Age at menarche: secular trends and association with adult anthropometric measures

Coming of age in war: Early life adversity, age at menarche, and mental health

Armed conflict and forced migration (ACFM) represent a set of extreme environments that are increasingly common for children and adolescents to experience. Adolescence may constitute a sensitive period (puberty and psychoneurological maturation) through which ACFM adversity leaves a lasting mark. Adolescence has become a focal point for analysis and intervention as it relates to the effects of early life adversity on puberty, linear growth, and mental health. Research in public health and psychological science suggests early life adversity (ELA) may accelerate puberty, heightening risks for mental health disorders. However, it is not well substantiated whether ACFM-derived adversities accelerate or delay relative pubertal timing. Secondly, ACFM provides salient context through which to probe the relationships between nutritional, psychosocial, and demographic changes and their respective impact on puberty and mental health. We conducted a narrative review which 1) examined constructions of early life adversity and their proposed influence on puberty 2) reviewed empirical findings (n = 29 studies, n = 36 samples) concerning effects of ACFM ELA on age at menarche and 3) discussed proposed relationships between early life adversity, puberty, and mental ill-health. Contrary to prior research, we found war-derived early life adversity was more consistently associated with pubertal delay than acceleration and may exert counterintuitive effects on mental health. We show that ELA cannot be operationalized in the same way across contexts and populations, especially in the presence of extreme forms of human stress and resilience. We further discuss the ethics of puberty research among conflict-affected youth.

Early or late menarche is associated with reduced fecundability in the Norwegian Mother, Father and Child Cohort Study

STUDY QUESTION

Is age at menarche associated with fecundability?

SUMMARY ANSWER

Both early (<11 years) and late (>15 years) menarche is associated with decreased fecundability.

WHAT IS KNOWN ALREADY

Previous studies on age at menarche and fecundability have been inconclusive. Women with early or late menarche are at increased risks of gynaecological and autoimmune diseases that may affect their ability to conceive.

STUDY DESIGN, SIZE, DURATION

We conducted a retrospective cohort study including 67 613 pregnant women, participating in the Norwegian Mother, Father and Child Cohort Study between 1999 and 2008, with self-reported information on age at menarche and time to pregnancy. We included planned pregnancies that were conceived either naturally or with the help of assisted reproductive technologies.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We calculated fecundability ratios (FRs) with 95% CIs representing the cycle-specific probability of conception by categories of age at menarche. FRs were adjusted for participants' pre-pregnancy body mass index, highest completed or ongoing education level, and age at initiation of trying to conceive.

MAIN RESULTS AND THE ROLE OF CHANCE

We observed a 7% lower probability of conceiving during any given menstrual cycle up to 12 cycles in women with early or late menarche. Among women with menarche >15 years, the adjusted FR was 0.93 (95% CI: 0.90-0.97), and among women with menarche <11 years, the adjusted FR was 0.93 (95% CI: 0.89-0.99), when compared to women with menarche between 12 and 14 years.

LIMITATIONS, REASONS FOR CAUTION

The study-population consisted of women pregnant in their second trimester, excluding those with persistent infertility. Recall of age at menarche and time to pregnancy may be inaccurate.

WIDER IMPLICATIONS OF THE FINDINGS

Both early (<11 years) and late (>15 years) menarche was associated with decreased fecundability. Women experiencing early menarche or late menarche may be counselled accordingly.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the Norwegian Institute of Public Health, Oslo, Norway, and by Telemark Hospital Trust, Porsgrunn, Norway and was partly supported by the Research Council of Norway through its centres of excellence funding scheme (project number 262700) and the Research Council of Norway (project no. 320656). The project was co-funded by the European Union (ERC, BIOSFER, 101071773). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. M.C.M. has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement no. 947684). The authors report no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Spatio-temporal trends of the age-at-menarche percentiles among Portuguese women since 1920

BACKGROUND

This work aims to study the spatio-temporal evolution of a woman's age at menarche in the central region of Portugal. One of the concerns of the study is early or late menarches; thus, we consider percentile regression to build the respective curves as opposed to the more traditional mean regression approach.

METHODS

We analysed the data from [Formula: see text] women born in the period 1920-1973 who attended a free breast cancer screening program between 1990 and 2019. Distributional regression models inside the package GAMLSS in R were considered. These methods allowed us not only to model the location (mean) of the specific probability distribution of the age at menarche, but also allowed for the scale (variance) parameter of this distribution to depend on covariates. Additionally, a spatial random-effect was considered in order to capture the correlation at the regional level. The obtained clustered spatial effects were analysed to assess geographical differences among the percentiles of the age at menarche by year of birth.

RESULTS

A decreasing trend in the age at menarche (about 1.5 years in 5 decades) and regional differences for all the considered percentiles were found. Women living in the north-central areas of the central region of Portugal tend to have menarche at older ages.

CONCLUSION

We obtained percentile estimates for the age at menarche by year of birth and region of residence and demonstrated that these two explanatory variables have an impact on the explanation about the decreasing trend in age at a woman's first menstruation.

Sex and gender differences in autoimmune demyelinating CNS disorders: Multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD) and myelin-oligodendrocyte-glycoprotein antibody associated disorder (MOGAD)

Multiple sclerosis (MS), Neuromyelitis optica spectrum disorder (NMOSD) and Myelin-Oligodendrocyte-Glycoprotein antibody associated disorder (MOGAD) are demyelinating disorders of the central nervous system (CNS) of autoimmune origin. Here, we summarize general considerations on sex-specific differences in the immunopathogenesis and hormonal influences as well as key clinical and epidemiological elements. Gender-specific issues are widely neglected starting with the lacking separation of sex as a biological variable and gender comprising the sociocultural components. As for other autoimmune diseases, female preponderance is common in MS and NMOSD. However, sex distribution in MOGAD seems equal. As in MS, immunotherapy in NMOSD and MOGAD is crucial to prevent further disease activity. Therefore, we assessed data on sex differences of the currently licensed disease-modifying treatments for efficacy and safety. This topic seems widely neglected with only fragmented information resulting from post-hoc analyses of clinical trials or real-world post-marketing studies afflicted with lacking power and/or inherent sources of bias. In summary, biological hypotheses of sex differences including genetic factors, the constitution of the immune system and hormonal influences are based upon human and preclinical data, especially for the paradigmatic disease of MS whereas specific data for NMOSD and MOGAD are widely lacking. Epidemiological and clinical differences between men and women are well described for MS and to some extent for NMOSD, yet, with remaining contradictory findings. MOGAD needs further detailed investigation. Sex-specific analyses of safety and efficacy of long-term immunotherapies need to be addressed in future studies designed and powered to answer the pressing questions and to optimize and individualize treatment.

Influence of Childhood Adversity and Infection on Timing of Menarche in a Multiethnic Sample of Women

Childhood adversities (CAs) and infections may affect the timing of reproductive development. We examined the associations of indicators of CAs and exposure to tonsillitis and infectious mononucleosis (mono) with age at menarche. A multiethnic cohort of 400 women (ages 40–64 years) reported exposure to parental maltreatment and maladjustment during childhood and any diagnosis of tonsillitis and/or mono; infections primarily acquired in early life and adolescence, respectively. We used linear and relative risk regression models to examine the associations of indicators of CAs individually and cumulatively, and history of tonsillitis/mono with an average age at menarche and early onset of menarche (<12 years of age). In multivariable models, histories of mental illness in the household (RR = 1.44, 95% CI: 1.01–2.06), and tonsillitis diagnosis (RR = 1.67, 95% CI: 1.20–2.33) were associated with early menarche (<12 years), and with an earlier average age at menarche by 7.1 months (95% CI: −1.15, −0.02) and 8.8 months (95% CI: −1.26, −0.20), respectively. Other adversities indicators, cumulative adversities, and mono were not statistically associated with menarcheal timing. These findings provided some support for the growing evidence that early life experiences may influence the reproductive development in girls.

Age at menarche, eating disorders, and their relationships with some parameters in female adolescents in Iran

Objective

Adolescence as one of the most challenging periods of humans’ growth is accompanied with major physical, behavioural, social-emotional, and neuroendocrine changes. Early maturation and eating disorders (EDs) have been reported to be associated with adverse health conditions. Therefore, the present study was conducted to assess age of onset of menarche (AM), EDs, and their possible relationships with weight, body mass index (BMI), waist circumference (WC), and socioeconomic status (SES) in the Iranian female adolescents.

