Age specific rubella seroprevalence of an unvaccinated population of adolescents in Ankara, Turkey.

This study was designed to detect the age-specific rubella seroprevalence of an unvaccinated population of adolescents in Ankara, Turkey. Four hundred and forty adolescents (227 females, 213 males), aged 9-16 years, who were admitted to the Adolescent Unit from July to August 2000 were included in this study. For each participant, a questionnaire was completed and rubella-specific IgG antibodies were screened quantitatively by enzyme-linked fluorescent assay. Of the 440 patients screened for rubella antibodies, 32 (7.3%) were seronegative. Rubella seronegativity values according to sex and age groups were as follows: 15.3, 6.6, and 1.3% in females, and 12.0, 6.1, and 6.2% in males, in the age groups of 9-10, 11-13, and 14-16 years, respectively. The routine health supervision visit recommended between the age of 11 and 12 is an ideal time to immunize unvaccinated adolescents.

Correlation of sex steroids with IGF-1 and IGFBP-3 during different pubertal stages.

Insulin-like growth factor 1 (IGF-1) is the major factor that affects linear bone growth. Also, androgens and estrogens are necessary for increasing longitudinal bone growth during sexual maturation. The aim of this study was to investigate the relationships among IGF-1 axis and sex steroids during pubertal development in healthy adolescents. In this cross-sectional study, IGF-1, IGF binding protein-3 (IGFBP-3) and sex steroid levels (estradiol in girls, testosterone in boys) of 205 healthy adolescents (101 female, 104 male) aged 9-17 years were measured. All subjects were apparently healthy, with no growth retardation and with skeletal ages appropriate for chronological ages, and none were taking medications known to influence calcium homeostasis. Greulich and Pyle's Radiographic Atlas of Skeletal Development of the Hand and Wrist was used for determination of skeletal ages. Tanner's classification was used to determine the pubertal developmental stage. Fasting blood samples were obtained from subjects between 09:00-10:00 h. Serum IGF-1 and IGFBP-3 levels differed significantly between pubertal developmental stages. Serum IGF-1 levels and IGF-1/IGFBP-3 ratios increased with proceeding stages and maximum mean values were found at stages III-IV in girls and at stage IV in boys. Estradiol levels of girls and testosterone levels of boys differed significantly between stages, and in both sexes, serum IGF-1 levels and IGF-1/IGFBP-3 ratios were significantly correlated with sex steroid levels. Increase in growth hormone secretion increases IGF-1 levels. Furthermore, increasing sex steroids with pubertal development increase the IGF-1 levels and IGF-1/IGFBP-3 ratios that affect bone growth.

The evaluation of desmopressin in treatment of adolescent nocturnal enuresis.

This study was designed to determine the effectiveness of desmopressin in the treatment of adolescent nocturnal enuresis and factors that may predict responsiveness. Eighteen adolescents (14 boys, 4 girls) with monosymptomatic nocturnal enuresis were treated with oral desmopressin for three months, starting with 0.2 mg at night and controlling the symptoms every two weeks. After this period, desmopressin was used every other day and the dose was reduced gradually. The treatment was completed at the end of six months. As factors that may predict response before treatment, a range of variables (family history of enuresis, educational levels of parents, number of children, first child in family, birth weight) and urine osmolality was evaluated. Disappearance of bedwetting by using desmopressin has been observed in adolescents who have a high urine osmolality. We did not observe any relapse during reducing desmopressin dose gradually, but on complete cessation of the treatment, relapses were seen. Six months after the end of the therapy, we could not find any patient who recovered completely. Desmopressin seems to be effective in the treatment of primary nocturnal enuresis while on therapy but during the long-term follow-up, all cases relapsed.

Prevalence of obesity in adolescents and the impact of sexual maturation stage on body mass index in obese adolescents.

OBJECTIVE: Puberty is a high-risk period for the development of obesity. The aim of this study was to determine the prevalence of obesity in adolescents admitted to an outpatient adolescent clinic and investigate the relationships between the increase of body mass index and sexual maturation stages in obese adolescents. MATERIAL AND METHODS: We recruited 6,462 adolescents, aged 9-16 years, admitted to the outpatient clinic of our Adolescent Unit, between May 1999 and September 2000. BMI was calculated as weight per height with weight in kilograms and height in meters. Adolescents with a BMI > or = 95th percentile for age and sex were defined as obese, with BMI's > or = 90th percentile but < 95th percentile were defined as overweight and considered at risk for obesity. Obese adolescents, with endocrine problems identified to cause obesity, were excluded from this study. Pearson correlation coefficients were used to assess the relationships between BMI and age. The differences between the sexual maturation stages were evaluated with Mann-whitney U Test. RESULTS: Out of 6,462 cases screened, 151 obese adolescents were found. Prevalence of obesity for the total sample surveyed was estimated at 2.3%. BMI values were significantly correlated with age in both sexes. In girls, only the increase of BMI values from stage I to stage II was found to be statistically significant. In boys, BMI values did not differ significantly between the sexual maturation stages but the number of obese cases were high in stages I and II. DISCUSSION AND CONCLUSION: The pubertal growth spurt (timing determined by sexual maturation stage) effects the amount of fat accumulation and the distribution of fat in different ways in boys and girls. So, not only the age and sex but also the sexual maturation stage has to be taken into account while evaluating the BMI values for investigating the risk of obesity in puberty.

