Secular trend in the sexual maturation of southern Chinese boys

A random sample of 3872 southern Chinese boys ranging from 7 to 21 years of age were selected from primary and secondary schools in Hong Kong for the assessment of sexual maturation. The median ages of onset of puberty and pubic hair development were 11.4 and 12.7 years, respectively. The advancement of sexual maturation coincides with the secular increase in height and weight for Chinese children in Hong Kong.     

中国九大城市男孩睾丸发育、阴毛发育和首次遗精年龄调查

目的 调查中国九大城市男孩青春发育的平均年龄.方法 采用全国协作性横向调查,于2003-2005年间进行.对象为代表中国东、西、南、北、中部地区的九大城市(包括北京、天津、青岛、上海、武汉、南宁、重庆、广州、福建)城区3-19.83岁的19 054名健康男孩.用睾丸计(Preder orchidometer)测量睾丸容积(ml);通过视诊法进行阴毛发育Tanner分期;发放调查表,由家长和(或)男孩本人填写遗精与否及具体日期.采用概率单位回归法(Probit analysis)计算睾丸发育、阴毛发育和首次遗精的平均年龄及95%可信区间(CI).以睾丸容积4 ml作为青春期启动的标志.将本次调查结果 与国内外文献报道的结果 相比较,并将首次遗精(初遗)年龄与1979年以来进行的五次全国性学生体质健康调查中的相似人群的初遗年龄进行比较.结果 9岁组12.99%的男孩睾丸发育已达4 ml.中国男孩青春期启动的中位年龄是10.55(95% CI 10.27～10.79)岁.阴毛发育Ⅱ期的中位年龄是12.78(95% CI 12.67～12.89)岁,首次遗精的中位年龄是14.05(95% CI 13.80～14.32)岁.1979年以来,中国城区男孩初遗年龄呈现年代提前的变化.结论 中国大城市城区男孩睾丸发育年龄较目前临床所用正常值早,并属当今睾丸青春发育较早、阴毛发育较迟的人群之列;自1979年以来,以呈现首次遗精为特征的性成熟年龄呈年代提前趋势.     

Pubertal characteristics among schoolgirls in Riyadh, Saudi Arabia

Puberty is the gradual transition period between childhood and adulthood. Many factors may contribute to the onset of puberty. The objective of the study was to determine the age of onset of secondary pubertal characteristics among Saudi Arabian girls. A cross-sectional study was conducted using a cluster sample design. Seven hundred and twenty-five schoolgirls between the ages of 6 and 16 years from diverse socioeconomic levels were included. During physical examinations, the height and weight of the girls were recorded, and the stages of breast and pubic hair development were determined according to Tanner stages; axillary hair development was determined according to modified stages. The median age at Tanner stage 2 for breast and pubic hair development was 10 years. The median age at stage 2 in modified scales for axillary hair development was 12 years. In conclusion, the median age of the onset of breast development at Tanner stage 2 for Saudi girls in Riyadh is lower than what has been reported in some countries in Europe, South Africa, Turkey and India but similar to girls in Hong Kong, China and white girls in the USA, which may support secular trends of an earlier onset of puberty.     

Reliability of pubertal self-assessment in Hong Kong Chinese children

Aim:   To validate a Tanner stages self-assessment questionnaire using gender-specific line drawings and brief explanatory text in Chinese.
Methods:   Design: A cross sectional study design. Setting: One primary and two secondary schools. Participants: 172 boys and 182 girls aged between 8 and 18 years. Main outcome measures: Students' self-assessments of pubertal maturation were compared with assessments made by a same gender rater using visual depiction physical examination. Raters' physical examinations were performed after the children had answered the self-assessment questionnaire individually and in private. Raters were blinded to the self-assessment results. Accuracy rates and weighted kappa statistic were used to evaluate the degree of agreement between children and raters.
Results:   Substantial to almost perfect agreement was found between self- and rater's assessments of breast development and pubic hair growth in girls [weighted kappa 0.72 ( P  < 0.0001, 95% CI 0.66, 0.79) and 0.83 ( P  < 0.0001, 95% CI 0.78, 0.87) respectively]. Moderate to substantial agreement was found between self- and rater's assessments of male genital development and pubic hair growth [weighted kappa 0.58 ( P  < 0.0001, 95% CI 0.48, 0.68) and 0.80 ( P  < 0.0001, 95% CI 0.74, 0.86) respectively]. Most agreements between self- and rater's assessments differed by only one Tanner stage. Agreement was higher for girls than boys. Girls tended to overestimate their breast stages and boys tended to underestimate their genitalia development.
Conclusion:   This study confirms that a Tanner pubertal self-assessment questionnaire with line drawings and explanatory Chinese text can reliably estimate sexual maturation status in Hong Kong Chinese children.     

