Decline in age at menarche among Spanish women born from 1925 to 1962

Age at menarche and asthma onset among US girls and women: findings from NHANES, 2001-2018

PURPOSE

To quantitatively estimate the association of age at menarche with the risk of childhood- and adult-onset asthma separately.

METHODS

A retrospective cohort study of 24,282 US girls and women was conducted using continuous National Health and Nutrition Examination Survey (NHANES) data from 2001 to 2018, and Cox proportional hazards regression models with censoring ages of 19 and 79 years were employed to separately estimate hazard ratios of childhood- and adult-onset asthma associated with age at menarche.

RESULTS

Each one-year increase in age at menarche was significantly associated with a 16% (hazard ratio [HR] = 0.84; 95% confidence interval [CI]: 0.77-0.91) decrease in the risk of childhood-onset asthma. Compared with age at menarche of 12-14 years, we observed a 56% (HR = 1.56; 95% CI: 1.19-2.04) increased risk of childhood-onset asthma for early menarche (age at menarche < 12 years) and a 40% (HR = 0.60; 95% CI: 0.32-1.10) decreased risk for late menarche (age at menarche ≥ 15 years). No significant association was noted between age at menarche and adult-onset asthma.

CONCLUSIONS

Early menarche may represent a risk factor for childhood-onset asthma, which indicates the need for timely and effective management of individuals with early menarche to prevent asthma.

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.

The health effects of soy: A reference guide for health professionals

Soy is a hotly debated and widely discussed topic in the field of nutrition. However, health practitioners may be ill-equipped to counsel clients and patients about the use of soyfoods because of the enormous, and often contradictory, amount of research that has been published over the past 30 years. As interest in plant-based diets increases, there will be increased pressure for practitioners to gain a working knowledge of this area. The purpose of this review is to provide concise literature summaries (400-500 words) along with a short perspective on the current state of knowledge of a wide range of topics related to soy, from the cholesterol-lowering effects of soy protein to the impact of isoflavones on breast cancer risk. In addition to the literature summaries, general background information on soyfoods, soy protein, and isoflavones is provided. This analysis can serve as a tool for health professionals to be used when discussing soyfoods with their clients and patients.

Neither soyfoods nor isoflavones warrant classification as endocrine disruptors: a technical review of the observational and clinical data

Soybeans are a rich source of isoflavones, which are classified as phytoestrogens. Despite numerous proposed benefits, isoflavones are often classified as endocrine disruptors, based primarily on animal studies. However, there are ample human data regarding the health effects of isoflavones. We conducted a technical review, systematically searching Medline, EMBASE, and the Cochrane Library (from inception through January 2021). We included clinical studies, observational studies, and systematic reviews and meta-analyses (SRMA) that examined the relationship between soy and/or isoflavone intake and endocrine-related endpoints. 417 reports (229 observational studies, 157 clinical studies and 32 SRMAs) met our eligibility criteria. The available evidence indicates that isoflavone intake does not adversely affect thyroid function. Adverse effects are also not seen on breast or endometrial tissue or estrogen levels in women, or testosterone or estrogen levels, or sperm or semen parameters in men. Although menstrual cycle length may be slightly increased, ovulation is not prevented. Limited insight could be gained about possible impacts of in utero isoflavone exposure, but the existing data are reassuring. Adverse effects of isoflavone intake were not identified in children, but limited research has been conducted. After extensive review, the evidence does not support classifying isoflavones as endocrine disruptors.

Space-time analysis of ovarian cancer mortality rates by age groups in spanish provinces (1989-2015)

BACKGROUND

Ovarian cancer is a silent and largely asymptomatic cancer, leading to late diagnosis and worse prognosis. The late-stage detection and low survival rates, makes the study of the space-time evolution of ovarian cancer particularly relevant. In addition, research of this cancer in small areas (like provinces or counties) is still scarce.

METHODS

The study presented here covers all ovarian cancer deaths for women over 50 years of age in the provinces of Spain during the period 1989-2015. Spatio-temporal models have been fitted to smooth ovarian cancer mortality rates in age groups [50,60), [60,70), [70,80), and [80,+), borrowing information from spatial and temporal neighbours. Model fitting and inference has been carried out using the Integrated Nested Laplace Approximation (INLA) technique.

RESULTS

Large differences in ovarian cancer mortality among the age groups have been found, with higher mortality rates in the older age groups. Striking differences are observed between northern and southern Spain. The global temporal trends (by age group) reveal that the evolution of ovarian cancer over the whole of Spain has remained nearly constant since the early 2000s.

CONCLUSION

Differences in ovarian cancer mortality exist among the Spanish provinces, years, and age groups. As the exact causes of ovarian cancer remain unknown, spatio-temporal analyses by age groups are essential to discover inequalities in ovarian cancer mortality. Women over 60 years of age should be the focus of follow-up studies as the mortality rates remain constant since 2002. High-mortality provinces should also be monitored to look for specific risk factors.