The importance of the measurement of the circumference of arm, arm muscle area and skinfold thickness during puberty.

Several methods are available to study lean and adipose tissue component of the upper arm, but the use of a specific technique is mostly determined by time and financial expense. Besides, anthropometric techniques (arm muscle area, mid-arm circumference and the triceps skinfold thickness), which are the most practical, simple, inexpensive and noninvasive, x-ray, ultrasound scanning, computed tomography (CT), or magnetic resonance images (MRI) are also used to determine separate measures of muscles, adipose tissue, and bone area. These radiographic methods are expensive and suitable only for research studies. This short review will try to stress the importance of the measurement of the circumference of arm, arm muscle area and skinfold thickness during puberty and adolescence.

Osteocalcin. A biochemical marker of bone turnover during puberty.

During bone remodelling, osteocalcin is produced by osteoblasts and its level increases during the events characterized by rapid bone turnover. Osteocalcin is a bone matrix protein, which is specific for bone metabolism and it is not influenced by metabolic bone disorders. Osteocalcin is an important marker of bone turnover in physiological and pathological conditions. Physiologically, serum osteocalcin was increased in children, particularly during the first year of life and during puberty, when evolution of the concentration was related to rapidity of physical growth. Evidence of a correlation with growth rates comes from the observation that serum osteocalcin levels parallel the height velocity curve, with higher values in childhood and during adolescence, that later fall to adult values. There are previous studies reporting that there is age- and sex-dependent change in serum osteocalcin levels in children and adolescents with a pattern resembling height velocity curves for children and serum osteocalcin elevation coincides with the pubertal growth spurt. These findings demonstrate that pubertal development and sex should be taken into account rather than chronological age when serum levels of osteocalcin are evaluated. In most of the studies relationships among osteocalcin and chronological age and bone age, but not pubertal developmental stage (sexual maturation stage) were investigated. The aim of our study was to determine whether osteocalcin is a useful marker for the pubertal growth spurt period. In this study, osteocalcin levels in male adolescents were examined in relation to their sexual maturation stage and age. According to our findings, the follow up of osteocalcin levels in relation to sexual maturation stages could be a new method to determine the phase of the pubertal growth spurt. An increase or decrease in osteocalcin levels on consecutive measurements may indicate the child's entering accelerated or decelerated stages of the growth spurt, respectively. We emphasize that the follow up of adolescent growth is made by determination of the sexual maturation stage, and not by age. Osteocalcin is a highly specific, reliable and useful marker for evaluation of the growth spurt and is not influenced by nonosseous disorders.

The influence of the sexual stages of adolescent boys on the circumference of the arm, muscle area and skinfold measurements.

The purpose of this study was to detect the changes in the circumference of the arm, skinfold thickness (SFT), arm muscle area (AMA) and arm fat area (AFA), during the sexual development of healthy adolescent boys. This study was done with 74 adolescent boys, aged 9-17 years, with no chronic diseases, no developmental delay, no current medication with height ages appropriate for their bone ages, and body mass indexes between 50-75 percentiles. Body weight and height, the circumference of the arm and the SFT were measured. Body mass index, AMA and AFA were calculated. The mean arm circumference and AMA increased significantly from Tanner stage 1 to 5. AMA was significantly and positively correlated with age, weight, height, body mass index, arm circumference, SFT. After adjusting for Tanner stages, AMA was not correlated with age. A significant negative correlation was found between AMA and arm fat area. In the present study, it was seen that the sexual stages affected the circumference of arm, AMA, and the skinfold thickness in healthy adolescent boys, who were appropriate for their bone ages, and had good nutritional status. Further studies are required to detect the effect of pubertal stage on arm anthropometry in different nutritional status including obesity and malnutrition.

The relationships between pubertal development, IGF-1 axis, and bone formation in healthy adolescents.

As IGF-1 is the major factor that affects bone growth, and both osteocalcin and bone-specific alkaline phosphatase are important markers of bone formation during puberty, there must be a relationship between these markers that does not change according to sex. The aim of this study was to investigate the relationships between pubertal development, the IGF-1 axis, and bone formation in healthy adolescents. Two hundred and five healthy children and adolescents were included in this cross-sectional study. Tanner's classification was used to determine the pubertal developmental stage. Serum IGF-1 levels and IGF-1/IGFBP-3 ratios increased with advancing pubertal stages, and maximum mean values were found at stages III-IV in girls and at stage IV in boys. Serum IGF-1 and IGFBP-3 levels were significantly correlated with osteocalcin and bone-specific alkaline phosphatase levels in boys, but not in girls. This difference between the sexes, and the relation of the IGF-1 axis to increased bone formation during puberty in both sexes, can be explained by the rate of increase of the IGF-1/IGFBP-3 ratio. We conclude that the timing of the increased bone formation rate during puberty; that is, the timing of the pubertal growth spurt, is determined by the maximum increase rate of the IGF-1/IGFBP-3 ratio. But this new hypothesis needs to be supported by longitudinal studies.