Results

In the study population, mean ± standard deviation (SD) of AM was 12.95 ± 1.14 years. Inverse significant relationships were found between weight and AM, also BMI and AM (p < 0.05). There was a negative association between weight and anorexia nervosa (AN), BMI and AN, also WC and AN (p < 0.001). A significant positive correlation was found between SES and AM, also EDs and AM (p < 0.05) then between weight and bulimia nervosa (BN) & binge-eating disorder (BED), BMI and BN & BED, also WC and BD & BED (p < 0.001). Our results also revealed that AM in mothers had a significant positive relationship with AM in their daughters (p < 0.001, r = 0.34).

Trend of Menarcheal Age among Korean Girls

BACKGROUND

Menarcheal age has been decreasing worldwide. However, few recent studies have observed trends in menarcheal age in larger populations, and the cutoff age for early menarche remains unclear. Therefore, we aimed to analyze recent trends of menarcheal age and to determine the cutoff age of early menarche based on nationally representative data.

METHODS

We conducted a cross-sectional study of 351,006 Korean girls aged 12-18 years who were born in 1988-2003 based on the data of the 2006-2015 Korea Youth Risk Behavior Survey. We identified the distribution of age at menarche using the complex sample Cox regression model. Trends in the prevalence of early menarche were determined using the complex sample linear model.

RESULTS

Ninety-five percent of all the participants reported they had experienced menarche. The mean menarcheal age was 13.0 years (95% confidence intervals [CIs], 12.92-13.04) for girls born in 1988 and decreased to 12.6 years (95% CI, 12.54-12.61) for girls born in 2003. The cutoff age (the 3rd percentile value) for early menarche was 10.5 years during the study period. The prevalence of early menarche significantly increased from 1.8% in 2006 to 3.2% in 2015 (P-for-trend < 0.001). Downward trends of menarcheal age were noted across all body mass index groups, and this trend was most prominent in the obese group.

CONCLUSION

We reported an ongoing downward trend in menarcheal age in Korean girls born in 1988-2003, decreasing by 0.4 years over the 15 years.

Timing and determinants of age at menarche in low-income and middle-income countries

INTRODUCTION

Understanding the timing and determinants of age at menarche is key to determining potential linkages between onset of puberty and health outcomes from a life-course perspective. Yet, we have little information in low-income and middle-income countries (LMICs) mainly due to lack of data. The aim of this study was to analyse trends in the timing and the determinants of menarche in LMICs.

METHODS

Using 16 World Fertility Survey and 28 Demographic and Health Surveys (DHS) from 27 countries, we analysed cohort trends and used fixed-effects models for DHS surveys to investigate sociodemographic and regional effects in the timing of age at menarche.

RESULTS

Trends of the mean age at menarche across time within and between countries show a declining or stalling path. Results of the determinant modelling show the relationship with wealth changes over time although not consistently across countries. We see a shift from poorer women having earlier menarche in earlier surveys to richer women having earlier menarche in later surveys in Indonesia, the Philippines and Yemen, while in Egypt, the reverse pattern is evident.

CONCLUSIONS

There is a considerable gap in both literature and data on menarche. We see a trend which is declining rapidly (from 14.66 to 12.86 years for the 1932 and 2002 cohorts, respectively), possibly at a faster pace than high-income countries and with a strong link to socioeconomic status. This study calls for menarche questions to be included in more nationally representative surveys and greater use of existing data because of its impact on life-course health in fast-ageing settings. Further studies will need to investigate further the use of the age at menarche as an indicator of global health.

Association between age at menarche and body mass index, waist circumference, waist to hip ratio, and waist to height ratio in adult women

OBJECTIVES

The aim of the present study was to examine associations between age at menarche and body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), and waist-to-hip ratio (WHR) in young adult women.

METHODS

Anthropometric data and age at menarche information were collected in two cross-sectional surveys conducted in the years 2004-2006 (Cohort 1) and 2016-2018 (Cohort 2). A total of 2419 women, aged 19-24 years., were included.

RESULTS

Statistically significant relationships between age at menarche and BMI, WHtR, and WC were observed. The values of the anthropometric parameters decreased with increasing age at menarche. The onset of menstruation before the age of 12 years. was linked to a heightened risk of overweight and obesity (BMI ≥ 25) and abdominal obesity defined as WC > 80 cm and/or WHtR ≥ 0.5. First menstruation after the age of 14 y. was associated with a lower risk of overweight and obesity (BMI ≥ 25, WC > 80 cm and/or WHtR ≥ 0.5), as well as a higher risk of being underweight (BMI < 18.5 and/or WHtR < 0.4). Associations between anthropometry and menarcheal timing were stronger in Cohort 1.

CONCLUSION

Both early and late onset of menarche are associated with abnormal body composition: Early menarche is associated with overweight, while later maturing girls have a heightened risk of underweight.

Medieval menarche: Changes in pubertal timing before and after the Black Death

OBJECTIVES

Bioarcheological evidence suggests stature increased in males but decreased in females after the Black Death (1348-1350 CE). Because tradeoffs between growth and reproduction can result in earlier ages at menarche and lower limb length, we assess menarcheal age between 1120 and 1540 CE to better understand the health of medieval adolescent females before and after the plague.

MATERIALS AND METHODS

Our sample comprises 74 adolescent females from St. Mary Spital, London (1120-1540 CE) within the age range during which menarche occurs (10-25 years). They were assessed as being pre- or post-menarcheal and divided into three groups: Early Pre-Black Death (n = 13), Late Pre-Black Death (n = 38), and Post-Black Death (n = 23). Changes in the ages of pre- and post-menarcheal females were assessed using Mann-Whitney tests.

RESULTS

The average age of post-menarcheal females increased from the Early- to Late Pre-Black Death periods and declined after the Black Death.

CONCLUSIONS

Short stature can reflect unfavorable growth environments, while younger menarcheal age indicates improved living conditions. The paradoxical pattern of female, but not male, stature reduction after the Black Death might reflect the association of early menarche with lower limb length and signal that adolescent females experienced improved health conditions after the epidemic. Our focus on pre- and post-menarche within a limited age span provides a novel approach for inferring average ages of menarche over time. Pathways to skeletal development and reproductive investment are part of an integrated system, providing a bridge between life history research in bioarchaeology and human biology.

Early age at menarche and its associated factors in school girls (age, 10 to 12 years) in Bangladesh: a cross-section survey in Rajshahi District, Bangladesh

Background

Early onset of menarche is one of the most important factors for breast cancer and other associated health hazards. The aim of this study was to investigate the early age at menarche and its associated factors in school girls (age, 10–12 years) in Rajshahi District, Bangladesh.

Methods

Data was collected from Rajshahi District, Bangladesh, using multistage random sampling. Independent sample t test and binary logistic regression model were used in this study. A total number of 386 school girls aged 10–12 years were considered as a sample for this study.

Results

This study revealed that more than 48% girls already attained menarche within the age of 12 years, among them 25.6%, 41.0%, and 58.3% girls experienced menarche at the age of 10, 11, and 12 years, respectively. It was observed that the menarcheal girls were significantly taller (p < 0.01) and heavier (p < 0.01) than non-menarcheal girls. The menarcheal girls’ mothers were heavier (p < 0.01), shorter (p < 0.01), had more BMI (p < 0.01), reached menarche (p < 0.05) earlier than non-menarcheal girls’ mothers. Menarcheal girls had less number of siblings (p < 0.01) and lower order of birth (p < 0.05) than non-menarcheal girls. After controlling the effect of other factors, multiple logistic regression model demonstrated that obese girls were more likely to attain menarche than under- [AOR = 0.279, CI 95% 0.075–0.986; p < 0.05] and normal [AOR = 0.248, CI 95% 0.082–0.755; p < 0.05] weight girls. Urban school girls had more chance to get menarche than rural school girls at same age (AOR = 0.012, 95% CI 0.003–0.047; p < 0.01).

Conclusions

Therefore, modern lifestyle changes may have the important factors for early age at menarche of the studied girls in Bangladesh.