A Systematic Literature Review of Factors Affecting the Timing of Menarche: The Potential for Climate Change to Impact Women's Health

Menarche is the first occurrence of a woman’s menstruation, an event that symbolizes reproductive capacity and the transition from childhood into womanhood. The global average age for menarche is 12 years and this has been declining in recent years. Many factors that affect the timing menarche in girls could be affected by climate change. A systematic literature review was performed regarding the timing of menarche and four publication databases were interrogated: EMBASE, SCOPUS, PubMed, and Cochrane Reviews. Themes were identified from 112 articles and related to environmental causes of perturbations in menarche (either early or late), disease causes and consequences of perturbations, and social causes and consequences. Research from climatology was incorporated to describe how climate change events, including increased hurricanes, avalanches/mudslides/landslides, and extreme weather events could alter the age of menarche by disrupting food availability or via increased toxin/pollutant release. Overall, our review revealed that these perturbations in the timing of menarche are likely to increase the disease burden for women in four key areas: mental health, fertility-related conditions, cardiovascular disease, and bone health. In summary, the climate does have the potential to impact women’s health through perturbation in the timing of menarche and this, in turn, will affect women’s risk of disease in future.

Life History Transitions at the Origins of Agriculture: A Model for Understanding How Niche Construction Impacts Human Growth, Demography and Health

Over recent millennia, human populations have regularly reconstructed their subsistence niches, changing both how they obtain food and the conditions in which they live. For example, over the last 12,000 years the vast majority of human populations shifted from foraging to practicing different forms of agriculture. The shift to farming is widely understood to have impacted several aspects of human demography and biology, including mortality risk, population growth, adult body size, and physical markers of health. However, these trends have not been integrated within an over-arching conceptual framework, and there is poor understanding of why populations tended to increase in population size during periods when markers of health deteriorated. Here, we offer a novel conceptual approach based on evolutionary life history theory. This theory assumes that energy availability is finite and must be allocated in competition between the functions of maintenance, growth, reproduction, and defence. In any given environment, and at any given stage during the life-course, natural selection favours energy allocation strategies that maximise fitness. We argue that the origins of agriculture involved profound transformations in human life history strategies, impacting both the availability of energy and the way that it was allocated between life history functions in the body. Although overall energy supply increased, the diet composition changed, while sedentary populations were challenged by new infectious burdens. We propose that this composite new ecological niche favoured increased energy allocation to defence (immune function) and reproduction, thus reducing the allocation to growth and maintenance. We review evidence in support of this hypothesis and highlight how further work could address both heterogeneity and specific aspects of the origins of agriculture in more detail. Our approach can be applied to many other transformations of the human subsistence niche, and can shed new light on the way that health, height, life expectancy, and fertility patterns are changing in association with globalization and nutrition transition.

Heritability of Age at Menarche in South Korean Female Twins

Genetic and environmental influences on age at menarche (AAM) have rarely been examined in Asian females. This study aimed to investigate the heritability of AAM in South Korean female twins. The AAM data from 1370 female twins (933 monozygotic [MZ] twins, 294 dizygotic [DZ] twins and 160 female members of opposite-sex DZ twins) born between 1988 and 2001 were analyzed. The age of the sample at the time of the assessment ranged from 16 to 28 years with a mean of 19.3 (SD = 2.2) years. The mean AAM in the total sample was 12.49 (SD = 1.41) years. Although the mean AAM decreased with increasing birth years, it levelled off in birth years 2000-2001. Maximum likelihood MZ and DZ twin correlations were 0.72 [95% CI (0.67, 0.76)] and 0.35 [95% CI (0.19, 0.50)], respectively. The results of model-fitting analysis indicated that the additive genetic and individual-specific environmental effects were 72% [95% CI (67%, 76%)] and 28% [95% CI (24%, 33%)], respectively. Neither nonadditive genetic nor shared environmental effects were significant.

Secular Trends and Socioeconomic Differentials in Menarcheal Age for South Korean Women

BACKGROUND

In this study, we assessed the secular trends and socioeconomic differentials in menarcheal age among women aged 25-64 year.

METHODS

Using the 5th Korea National Health and Nutrition Examination Survey (KNHANES, 2010-2012), bivariate analysis and one-way analysis of variance were used to test the statistical differences between age groups.

RESULTS

The mean age at menarche was 14.3 yr with a steep decrease in the younger cohort: from 15.9 yr in 1951-1955 to 13.1 yr in 1986-1990. Height as a proxy marker for early nutrition showed an inverse relationship with menarcheal age. The earlier menarcheal age patterns in women of higher socioeconomic position were observed according to one's education, monthly family income, occupation, region (urban vs. rural), and parental education.

CONCLUSION

This result suggests a fast and ongoing trend in age at menarche and the socioeconomic discrepancy among Korean women in the last four decades.

