Sexual maturation in Turkish boys

Ages of onset and attainment of various stages of secondary sexual characters were assessed from cross-sectional data on 1530 city schoolboys in Istanbul, Turkey. The subjects were grouped into four socio-economic classes.Ages of onset of pubic hair (11.80 years), axillary hair (13.15 years), facial hair (14.45 years) and laryngeal development (13.37 years) were relatively early in the highest socioeconomic class and agreed with recent values reported for European boys. In lower socioeconomic classes there was a relative delay of onset and attainment of the subsequent stages of secondary sexual characters.Acne was encountered in a significant proportion of the boys and increased in frequency with age. Socioeconomic level had no effect on its frequency. Gynaecomastia, unilateral in nearly half of the instances, was encountered in 7.0 per cent of the subjects. The frequency of gynaecomastia was lower in class 1 boys.     

Sexual maturation in Turkish boys

Ages of onset and attainment of various stages of secondary sexual characters were assessed from cross-sectional data on 1530 city schoolboys in Istanbul, Turkey. The subjects were grouped into four socio-economic classes.

Ages of onset of pubic hair (11·80 years), axillary hair (13·15 years), facial hair (14·45 years) and laryngeal development (13·37 years) were relatively early in the highest socioeconomic class and agreed with recent values reported for European boys. In lower socioeconomic classes there was a relative delay of onset and attainment of the subsequent stages of secondary sexual characters.

Acne was encountered in a significant proportion of the boys and increased in frequency with age. Socioeconomic level had no effect on its frequency. Gynaecomastia, unilateral in nearly half of the instances, was encountered in 7·0 per cent of the subjects. The frequency of gynaecomastia was lower in class 1 boys.     

Sexual maturation of Greek boys

BACKGROUND: Sexual maturation is dependent on genetic and environmental factors, therefore each ethnic group has to have its own normative data. AIM: This study describes the sexual maturation of Greek boys. SUBJECTS AND METHODS: We examined cross-sectionally 1266 healthy boys, aged 8-16 years. Pubertal staging in each boy was assessed according to Tanner's classification. Our data were also compared with those of a study performed in 1968. RESULTS: The first pubertal sign was genital enlargement (G2) that occurred at a mean age of 11.0 (+/- 1.3) years followed by pubic hair development (PH2) at 11.5 (+/- 1.5) years of age. There was no clear change in pubertal maturation from the 1968 study. CONCLUSIONS: The age at which genital development occurs in Greek boys is no different from that of other Caucasian populations. However, pubic hair in Greek boys develops significantly earlier.     

Sexual maturation of Greek boys

Background : Sexual maturation is dependent on genetic and environmental factors, therefore each ethnic group has to have its own normative data. Aim : This study describes the sexual maturation of Greek boys. Subjects and methods : We examined cross-sectionally 1266 healthy boys, aged 8-16 years. Pubertal staging in each boy was assessed according to Tanner's classification. Our data were also compared with those of a study performed in 1968. Results : The first pubertal sign was genital enlargement (G2) that occurred at a mean age of 11.0 ( &#45 1.3) years followed by pubic hair development (PH2) at 11.5 ( &#45 1.5) years of age. There was no clear change in pubertal maturation from the 1968 study. Conclusions : The age at which genital development occurs in Greek boys is no different from that of other Caucasian populations. However, pubic hair in Greek boys develops significantly earlier.     

Validation of methods for predicting adult stature in Turkish girls

The original or revised methods for prediction of adult stature of Tanner–Whitehouse (TW), Roche-Wainer-Thissen (RWT), and Bayley–Pinneau (BP) were validated in a mixed longitudinal study of Turkish girls, 9–14 years of age. Comparison of 727 estimations of 102 girls showed that the RWT'93 revision is an improvement over the original method by reducing the standard deviation, and absolute median and mean of residuals. The TW'83 (3v) method, by dropping the variable midparent stature, was reduced in accuracy before age 12. The addition of the previous annual increment in stature improved the predictions, while further addition of the increment in skeletal age did not. In relation to overall accuracy and reliability, BP (0.75) and TW'75 (0.73) had the highest R² values, while RWT'75 had the lowest (0.55). Regarding individual consistency of multiple predictions, the RWT methods ranked best and TW'83 relatively poorest. Systematic errors found in Turkish girls were similar to those found in French, Swiss, and Finnish girls. © 1995 Wiley-Liss, Inc.     