Variation in menarcheal age of school-aged female athletes engaged in different types of sport

It is widely known from the literature that the rate of physical development and sexual maturation is not only determined by genetics but is also modified by physical workload factors. Given the above, this paper aimed at comparing menarcheal age of school-aged athletes engaged in different types of sport (and their respective workloads) after controlling for physical traits such as body height and mass and slenderness ratio. The survey was conducted in 2017 in 6 sports schools in Poland’s Lubuskie Voivodeship. Body height and mass were measured and the slenderness index (body height divided by the cubic root of body weight) was used to establish body build. The age of menarche was self-reported by the study participants. In total, 232 girls aged 9–18 were included in the research, of whom 125 reported their age of menarche. The age-adjusted arithmetic means and standard deviations were calculated for the study participants’ estimates. The raw data were then transformed into standardized z-score values. The significance of differences was assessed by Mann-Whitney U test as an alternative to the t-test when a given variable was not normally distributed. Pearson’s correlation coefficient was used to evaluate linear relations between the workload and age at menarche. It was found that dancers, acrobats and swimmers reported the youngest menarcheal ages. Girls practising most demanding sport disciplines (in terms of strength and endurance) reported the oldest age at menarche. Girls practising more than 3 times per week had menarche later than those practising 3 times a week or less, and the difference was statistically significant. In conclusion it might be stated that the type of sport discipline has a significant effect on age of menarche. Sport disciplines involving heavier physical exertion usually delay the onset of menstruation.

Associations between maternal age at menarche and anthropometric and metabolic parameters in the adolescent offspring

OBJECTIVE

We examined the associations between maternal age at menarche and anthropometry and metabolism in adolescent offspring.

METHODS

Anthropometric, metabolic and blood pressure data were obtained from 304 girls and 190 boys aged 11-16 years attending school in Hangzhou (China). Age at menarche for both mothers and daughters was self-reported. Fasting blood samples were obtained and all participants underwent clinical examinations. Obesity was defined as BMI ≥95th percentile for age and sex.

RESULTS

Older maternal age at menarche was associated with older age of their daughters at menarche (r = 0.21; P < 0.001). Mother's age at menarche was not associated with anthropometry or metabolism of daughters. However, younger maternal age at menarche was associated with increased hip and waist circumferences, and BMI SDS of their sons. Boys whose mothers were ≤13 years at menarche had an adjusted relative risk of obesity 3-fold greater than sons of mothers with a later menarcheal onset (2.96; 95% CI 1.49, 5.87). Among daughters, every 1-year increase in their age at menarche was associated with a 0.34 SDS reduction in BMI. Increasing age at menarche was also associated with reduced waist and hip circumferences (-1.5 and -1.8 cm/y, respectively) and waist-to-height ratio (-0.008 per year). Girls in the youngest menarcheal age tertile (8.8-11.6 years) had diastolic blood pressure 2.2 mm Hg higher than other girls (P = 0.029).

CONCLUSIONS

Younger maternal age at menarche is associated with increased obesity risk in their sons, but not daughters. However, girls who experience menarche earlier have a less favourable anthropometric profile.

The associations between left-hand digit ratio (2D:4D) and puberty characteristics among Chinese girls

BACKGROUND

The aim of this study was to analyse the associations of left-hand digit ratio (2D:4D), digit length and puberty characteristics to show the role of prenatal hormones in development among Chinese girls.

METHOD

A total of 318 Chinese girls aged 8-15 years were recruited using a stratified cluster sampling method. The index finger (2D), ring finger (4D) of the left hand, oestradiol and testosterone were measured, and age at menarche (AAM), breast (high and low) and pubic hair (high and low) development were recorded.

RESULTS

Girls who had experienced menarche had longer left digits (2D and 4D) and higher oestradiol, testosterone than those who had not. The high breast group had longer digits (2D and 4D), and higher oestradiol than the low breast group. With regard to pubic hair development, the high group had high 2D:4D, longer 2D and higher oestradiol, testosterone than the low group. After adjusting for oestradiol and testosterone, 4D length was positively related to occurrence of menarche. In addition, 2D and 2D:4D were significantly correlated with pubic hair development after adjusting for oestradiol, respectively.

CONCLUSION

Prenatal hormone level may be related to the development of puberty characteristics among Chinese girls.

Time Trends in Age at Menarche and Related Non-Communicable Disease Risk during the 20th Century in Mexico

Developed countries have shown a time trend towards a younger age at menarche (AAM), which is associated with increased risk of later obesity and non-communicable diseases. This study aimed to assess whether a time trend in AAM is associated with disease risk in Mexican women (n = 30,826), using data from the Mexican National Health Survey (2000). Linear and log binomial regression was used for nutritional and disease outcomes, while Welch⁻ANOVA was used to test for a time trend. AAM (in years) decreased over time (p < 0.001), with a maximal difference of 0.99 years between the 1920s (13.6 years) and 1980s (12.6 years ). AAM was negatively associated with weight (β = -1.01 kg; 95% CI -1.006, -1.004) and body mass index (BMI) (β = -1.01 kg/m²; -1.007, -1.006), and positively with height (β = 0.18 cm; 0.112, 0.231). AAM was associated with diabetes (RR = 0.95; 0.93, 0.98) and hypercholesterolemia (RR = 0.93; 0.90, 0.95), but not with hypertension, breast cancer or arthritis. In Mexico, AAM decreased significantly during the 20th century. AAM was inversely associated with adult weight and BMI, and positively with height. Women with a later AAM had a lower risk of diabetes and hypercholesterolemia.

Body Mass Index Categories and Attained Height in Portuguese Adults

OBJECTIVE

To analyze the associations between height and BMI categories in a Portuguese representative sample.

METHODS

This is a cross-sectional study with a representative sample of 32,644 Portuguese adults (52.4% females). Sociodemographic and lifestyle characteristics were obtained along with self-reported height and weight. We performed generalized linear models to assess the differences in attained height across BMI categories; analyses were adjusted for age, gender, education, family income per month, proxy reporting information, dietary patterns, and smoking.

RESULTS

BMI categories included underweight and normal weight (46.4%), overweight (37.6%), obese class I and II (15.2%), and obese class III (0.8%). Adults with normal weight had a significantly higher height (females +7 cm and males +5 cm) when compared to obese class III. As BMI categories increased, height decreased. In females and males, after adjusting for confounders, estimates of attained height decreased when compared to the unadjusted model (β = -0.049, 95% CI = -0.050; -0.049 and β = -0.030, 95% CI = -0.031; -0.029, respectively), although they remained still significant.

CONCLUSION

Our results suggest a significant difference in attained height between BMI categories. Future intervention programs aiming at preventing overweight and obesity should monitor sociodemographic, health and environmental conditions that affect attained height potential.

Heavier birth weight associated with taller height but not age at menarche in US women born 1991-1998

OBJECTIVES

Heavier birth weight predicts taller adult height, but it remains unknown the extent to which this additional height increment results from a faster average growth rate versus an extension of the growth period. Aiming to distinguish these effects, this study examined associations between birth weight (BW), age at menarche (an established proxy for growth duration), and near-adult height in a cohort of US young women born in the 1990s.

METHODS

Multiple regression evaluated age-adjusted height as an outcome of BW, age at menarche, indicators of family socioeconomic status, and other potential confounders in a sample of US teens who participated in the National Health and Nutrition Examination Survey between 2007 and 2012 (N = 342). Relevant interactions were also evaluated.

RESULTS

Mean ± SD was 11.9 ± 1.2 years and 3262 ± 592 g for age at menarche and BW, respectively. BW did not predict age at menarche (β = -.01, p = .838). Girls were 1.3 cm taller per year delay in menarche (p < .001) and 2.9 cm taller per 1 kg increase in BW (p < .001). Additionally, the greatest gain in height associated with delayed menarche was observed among the heaviest BW quartile.

CONCLUSIONS

Girls born heavier were taller but experienced menarche at similar ages to girls born lighter. To the extent that age at menarche reflected growth duration, these results demonstrate faster average growth among heavier-born girls. Consistent with fetal programming of average growth rate, these results held after adjustment for confounders of postnatal growth like family socioeconomic status.