Age at menarche in Polish University students born before, during and after World War II: Economic effects

Although the relationships between economic conditions and biological variables over the past two centuries in Poland are reasonably well-documented, the influence of economic and political disruptions, including nutritional privation, during the years immediately before, during and shortly after World War II (WWII) has received less attention. This paper considers the association between age at menarche and body size of university students born before, during and after WWII and father's level of education, a commonly used indicator of family economic status in Poland. Subjects were 518 university students surveyed between 1955 and 1972, birth years 1931 through 1951. The sample was divided into three birth cohorts: before (n=237), during (n=247) and after (n=34) WWII. Age at menarche was compared among birth cohorts, and by weight status and father's level of education. Age at menarche increased slightly but significantly among women born during WWII (14.4 yrs) compared to those born before (14.2 yrs) and after (13.9 yrs) the war. Controlling for year of birth and age of the student, age at menarche was significantly earlier in overweight (13.42±0.35 yrs) than in normal weight (14.33±0.06 yrs) and thin (14.54±0.21 yrs) women. Adjusted mean ages at menarche in small samples of overweight women did not differ by father's level of education, and were earlier than corresponding ages of thin and normal weight women. Adjusted mean ages at menarche did not differ between thin and normal weight women with fathers having primary or no education, but were slightly later in thin than in normal weight women with fathers having a vocational, secondary or higher education. Although age at menarche was associated with father's level of education, young adult weight status was a somewhat more important correlate.

Menstrual irregularity and use of oral contraceptives in female adolescent athletes in Swedish National Sports High Schools

Objective Female adolescent athletes seem to use oral contraceptives (OCs) in the same proportion as the general population. In athletes not using OCs, menstrual irregularity (MI) is reported to be common but there are few studies of MI in adolescent athletes. The aim of the study was to survey menarche, menstrual irregularity and use of OCs in adolescent athletes in the National Sports High Schools in Sweden. A further aim was to study the associations between current sport injury and menstrual irregularity as well as use of OCs. Subjects Two hundred and ninety-eight female adolescent athletes at Swedish National Sports High Schools. Methods A web-based questionnaire containing questions related to menstrual status, contraception and current injury. Results One third (32.6%) of the athletes used OCs and of the remaining athletes 31.8% had MI. The group of athletes with MI had a significantly (p = 0.038; Cohen's d, 0.32) lower BMI and consisted of a significantly (p = 0.043) higher proportion of endurance athletes. OC users were less likely to participate in endurance sports compared to non-OC users (p = 0.024). Current injury was equally distributed in the OC and the non-OC group but athletes with MI had fewer sports injuries compared to eumenorrheic women. Conclusion OCs are frequently used among athletes at Swedish National Sports High Schools. OC users were less likely to participate in endurance sports compared to non-OC users. MI was common and athletes with MI had lower BMI compared to eumenorrheic athletes. Sports injuries were not associated with use of OC and eumenorrheic athletes had a higher proportion of current injury.

Health impact of childhood and adolescent soy consumption

Soyfoods have been intensely researched, primarily because they provide such abundant amounts of isoflavones. Isoflavones are classified as both plant estrogens and selective estrogen receptor modulators. Evidence suggests that these soybean constituents are protective against a number of chronic diseases, but they are not without controversy. In fact, because soyfoods contain such large amounts of isoflavones, concerns have arisen that these foods may cause untoward effects in some individuals. There is particular interest in understanding the effects of isoflavones in young people. Relatively few studies involving children have been conducted, and many of those that have are small in size. While the data are limited, evidence suggests that soy does not exert adverse hormonal effects in children or affect pubertal development. On the other hand, there is intriguing evidence indicating that when soy is consumed during childhood and/or adolescence, risk of developing breast cancer is markedly reduced. Relatively few children are allergic to soy protein, and most of those who initially are outgrow their soy allergy by 10 years of age. The totality of the available evidence indicates that soyfoods can be healthful additions to the diets of children, but more research is required to allow definitive conclusions to be made.

Studying the relationship between a woman's reproductive lifespan and age at menarche using a Bayesian multivariate structured additive distributional regression model

Studies addressing breast cancer risk factors have been looking at trends relative to age at menarche and menopause. These studies point to a downward trend of age at menarche and an upward trend for age at menopause, meaning an increase of a woman's reproductive lifespan cycle. In addition to studying the effect of the year of birth on the expectation of age at menarche and a woman's reproductive lifespan, it is important to understand how a woman's cohort affects the correlation between these two variables. Since the behavior of age at menarche and menopause may vary with the geographic location of a woman's residence, the spatial effect of the municipality where a woman resides needs to be considered. Thus, a Bayesian multivariate structured additive distributional regression model is proposed in order to analyze how a woman's municipality and year of birth affects a woman's age of menarche, her lifespan cycle, and the correlation of the two. The data consists of 212,517 postmenopausal women, born between 1920 and 1965, who attended the breast cancer screening program in the central region of Portugal.

Body structure and maturation – the association with environmental factors

The main objective of the study was to determine the relationship between physique, maturation and some environmental factors. The study was conducted in Warsaw, between 2012 and 2013 in randomly selected schools. The material included 171 girls, aged 12–20 years. Body height and weight, upper and lower extremity length, subcutaneous fat folds on arm, subscapular and abdominal, circumferences of arm, chest, waist and hip were measured. Body proportion indices were calculated. The questionnaire form provided information on parental education and profession, and the number of children in family. Girls were asked about age at menarche, number of daily meals, level of physical activity, participation is sport, and level of stress at home and at school. The principal component analysis was applied and 4 factors were extracted from the set of living condition characteristics (F1 – Parental education & father’s occupation, F2 – Mother’s occupation and the number of children, F3 – Stress, F4 – Physical activity and number of daily meals). Regression analysis allowed to evaluate the association of body build characteristics and age at menarche with the four factors. Factor 1 and 4 were the only ones which showed a statistically significant association with body build. The results showed that girls who were taller, with smaller arm and waist circumferences and less adiposity came from families with higher parental education and better father’s profession. Taller stature, longer legs and less adiposity characterized girls who were more physically active and consumed more than three meals a day.