Secular trends in growth and maturation in British girls

Over a period of 28 years, a succession of cross-sectional surveys was carried out on young women entering the University College of Swansea (1959–1970) and then the University of Warwick (1971–1986) each year. Recall data on age at menarche and measurements of stature provide an indication of secular trends in growth and maturation in this section of the population of Britain. The earlier trend to younger age at menarche came to an end in girls born in approximately 1946 and entering university in 1964, and subsequently reversed, so that there is now a secular increase in menarcheal age. The successive analyses of stature show no such reversal, but instead a steady increase in mean stature throughout the period. © 1994 Wiley-Liss, Inc.     

Relationship of physical performance to maturation in perimenarchal girls

The relationship of physical performance to maturation, characterized by the onset of menarche, was examined annually from 1989 to 1992 among 61 healthy, active perimenarchal girls from 10 to 14 years. Within each age group, differences in selected physical performance variables between and among three maturity groups, early, average, and late, were compared. Subjects categorized as having early or late maturation were those whose age at menarche was minus or plus, respectively, one standard deviation from the mean age at menarche 12.70 + 0.99 yr (range 10.29–14.65). Subjects demonstrated steady progression with age in breast and pubic hair development. Weight, estimated lean body weight and fat weights, and stature increased significantly with age and maturation. With the exceptions of flexibility, bent arm hang, standing vertical jump, and relative maximum oxygen uptake, the performance measures of running speed, functional strength, explosive strength, static strength, upper body power, and aerobic power improved significantly with age and maturation. Generally more mature subjects tended to perform significantly better than the less mature, but there are fewer significant performance differences between and among maturation groups within specific age groups. Therefore, whereas more mature 10- and 14-year-old females may, within the same age group, have only a very slight advantage in some physical performance abilities over their less mature age mates, more mature females aged 11, 12, and 13 years have a greater physical performance advantage. Am. J. Hum. Biol. 9:163–171, 1997. © 1997 Wiley-Liss, Inc.     

Sexual maturation and growth pattern in Egyptian boys

The mean ages of attainment of successive stages of puberty were estimated in a cross-sectional sample of 453 Egyptian schoolboys from a semi-urban area of Cairo, ranging in age from 9 to 17 years. The stages of puberty were as defined by Tanner (1962).

The mean age of onset of puberty (stage 2) was 11·1 years, assessed either by genitalia or by pubic hair. Stage 5 occurred at age 16·2 years, again both for genitalia and pubic hair. The time interval between these ages, 5·1 years, was 2 years longer than for British or Chinese boys.

There was a highly significant effect of social class on the mean ages of attainment, and the heights and weights of the boys were also related to social class, the class 1 boys being taller and heavier than Tanner's British boys.     

Exercise-induced hormone responses in girls at different stages of sexual maturation

The dependence of exercise-induced hormone responses on sexual maturation was tested in a 3-year longitudinal experiment on 34 girls (aged 11–12 years at the beginning). Sexual maturation was evaluated by Tanners five-stage scale. Children cycled for 20-min at 60% maximal oxygen uptake once a year. Cortisol, insulin, growth hormone, β-oestradiol, progesterone and testosterone concentrations in venous blood were determined by radioimmunoassay procedures. Basal concentrations of growth hormone increased and of cortisol decreased when breast stage III was reached. Reaching breast stage IV was associated with an increase in basal concentrations of β-oestradiol, progesterone and testosterone. The exercise induced significant increases in concentrations of cortisol, growth hormone and β-oestradiol and a decrease in insulin concentration. At breast stage III the increase in cortisol concentration was to a lower level [467 (SEM 42) vs 567 (SEM 46)nmol · l^?1] and growth hormone concentration to a higher level [29.4 (SEM 0.5) vs 12.8 (SEM 0.4)ng · ml^?1], while the fall in insulin concentration was less pronounced [postexercise level 10.6 (SEM 0.9) vs 7.8 (SEM 0.8)mU · l^?1] than in stage II. The magnitude of the cortisol response was reduced in the last stage of breast development (+42.1% vs +55.5% at stage II, +66.2% at stage III, and +50.0% at stage IV). The magnitude of β-oestradiol response was the lowest in breast stage IV (+15.8%) and the highest at stage V (+41.1%). The progesterone response became significant at stage IV and testosterone response at stage V. In conclusion, we found that reaching breast stage III was associated with altered responses of cortisol, insulin and growth hormone concentrations while the responses of the sex hormone concentrations became pronounced in the last stages of sexual maturation.     