Menarcheal Age and Risk of Type 2 Diabetes: A Community-Based Cohort Study

OBJECTIVE

It has been reported that early menarche is associated with higher risk for type 2 diabetes. We aimed to explore the association between age at menarche and risk of type 2 diabetes in a population-based cohort study.

METHODS

For the purpose of the present study, 5191 subjects of reproductive age who were participants of the Tehran Lipid and Glucose Study and also met the eligibility criteria were selected. Demographic, lifestyle, reproductive, and anthropometric data as well as risk factors for metabolic diseases were collected. Menarcheal age was categorized into five categories, as <11 years, 11-12 years, 13-14 years, 15-16 years, and >17 years. Diabetes and pre-diabetes were defined according to the American Diabetes Association criteria. Logistic regression analysis was used to assess the risk of the menarcheal age group for type 2 diabetes and pre-diabetes.

RESULTS

Of 5625 participants, 673 women had pre-diabetes and 187 had diabetes. Early menarche was associated with higher risk of diabetes and pre-diabetes, compared to the reference group (13-14 years), (OR=3.55, 95% CI: 1.6-7.8 and OR=2.55, 95% CI:1.4-4.8, respectively), an association which remained after further adjustment for potential confounders including family history of diabetes, parity, education, age, body mass index, waist circumference, smoking history, physical activity, and duration of oral contraceptives use.

CONCLUSION

Results showed early menarche to be a potential risk factor for type 2 diabetes and pre-diabetes.

Association of Age at Menarche with Anthropometric Measures in Punjabi Bania Girls

INTRODUCTION

Menarcheal age is the age at which menstruation begins. Menarcheal age is regarded as a sensitive indicator of physical, biological and psychological environment.

AIM

1) To determine the menarcheal age and to examine the relationship between current age at menarche with anthropometric measures in Punjabi bania girls. 2) To develop maturity standards for Bania girls.

MATERIALS AND METHODS

The present cross-sectional survey was carried out on 200 bania girls at the age of onset of menarche. Menarcheal data was obtained by status quo method by asking about whether menarche has been experienced or not. In the present survey adolescent girls were interviewed with the help of pre-designed questionnaire. Statistical analysis was carried out in SPSS software, version 16.0. The data were analysed using descriptive statistics and one-way ANOVA. Pearson's correlation coefficient was used for correlation studies.

RESULTS

A total of 200 Punjabi bania girls were examined in the study. The median age of onset of menarche in these girls was 12.3 years. Menarcheal age was positively associated with bi-acromial width, bi-iliac width and arm span.

CONCLUSION

The present research has revealed secular trend in the age of onset of menarche as indicated by median age of 12.3 years in Bania girls. The bi-acromial width, bi-iliac width and arm span were also correlated with the age of menarche.

Genetic evidence for natural selection in humans in the contemporary United States

Recent findings from molecular genetics now make it possible to test directly for natural selection by analyzing whether genetic variants associated with various phenotypes have been under selection. I leverage these findings to construct polygenic scores that use individuals' genotypes to predict their body mass index, educational attainment (EA), glucose concentration, height, schizophrenia, total cholesterol, and (in females) age at menarche. I then examine associations between these scores and fitness to test whether natural selection has been occurring. My study sample includes individuals of European ancestry born between 1931 and 1953 who participated in the Health and Retirement Study, a representative study of the US population. My results imply that natural selection has been slowly favoring lower EA in both females and males, and are suggestive that natural selection may have favored a higher age at menarche in females. For EA, my estimates imply a rate of selection of about -1.5 mo of education per generation (which pales in comparison with the increases in EA observed in contemporary times). Although they cannot be projected over more than one generation, my results provide additional evidence that humans are still evolving-albeit slowly, especially compared with the rapid changes that have occurred over the past few generations due to cultural and environmental factors.

Pubertal Development and Prepubertal Height and Weight Jointly Predict Young Adult Height and Body Mass Index in a Prospective Study in South Africa

BACKGROUND

Height and adiposity track over childhood, but few studies, to our knowledge, have longitudinally examined the mediating relation of the timing and progression of puberty.

OBJECTIVE

We assessed interrelations between prepubertal height and body mass index, the progression through puberty, and young adult height and adiposity.

METHODS

We analyzed data from the Birth to Twenty Plus study (females, n = 823; males, n = 765). Serial measures of anthropometry and pubertal development were obtained between ages 9 and 16 y. We used latent class growth analysis to categorize pubertal development with respect to pubic hair (females and males), breasts (females), and genitalia (males) development. Adult height and weight were obtained at ages 18 to 20 y.

RESULTS

Among females, higher latent class (earlier initiation and faster progression through puberty) was associated with an increased risk of obesity [pubic hair class 3 compared with class 1: RR, 3.41 (95% CI: 1.57, 7.44)] and inconsistent associations with height. Among males, higher latent class was associated with increased adult height [pubic hair development class 3 compared with class 1: 2.43 cm (95% CI: 0.88, 4.00)] and increased risk of overweight/obesity [pubic hair development class 3 compared with class 1: OR, 3.44 (95% CI: 1.44, 8.20)]. In females, the association with adult height became inverse after adjusting for prepubertal height [pubic hair development class 3 compared with class 1: females, -1.31 cm (95% CI: -2.32, -0.31)]; in males, the association with height was attenuated with this adjustment [-0.56 cm (95% CI: -1.63, 0.52)]. Associations with adiposity were attenuated after adjusting for prepubertal adiposity.

CONCLUSIONS

Progression through puberty modifies the relation between prepubertal and adult anthropometry. Screening for early or rapid progression of puberty might identify children at an increased risk of becoming overweight or obese adults.

Age related changes in pelvis size among adolescent and adult females with reference to parturition from Naraingarh, Haryana (India)

This research examines the ontogenic patterns of changes in growth during adolescence, pelvis variations and growth during twenties and thirties of age, structural remodeling of pelvis related to childbirth and relationship of pelvis area with physique based on the cross-sectional data on 391 females from the state of Haryana. Peak growth velocity for body height and breadths of skeletal traits occurred between 11 and 12 years, much before mean age of menarche at 13.5 years; while for body weight and body mass index (BMI) occurred between 14 and 15 years, after the mean age of menarche. Untill the age 11 years, 11.87% of growth in stature was remaining, 19.37% for bi-cristal breadth, 25.96% for bi-ischial breadth and 35.82% for pelvic area. The hypothesis of critical value of pelvic width of 240mm at iliocristale for menarche to occur has been only a statistical association. Higher prevalence of malnutrition during pubertal phase than pre- and post-pubertal phases was due to greater nutritional needs during puberty. Among adult females, BMI was very poorly correlated with stature but very strongly correlated with body breadths, body breadth-stature indices and body weight. The body mass and pelvis size continued to change during 20s and first half of 30s. The continued increase of BMI was due to increase in body fat and muscle mass in females 18 years and older. To tease apart age and parturition effects on pelvis variations, the analysis showed that pelvic bones remodeling took place after the first child was born and not after the subsequent births, and it was a sign of childbirth phenotypic plasticity rather than age. Pelvis area was strongly associated with stature, BMI and age. Mean pelvic area of tall females was greater than those of medium and short stature. Females with broad shoulders had significantly greater mean pelvis area than those with narrow shoulders and medium shoulders. Females having thin/lean physique had the smallest mean pelvis area compared to those having medium and obese types of physiques. The stepwise multiple regression analysis revealed that BMI was the major determinant factor (multiple r=0.37) of pelvis area; addition of stature component increased the value of multiple r to 0.50, while addition of age marginally increased multiple r to 0.53.

Adult height, nutrition, and population health

In this review, the potential causes and consequences of adult height, a measure of cumulative net nutrition, in modern populations are summarized. The mechanisms linking adult height and health are examined, with a focus on the role of potential confounders. Evidence across studies indicates that short adult height (reflecting growth retardation) in low- and middle-income countries is driven by environmental conditions, especially net nutrition during early years. Some of the associations of height with health and social outcomes potentially reflect the association between these environmental factors and such outcomes. These conditions are manifested in the substantial differences in adult height that exist between and within countries and over time. This review suggests that adult height is a useful marker of variation in cumulative net nutrition, biological deprivation, and standard of living between and within populations and should be routinely measured. Linkages between adult height and health, within and across generations, suggest that adult height may be a potential tool for monitoring health conditions and that programs focused on offspring outcomes may consider maternal height as a potentially important influence.