Changing trends in reproductive/lifestyle factors in UK women: descriptive study within the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS)

OBJECTIVE

There has been considerable interest in the impact of reproductive factors on health but there are little data on how these have varied over time. We explore trends in reproductive/lifestyle factors of postmenopausal British women by analysing self-reported data from participants of the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS).

DESIGN

Prospective birth cohort analysis.

SETTING

Population cohort invited between 2001 and 2005 from age-sex registers of 27 Primary Care Trusts in England, Wales and Northern Ireland and recruited through 13 National Health Service Trusts.

PARTICIPANTS

202 638 postmenopausal women aged 50-74 years at randomisation to UKCTOCS between April 2001 and October 2005.

INTERVENTIONS

Women were stratified into the following six birth cohorts (1925-1929, 1930-1934, 1935-1939, 1940-1944, 1945-1949, 1950-1955) based on year of birth. Self-reported data on reproductive factors provided at recruitment were explored using tabular and graphical summaries to examine for differences between the birth cohorts.

OUTCOME MEASURES

Trends in mean age at menarche and menopause, use of oral contraceptives, change in family size, infertility treatments, tubal ligation and hysterectomy rates.

RESULTS

Women born between 1935 and 1955 made up 86% of the cohort. Median age at menarche decreased from 13.4 for women born between 1925 and 1929 to 12.8 for women born between 1950 and 1955. Increased use of the oral contraceptives, infertility treatments and smaller family size was observed in the younger birth cohorts. Tubal ligation rates increased for those born between 1925 and 1945, but this increase did not persist in subsequent cohorts. Hysterectomy rates (17-20%) did not change over time.

CONCLUSIONS

The trends seen in this large cohort are likely to reflect the reproductive history of the UK female postmenopausal population of similar age. Since these are risk factors for hormone-related cancers, these trends are important in understanding the changing incidence of these cancers.

TRIAL REGISTRATION NUMBER

International Standard Randomised Controlled Trial Number: 22488978.

Age at menarche predicts age at onset of major affective and anxiety disorders

BACKGROUND

Menarche age has been associated inconsistently with the occurrence, timing or severity of major depressive disorder (MDD), but rarely studied in women with bipolar (BDs) or anxiety disorders.

METHODS

We investigated women patients at a Sardinian mood disorder center for associations of age at menarche with age at illness onset for major affective or anxiety disorders, year of birth, and other selected factors, using bivariate comparisons and multivariate regression modeling.

RESULTS

Among women (n=1139) with DSM-IV MDD (n=557), BD-I (n=223), BD-II (n=178), or anxiety disorders (n=181), born in 1904-1998, of mean age 42.9 years, menarche age averaged 12.8 [CI: 12.7-12.9] years. Illness onset age averaged 30.9 [30.1-31.8] years, ranking: BD-I, 25.8; anxiety disorders, 28.0; BD-II, 30.3; MDD, 34.1 years. Menarche age declined secularly over birth years, and was associated with younger illness-onset, having no or fewer siblings, more psychiatrically ill first-degree relatives, living in rural environments, being suicidal, substance abuse, and being unemployed. Earlier menarche and earlier illness-onset were significantly associated for onset age groups of ≤ 20, 20-39, and > 40 years. Menarche age versus diagnosis ranked: BD-II<BD-I<anxiety disorders<MDD.

CONCLUSIONS

Age at menarche in Sardinia, as elsewhere, has declined over the past decades. It was strongly associated with age at onset of bipolar and anxiety, as well as major depressive disorders across the age range, suggesting sustained effects of biological maturational factors.

The Decreasing Age at Menarche in Mexico

STUDY OBJECTIVE

To estimate the current age at menarche in 2 urban areas from Mexico and to analyze secular trends in the age at menarche in Mexico City.

DESIGN

Cross-sectional survey and secondary data analyses.

SETTING

(1) Samples of female students from Mexico City and from the city of Xalapa; and (2) national health surveys.

PARTICIPANTS

(1) Pre- and postmenarcheal students, aged 8-17 years; and (2) data for women born between 1904 and 1999 who grew up in Mexico City were obtained from 3 relevant national health surveys.

INTERVENTIONS AND MAIN OUTCOME MEASURES

(1) Students were asked if they had had their first period and when it occurred; (2) information on year of birth and age at menarche for the remaining women was obtained from the national surveys; data were divided in groups according to the decade in which the women were born.

RESULTS

(1) The estimated mean age at menarche was 11.40 and 11.34 years in Mexico City and Xalapa respectively. (2) There were significant differences in age at menarche among women who were born in the different decades analyzed. Women who were born in the 1990s or later reported an earlier age at menarche than those who were born from the 1940s to 1980s (P < .0001).