Declining age of puberty of school girls in southern Thailand

Background

Declines in the onset age of secondary sexual development have been reported in a number of recent studies in western and Asian countries. A study of Hat-Yai school girls in 1994 in Thailand showed that the ages at thelarche and menarche were 9.9 and 12.4 years, respectively. This study was to determine whether there was a decline in the average age of puberty in Hat-Yai school girls from 1994 to 2012.

Methods

A cross-sectional study was conducted in 2140 healthy Hat-Yai school girls, aged 6–18 years, from June 2011 to March 2012. Breast and pubic hair development was assessed by the Tanner staging method. Probit analysis was used to calculate the median ages of different stages of breast and pubic hair development, and the age of menarche.

Results

The median ages of girls having thelarche and menarche were 9.6 (95% CI, 9.4–9.8) and 12.2 (95% CI, 11.9–12.4) years, which declined from 9.9 (95% CI, 9.7–10.1) and 12.4 years (95% CI, 12.2–12.6) in the 1994 study respectively, however, without statistical significance. The youngest ages of girls who had breast stage 2 and menarche were 7.2 and 9.2 years, respectively. The final height at age 14 years in this cohort (157.3 cm) was 2.3 cm greater than that of girls in 1994 (155.0 cm).

Conclusions

From 1994 to 2012, the age at onset of thelarche and menarche of girls in Hat-Yai municipality declined by 0.2 and 0.3 years, respectively. The earlier age at onset of puberty had no effect on final adult height.     

北京市儿童青少年女性青春期性征发育流行病学研究

摘要 目的：了解北京市6~18岁学龄女生青春期第二性征发育现状,以及人群性早熟发生率。方法：利用2004年北京市儿童代谢综合征调查（BCAMS）总样本中9 778名6~18岁中小学女生的青春期发育数据，用概率单位回归法计算月经初潮、乳房、阴毛不同发育时期的中位年龄。8岁前乳房或阴毛发育达Tanner II 期（B2,P2），或10岁前月经初潮者被定义为性早熟。结果：9 778名6~18岁中小学女生中城市人口5 040人，占总样本51.5%。北京市学龄女生月经初潮年龄平均为 （12.1±1.1）岁，城市女生（11.9±1.1）岁，农村女生（12.5±1.1）岁；女性第二性征开始发育年龄（总体/城市/农村）分别为，乳房：（9.5±1.2）岁/（9.3±1.1）岁/(9.6±1.2）岁；阴毛:(11.1±1.1）岁/(10.8±1.1）岁/(11.4±1.1）岁。城市女生月经初潮、乳房和阴毛发育均显著早于农村女生。月经初潮早发生率为0.79%，城市高于农村（1.03%：0.55%；x2=6.93，P<0.01）；乳房、阴毛早发育率分别为2.91%和0.22%。1962~1982年期间，北京女生月经初潮年龄平均每10年提前0.7岁（8.4个月）；近10年平均提前0.43岁（5.2个月）。结论：北京市城区女生青春期第二性征发育明显早于郊区县女生。月经初潮年龄提前的长期变化趋势依然存在，但近10年这一趋势趋于减缓。     