Genome-wide association and identification of candidate genes for age at puberty in swine

Background

Reproductive efficiency has a great impact on the economic success of pork production. Gilts comprise a significant portion of breeding females and gilts that reach puberty earlier tend to stay in the herd longer and be more productive. About 10 to 30 % of gilts never farrow a litter and the most common reasons for removal are anestrus and failure to conceive. Puberty in pigs is usually defined as the female’s first estrus in the presence of boar stimulation. Genetic markers associated with age at puberty will allow for selection on age at puberty and traits correlated with sow lifetime productivity.

Results

Gilts (n = 759) with estrus detection measurements ranging from 140–240 days were genotyped using the Illumina PorcineSNP60 BeadChip and SNP were tested for significant effects with a Bayesian approach using GenSel software. Of the available 8111 five-marker windows, 27 were found to be statistically significant with a comparison-wise error of P < 0.01. Ten QTL were highly significant at P < 0.005 level. Two QTL, one on SSC12 at 15 Mb and the other on SSC7 at 75 Mb, explained 16.87 % of the total genetic variance. The most compelling candidate genes in these two regions included the growth hormone gene (GH1) on SSC12 and PRKD1 on SSC7. Several loci confirmed associations previously identified for age at puberty in the pig and loci for age at menarche in humans.

Conclusions

Several of the loci identified in this study have a physiological role for the onset of puberty and a genetic basis for sexual maturation in humans. Understanding the genes involved in regulation of the onset of puberty would allow for the improvement of reproductive efficiency in swine. Because age at puberty is a predictive factor for sow longevity and lifetime productivity, but not routinely measured or selected for in commercial herds, it would be beneficial to be able to use genomic or marker-assisted selection to improve these traits.

Electronic supplementary material

The online version of this article (doi:10.1186/s12863-016-0352-y) contains supplementary material, which is available to authorized users.

Age at menarche and its association with dysglycemia in Korean middle-aged women

Objective

Recent studies have demonstrated that earlier menarche is associated with increased risks of prediabetes and diabetes in white women; however, the associations have not been fully explored in Asian populations. We investigated the associations between age at menarche and prediabetes and/or diabetes in Korean middle-aged women.

Methods

This was a cross-sectional study of 2,039 premenopausal and postmenopausal women aged 44 to 56 years who visited the health promotion center for medical checkups. Participants were divided into three groups based on age at menarche: early (<13 y), average (13-16 y), and late (>16 y).

Results

The mean (SD) age at menarche was 14.6 (1.6) years. Of 2,039 women, 820 and 85 women had prediabetes (impaired fasting glucose and/or 5.7%-6.4% glycated hemoglobin) and diabetes, respectively. On logistic regression analysis, earlier menarche was significantly associated with prediabetes (odds ratio [OR], 1.80; 95% CI, 1.24-2.61; P = 0.002), diabetes (OR, 2.43; 95% CI, 1.04-5.69; P = 0.04), and dysglycemia (OR, 1.85; 95% CI, 1.28-2.66; P = 0.001), after adjusting for a number of confounding factors, compared with average age at menarche. On linear regression analysis, earlier age at menarche was significantly associated with increased fasting insulin, homeostatic model assessment for insulin resistance, homeostatic model assessment for β-cell function, body mass index, and waist circumference.

Conclusions

Age at menarche is inversely associated with various forms of dysglycemia. A history of earlier menarche may be helpful in predicting prediabetes and subsequent diabetes in Korean women.

The Health Examinees (HEXA) study: rationale, study design and baseline characteristics

BACKGROUND

Korea has experienced rapid economic development in a very short period of time. A mixture of traditional and modern risk factors coexists and the rapid change in non-genetic factors interacts with genetic constituents. With consideration of these unique aspects of Korean society, a large-scale genomic cohort study-the Health Examinees (HEXA) Study-has been conducted to investigate epidemiologic characteristics, genomic features, and gene-environment interactions of major chronic diseases including cancer in the Korean population.

MATERIALS AND METHODS

Following a standardized study protocol, the subjects were prospectively recruited from 38 health examination centers and training hospitals throughout the country. An interview- based questionnaire survey was conducted to collect information on socio-demographic characteristics, medical history, medication usage, family history, lifestyle factors, diet, physical activity, and reproductive factors for women. Various biological specimens (i.e., plasma, serum, buffy coat, blood cells, genomic DNA, and urine) were collected for biorepository according to the standardized protocol. Skilled medical staff also performed physical examinations.

RESULTS

Between 2004 and 2013, a total of 167,169 subjects aged 40-69 years were recruited for the HEXA study. Participants are being followed up utilizing active and passive methods. The first wave of active follow-up began in 2012 and it will be continued until 2015. The principal purpose of passive follow-up is based on data linkages with the National Death Certificate, the National Cancer Registry, and the National Health Insurance Claim data.

CONCLUSIONS

The HEXA study will render an opportunity to investigate biomarkers of early health index and the chronological changes associated with chronic diseases.

Generational Differences in the Workplace: There Is Complexity Beyond the Stereotypes

The topic of generational differences in the workplace has been immensely popular over the past decade, spawning a large number of academic publications and a far greater number of consulting reports, popular press books, magazine articles, media reports, blogs, and infographics. Indeed, a new industry of consultants and public speakers seems to have emerged primarily to capitalize on the popularity of this topic. As Costanza and Finkelstein (2015) note, the research on this “hot topic” has often seemed opportunistic, lacking rigor and depth. The relative ease of cutting existing cross-sectional data by age and calling it a generation study has tempted researchers to hop on the bandwagon, resulting in a large number of empirical studies with nearly identical literature reviews that overrely on popular press and opinion-based literature. There has been a lamentable tendency toward blind empiricism with little or no connection to theory, as has been stated elsewhere (Lyons & Kuron, 2014; Parry & Urwin, 2011).

Association of maternal menarcheal age with anthropometric dimensions and blood pressure in children from Greater Bilbao

BACKGROUND

Earlier menarche has been related to shorter height and greater obesity-related anthropometric dimensions and blood pressure in women. Boys and girls with earlier maternal menarcheal age (MMA) have shown greater height and body mass index (BMI) in childhood.

AIM

To analyse associations of menarcheal age with their own and their children's anthropometric dimensions and blood pressure.

SUBJECTS AND METHODS

The sample consisted of 493 women and their children (aged 2-19 years) from Greater Bilbao (Basque Country, Spain). For both generations there is information on 19 anthropometric dimensions, blood pressure and socio-demographic characteristics. Linear regressions adjusted for different covariates were used to analyse the associations.

RESULTS

Menarcheal age in women showed the greatest positive associations with iliospinal height and ectomorphy and negative associations with BMI, sum of six skin-folds, endomorphy and mesomorphy. Boys with earlier MMA had greater body heights and breadths, particularly iliospinal height and biacromial breadth (0.10 z-score/year; p < 0.05). In girls, earlier MMA predicted greater sitting height, biepicondylar humerus breadth, weight and sum of four circumferences (0.07-0.09 z-score/year; p < 0.05). However, there was some evidence that MMA was positively associated with body heights, ectomorphy and blood pressure in girls aged ≥12.

CONCLUSION

Children with earlier MMA tend to have greater anthropometric dimensions. Adolescent growth spurt might affect these relationships, at least in girls.

Pubertal timing, bone acquisition, and risk of fracture throughout life

Pubertal maturation plays a fundamental role in bone acquisition. In retrospective epidemiological surveys in pre- and postmenopausal women, relatively later menarcheal age was associated with low bone mineral mass and increased risk of osteoporotic fracture. This association was usually ascribed to shorter time exposure to estrogen from the onset of pubertal maturation to peak bone mass attainment. Recent prospective studies in healthy children and adolescents do not corroborate the limited estrogen exposure hypothesis. In prepubertal girls who will experience later menarche, a reduced bone mineral density was observed before the onset of pubertal maturation, with no further accumulated deficit until peak bone mass attainment. In young adulthood, later menarche is associated with impaired microstructural bone components and reduced mechanical resistance. This intrinsic bone deficit can explain the fact that later menarche increases fracture risk during childhood and adolescence. In healthy individuals, both pubertal timing and bone development share several similar characteristics including wide physiological variability and strong effect of heritable factors but moderate influence of environmental determinants such as nutrition and physical activity. Several conditions modify pubertal timing and bone acquisition, a certain number of them acting in concert on both traits. Taken together, these facts should prompt the search for common genetic regulators of pubertal timing and bone acquisition. It should also open epigenetic investigation avenues to pinpoint which environmental exposure in fetal and infancy life, such as vitamin D, calcium, and/or protein supplies, influences both pubertal timing and bone acquisition.