Association between overweight and early sexual maturation in Portuguese boys and girls

Step functions representing median attainment ages of successive counts on numbers of permanent teeth present in the mouth were obtained separately for 12 early-emerging teeth (I₁, I₂ and M₁) and for 16 late-emerging teeth (C, Pm₁, Pm₂, and M₂). Displacement of each step function to best fit of individual tooth counts defined the variation in dental maturation for early teeth and for late teeth. Moreover, differences in the displacements of the two-step functions defined individual variations in the duration of the emergence process.     

Association between overweight and early sexual maturation in Portuguese boys and girls

OBJECTIVE: The purpose of this study was to examine the relationship between sexual maturation (SM), and the prevalence of overweight among boys and girls. SUBJECTS AND METHODS: The sample of this cross-sectional study included 819 children and adolescents (382 boys and 437 girls), aged 10-15 years old randomly selected from 30 schools in the Porto region. Anthropometrical measurements (body height, weight and skinfolds thickness) were determined by standard anthropometrical methods. Body mass index (BMI) was calculated from the ratio weight/height(2) (kg/m(2)). The sum of tricipital and subscapular skinfolds (TriSub) was also used. Physicians collected data on Tanner stages during physical examination. Subjects were grouped using the quartiles of the decimal age adjusted for Tanner stages of SM and gender. RESULTS: The prevalence of overweight was higher in early maturing boys (30.5%) and early maturing girls (32.7%). The late maturers presented a lower prevalence (p < 0.05) of overweight (20.3% boys and 18.3% girls). Logistic regression analysis illustrates that early maturing is associated with an increased risk for overweight or obesity for boys (OR: 1.87 and 95% CI: 0.99-3.50) and girls (OR: 2.14 and 95% CI: 1.12-4.07), when compared with the boys and girls of the fourth quartile (p < 0.05). CONCLUSIONS: We conclude that there is an association between early SM and the prevalence of overweight in both genders.     

Sexual maturation of female house mice: social inhibition

Young female laboratory mice reared in the presence of an adult male mouse or male bedding containing a pheromone reach sexual maturity earlier than control females. A pheromone produced by grouped female mice leads to long, irregular estrous cycles or anestrus. The present study demonstrated that a female-produced pheromone delays sexual maturation when females are grouped and that free social interaction and tactile contact among the grouped females are necessary for the production of this inhibitory pheromone. Both young and adult females caged in groups produced the inhibitory pheromone. This study provided additional support for the hypothesis that in female mice morphological and sexual development are under separate control mechanisms. Two pheromones may be active in reproductive processes of female mice: one exhibiting inhibitory effects and the other acceleratory effects.     

Catch‐up reproductive maturation in rural Tonga girls,Zambia?

To compare the timing of reproductive maturation among urban and rural Tonga girls in Zambia, anthropometric measures and Tanner stages of breast development were obtained. Subjects were 774 (282 rural, 492 urban) girls ages 6-18. Results indicate that rural girls are shorter and have smaller triceps and subscapular skinfolds than their urban counterparts. Median age at menarche for the entire sample, as estimated by probit analysis, was 14.8 years (95% CL = 14.34-15.40). Onset of breast development among urban girls was significantly younger than for the rural girls: 11.47 (95% CL 11.22-11.71) years vs. 13.15 (95% CL 12.40-14.15) years. In contrast, the two groups did not differ in timing of pubertal completion as assessed by median age for Tanner Breast Stage 5: 17.01 (95% CL 16.30-18.33) vs. 16.96 (95% CL 16.37-17.56) years. Predictors of pubertal onset, based on multivariate logistic regression, included dental maturation, height, and triceps skinfold. Triceps skinfold was the only significant predictor of pubertal completion. These results suggest that rural girls progress through puberty more rapidly than the urban girls despite their later start. This finding of maturational catch-up contrasts with earlier urban/rural comparisons of girls as well as previous results among Gwembe boys, for which later pubertal onset is associated with longer duration of pubertal maturation. While the mechanism remains unclear, biocultural explanations suggest preferential feeding during adolescence as a source for rural girl's maturational catch-up.     

Sexual size and shape dimorphism in Turkish common toads (Bufo bufo Linnaeus 1758)

Differences in male and female traits (sexual dimorphism [SD]) are widespread in animals. Dimorphism in morphological characters evolves under the effect of environmental and genetic factors and is shaped by natural and sexual selection. In this study, intersexual differences in size and shape in common toad, Bufo bufo, populations in Turkey were investigated. For this, linear measurements of 27 body-related morphometric characters in a sample of 140 individuals (70 males and 70 females) were compiled. The data were analyzed using univariate and multivariate statistical methods. The results show SD in body size with females having larger body size, a trait related with fecundity and thus probably under sexual selection. Body shape differences, which are associated with head width and dorsal head, are likely to prey size. Male-biased differences observed in nasal characters and tympanum may also be associated with sexual selection (male–male competition). Our findings are consistent with previous studies of major of Anura and support a role for selection pressures acting differentially upon individuals from both sexes, resulting in the evolution of sexually dimorphic traits.     