Assessment of pubertal development in Egyptian girls

Puberty is a significant event of human growth and maturation associated with marked physiological and psychological changes. The aim of this study was to assess normal pubertal development in Egyptian girls to define normal, precocious and delayed puberty. The present study included a cross-sectional sample of 1,550 normal Egyptian girls of high and middle socioeconomic class living in Cairo. Their ages ranged from 6.5 to 18.5 years. Pubertal assessment was made according to Tanner staging. The mean menarcheal age (MMA) was estimated using probit analysis. Weight and height were measured and body mass index (BMI) was calculated. The mean age at breast bud stage (B2) was 10.71+/-1.6, pubic hair stage (PH2) was 10.46+/-1.36, while axillary hair stage (A2) was 11.65+/-1.62 and MMA was 12.44 years. The mean age at attainment of puberty was compared with those of other Egyptian studies and other populations. Girls of the present study started pubertal development and achieved menarche earlier than those of previous Egyptian studies confirming a secular trend. Differences between the present study and other worldwide studies can be attributed to various genetic, racial, geographical, nutritional, and secular trend factors.     

北京市儿童青少年青春期发育与肥胖相关关系的研究

目的 分析北京市6~18岁儿童青少年青春期发育与超重肥胖的关系。方法 利用2004年北京市儿童青少年代谢综合征调查总样本中19 085名6~18岁儿童青少年的青春期发育、体重指数（BMI）和体脂含量百分比（FMP）等数据。采用女性乳房和男性睾丸容积Tanner分期指标衡量青春期发育，结合个体年龄将群体分为早、晚发育组；以BMI和生物电阻抗法所测FMP作为反映体脂含量的指标；7~18岁人群超重和肥胖的诊断采用中国肥胖问题工作组（WGOC）推荐的中国学龄儿童青少年超重、肥胖筛查BMI值分类标准进行，6岁组采用美国疾病预防与控制中心 2000年发布的儿童超重和肥胖BMI标准第P85和第P95分位值进行诊断；采用多元线形回归、Logistic回归分析早发育与体脂含量和超重、肥胖的相关联系。结果 早发育组的超重（合并肥胖）率和肥胖率均高于晚发育组，女性两组间差异大于男性；控制可能的混杂因素后，女性BMI和FMP与早发育呈正相关（BMI：β=2.25，P<0.001；FMP：β=4.55，P<0.001）；而男性BMI和FMP与早发育的联系相反，早发育组的BMI高于晚发育组，而FMP却低于晚发育组；以晚发育为参照组，控制年龄、城郊居住地等因素的影响后，早发育预测超重、肥胖的OR值（95%CI）：女性为3.39（2.94~3.92）和3.12（2.53~3.85），男性为1.12（0.96~1.31）和1.31（1.06~1.62）。结论 北京市儿童青少年青春期发育与肥胖密切相关，在评价超重、肥胖率及进行不同地区间肥胖流行状况的比较时，要注意青春期发育的效应修正作用。     

EVENTS OF PUBERTY IN 186 TASMANIAN SCHOOLGIRLS

This paper presents data on the physical effects of puberty in a group of Tasmanian schoolgirls. The mean age at menarche in 181 girls was 12.86 years. In the majority, the menarche occurred just before the attainment of maximum height and full sexual maturity as judged by breast development and pubic hair growth. A proportion of the girls (19 per cent) reported menstrual symptoms such as abdominal pain and irregularity.     

A mixed-longitudinal study on the pattern of pubertal growth: relationship to socioeconomic status and caloric-intake--IV

The pubertal growth pattern was observed on 791 girls belonging to upper and low SES. These girls ranged between 7-16 years. The effect of calorie intake on the pubertal growth was also ascertained. The development of breast was first to appear at the age of 8.25 years. It was followed by pubic and axillary hair development. The mean age of menarche was 12 years and 12.8 years for USES and LSES, respectively. The onset of menarche, breast and pubic hair was significantly delayed in LSES girls by 0.8 years. Menarche was found to correlate better with breast development than pubic or axillary hair. The girls on adequate calories showed early onset of breast, pubic hair and axillary hair development and of menarche. Similarly, these girls attained mature stage (adult) of these variables earlier compared to those who were on inadequate calories. However, intermittent developmental stages of pubic hair and axillary hair showed no consistency with intake of calories. The girls on inadequate calories showed approximately one year late onset of breast and pubic hair development. The present observations suggest that the onset of puberty is strongly influenced by environment but its attainment is under the genetical control.     