Grandparental education, parental education and child height: evidence from Hong Kong's "Children of 1997" birth cohort

PURPOSE

Adult height is the sum of growth during fetal, infancy, childhood, and puberty, controlled by different biological factors. In long-term developed Western populations, height is positively associated with socioeconomic position, but less clearly so in recently developing populations. We aimed to elucidate socioeconomic influences on height at different growth phases.

METHODS

We examined the associations of parents' education and grandparents' education with birth weight and height gain z-scores during infancy (birth to <2 years), childhood (2 to <8 years), and puberty (8 to <14 years) adjusted for parents' height using generalized estimating equations in Hong Kong's "Children of 1997" birth cohort (n = 8264).

RESULTS

Parents' education, but not grandparents', was positively associated with birth weight (z-score, 0.07; 95% confidence interval [CI] 0.01-0.12 for grade ≥12 compared with grade ≤9) and height gain during infancy (0.11; 95% CI, 0.05-0.18), adjusted for gender, gestational age, initial size, parity, parents' age, parents' birthplace, and parents' height. Conversely, similarly adjusted, grandparents' education, but not parents', was associated with height gain during childhood (0.11; 95% CI, 0.04-0.18).

CONCLUSIONS

Parental education was associated with fetal and infant, but not childhood, linear growth, suggesting the mechanism underlying socioeconomic influences on height at different growth phases may be contextually specific.

Relationships between biomarkers of inflammation, ovarian steroids, and age at menarche in a rural Polish sample

OBJECTIVES

To test the hypothesis that life history trade-offs between maintenance and reproductive effort would be evident through inverse associations between levels of a biomarker of inflammation [C-reactive protein (CRP)], and ovarian hormones. Associations between CRP and age at menarche were also explored.

METHODS

Urinary CRP, salivary progesterone, and estradiol were measured over one menstrual cycle from rural Polish women (n = 25), representing a natural fertility sample. Age of menarche was assessed through interview recall methods. We used minimum second-order Akaike Information Criteria as a means of multiple regression model selection, and repeated measures ANOVA to test cycle-dependent hypotheses.

RESULTS

Comparisons of individuals in high and low CRP tertiles revealed that those with high CRP had significantly lower progesterone (luteal P = 0.03, mid luteal P = 0.007) but not estradiol (follicular P = 0.21, luteal P = 0.15) concentrations through the menstrual cycle. However, when the age at menarche was included in the analysis, both age at menarche and urinary CRP were negatively associated with estradiol (R(2) = 0.44, P = 0.0007). Age at menarche and estradiol were the strongest negative predictors of CRP (R(2) = 0.52, P = 0.0001).

CONCLUSIONS

Inflammation itself may suppress ovarian function, or indicate immune challenges that lead to ovarian suppression. The timing of menarche may also influence adult inflammatory sensitivity and ovarian hormone concentrations. This lends support to existing models of trade-offs between maintenance and reproduction in women.

Age at menarche among in-school adolescents in Sawla Town, South Ethiopia

BACKGROUND

Although a declining trend in age at menarche has been observed in developed countries over decades commonly attributed to childhood excessive weight gain and sedentary life, little is known about this case in the developing countries.

METHODS

A cross-sectional study design and multistage sampling was used to include 660 school adolescents for analysis. Data collection included weight and height measurements. Multinomial logistic regression analyses were done for early and late age of menarche, in reference to average age at menarche, to measure the association of age at menarche with some socio-demographic variables and body habits.

RESULTS

The mean age at menarche was 13.9±1.2 years (95%CI, 13.8-14.0). The menarche ages ranged between 10 and 12 years for 10.5%, 13 and 14 years for 54.5%, and 15+ years for 35%. Low menarche age was independently associated with high calorie consumption, high protein diet, more coffee intake, low physical activity and parents' low educational background. Low body mass index, low parents' income, exercise, and Amhara ethnic background were associated with late menarche age.

COCLUSION

The mean menarche age found in this study was higher than the report from developed countries. But, the proportion of adolescents with low menarche age was comparable with reports from developed countries. Inactive adolescents were more likely to see menarche earlier than average age. Healthy eating habits, regular exercise and nutrition education need to be promoted among school children.

Genome-wide association and longitudinal analyses reveal genetic loci linking pubertal height growth, pubertal timing and childhood adiposity

The pubertal height growth spurt is a distinctive feature of childhood growth reflecting both the central onset of puberty and local growth factors. Although little is known about the underlying genetics, growth variability during puberty correlates with adult risks for hormone-dependent cancer and adverse cardiometabolic health. The only gene so far associated with pubertal height growth, LIN28B, pleiotropically influences childhood growth, puberty and cancer progression, pointing to shared underlying mechanisms. To discover genetic loci influencing pubertal height and growth and to place them in context of overall growth and maturation, we performed genome-wide association meta-analyses in 18 737 European samples utilizing longitudinally collected height measurements. We found significant associations (P < 1.67 × 10(-8)) at 10 loci, including LIN28B. Five loci associated with pubertal timing, all impacting multiple aspects of growth. In particular, a novel variant correlated with expression of MAPK3, and associated both with increased prepubertal growth and earlier menarche. Another variant near ADCY3-POMC associated with increased body mass index, reduced pubertal growth and earlier puberty. Whereas epidemiological correlations suggest that early puberty marks a pathway from rapid prepubertal growth to reduced final height and adult obesity, our study shows that individual loci associating with pubertal growth have variable longitudinal growth patterns that may differ from epidemiological observations. Overall, this study uncovers part of the complex genetic architecture linking pubertal height growth, the timing of puberty and childhood obesity and provides new information to pinpoint processes linking these traits.

Determinants of sexual health knowledge in adolescent girls in schools of Riyadh-Saudi Arabia: a cross sectional study

Background

There are many social and cultural factors affecting the sexual knowledge of adolescents. This study measured the sexual health knowledge level of adolescents and identified its association with role of parents, friends and school environment in adolescent girls in Riyadh, Saudi Arabia.

Methods

Four hundred and nineteen Saudi female students belonging to intermediate and secondary grades were randomly selected from four public and private girl schools. 255 (69.8%) students were ≤15 years and 164 (39.2%) were >15 years. A self-administered structured questionnaire comprising of socio-demographic information, role of parents and teachers, availability of school curriculum on sexual health was used. Sexual health knowledge was assessed through questions on identification of physical changes during puberty for ≤15 years and separate questions on sexually transmitted infections for >15 years.

Results

54% of ≤15years and 70.7% of >15 years had poor sexual health knowledge. Multivariate analysis found determinants for poor sexual health education in ≤15years are: lower education level of both parents (OR 10.87; 95% CI 2.44–48.38), second birth order or more (OR 2.32; 95% CI 1.24–4.33) and absence of school curriculum on sexual health (OR 0.56; 95% CI 0.33–0.95). Determinants for >15 years of age are : mothers with low literacy (OR 3.08, 95% CI 1.42–6.71), as for sources of poor sexual knowledge : parents (OR 10.10; 95% CI 2.70–37.74), schools (OR 6.95; 95% CI 1.95–24.78) maids (OR 4.57; 95% CI 1.26–16.59) and media (OR 5.12; 95% CI 1.29–20.07) were statistically significant factors.

Conclusion

Government agencies with collaboration of all stake holders should develop policies and programs for implementing and evaluating integrated and comprehensive sexual educational programs for adolescents in Saudi Arabia.