Self-assessment and physician assessment of sexual maturation in Brazilian boys and girls: Concordance and reproducibility

This study considered the concordance of self-assessment and physician assessment of sexual maturity status; breasts, and pubic hair in girls, and genitals and pubic hair in boys. The subjects were Brazilian children, youth and young adults, 174 females and 178 males, 6–26 years of age. Each subject evaluated his/her level of sexual maturation and then was examined by a physician. The sexual maturity ratings of the subjects and physicians were compared. Overall, the results showed moderate to high concordance (60.9–71.3%) for both assessments of secondary sex characteristics; better concordance was found for pubic hair (69.7–71.3%) than for the breasts or genitals (60%). Age did not appear to influence the accuracy of self-evaluation; rather, accuracy was more dependent on stage of maturation of the subject. Correlations between self- and physician assessments, and replicate self- and physician assessments were relatively high. © 1994 Wiley-Liss, Inc.     

Body size,biological maturation,and sport participation related to cortical bone in adolescent girls

The purposes of this study were twofold: (1) to describe the growth of metacarpal bone dimensions in a large sample (n = 819) of Flemish girls, 12–18 years, and (2) to investigate the relationship among cortical bone dimensions, biological maturation, and participation in sports activities. Besides body mass and stature, Tanner-Whitehouse skeletal age (SA) was estimated and menarcheal status was assessed. Second metacarpal bone dimensions were measured on radiographs. Sports participation was determined by a standardized questionnaire. Results show that whereas medullary diameter decreased, all other second metacarpal dimensions increased significantly with age. When the girls were divided into five subgroups by SA, significant differences were found for metacarpal bone dimensions among the groups. Analysis of covariance revealed that skeletal maturity significantly differentiated for medullary diameter, cortical thickness, cortical area, and percent cortical area, even when chronological age, body mass, and stature were partialled out. However, no differences were found between contrasting SA groups for metacarpal length and periosteal diameter when chronological age, body mass, and stature were held constant. The metacarpals of postmenarcheal girls are ～4% longer and ～7% wider, and had ～14% more bone area than age-matched, premenarcheal peers. No differences were found in periosteal diameter between pre- and postmenarcheal 14–15-year-old girls. Finally, sports participation was not associated with cortical bone in this group of healthy females (?0.16 ≤ r ≤ 0.17). © 1994 Wiley-Liss, Inc.     

Effect of familial distress on growth and maturation of girls: A longitudinal study

A longitudinal sample of girls (N = 271), all born during the same year, were examined at yearly intervals during a period of 11 (N = 174) or 8 years (N = 97). The data gathered included the following: age at menarche, anthropometric dimensions, skeletal maturity scores with the TW2 method, and questionnaire information about the present and past socioeconomic situation and family dynamics. The girls were divided into two groups. Group A (N = 207) comprised girls who lived in families free of strong traumatic events. Group B (N = 64) included girls whose family dysfunction exposed them to prolonged distress. Two anthropometric dimensions were central to the analysis: height and subischial leg length. Age at attaining four different maturity stages were also used: age at menarche, age at a Carpal score of 1,000, age at the RUS score of 1,000, and age at the total bone score of 995. The mean age at menarche of girls from group A was 13.3 years and that for girls in group B was 12.9 (F = 6.295, P < 0.01). There was no correlation between age and height at final stages of skeletal maturation, i.e., at a total bone score of 995 or a RUS score of 1,000 in group A. There was no significant difference in height between girls whose skeletal maturity was completed early and those in whom it was completed late. Girls from group B, whose skeletal maturity was reached earlier, were shorter than those who grew until a later age. In group B, the stature was positively correlated with the age at which the late stages of skeletal maturation was attained (r = 0.26 at a RUS score of 1,000 and r = 0.28 at a total bone score of 995, P < 0.05). Regardless of the ages at which any of the four maturity levels were reached by girls from group A, they were, on average, taller than those from group B at the same maturity level. Only at a RUS score of 1,000, when the sample size is reduced, the difference was not significant. The results show that girls exposed to familial distress are more likely to have an early puberty, which is associated with short final stature. Am. J. Hum. Biol. 13:771–776, 2001. © 2001 Wiley‐Liss, Inc.