Sequential changes at puberty in boys

A cross-sectional study of 1602 school boys of Sirohi town aged 8 to 18 yr for development of secondary sex characters using Tanner’s sexual maturity ratings carried out. Mean (±SE) age of onset of puberty is 9.95 (±0.06) yr and that of completion is 16.26 (±0.08) yr. Though boys of Rajasthan begin earlier to have pubertal changes, but total time taken to attain full maturation is longer than British. The Growth of genitalia starts first and completes in last, whereas that of pubic hair starts later but completes earlier. Facial hair and axillary hair follow pubic hair in development. Development of breast and apocrine function take place between stage 3 and 4 of genital growth.     

Age of puberty in a representative sample of Iranian girls

Background  To obtain normal references for growth and pubertal development in a given population, assessment of pubertal stages is of great importance. This study aimed to determine the age of appearance of secondary sexual characteristics in a representative sample of Iranian girls. Methods  This cross-sectional study was conducted during 2005–2006 in 3192 girl students, aged 6–17 years, in Isfahan, Iran. Participants were selected by multistage random cluster sampling from school students. Secondary sexual characteristics were evaluated by inspection and palpation, and were recorded according to Tanner staging. The self-reported date of menarche (if any) was recorded as well. Data were analyzed with Probit analysis based on the status quo method. Results  The median ages (10th–90th percentile) of Tanner stage 2 breast development (B2) and Tanner stage 2 pubic hair growth (PH2) were 10.14 years (8.33–11.95 years) and 10.78 years (9.09–12.48 years), respectively. The ages of the 3rd percentile for B2 and PH2 were 7.48 and 8.29 years, respectively. The median age of menarche among the 3192 girls who had experienced menarche was 12.65 years (11.18–14.11 years). Conclusions  The median age of puberty onset is 10.14 years, and the onset of puberty before 7.5 years is considered as precocious puberty in a representative sample of Iranian girls. The values obtained from the present study can provide baseline data for analysis of time trends, as well as for international comparisons.     

New reference for the age at childhood onset of growth and secular trend in the timing of puberty in Swedish

The objectives of the present work were to present a new reference for the age at childhood onset of growth and to investigate the secular trend in the timing of puberty in a community‐based normal population in Sweden. A total of 2432 children with longitudinal length/height data from birth to adulthood were used to determine the two measures by visual inspection of the measured attained length/height and the change in growth velocity displayed on a computer‐generated infancy‐childhood‐puberty (ICP) based growth chart. The series represents a sample of normal full‐term children born around 1974 in Göteborg, Sweden. We found about 10% of children were delayed (>12 mo of age) in the childhood onset of growth based on the previous reported normal range, i.e. 14% in boys and 8% in girls. Distribution of the age at childhood onset of growth was skewed. The medians were 10 and 9 mo for boys and girls, respectively. After natural logarithmic transformation, the mean and standard deviation (SD) were 2.29 (anti‐log 9.9 mo) and 0.226 for boys, 2.23 (anti‐log 9.3 mo) and 0.220 for girls, respectively. The 95% normal ranges were 6.3‐15.4 and 6.0‐14.3 for boys and girls, respectively. The distribution of the timing of PHV was close to the normal distribution. The mean values were 13.5 y for boys and 11.6 y for girls with 1 y SD for both sexes. Conclusion: A downward secular trend in the onset of puberty was clearly shown in the population. The age at childhood onset of growth did not correlate with the timing of puberty (r=?0.01 and 0.05, p > 0.7 and 0.1 in boys and girls, respectively). Normal ranges of the age at childhood onset of growth are in need of revise, as this study indicates. The new reference presented here could be a reliable indicator in further studies.     

Invasive Haemophilus influenzae type b infections in children hospitalized in Hong Kong, 1986–1990

A 5-year territory-wide retrospective survey of invasive Haemophilus influenzae type b diseases was conducted in Hong Kong. Between 1986 and 1990, 57 cases (28 male) were recorded in children less than 12 years old (37 cases of meningitis, 9 of septicaemia and 11 of bacteraemic pneumonia). The annual incidence for children less than 5 years old was 2.7 per 10⁵ (95% confidence interval (CI) 2.0–3.5). Of the 57 cases, 39 were Chinese and 18 non-Chinese (7 Vietnamese refugees, 6 Caucasians, 5 others). The annual incidence in Vietnamese refugees less than 5 years old was 42.7 per 10⁵ (95% CI 17.2–87.9), giving a relative risk of 18.5 (95% CI 8.3–41.0). Chinese patients (68%) were under-represented as Chinese accounted for at least 94% of the population. Moreover, 14 of the 39 Chinese patients had pre-existing medical problems, compared with only 1 of the 18 non-Chinese patients (p = 0.022).     