ADULT ANTHROPOMETRIC MEASURES AND SOCIO-DEMOGRAPHIC FACTORS INFLUENCING AGE AT MENARCHE OF UNIVERSITY STUDENTS IN MALAYSIA

Early onset of menarche has been shown to be associated with breast cancer and ischaemic heart disease. Studies on age at menarche of the Malaysian population are poorly documented. This study aimed to determine the influence of anthropometric and socio-demographic factors on the age at menarche of university students in Malaysia. Data were obtained in 2010–11 from 961 students between the ages of 18 and 25 years from the University of Malaya using stratified sampling, and multiple regression analysis was applied. Sixty-three per cent of students reached menarche at the age of 12 or 13 years, with the mean and median of age at menarche being 12.45±1.17 and 12.01 years, respectively. Menarcheal age was positively associated with height (p<0.05) and negatively associated with BMI (p<0.001). Students from urban areas attained menarche earlier than those from rural areas (p<0.05). Students from small-sized families attained menarche earlier than those from larger families (p<0.05). First-born students experienced menarche earlier than those who were seventh-born or later. Obese and overweight students reached menarche earlier than students who were underweight or of normal weight (p<0.01). The variations in age at menarche among the Malaysian ethnic groups were statistically insignificant. The results suggest that heavier and first-born students from small families are more likely to attain menarche earlier than their counterparts.

Evaluation of GWAS-identified genetic variants for age at menarche among Chinese women

STUDY QUESTION

Do genetic polymorphisms which influence age at menarche in women of European ancestry also influence women of Chinese ancestry?

SUMMARY ANSWER

Many genetic variants influencing age at menarche in European populations appear to impact Chinese populations in a similar manner.

WHAT IS KNOWN AND WHAT THIS PAPER ADDS

Prior genome-wide association studies have uncovered 42 SNPs associated with age at menarche in European populations. This study is the first to demonstrate that many of the genetic determinants of age at menarche are shared between European and Chinese women.

PARTICIPANTS AND SETTING

We evaluated 37 of 42 SNPs identified as associated with age at menarche from a recent, large meta-analysis, consisting primarily of women of European ancestry, in a population of 6929 Chinese women from Shanghai, China. We also constructed weighted genetic risk scores (GRSs) combining the number of effect variants for all 37 SNPs, or only the SNPs associated with age at menarche among our study population, to evaluate their joint influence on age at menarche.

MAIN RESULTS

For 32 of the 37 evaluated variants, the direction of the allele associations were the same between women of European ancestry and women of Chinese ancestry (P = 3.71 × 10(-6), binomial sign test); 9 of these were statistically significant. Subjects in the highest quintile of GRSs began menarche ∼5 months later than those in the lowest quintile. BIAS, LIMITATIONS AND GENERALIZABILITY TO OTHER POPULATIONS: Age at menarche was obtained by self-report, which can be subject to recall errors. The current analysis was restricted to loci which met or approached GWAS significance thresholds and did not evaluate loci which may act predominantly or exclusively in the Chinese population. The smaller sample size for our meta-analysis compared with meta-analyses conducted in European populations reduced the power to detect significant results.

STUDY FUNDING/COMPETING INTERESTS

This study was supported, in part, by grants from US National Institutes of Health (grants R01CA124558, R01CA090899, R01CA070867; R01CA064277 and R01CA092585 and UL1 RR024975), Ingram professorship funds and Allen Foundation funds. There are no competing interests to declare.

The contribution of rectangularization to the secular increase of life expectancy: an empirical study

BACKGROUND

In low-mortality countries, life expectancy is increasing steadily. This increase can be disentangled into two separate components: the delayed incidence of death (i.e. the rectangularization of the survival curve) and the shift of maximal age at death to the right (i.e. the extension of longevity).

METHODS

We studied the secular increase of life expectancy at age 50 in nine European countries between 1922 and 2006. The respective contributions of rectangularization and longevity to increasing life expectancy are quantified with a specific tool.

RESULTS

For men, an acceleration of rectangularization was observed in the 1980s in all nine countries, whereas a deceleration occurred among women in six countries in the 1960s. These diverging trends are likely to reflect the gender-specific trends in smoking. As for longevity, the extension was steady from 1922 in both genders in almost all countries. The gain of years due to longevity extension exceeded the gain due to rectangularization. This predominance over rectangularization was still observed during the most recent decades.

CONCLUSIONS

Disentangling life expectancy into components offers new insights into the underlying mechanisms and possible determinants. Rectangularization mainly reflects the secular changes of the known determinants of early mortality, including smoking. Explaining the increase of maximal age at death is a more complex challenge. It might be related to slow and lifelong changes in the socio-economic environment and lifestyles as well as population composition. The still increasing longevity does not suggest that we are approaching any upper limit of human longevity.

The epigenetic lorax: gene-environment interactions in human health

Over the last decade, we have witnessed an explosion of information on genetic factors underlying common human diseases and disorders. This 'human genomics' information revolution has occurred as a backdrop to a rapid increase in the rates of many human disorders and diseases. For example, obesity, Type 2 diabetes, asthma, autism spectrum disorder and attention deficit hyperactivity disorder have increased at rates that cannot be due to changes in the genetic structure of the population, and are difficult to ascribe to changes in diagnostic criteria or ascertainment. A likely cause of the increased incidence of these disorders is increased exposure to environmental factors that modify gene function. Many environmental factors that have epidemiological association with common human disorders are likely to exert their effects through epigenetic alterations. This general mechanism of gene-environment interaction poses special challenges for individuals, educators, scientists and public policy makers in defining, monitoring and mitigating exposures.

A study of menarcheal age in northern iran (rasht)

OBJECTIVES

The event of menarche is an exceptional phenomenon, which occurs once in a lifetime. It is the precursor of future fertility. The onset of menarche is mainly dependent on genetic factors, however geographical and nutritional factors among other factors have been attributed to the events of menarche. The aim of this study is to determine the age of onset of menarche and the factors which induce it in northern Iran.

METHODS

This is a cross sectional study which will assess the onset of menarche in girls between the age of 11-16 years. The subjects were either in middle or high school and had experienced menarche within 6 months prior to the study. This study revolves around 600 girls who were selected using stratified randomized sampling techniques. The data was collected in the form of a questionnaire which focused on age, weight (was measured to the nearest 0.1 kg using a balance beam scale), height (was measured to nearest 0.1cm with a manual height board), and Body Mass Index (BMI: kg/m2) was used as an index of relative weight. Principal Component Analysis (PCA) was applied to analyze Socio-economic Status (SES). The defined standard age of the first menstrual event was applied as the standard. The data collected was analyzed using the Statistical Package for the Social Sciences (SPSS.10) statistical analysis software and the Chi-square and Analysis of Variance (ANOVA) tests were applied. In an effort to establish the factors associated with the age of menarche, multivariate analysis was performed based on linear logistic regression which was performed using a model where all the variables changing the risk estimated by more than 10%. Statistical significance was determined at P<0.05.

RESULTS

The mean age at menarche was observed to be 12.99±1.33yrs (ranging from 10.16 to 15.91 yrs). The study showed that menarche occurred during the summer for 270 (45%) patients making it the most common season for menarche while winter was the least common season. The mean age of menarche was delayed in patients from low SES groups and it occurred earlier in patients from high SES. In girls with low BMI, menarche occurred earlier in comparison to girls with high BMI. There was a significant correlation between session and age of menarche (p<0.05). There was no significant relationship statistically between BMI and age of menarche (p>0.05). Linear regressions showed no significant effect of BMI on the age of menarche but there was a significant correlation between season and SES on the age of menarche.

CONCLUSION

The age of menarche and the most common seasons for menarche were similar to previous studies. Results from this study showed that the age of menarche decreased with higher SES, and also the age of menarche in girls with high and low BMI occurred earlier. However, previous studies showed that it ocurred earlier in high BMI and later in low BMI. It appears that genetic and environmental factors have influenced these differences.

The effect of female height on reproductive success is negative in Western populations, but more variable in non-western populations

OBJECTIVE

In this article we examine the association between female height and reproductive success in a US sample and present a review of previous studies on this association. We also outline possible biological explanations for our findings.

METHODS

We used data from a long-term study of 5,326 female Wisconsin high school graduates to examine the association between female height and reproductive success. Twenty-one samples on this association were covered by our literature review.

RESULTS

Shorter women had more children surviving to age 18 than taller women, despite increased child mortality in shorter women. Taller women had a higher age at first birth and age at first marriage and reached a higher social status, but the negative effect of height on reproductive success persisted after controlling for these variables. However, while these effects were quite consistent in Western populations, they were not consistently present in non-Western populations. Our review also indicated that child mortality was almost universally higher among shorter women.

