex, anthropometry and blood pressure

OBJECTIVES: To study carotid and femoral intima-media thicknesses and diameters in relation to age, sex, morphologic status and blood pressure. PARTICIPANTS: The subjects were 369 men and women (aged 10-54 years) from the Stanislas cohort, with no known cardiovascular disease. METHODS: Intima-media thicknesses and diameters were measured by B-mode ultrasonography. The effects of sex, age, smoking, anthropometric variables, cholesterol and blood pressure were studied using bivariate and regression analysis. RESULTS: Carotid and femoral intima-media thicknesses were not affected by age nor by sex up to 18 years of age. Thereafter, they increased sharply in men and remained higher than in women. Values were correlated with systolic blood pressure only in men, and with fat-free mass in children and young adults only at the femoral site. Smoking, body mass index and fat mass were associated with intima-media thicknesses only in adults. Carotid diameter was little affected by age during childhood and in adults. Femoral diameter increased up to the age of 18 in both sexes and remained unaffected by age thereafter. This increase was more pronounced in boys, and so values became consistently greater in males aged over 14 years. Carotid diameter was correlated with body mass index or fat mass whereas femoral diameter was correlated with weight or fat-free-mass in children and men. The opposite was observed in women. CONCLUSION: Sex differences occur before adolescence for arterial diameter, but only at an adult age for intima-media thickness. In young subjects, carotid geometry seems to be influenced by blood pressure and excess body weight, while femoral artery geometry seems to be related to blood pressure and body growth.     

Two decades of annual medical examinations in Japanese obese children: do obese children grow into obese adults?

OBJECTIVE: To investigate trends in frequency of obese children in Japan over two decades, the frequency of obese children who grow into obese adults and predictive factors for adult obesity. DESIGN: Annual cross-sectional studies for 22 y (1974-1995) with a follow-up study. SUBJECTS: Cross-sectional: Cumulatively 13,186 obese (% of standard body weight (SBW): > or = 120%) schoolchildren including 3158 extremely obese (> or = 140% of SBW) children out of 203,088 schoolchildren (age: 6-14 y) in Izumiohtsu City, Osaka, Japan. Follow-up: 151 initially obese children (initial age: 6-14 y and age at follow-up: 20-35 y) who lived in Izumiohtsu City. Control: 3552 Japanese men and 4631 Japanese women (age: 20-35 y). MEASUREMENTS: Cross-sectional: height, weight, trunk circumference, skin-fold thickness, blood pressure and blood biochemicals. Follow-up: height, weight, trunk circumference, skin-fold thickness during childhood, and body height and weight at follow-up. Adulthood obesity: > or = 120% of the average body mass indices (BMI) of the controls. RESULTS: Frequency of obese children increased from 5% to more than 10%, and that of extremely obese children increased from 1% to more than 2% during these 22 y. These increases were most prominent in the schoolboys aged 9-11 y. Prevalence of hyperglycemia and hyperlipidemia in the extremely obese children did not change, and that of hypertension and abnormal liver function gradually decreased during these two decades. After coming of age, 32.2% of the initially obese boys (relative risk: 5.3) and 41.0% of the initially obese girls (relative risk: 6.7) remained obese. BMI, percentage of the SBW and skin-fold thickness at the biceps during childhood were significantly larger in currently-obese girls. Positive correlations were demonstrated between these variables and percentage SBW at follow-up. CONCLUSIONS: Childhood obesity is increasing in Japan, especially in boys aged 9-11 y. Approximately 32% of the obese boys and 41% of the obese girls grow into obese adults, and the degree of obesity is a predictive factor for adult obesity.     

Peak expiratory flow rate in Nigerian school children

Peak expiratory flow rate (PEFR) was measured using the Wright's peak flow meter in 263 school boys and 275 school girls living in Lagos, Nigeria. Their ages ranged from 6.0 years to 19.0 years (mean 11.9 +/- 3.8 yrs. for boys and 11.8 +/- 3.9 yrs. for girls). Mean PEFR was 359.2 +/- 102.0 L/min (range 160.0-610.0 L/min) in boys and 327.7 +/- 81.3 L/min (range 160.0-500.0 L/min) in girls. Apart from ages 17, 18 and 19, peak expiratory flow rates were similar in both boys and girls. In both sexes, PEFR correlated positively and significantly with age, height, weight and body surface area. Also in both sexes and in all age groups studied, PEFR was significantly higher than predicted values obtained from previous Nigerian and caucasian prediction equations. When compared with values obtained from a second caucasian prediction equation, observed values were significantly higher in the 6-10 years and 16-19 years age groups in boys and 11-15 years and 16-19 years age groups in girls. New prediction equations for calculating PEFR in Nigerian boys and girls are presented. Observed PEFR may be due to enhanced stature in Nigerian children resulting from improved environment and genetic factors.     