Growth and development in simple obesity

It is well known that fat children tend to be taller than their peers and to present a slight acceleration of skeletal and pubertal maturation. To verify this tendency and to examine some of the points that are still controversial, auxological data were studied concerning 303 subjects (141 males and 162 females, aged 6–16 years) affected by simple obesity. Subjects were seen to be taller than average by about 1 SD from 6 to 9 years of age, becoming close to or shorter than average at later ages. Height below the 10th percentile was common in 17% of males and 8% of females, due to hereditary shortness, growth delay or late puberty. Girls had early puberty and menarche; the rate of sexual maturation was variable in boys.Abbreviations SO simple obesity - BMI body mass index - GP Greulich and Pyle method - TW2-RUS Tanner and Whitehouse method for skeletal age assessment (radius, ulna and short bones score) - GECS growth evaluation computerized system - G genital development - B breast development - PH pubic hair development - M menarche - SDS standard deviation scores     

Pelvic ultrasonography in normal girls and in girls with pubertal precocity

This prospective study sought to evaluate the role of pelvic ultrasonography in differentiating between various types of pubertal precocity. A control group of 117 normal girls (aged 1.1-15.6) was studied and compared with 87 girls with premature sexual maturation (aged 1.1-9.2y). Of these patients 19 had central precocious puberty (CPP), 48 had isolated premature thelarche (IPT) and 20 had premature adrenarche (IPA) Pelvic ultrasound variables evaluated were: (i) uterus: longitudinal diameter (uterine length), cross-sectional area (CSA) and fundo-cervical ratio; and (ii) ovaries: volume and morphology. Ovarian morphology was subdivided in 6 different appearances: solid, microcystic, paucicystic, multicystic, macrocystic, and major isolated cyst. In normal control girls, uterine length and CSA increased with age, although no cut-off values could be defined between different age ranges, and they were correlated with breast stage; fundo-cervical ratio was stable through childhood and increased after age 9. Ovarian volume was significantly greater in pubertal girls with breast stage 2 than in those with only pubic and/or axillary hair. There was a clear predominance of solid ovarian appearances in the age range 2-7, with the multicystic appearance being seen only after age 7, a minority being macrocystic. After age 10 all the different patterns were observed, and after age 13 the frequency of a macrocystic pattern increased. Significantly more mature ovarian appearances were observed in subjects with breast development compared with those without, independently of the presence of pubic hair. Patients with IPT had no significant differences in pelvic ultrasound measurements when compared with age-matched controls. All the different morphological ovarian appearances were observed in IPT, in contrast to age-matched controls, where only the less mature patterns (solid, micro- and paucicystic) were seen. Patients with CPP had significantly more mature patterns of ovarian morphology compared with age-matched controls, but did not differ from pubertal pre-menarcheal controls. Those patients with IPA differed from age-matched controls only in having significantly greater uterine length and CSA. Comparison of the pelvic ultrasound parameters between patient groups (IPT, CPP, IPA) and age-matched controls revealed significantly higher values in CPP for uterine length, uterine CSA and ovarian volume. Ovarian volume was also greater in IPT than in IPA. Ovarian morphology was significantly different in patients (IPT, CPP, IPA) compared with age-matched controls, but none of the ovarian morphological appearances was exclusive to a single condition. In conclusion: (i) pelvic ultrasound parameters increase progressively from birth to maturity, but no clear cut-off values can be established between age ranges; (ii) pelvic ultrasound variables reach adult values during puberty, with differences in the timing that may reflect geographical variations; (iii) the multicystic ovarian appearance occurs just before the onset of puberty; (iv) pelvic ultrasonography cannot always differentiate clearly between different disturbances of puberty and therefore cannot supersede other observations and investigations in the evaluation of pubertal disorders; and (v) in this study we propose a more detailed pelvic ultrasound terminology that can avoid apparent confusion in defining ovarian ultrasound appearance.     

