Earlier Menarche Can Be an Indicator of More Body Fat:Study of Sexual Development and Waist Circumference in Chinese Girls

Objective This paper aims to study the relationship between body fat and sexual development in Chinese girls with different waist circumference.Methods Six thousand one hundred and fifty six girls aged 6-19 were sampled.Their body weight,height,waist circumference,percentage of body fat and secondary sex characteristics were measured.All the subjects were divided into three groups：low class waist circumference,moderate class waist circumference and high class waist circumference.The menarche percentages were analyzed by using the status method.The menarche ages were analyzed by using the retrospective method.Estimates for mean age at entry into a pubertal stage and menarche were calculated by a probit analysis.Results The incidences of moderate class and high class waist circumstance were 20.94% and 25.27%,respectively.The sexual development of the former was earlier than that of the latter.The percentages of the menarche were detected as high classmoderate classlow class.The menarche ages were expressed as high classmoderate classlow class.Conclusion A close association is found between the waist circumference and sexual development,especially the menarche age.Girls with high class waist circumference are more vulnerable to earlier menarche and excess body fat.It is important to control the occurrence of central obesity through monitoring the change of waist circumference in puberty for girls＇ health.

The Secular Tendency of the Age at Menarche in a Representative Sample of Mexican Girls from an Urban Zone in Central Mexico

Objective: To investigate the age at menarche, pubarche and telarche in a representative sample of residents of an urban zone of Leon, Guanajuato, Central Mexico and to evaluate the secular change of the age at menarche between 1985 and 2000. Methods: Using status quo and retrospective methods, menarcheal, pubarcheal and telarcheal status of girls 8 - 17 years of age (n = 1093) were determined. Multiple regression analysis and logistic regression were used to determine factors that were related to or predictive of age at menarche. Results: Median ages for menarche, pubarche and telarche in our studied sample were: 11.9 ± 0.04;11.13 ± 1.25 and 10.84 ± 1.34 years, respectively. A direct correlation was found between the age of menarche of adolescents and that of their mother (p p p = 0.001), but an indirect correlation was found with the girls’ hip circumference (p = 0.004). We demonstrated a clear secular tendency towards an earlier onset of menarche by comparing our results (11.9 ± 0.04) with data from 1985 (12.8 ± 1.3) for adolescents from the same city. Conclusion: We demonstrated a clear reduction in age at menarche of approximately 0.75 year/decade, higher than Tanner’s finding in 1962, but similar than that of Malina et al. in 2004.

Age at Menarche among School Adolescents Girls in Saudi Arabia: Environmental Factors

Background: Menarche is the first menstrual period of a girl at puberty. The timing of menarche is significant for health in future life. Saudi Arabia has developed immensely over the last three decades as evidenced by the economic and health sectors throughout all parts of the vast Kingdom. The current study measured the menarche age of school adolescents Girls in Saudi Arabia and explored environmental factors that could impact the onset of menarche. Method: This cross-sectional study was conducted on 1486 healthy Saudi school adolescents’ girls between 10 - 19 years old. The data were collected in 2016 using self-administered questionnaires. Health status, dietary intake, physical activities and parent’s education were recorded along with other environmental factors. Data were analyzed using SPSS version 17.1. Results: Out of 1486, 767 girls (51.6%) had experienced menarche with a mean age of 12.46 ± 1.57;681 girls (45.8%) had experienced menarche at age of 13 - 15;38 girls (2.6%) had experienced menarche at age of 16. A significant association between menarche and social factors was detected. Besides, the study discovered a significant association between menarche and the lifestyle of the studied groups.

Analysis on Menarche Age of Chinese Reproductive Women

To analyze the age of menarche of Chinese reproductive women and some related factors. Material & Methods The data used in this paper was collected through 'National Demography and Reproductive Health Survey' of China in 1997. Results The menarche age declined successively and dramatically, from 16.45 years of the women born in 1947～1949 to 13.86 of those born in 1980～1982, decreasing by 0.65 years per decade. Conclusions The results revealed that some factors such as residence, year of birth, nationality, education level and living region had effects on the menarche age.