Integrated concentrations of luteinizing hormone and puberty

Integrated serum concentrations of luteinizing hormone have been compared among 30-minute collections from 10 boys (6-18 years old) and 5 girls (5-11 years old). This study suggests that perpubertal as well as pubertal boys have greater mean integrated concentrations of LH during sleep than during waking. One of two pubertal girls had greater concentrations of LH during sleep, while three prepubertal girls did not.     

Height, weight and menarche in Swedish urban school children in relation to socio-economic and regional factors

During the period 1964-1973, a defined sample of 740 Swedish urban school children (360 girls and 380 boys) from 40 different urban areas all over the country were followed longitudinally. Height and weight were measured twice a year and age at menarche was recorded. Mean ages at peak height velocity (PHV) and peak weight velocity (PWV) were 11-91 years (SD 0-95) and 12-50 years (SD 1-08) for girls with average values of 8-30 cm/year (SD 1-32) and 7-37 kg/year (SD 1-94). Mean age at menarche was 13-05 years (SD 1-03). PHV and PWV in boys occurred on average at 14-09 years (SD 1-11) and 14-30 years (SD 1-11) with magnitudes of 9-84 cm/year (SD 1-40) and 9-07 kg/year (SD 2-04). No significant differences between socio-economic strata defined by father's occupation and family income were found either for height and weight or for ages at PHV, PWV and menarche. Girls but not boys in the lowest social group (III) had more weight for height during puberty than had girls in social groups I and II. Between the three main geographical regions of Sweden some differences were found. Boys in the South were at the ages of 17 and 18 on average heavier than boys from the rest of the country. Boys and girls in the South had PHV, PWV and menarche half a year later than children in Middle Sweden. In analysis of variance for age at PHV significant interaction terms were found for regions times urbanization. In the South and North age at PHV was earlier the higher the urbanization level, but in Middle Sweden the reverse occurred.     

Urinary calcium oxalate saturation in healthy infants and children

PURPOSE: A number of factors influence the development of renal calculi, the most essential of which is the supersaturation of urine with lithogenic substances. Calcium oxalate stones occur most frequently in adult and pediatric patients with urolithiasis. Therefore, we established normal age and sex related data for urinary calcium oxalate saturation in infancy and childhood to allow a more specific prediction of the risk of (recurrent) stone disease. MATERIALS AND METHODS: We collected 24-hour urine samples from 473 healthy infants and children without a history of renal stones. Urinary lithogenic and stone inhibitory substances were measured, and the urinary calcium oxalate saturation was calculated using a computer program. RESULTS: Mean urinary calcium oxalate saturation was always higher in boys than in girls, which was significant in infancy (5.22 versus 2.03, p < 0.05) and at ages 7 to 9 years (8.84 versus 5.47, p < 0.05). The saturation first increased (p < 0.05) until age 7 to 9 years in boys and girls, and remained at high levels at ages 10 to 12 years (7.03 versus 5.49, p < 0.05 compared to infancy). Calcium oxalate saturation then decreased until adolescence when values were comparable to those of infancy (5.29 versus 3.35). CONCLUSIONS: We recommend calculating urinary calcium oxalate saturation for diagnostic purposes as well as for therapy control. Normal age and sex related values must be considered.     

A rare presentation of thoracic aortic dissection as detected by transoesophageal echocardiography

Sex-based differences in serum leptin concentrations have been reported in adolescence and adulthood. To discover when such differences were generated, serum leptin concentrations were measured in umbilical cord blood from 46 healthy infants and in the mother's blood at delivery. Considering the respective body weights of the mothers and infants (68.5 +/- 1.3 kg and 3.3 +/- 0.0 kg), umbilical cord concentrations of leptin were disproportionately high in the infants (9.4 +/- 1.2 micrograms/l) compared with those in the mothers (18.7 +/- 1.3 micrograms/l). There was a wide variation in the infants leptin values (1.2 +/- 56.8 micrograms/l) that did not correlate with height, weight, cephalic circumference, or any other growth-related parameter. The most striking differences emerged when results were analysed by sex: umbilical cord concentrations of leptin in the girls (12.9 +/- 2.2 micrograms/l) were significantly (P < 0.01) greater than those in the boys (6.8 +/- 0.9 micrograms/l), although no differences in leptin concentrations were observed between the mothers who gave birth to a girl (19.5 +/- 2.2 micrograms/l) and those who gave birth to a boy (18.1 +/- 1.7 micrograms/l). The sex-based differences were not attributable to any growth-related differences between the sexes, except heavier placental weights in the girls (P < 0.007) than in the boys. These differences in leptin concentrations may reflect a sex-based difference in the regulation of leptin production by the fetal adipose tissue.     