Secular trend of puberty

The aim of our study was to evaluate the age of the onset of pubertal characteristics in a population of Northern Italy and to compare our data with the pubertal staging scale defined by Tanner in 1976. These observations may help us to verify if even in Italy there is a positive secular change in sexual maturation, as has been observed in many European countries. We studied 3510 children (1868 males and 1642 females) aged 6-15 years, born between 1983 and 1996. In every subject sexual maturity was evaluated according to Tanner stages. We calculated the percentile distribution for ages of attainment of B2 and PH2 stages for females and G2, PH2 and testicular volume = or >4 ml (VT4) for males. In females the percentile values for B2 were: 3rd=8.1, 50th=10.5, and 97th=12.6 years. In males the percentile values for G2 and VT4 were: 3rd=8.8 and 9.1 years respectively, 50th=11 years, and 97th=13.4 and 13.3 years respectively. 3rd, 50th, and 97th centiles for pubic hair stage 2 were 8.1, 10.6 and 12.6 years for females and 8.8, 11.2 and 13.4 years for males. For all stages an earlier pubertal development was seen in comparison with Tanner data. One hundred-twenty-five girls had already reached menarche. Median (interquartile range) age at menarche was 11.9 (11.4-12.4) years showing a decrease compared with Tanner values. Our data clearly demonstrate a positive secular trend in pubertal development and point out the need of having updated references values of the timing of sexual maturation for the whole Italian population.     

Pubertal development in The Netherlands 1965-1997

We investigated pubertal development of 4019 boys and 3562 girls >8 y of age participating in a cross-sectional survey in The Netherlands and compared the results with those of two previous surveys. Reference curves for all pubertal stages were constructed. The 50th percentile of Tanner breast stage 2 was 10.7 y, and 50% of the boys had reached a testicular volume of 4 mL at 11.5 y of age. Median age at menarche was 13.15 y. The median age at which the various stages of pubertal development were observed has stabilized since 1980. The increase of the age at stage G2 between 1965 and 1997 is probably owing to different interpretations of its definition. The current age limits for the definition of precocious are close to the third percentile of these references. A high agreement was found between the pubic hair stages and stages of pubertal (genital and breast) development, but slightly more in boys than in girls. Menarcheal age was dependent on height, weight, and body mass index. At a given age tall or heavy girls have a higher probability of having menarche compared with short or thin girls. A body weight exceeding 60 kg (+1 SDS), or a body mass index of >20 (+1 SDS), has no or little effect on the chance of having menarche, whereas for height such a ceiling effect was not observed. In conclusion, in The Netherlands the age at onset of puberty or menarche has stabilized since 1980. Height, weight, and body mass index have a strong influence on the chance of menarche.     

Variations in the Pattern of Pubertal Changes in Boys

Mixed longitudinal data on the physical changes at puberty in 228 normal boys are presented together with normal standards for stages of genital and pubic hair development.The genitalia began to develop between the ages 9½ years and 13½ years in 95% of boys (mean = 11.6 ± 0.09) and reached maturity at ages varying between 13 and 17 (mean = 14.9 ± 1.10). The age at which pubic hair first appeared was not accurately determined, but its development through the later stages was studied. It reached the equivalent of an adult female distribution at a mean age of 15.2 ± 0.01 years.On average the genitalia reached the adult stage 3.0 years after they first began to develop; but some boys completed this development in as little as 1.8 years while others took as much as 4.7 years. Some boys complete the whole process in less time than others take to go from Stage G2 to Stage G3. The genitalia begin to develop before pubic hair is visible in photographs in practically all boys.The 41 boys in whom it could be studied reached their maximum rate of growth (peak height velocity) at a mean age of 14.1 ± 0.14 years.Very few boys (about 5%) reached peak height velocity before their genitalia were in Stage 4 and over 20% did not do so until their genitalia were adult. Peak height velocity is reached, on the average, nearly 2 years later in boys than in girls, but the boys'' genitalia begin to develop only about 6 months later than the girls'' breasts. Pubic hair appears about 1½ years later in boys than in girls.