CONCLUSIONS

We conclude that shorter women have a higher number of live births but that final reproductive success depends on the positive effect of height on child survival.

Age at menarche is associated with prediabetes and diabetes in women (aged 32-81 years) from the general population: the KORA F4 Study

AIMS/HYPOTHESIS

The aim of this study was to examine the association between age at menarche and prediabetes as well as diabetes, considering confounding factors and the possible mediating role of adult obesity.

METHODS

This cross-sectional study analysed data on 1,503 women aged 32-81 years from the German population-based KORA (Cooperative Health Research in the Region of Augsburg, South Germany) F4 Study (2006-2008). Data were collected by standardised interviews, physical examinations, and whole blood and serum measurements, including administration of an OGTT in non-diabetic participants.

RESULTS

Of the 1,503 women, 226 showed a prediabetic state (impaired fasting glucose and/or impaired glucose tolerance) and 140 persons had diabetes (45 participants with previously undiagnosed diabetes and 95 with known diabetes). In Poisson regression analysis, age at menarche was significantly inversely associated with prediabetes or diabetes after adjustment for year of birth (RR 0.88; 95% CI 0.82, 0.94, p < 0.0001 per additional year of menarche) and after additional adjustment for a number of confounding factors (RR 0.88; 95% CI 0.83, 0.94, p = 0.0001). Further adjustment for current BMI slightly attenuated the association with prediabetes or diabetes (RR 0.89; 95% CI 0.83, 0.95, p = 0.0009), but the association remained clearly significant.

CONCLUSIONS/INTERPRETATION

Age at menarche seems to be inversely associated with prediabetes and diabetes independent of confounding factors including current BMI. Women at risk for diabetes might be identified by a history of young age at menarche.

Bone mineral density in girls with functional hypothalamic amenorrhea subjected to estroprogestagen treatment--a 4-year prospective study

The aim of this study was to evaluate the effects of 4-year estroprogestagen therapy (EP) on the bone mineral density (BMD) of 16- to 17-year-old girls with functional hypothalamic amenorrhea (FHA, n = 78). Baseline values of hormonal parameters, bone fraction of alkaline phosphatase (BALP), and cross-linked n-telopeptide of type I collagen (Ntx) were taken along with BMD measurements. Follow-up measurements of laboratory parameters were performed after 6 months of EP treatment. BMD was measured on a yearly basis. Six-month treatment resulted in a marked increase in estradiol levels and a significant decrease in BALP and Ntx. The relative increase in BMD was highest after the second year of treatment. Based on the dynamics of BMD changes during the first year of treatment, we identified a subgroup with no or insignificant reactions to the treatment. It was characterized by significantly higher baseline BMD and markedly lower baseline Ntx compared to the patients who responded to 1-year therapy well or extremely well. Further follow-up proved, however, that this subgroup did not differ significantly in terms of the long-term prognosis for BMD normalization. In conclusion, this study showed that EP therapy is effective in the treatment of BMD disorders associated with FHA.

Concerted actions of insulin-like growth factor 1, testosterone, and estradiol on peripubertal bone growth: a 7-year longitudinal study

A better understanding of how bone growth is regulated during peripuberty is important for optimizing the attainment of peak bone mass and for the prevention of osteoporosis in later life. In this report we used hierarchical models to evaluate the associations of insulin-like growth factor 1 (IGF-1), estradiol (E(2) ), and testosterone (T) with peripubertal bone growth in a 7-year longitudinal study. Two-hundred and fifty-eight healthy girls were assessed at baseline (mean age 11.2 years) and at 1, 2, 3.5, and 7 years. Serum concentrations of IGF-1, E(2) , and T were determined. Musculoskeletal properties in the left lower leg were measured using peripheral quantitative computed tomography (pQCT). Serum levels of IGF-1, E(2) , and T increased dramatically before menarche, whereas they decreased, plateaued, or increased at a lower rate, respectively, after menarche. IGF-1 level was positively associated with periosteal circumference (PC) and total bone mineral content (tBMC) throughout peripuberty but not after adjustment for muscle cross-sectional area (mCSA). On the other hand, IGF-1 was associated with tibial length (TL) independently of mCSA before menarche. T was positively associated with TL, PC, tBMC, and cortical volumetric bone mineral density, independent of mCSA, before menarche but not after. E(2) was associated with TL positively before menarche but negatively after menarche. These findings suggest that during puberty, circulating IGF-1 promotes bone periosteal apposition and mass accrual indirectly, probably through stimulating muscle growth, whereas the effects of sex steroids on bone growth differ before and after menarche, presenting a biphasic pattern. Hence the concerted actions of these hormones are essential for optimal bone development in peripuberty.

Secular trends in age at menarche in women in the UK born 1908-93: results from the Breakthrough Generations Study

Menarcheal age decreased over time in Western countries until cohorts born in the mid-20th century. It then stabilised, but limited data are available for recent cohorts. Menarche data were collected retrospectively by questionnaire in 2003-10 from 94,170 women who were participating in the Breakthrough Generations Study, aged 16-98 years, born 1908-93 and resident in the UK. Average menarcheal age declined from women born in 1908-19 (mean=13.5 years) to those born in 1945-49 (mean=12.6 years). It was then stable for several birth cohorts, but resumed its downward trend in recent cohorts (mean=12.3 years in 1990-93 cohort). Trends differed between socio-economic groups, but the recent decline was present in each group. In conclusion, menarcheal age appears to have decreased again in recent cohorts after a period of stabilisation.

A study on the menstruation of Korean adolescent girls in Seoul

PURPOSE

Westernized eating habits have been associated with early-age menstruation, which increases the incidence of dysmenorrhea and premenstrual syndrome among adolescent girls. We therefore surveyed changes in menarche timing and the general menstrual characteristics of adolescent girls in Seoul, Korea.

METHODS

We surveyed 538 teenage girls who visited our hospital between July and November 2007. Items explored included age at menarche, general menstrual characteristics, occurrence of premenstrual syndrome and treatment thereof, and an association between present dysmenorrhea and a family history of the condition.

RESULTS

Average age at menarche was 12.6 years, with 29% (n=156) subjects beginning menstruation at age 12 years. The prevalence of dysmenorrhea was 82% (n=435). The main symptoms were abdominal (53.2%) and lower back pain (34.2%), and 15.2% of girls who experienced such symptoms required medication. Present dysmenorrhea, and a family history thereof, were statistically correlated (P<0.05). In addition, 58.8% (n=316) of teenage girls had symptoms of premenstrual syndrome. The most frequent psychological symptoms were fatigue (36.4%) and nervousness (38.7%), whereas the most common physical symptom was menstrual cramps (46.5%). Most subjects (87.6%) tolerated the symptoms of premenstrual syndrome without medication; 11.4% took medicines including painkillers; but only 0.1% of subjects visited a doctor.

CONCLUSION

The average age at menarche in Korean girls was 12.6 years, thus younger than in the past. Most teenage girls experienced dysmenorrhea and premenstrual syndrome, but few consulted a doctor. Organized treatment plans are required to manage menstrual problems in teenage girls.

Menarcheal age among urban Kenyan primary school girls

AIM

To determine the mean menarcheal age among urban primary school girls in Kenya.

SUBJECTS AND METHODS

A structured questionnaire was administered to 820 primary grade 6-8 girls aged between 12 and 17 years in five public primary schools, Langata division of Nairobi West district, Nairobi Kenya. The girls came from low and middle socioeconomic status residences. Declared menarcheal age by recall to the nearest month was recorded. Data were analysed using SPSS version 15.0 for windows. The results are presented using tables and bar charts.

RESULTS

The mean menarcheal age was 12.5 ± 2.8 years with peak at 12-14 years. A substantial number of girls (10.8%) attained menarche before the age of 11 years, with 2% of them attaining it before 10 years. None attained menarche before nine or after 16 years. Of those who attained early menarche, 64.3% were from middle while only 35.7% came from low socioeconomic status residence, respectively.

CONCLUSION

Mean menarcheal age of 12.5 years is lower than previously reported with over 10% of the girls attaining menarche by 11 years. Early commencement of reproductive health education and follow-up for complications of early menarche is recommended.