CONCLUSION

These results could be helpful to health and education professionals who should take into account that because there is currently a widening gap between the physical and psychosocial maturity of girls, they might need special support.

What does the mean menarcheal age mean?-An analysis of temporal pattern in variability in a historical swiss population from the 19th and 20th centuries

OBJECTIVES

Age at menarche is one of the most important factors when observing growth and development. The aim of this study was to assess the temporal pattern in variability of menarcheal age for a historic Swiss population from the 19th and 20th centuries.

METHODS

Medical health records from the Bernese women's hospital (Switzerland) were analyzed. From 10,081 women of a historical Swiss population (born from 1815 to 1954), menarcheal age was calculated. A possible decline in average menarcheal age and variance and skewness were analyzed with the use of descriptive statistics, generalized additive models, and correlation.

RESULTS

Mean menarcheal age declined from 17.34 years (n = 358) around 1830 to 13.80 years (n = 141) around 1950. Within-cohort variance decreased from 7.5 to 2.1 year(2) . Skewness was negatively correlated with birth year (r = -0.58).

CONCLUSION

This study provided evidence for a secular trend in various statistical parameters for age at menarche since the 19th century. Furthermore, the results of the analysis of temporal pattern in variability revealed that the secular trend in menarcheal age happened in two phases. Am. J. Hum. Biol. 28:705-713, 2016. © 2016 Wiley Periodicals, Inc.

International Variation in Female Breast Cancer Incidence and Mortality Rates

BACKGROUND

Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer-related death among women worldwide. Herein, we examine global trends in female breast cancer rates using the most up-to-date data available.

METHODS

Breast cancer incidence and mortality estimates were obtained from GLOBOCAN 2012 (globocan.iarc.fr). We analyzed trends from 1993 onward using incidence data from 39 countries from the International Agency for Research on Cancer and mortality data from 57 countries from the World Health Organization.

RESULTS

Of 32 countries with incidence and mortality data, rates in the recent period diverged-with incidence increasing and mortality decreasing-in nine countries mainly in Northern/Western Europe. Both incidence and mortality decreased in France, Israel, Italy, Norway, and Spain. In contrast, incidence and death rates both increased in Colombia, Ecuador, and Japan. Death rates also increased in Brazil, Egypt, Guatemala, Kuwait, Mauritius, Mexico, and Moldova.

CONCLUSIONS

Breast cancer mortality rates are decreasing in most high-income countries, despite increasing or stable incidence rates. In contrast and of concern are the increasing incidence and mortality rates in a number of countries, particularly those undergoing rapid changes in human development. Wide variations in breast cancer rates and trends reflect differences in patterns of risk factors and access to and availability of early detection and timely treatment.

IMPACT

Increased awareness about breast cancer and the benefits of early detection and improved access to treatment must be prioritized to successfully implement breast cancer control programs, particularly in transitioning countries.

Secular trends in age at menarche among Chinese girls from 24 ethnic minorities, 1985 to 2010

BACKGROUND

Declining age at menarche has been observed in many countries. In China, a decrease of 4.5 months per decade in the average age at menarche among the majority Han girls has recently been reported. However, the trends in age at menarche among ethnic minority girls over the past 25 years remain unknown.

OBJECTIVES

To compare the differences in median age at menarche among girls aged 9-18 years across 24 ethnic minorities in 2010 and to estimate the trends in age at menarche in different ethnic minorities from 1985 to 2010.

DESIGN

We used data from six cross-sectional Chinese National Surveys on Students' Constitution and Health (1985, 1991, 1995, 2000, 2005, and 2010). The median age at menarche was estimated by using probit analysis.

RESULTS

In 2010, the ethnic minorities with the earliest age at menarche were the Koreans (11.79 years), Mongolians (12.44 years), and Zhuang (12.52 years). The three ethnic minorities with the latest age at menarche were the Sala (14.32 years), Yi (13.74 years), and Uighurs (13.67 years). From 1985 to 2010, the age at menarche declined in all 24 minority groups. The Lisu, Kazakh, and Korean minorities showed the largest reductions in age at menarche by 1.79 (p<0.05), 1.69 (p<0.05), and 1.57 (p<0.05) years, respectively, from 1985 to 2010. The Yi, Sala, and Li minorities showed the smallest reductions, with age at menarche declining by only 0.06 (p>0.05), 0.15 (p>0.05), and 0.15 (p>0.05) years, respectively, in the same period.

CONCLUSION

A large variation in age at menarche was observed among different ethnic minorities, with the earliest age at menarche found among Korean girls. A reduction in the average age at menarche appeared among most of the ethnic minorities over time, and the largest decrease was observed in Lisu, Kazakh, and Korean girls. Thus, health education should focus on targeting the specific needs of each ethnic minority group.

Long-term secular trends in the age at menarche in Israel: a systematic literature review and pooled analysis

BACKGROUND/AIMS

A worldwide decline in the age at menarche (AAM) has been reported in recent decades. This trend has been also clinically observed among Israeli women and was reported in our previous study.