Emergence of delinquency and depressed mood throughout adolescence as predictors of late adolescent problem substance use.

Delinquency is a positive predictor of adolescent problem substance use, and depressed mood may increase risk for substance problems. The extent to which effects of delinquency and depressed mood on problem substance use vary depending on when during adolescence the predictors are assessed is unknown. The authors used 5 multigroup path analyses to examine effects of delinquency and depressed mood at ages 11, 12, 13, 14, and 16 years on problem substance use at age 18, and mediation of those effects through alcohol use at age 16 across gender. Participants were 429 rural youths (222 girls and 207 boys) and their families. Indirect positive effects of delinquency on the outcome were observed for boys; direct positive effects of depressed mood were observed for girls. Prevention implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Smoking, body image and reducing diet. A three-year follow-up of adolescents aged 15-18 years

Several studies indicate that the differences in smoking habits which have hitherto prevailed between the sexes are decreasing, partly because of the increase in smoking among young Norwegian women. It has been suggested that concern about body image and weight gain is of particular relevance to women taking up smoking. In this article we present findings from a cohort study among 646 adolescents between the ages of 15 and 18 years. The results indicate that boys start smoking later than girls, and that concern about weight gain, body image and dieting plays a more important role in girls' than in boys' smoking habits at the age of 15. These factors are unrelated to boys' smoking habits at the age of 18, whereas they contribute significantly in predicting girls' smoking habits three years later. Furthermore, the results show that among girls, those who smoke are more concerned about gaining weight. Our findings emphasize the importance of implementing smoking prevention programmes at different age levels, using different motivating factors for boys and girls.     

Smoking, body image and dieting habits among adolescents. A 3-year follow-up of adolescents aged 15-18 years

Several studies indicate that the differences in smoking habits which have hitherto prevailed between the sexes are decreasing, partly because of the increase in smoking among young Norwegian women. It has been suggested that concern about body image and weight gain is of particular relevance to women taking up smoking. In this article we present findings from a cohort study among 646 adolescents between the ages of 15 and 18 years. The results indicate that boys start smoking later than girls, and that concern about weight gain, body image and dieting plays a more important role in girls' than in boys' smoking habits at the age of 15. These factors are unrelated to boys' smoking habits at the age of 18, whereas they contribute significantly in predicting girls' smoking habits three years later. Furthermore, the results show that among girls, those who smoke are more concerned about gaining weight. Our findings emphasize the importance of implementing smoking prevention programmes at different age levels, using different motivating factors for boys and girls.     

The emergence of gender difference in depressed mood during adolescence: the role of intensified gender socialization

The prevalence of depressive mood was examined in a representative and nationwide sample of approximately 12,000 Norwegian adolescents. From the age of 14, girls scored 0.5 SD above boys in depressed mood, a difference that was stable throughout the adolescent period. At the age of 12, no gender difference was found. The gender difference was due to girls becoming more depressed from 13 to 14 years of age. An extended version of the gender intensification hypothesis (J. P. Hill & M. E. Lynch, 1983) was tested as an explanation for the gender difference in depressed mood. Structural equation modeling and regression analyses showed that the gender difference could be explained, in part, by increased developmental challenges for girls--pubertal development, dissatisfaction with weight and attainment of a mature female body, and increased importance of feminine sex role identification. Depressed mood was not associated with masculinity or school change, as had been predicted.     

Protection of both auditory hair cells and auditory neurons from cisplatin induced damage

Knowledge about body composition is important in metabolic and nutritional studies. In this cross-sectional study the body composition of 403 healthy white Dutch children and adolescents was evaluated by using dual-energy X-ray absorptiometry (DXA). Possible determinants of body composition were analyzed. In 85 subjects the results of bioelectrical impedance analysis (BIA) were compared with DXA. Fat mass, lean tissue mass, and bone mineral content were greater in older boys and girls. Percentage body fat was greater in older girls but not in boys and it was higher in girls than in boys at all ages. From the age of 14 y boys had higher lean tissue mass and bone mineral content than girls. Tanner stage had a significant relation with body composition in both sexes. Percentage body fat was lower in boys in stage 4 than in stage 3 and was higher in consecutive Tanner stages in girls. After adjustment for age, Tanner stage was significantly positively related to lean tissue mass and bone mineral content in boys and girls and to percentage body fat and fat mass in girls. The profession of the parents and the education of the father had a significant negative correlation with percentage body fat and fat mass in girls (P < 0.01). Physical activity was related to lean tissue mass (P = 0.001) but not to fat mass in boys after adjustment for age. A high correlation and a small difference was found between lean body mass by BIA and lean tissue mass by DXA. Body composition in healthy Dutch children and adolescents is related to age, sex, Tanner stage, socioeconomic status, and physical activity.