Menarcheal Age and Nutritional Status of Secondary School Adolescent Girls in Nnewi, South-East Nigeria

Background: Menarche is an important indicator of pubertal development in adolescent girl. Age at menarche has declined over the years attributable to many factors. Objective: To determine the age at menarche of secondary school adolescent girls and its relationship with anthropometric values, nutritional status, social class of parents, and category of school. Subjects and Methods: Cross-sectional study of 311 secondary school adolescent girls (10-19 years) from two secondary schools (boarding school-Maria Regina secondary school Nnewi and Anglican Girls Secondary School Nnewi-day school) in Nnewi North LGA of Anambra State, Southeastern Nigeria, between May and June 2018. Semi-structured questionnaires were used to extract their data on sociodemographic characteristics and age at menarche. Height and weight were measured using WHO recommended methods. Body mass index (BMI) was determined using the Quetelet index (kg/m2). The relationship between menarche and anthropometric measurement was determined. Results: Of the 313 participants, 212 (68.2%) were post menarcheal, while 99 (31.8%) were pre-menarcheal. The mean age at menarche was 12.79 ± 1.20 years. Early menarcheal age was associated with significantly higher anthropometric values and BMI. Boarding-students had significantly lower menarcheal age (12.69 ± 1.26) compared to the day students (12.86 ± 1.15);students with parents of the high social class had lower menarcheal age (12.56 ± 1.51), compared to those with parents of low social class (12.90 ± 1.05). Conclusion: There was a significant relationship between age at menarche and the nutritional status of the participants. Students with parents of high social class and those in boarding houses had a relatively lower age at menarche. Adequate attention should be given to the nutrition of premenarcheal school girls and those of parents with low social class. Boarding school authorities should ensure measures to alleviate stress amongst boarding-school students.

Secular trends and urban–rural disparities in the median age at menarche among Chinese han girls from 1985 to 2019

Background Menarche is a substantial milestone of female puberty.Timing of age at menarche is considered the key to understanding the potential linkages with women’s health outcomes later in life.This study aimed to explore the secular trends and urban‒rural disparities in the median age at menarche among Chinese Han girls from 1985 to 2019.Methods Data were extracted from the 1985,1995,2005,2014,and 2019 Chinese National Surveys on Students’Constitution and Health,which were nationally representative cross-sectional studies,and a total of 173,535 Han girls aged 9–18 years were examined.Girls were asked whether menarche had occurred.The median age at menarche was estimated by probit analysis.Z tests were used to compare the differences between survey years and between urban and rural areas.Results The median age at menarche among Chinese Han girls decreased from 13.37 years in 1985 to 12.00 years in 2019,and the overall decrease was more significant in rural areas(1.77 years)than in urban areas(0.99 years).The average five-year change in the decrease in the median age at menarche showed an accelerating and then slowing pace;and it was observed similarly in both urban and rural areas.The urban‒rural disparities shrank from 0.64 years in 1985 to 0.44 years in 1995,then to 0.27 years in 2005,0.24 years in 2014,and finally to−0.14 years in 2019.Conclusions The median age at menarche among Chinese Han girls continued to decline from 1985 to 2019 but at a slowing pace in the last five years.Urban‒rural disparities gradually narrowed.Sexual and reproductive health education and interventions to prevent the decline in the age of menarche are needed,especially in rural areas.

Bivariate genome-wide association study suggests that the DARC gene influences lean body mass and age at menarche

Lean body mass （LBM） and age at menarche （AAM） are two important complex traits for human health. The aim of this study was to identify pleiotropic genes for both traits using a powerful bivariate genome-wide association study （GWAS）. Two stud- ies, a discovery study and a replication study, were performed. In the discovery study, 909622 single nucleotide polymor- phisms （SNPs） were genotyped in 801 unrelated female Han Chinese subjects using the Affymetrix human genome-wide SNP array 6.0 platform. Then, a bivariate GWAS was performed to identify the SNPs that may be important for LBM and AAM. In the replication study, significant findings from the discovery study were validated in 1692 unrelated Caucasian female subjects One SNP rs3027009 that was bivafiately associated with left arm lean mass and AAM in the discovery samples （P=7.26x10-6） and in the replication samples （P=0.005） was identified. The SNP is located at the upstream of DARC （Duffy antigen receptor for chemokines） gene, suggesting that DARC may play an important role in regulating the metabolisms of both LBM and AAM.