METHODS

We reviewed the literature reporting the mean AAM in Israel during the past century. Studies were excluded if participants had been investigated due to illness or any condition which could affect sexual maturation. Mean AAM was analyzed using a simple linear regression weighted for number of participants in each birth cohort and stratified to birth cohorts before and after 1970, based on the outcome of our previous study.

RESULTS

AAM varied little among women born between 1875 and 1970, but there was a clear downwards trend from 13.4 in 1970 to 12.8 two decades later. In a stratified analysis we found a significant negative association between birth year and AAM in the birth cohort after 1970 (standardized β coefficient = -0.94 per year, R(2) = 0.87; p < 0.001).

CONCLUSION

These results suggest a significant decline in mean AAM in Israeli women born in 1970 or later.

Genetic Regulation of Puberty Timing in Humans

Understanding the regulation of puberty timing has relevance to developmental and human biology and to the pathogenesis of various diseases. Recent large-scale genome-wide association studies on puberty timing and adult height, body mass index (BMI) and central body shape provide evidence for shared biological mechanisms that regulate these traits. There is a substantial genetic overlap between age at menarche in women and BMI, with almost invariable directional consistency with the epidemiological associations between earlier menarche and higher BMI. By contrast, the genetic loci identified for age at menarche are largely distinct from those identified for central body shape, while alleles that confer earlier menarche can be associated with taller or shorter adult height. The findings of population-based studies on age at menarche show increasing relevance for other studies of rare monogenic disorders and enrich our understanding of the mechanisms that regulate the timing of puberty and reproductive function.

Menarche age in Iran: A meta-analysis

BACKGROUND

Research shows that the age at menarche, as an essential element in the reproductive health of women, had been decreasing in the 19(th) and 20(th) centuries, and shows a huge variation across different countries. There are numerous studies performed in Iran reporting a range of age at menarche. Thus, this meta-analysis aimed to determine the overall mean age at menarche of the girls in Iran.

MATERIALS AND METHODS

All relevant studies were reviewed using sensitive and standard keywords in the databases from 1950 to 2013. Two raters verified a total of 1088 articles based on the inclusion criteria of this study. Forty-seven studies were selected for this meta-analysis. Cochran test was used for samples' homogeneity (Tau-square). The mean age at menarche of the girls in Iran with 95% confidence interval (CI) from the random effects was reported.

RESULTS

The homogeneity assumption for the 47 reviewed studies was attained (Tau-square = 0.00). The mean (95% CI) menarche age of Iranian girls from the random effects was 12.81 (95% CI: 12.56-13.06) years.

CONCLUSIONS

The results of this study showed that mean age at menarche was less than that of some European developed countries such as Switzerland, Sweden, and Denmark, more than that reported in some countries such as Greece and Italy, and similar to the values obtained in the United States of America and Colombia. Lower age at menarche in Iran may be largely attributed to the changes in lifestyle and diet of the children.

Structured additive regression modeling of age of menarche and menopause in a breast cancer screening program

Breast cancer risk is believed to be associated with several reproductive factors, such as early menarche and late menopause. This study is based on the registries of the first time a woman enters the screening program, and presents a spatio-temporal analysis of the variables age of menarche and age of menopause along with other reproductive and socioeconomic factors. The database was provided by the Portuguese Cancer League (LPCC), a private nonprofit organization dealing with multiple issues related to oncology of which the Breast Cancer Screening Program is one of its main activities. The registry consists of 259,652 records of women who entered the screening program for the first time between 1990 and 2007 (45-69-year age group). Structured Additive Regression (STAR) models were used to explore spatial and temporal correlations with a wide range of covariates. These models are flexible enough to deal with a variety of complex datasets, allowing us to reveal possible relationships among the variables considered in this study. The analysis shows that early menarche occurs in younger women and in municipalities located in the interior of central Portugal. Women living in inland municipalities register later ages for menopause, and those born in central Portugal after 1933 show a decreasing trend in the age of menopause. Younger ages of menarche and late menopause are observed in municipalities with a higher purchasing power index. The analysis performed in this study portrays the time evolution of the age of menarche and age of menopause and their spatial characterization, adding to the identification of factors that could be of the utmost importance in future breast cancer incidence research.

Socioeconomic status and age at menarche in indigenous and non-indigenous Chilean adolescents

The objective was to analyze the relationship between socioeconomic status and age at menarche among indigenous and non-indigenous girls in the Araucanía Region of Chile, controlling for nutritional status and mother's age at menarche. A total of 8,624 randomly selected girls from 168 schools were screened, resulting in the selection of 207 indigenous and 200 non-indigenous girls who had recently experienced menarche. Age at menarche was 149.6 ± 10.7 months in the indigenous group and 146.6 ± 10.8 months in the non-indigenous group. Among the non-indigenous, the analysis showed no significant association between age at menarche and socioeconomic status. In the indigenous group, age at menarche among girls with low socioeconomic status was 5.4 months later than among those with higher socioeconomic status. There were no differences in nutritional status according to socioeconomic level. Obesity was associated with earlier menarche. Menarche occurred earlier than in previous generations. An inverse relationship between socioeconomic status and age at menarche was seen in the indigenous group only; low socioeconomic status was associated with delayed menarche, regardless of nutritional status or mother's age at menarche.