鄂温克族与鄂伦春族的群体遗传学研究(续)

本次调查采印了645名鄂温克族和424名鄂伦春族中、小学生和部分牧民、猎民的指纹和掌纹。观察了各型指纹出现率、指纹总嵴数、atd角和掌褶纹等指标。 1.各型指纹出现率 弓(A)、尺侧箕(L^u)、桡侧箕(L^r)和斗(W)的出现频率见表11。额左旗和陈旗鄂温克人中斗多于箕,与汉族相似。有些指纹型在某个手指上较为多见。

Reproductive disturbances among Saudi adolescent girls and young women with type 1 diabetes mellitus

AIM To identify reproductive disturbances among adolescent girls and young women with type 1 diabetes mellitus(T1 DM) in Saudi Arabia.METHODS This cross sectional study was conducted among 102 female with T1 DM,(aged 13-29 years) who attended the Diabetes Clinic at Diabetes Treatment Center, Prince Sultan Military Medical City, Saudi Arabia between April 2015 to March 2016. Clinical history, anthropometric characteristics and reproductive disturbance were collected through a questionnaire.RESULTS Of 102 patients included in this analysis, 26.5%(27/102) were reported that they experienced an irregular menses. Of these patients, when compared to whose diabetes was diagnosed before menarche(35.4%, 17/48), patients diagnosed with diabetes after menarche(18.5%, 10/54) showed significantly less irregular menses(difference 16.9%, P = 0.04). Similarly, compared to patients diagnosed with diabetes prior to menarche(mean age 12.9 years; n = 48), patients diagnosed with diabetes after menarche(meanage 12.26 years; n = 54) were found to have 0.64 years delay in the age of menarche(P = 0.04). Among the studied patients, 15.7%(16/102) had polycystic ovary syndrome(PCOS). Of these PCOS patients, 37.5%(6/16) had irregular menses, 6.3%(1/16) had Celiac disease, 37.5%(6/16) had Hashimoto thyroiditis and 18.7%(3/16) had acne.CONCLUSION More than one fourth of the study population with T1 DM experiencing an irregular menses. Adolescent girls and young women diagnosed with diabetes prior to menarche showed higher menstrual irregularity and a delay in the age of menarche.

Application of Survival Analysis in Studies of Human Ontogeny

The main goal of this work is to demonstrate the suitability of survival analysis for ontogenetic studies. The research material includes retrospective data of the age of the occurrence of ontogenetic events such as birth (N = 487), menarche (N = 2016) and menopause (N = 3597). In order to study the time of occurrence of ontogenetic events and to indicate the impact of environmental factors the survival analysis was applied. First, the percentiles of functions established for studied events were calculated. Next, the Kaplan-Meier survival curves were derived. In the last step theinfluence of environmental factors was established and the comparison of groups determined based on the chosen factors was performed. The delivery time shows that 14% of infants were bornpreterm. The risk of preterm delivery increases with the severity of factors disrupting pregnancy (from none to coexisting maternal and fetal risk factors) (;p < 0.001). In the case of menarche percentile positions indicate that the menarche occurs between the 12thand the 14thyear of life as the period in which most girls exceed the puberty threshold. The Cox’s proportional hazard model indicates that the time of menarche occurrence is significantly depended (;p < 0.001) on the place of the mother’s residence and number of children in the family (respectively p < 0.03 and p < 0.001). The time interval established for 50% occurrence of this experience was designated between the 49th and the 52nd years of life. The time of menopause occurrence is significantly depended on both of considered factors: the educational level and smoking cigarettes (, p < 0.001). Survival analysis is suitable for studies of the distribution in time of developmental events. It can be used to indicate the factors which significantly influence the course of development by modifying the duration of developmental stages.

Timing and secular trend of pubertal development in Beijing girls

Background:Historical research is limited in changes in pubertal development in Chinese girls.We aimed to identify the timing of pubertal characteristics and the secular trend of menarche age among Beijing girls from the 1980s through the 2000s.Methods:Six data sets were analyzed,including the Beijing Child and Adolescent Metabolic Syndrome study in 2004,where 9778 Bejing girls aged 6–18 years were studied.The Fetal Origins of Adult Disease study provided retrospective menarche age from 1940 through 1960.Other four studies were conducted in Beijing to obtain supplementary information to assess secular trend in menarche age.Linear regression method was used to analyze the data.Results:Among Beijing girls in 2004,the median age at menarche was 12.1 years,which was 0.6 years earlier in urban than in rural areas.The median age at Breast Tanner Stage 2 was 9.5±1.2 years,representing 9.4±1.1 years and 9.6±1.2 years for urban and rural girls,respectively.In contrast,the median age at Pubic Hair Tanner Stage 2 was 11.1±1.1 years,representing 10.8±1.1 and 11.4±1.1 years for urban and rural girls,respectively.The menarche age of urban girls decreased by 4.2 months per decade,and that of rural girls by 9.6 months per decade from 1980 to 2004.Conclusions:Urban girls mature earlier than rural girls in Beijing.A secular trend towards earlier menarche was observed between the 1980s and the 2000s.

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 fi nal 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 fi nal adult height.