Trends in incidence of breast cancer among women under 40 in seven European countries: a GRELL cooperative study

Young women are not usually screened for breast cancer (BC). The trends in incidence in this population may better reflect changes in risk factors. However, studies on this subject are scarce and heterogeneous. The aim of this study was to describe the trends in incidence of BC in women under 40 from 1990 to 2008, using pooled European data. Thirty-seven European population-based cancer registries from Belgium, Bulgaria, France, Italy, Portugal, Spain and Switzerland participated in this study. World age-standardized incidence rates were first analyzed graphically and then using a Poisson regression model, in order to estimate average annual percent changes (AAPCs). The overall incidence rate of BC in the area covered increased linearly during the study period by 1.19% (0.93; 1.46) on average per year. This increase varied between countries from 0.20% (-0.53; 0.64) in Bulgaria to 2.68% (1.97; 3.40) in Portugal. In Italy, after a significant rise of 2.33% (1.14; 3.54) per year, BC incidence began decreasing in 2002 by -2.30% (-4.07; -0.50) yearly. The rise in incidence was greater for women under 35 and for ductal carcinomas. This increase can be due to a rise in risk factors and/or changes in diagnosis and surveillance practices, but we could not clearly distinguish between these two non-exclusive explanations.

Trends in menarcheal age between 1955 and 2009 in the Netherlands

AIM

To assess and compare the secular trend in age at menarche in Dutch girls (1955-2009) and girls from Turkish and Moroccan descent living in the Netherlands (1997-2009).

METHODS

Data on growth and maturation were collected in 20,867 children of Dutch, Turkish and Moroccan descent in 2009 by trained health care professionals. Girls, 9 years and older, of Dutch (n = 2138), Turkish (n = 282), and Moroccan (n = 295) descent were asked whether they had experienced their first period. We compared median menarcheal age in 2009 with data from the previous Dutch Nationwide Growth Studies in 1955, 1965, 1980 and 1997. Age specific body mass index (BMI) z-scores were calculated to assess differences in BMI between pre- and postmenarcheal girls in different age groups.

RESULTS

Median age at menarche in Dutch girls, decreased significantly from 13.66 years in 1955 to 13.15 years in 1997 and 13.05 years in 2009. Compared to Dutch girls there is a larger decrease in median age of menarche in girls of Turkish and Moroccan descent between 1997 and 2009. In Turkish girls age at menarche decreased from 12.80 to 12.50 years and in Moroccan girls from 12.90 to 12.60 years. Thirty-three percent of Turkish girls younger than 12 years start menstruating in primary school. BMI-SDS is significantly higher in postmenarcheal girls than in premenarcheal girls irrespective of age.

CONCLUSION

There is a continuing secular trend in earlier age at menarche in Dutch girls. An even faster decrease in age at menarche is observed in girls of Turkish and Moroccan descent in the Netherlands.

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.

Age at menarche and its relationship to body mass index among adolescent girls in Kuwait

Background

Despite the increasing rates of childhood obesity and rapid change in socio-economic status, the mean age at menarche remains mostly unknown among contemporary girls in Kuwait and other countries in the Gulf region. This study aimed to estimate the mean age at menarche among schoolgirls in Kuwait and investigate the association between age at menarche and obesity.

Methods

A cross-sectional study was conducted on 1,273 randomly selected female high school students from all governorates in Kuwait. Overweight was defined as higher than or equal to the 85th percentile and obesity as higher than or equal to the 95th percentile using growth charts provided by the Centres for Disease Control and Prevention (CDC, 2000). Data on menarche, socio-demographic status, physical activity and diet were collected using confidential self-administered questionnaire.

Results

Out of 1,273 students, 23 (1.8%) were absent or refused to participate. The mean age at menarche was 12.41 years (95% CI: 12.35-12.48). The prevalence of early menarche, defined as less than 11 years of age, was 8.5% (95% CI: 7.0-10.2%). The prevalence of obesity and overweight was 18.3% (95% CI: 16.2-20.6%) and 25.8% (95% CI: 23.42-28.30%), respectively. Age at menarche was inversely and significantly associated with odds of overweight and obesity after adjusting for potential confounders, odds ratio 0.84 (0.77-0.93); (p = 0.001).

Conclusion

Age at menarche among contemporary girls in Kuwait is similar to that in industrialized countries. There is an inverse association between age at menarche and obesity or overweight. Trends in menarcheal age should be monitored and time of sexual maturation and its related factors should be taken into account in strategies that aim to combat obesity.

Determinants of age at menarche and time to menstrual cycle regularity in the French E3N cohort

PURPOSE

Early menarche has been associated with a greater risk of several major chronic diseases. Although largely genetically determined, age at menarche also has been related to environmental and lifestyle factors.

METHODS

Using linear regression models, we explored simultaneously several pre- and postnatal factors as potential determinants of age at menarche and time to menstrual cycle regularity in 96,493 women participating, since 1990, in the French E3N prospective cohort.

RESULTS

Younger age at recruitment, greater father's income index, urban birth place, greater birth length, and larger body silhouette during childhood were associated with an earlier age at menarche (from -1.3 to -4.6 months, P(trend) < .0001) whereas greater family size, food deprivation during childhood, and greater birth weight resulted in a delayed menarche (from +1.5 months to +5.3 months, P(trend) < .0001). Father's income index, urban birth place, and prematurity predicted a shorter time to menstrual cycle regularity (from -1.1 to -1.9 months, P(trend) < .04), whereas birth cohort, larger body silhouette at menarche, and childhood exposure to passive smoking were associated with a longer time to menstrual cycle regularity (from +1.1 months to +8.6 months, P(trend) < .006).

CONCLUSIONS

Age at menarche and menstrual cycle regularity are significantly influenced by several individual, environmental and lifestyle factors.

Association analyses suggest the effects of RANK and RANKL on age at menarche in Chinese women

OBJECTIVES

Age at menarche (AAM), the time of the first menstrual bleeding, is an important developmental milestone in the female life. It marks the beginning of the reproductive period. AAM is implicated in the risk of many health complications in later life. In this study, we conducted an analysis for association of single nucleotide polymorphisms (SNPs) and common haplotypes of two candidate genes, RANK (receptor activator of the NF-κB) and RANKL (receptor activator of the NF-κB ligand), with AAM in 825 unrelated Chinese women.

METHODS

In total, 73 SNPs of RANKL and 23 SNPs of RANK were genotyped. The SNPs and common haplotypes were then analyzed for their association with AAM. Age and age( 2 ) were used as covariates.

RESULTS

We found five individual SNPs (rs7239261, rs8094884, rs3826620, rs8089829, and rs9956850) of RANK significantly associated with AAM (p < 0.05). Although no significant association was identified for the RANKL gene, three polymorphisms showed nearly significant (0.05 < p < 0.08) association with AAM. Seven haplotypes of RANK were significantly associated with AAM (p < 0.05); the most significant association of the AT haplotype composed by rs1805034 and rs4524034 (p = 9.4 × 10(-4)) remained significant (p = 0.0235) after the Bonferroni correction for multiple testing. Three haplotypes of RANKL were significantly associated with AAM (p < 0.05). Importantly, the association of rs3826620 replicated our previous findings for Caucasian females.

CONCLUSIONS

The results of the present study suggest that the RANK and RANKL are two candidate genes for AAM in Chinese women.

Re-examining heritability: genetics, life history and plasticity

Human life-history traits (growth, maturation, nutritional status) are increasingly associated with risk of chronic degenerative disease. Twin studies suggest high heritability of such traits; however, although sophisticated approaches have identified genetic variation underlying a proportion of this heritability, studies also increasingly demonstrate significant plasticity, and many life-history traits are able to change by one standard deviation (SD) over 3-6 generations. Developments in our understanding of the contributions of genetics and plasticity to human life history are likely to improve understanding of the growing burden of chronic diseases. We argue that a life-history approach to understanding variation in the human phenotype must integrate these two risk components, and highlight the important contribution of plasticity to changes in disease prevalence.

Early menarche and psychopathological symptoms in young Chinese women

OBJECTIVE

To evaluate the psychopathological symptoms, suicide, and self-harming behaviors among students with early, on-time, and late menarche in high school and college and the association of early menarche with these disorders.

METHODS

The design consisted of a cross-sectional study of 5597 high school students and 2768 college students. Menarche age, suboptimal mental health status, anxiety, depression, suicide, and self-harming behaviors were obtained by self-report questionnaire.

RESULTS

In high school students, all the disorders occurred at significantly higher frequency in those with early menarche than in those with on-time and late menarche. In college students, only suboptimal mental health status, depression, and suicidal ideation happened at significantly higher frequency in the early menarche group than in the other two groups. The college group had a lower frequency of all the disorders than the high school group for all three groups of girls, that is, with early, on-time, or late menarche. In a multivariate logistic regression model, early menarche persisted as a risk factor for all the disorders after other factors were controlled.

CONCLUSIONS

Psychopathological symptoms, suicide, and self-harming behaviors are more common in early menarche students than in on-time and late menarche students. The effects of early menarche on the disorders might dissipate over time. Early menarche might serve as a predictor for the disorders in Chinese girls.

Epidemiology of breast cancer in young women

Breast cancer is mainly a postmenopausal disease, but in younger women breast tumors often exhibit more aggressive features and worse prognosis. Furthermore, high-risk and low-risk tumors present different age distributions suggesting that breast cancer comprises a mixture of two different disease processes. In agreement with this hypothesis, breast cancer presents different epidemiologic traits in pre- and postmenopausal women. Regarding racial distribution, incidence is higher in black women at younger ages in US, while the reverse is true among women older than 50 years. Genetic predisposition is a stronger risk factor in young women. On the contrary, nulliparity and obesity decrease the risk of early-onset breast cancers while are associated with higher incidence in older women. Epidemiologic data related with the hormonal exposure in utero suggest that the effect is stronger in early breast cancers. In most developed countries, breast cancer has shown an upward trend until recent years in postmenopausal women, while incidence rates in younger women have been stable. However, Spain is an exception to this rule: Spanish women younger than 45 years of age have registered a steady increase of breast cancer that may be related with the remarkable lifestyle changes experienced by women born in the second half of the twentieth century.