Association Between Markers of Adiposity During Childhood and Puberty Onset in Latino Girls.

CONTEXT: Prepubertal adiposity is associated with earlier puberty. It is unclear when this association starts, if all adiposity markers are similarly associated, and whether all pubertal milestones are similarly affected. OBJECTIVE: To evaluate the association between different adiposity markers during childhood and the timing of different pubertal milestones in Latino girls. DESIGN, SETTING, AND PARTICIPANTS: Longitudinal follow-up of 539 female participants of the Chilean Growth and Obesity Cohort recruited from childcare centers (mean age 3.5 years) from the southeast area of Santiago, Chile. Participants were singletons born between 2002 and 2003 within the normal birthweight range. Since 2006, a trained dietitian measured weight, height, waist circumference (WC) and skinfolds to estimate body mass index (BMI) Centers for Disease Control and Prevention percentiles, central obesity, percentage of fat mass (%FM), and fat mass index (FMI, fat mass/height2). MAIN OUTCOME: Since 2009, sexual maturation was assessed every 6 months to assess age at (1) thelarche, (2) pubarche, (3) menarche, and (4) peak height velocity (PHV). RESULTS: At thelarche, 12.5% were obese and 2% had central obesity. The median age of pubarche, menarche, and PHV were all associated with markers of adiposity at different time points during childhood whereas thelarche only with %FM and FMI. Adiposity clusters models showed that children with trajectories of high WC, %FM, and FMI during childhood were related with earlier thelarche, pubarche, menarche, and PHV but BMI trajectories only with menarche and PHV. CONCLUSIONS: Higher WC, %FM, and FMI were associated with earlier age at thelarche, pubarche, menarche, and PHV. The effect of BMI was less consistent.

Marginal Food Security Predicts Earlier Age at Menarche Among Girls From the 2009-2014 National Health and Nutrition Examination Surveys.

STUDY OBJECTIVE: This study analyzed the relationship between household food security and variation in age at menarche, as well as the connections between food insecurity, nutritional status, and allostatic load, among girls aged 12-15 years from the 2009-2014 United States National Health and Nutrition Examination Survey (NHANES). METHODS: Data analysis included mean comparisons of age at menarche among household food security groups (high, marginal, low, and very low) as well as categorical variables known to associate with age at menarche (ethnicity, poverty status, body mass index [BMI], allostatic load, and milk consumption). χ2 Analyses were used to test the associations between household food security and additional categorical variables. Univariate and multivariate regression models were used to test the relationship between variation in age at menarche and household food security, ethnicity, BMI, and allostatic load categories while controlling for age. RESULTS: Non-Hispanic Black and Hispanic/Mexican American girls had earlier mean ages at menarche, higher mean BMIs, and disproportionately experienced household food insecurity when compared to non-Hispanic White-identifying girls. In the univariate analyses, marginal household food security, Hispanic/Mexican American and Black ethnicities, overweight and obese BMI categories, and marginal-high allostatic load were each associated with lower age at menarche compared to reference categories. These associations were maintained in the multivariate analysis, although only Hispanic/Mexican American ethnicity predicted earlier menarche when compared to that of non-Hispanic White girls. CONCLUSIONS: Marginal household food security, particularly for girls who identified as non-White, predicted earlier age at menarche independent of nutritional status and allostatic load. At the same time, having more energetic resources (ie, higher BMI) also significantly predicted earlier menarche.

Age at menopause in India: A systematic review.

BACKGROUND AND AIMS: Menopause is a physiological process in nature and hence, variations in the age of menopause are not expected. Hence, the study was conducted with an objective to calculate the reliable estimates of age at menopause for India, and understand the differentials in women's age at menopause throughout the country. METHODS: A total of 202 studies of age at menopause, covering the period 2009-2020, were accessed from PubMed database and Google. Of these only ten studies met the selection criteria for this paper, which is that the data for these studies must be collected from house-to-house surveys. RESULTS: The average age at menopause in India, with minimal publication bias, is 46.6 years (95% CI: 44.83, 48.44). In one study slightly above 1.96 Standard Deviation, was observed, as ascertained by Funnel Plot and Egger's test. The mean age ranged from a minimum of 44.69 years (95% CI: 35.01, 54.37) to a maximum of 48.95 (95% CI: 42.29, 55.61) years. Furthermore, the age at menopause did not exhibit any significant variation by age at menarche, although the association was positive. CONCLUSIONS: The age at menopause showed positive association with age at menarche. In India, during the period 2009-2020, it was 46.6 years, which significantly lower than the age in some developed countries. The differences may be methodological since no information was found regarding the distribution of age at menopause in the studies that were considered for meta-analysis.

Racial/Ethnic Differences in Age at Menarche and Lifetime Nonmedical Marijuana Use: Results from the NHANES 2005-2016.

Early age at menarche has been linked to many adverse health outcomes among women, including substance use. However, little is known on the association between age at menarche and nonmedical use of marijuana, and no study has assessed the potential racial/ethnic differences. In this study, the 2005-2016 National Health and Nutrition Examination Survey data were used to investigate the association between age at menarche and the risk of lifetime nonmedical use of marijuana. Logistic regression models were used to examine such association adjusting for sociodemographic factors. Interactions between age at menarche and race/ethnicity were also assessed. Among the 10,302 women included, 53.9% had lifetime nonmedical use of marijuana. The regression model shows that women with early menarche had 1.26 (95% CI 1.09, 1.45) times the odds of having lifetime nonmedical use of marijuana compared with women with normal age at menarche. When assessing the association by race/ethnicity, marginally positive associations were observed for both the early and late menarche groups among non-Hispanic White women. However, among women with race/ethnicity other than non-Hispanic White, early menarche is significantly associated with increased risks of lifetime nonmedical marijuana use, while late menarche is significantly associated with decreased risks. This study suggests that early menarche may be a risk factor of lifetime nonmedical use of marijuana, and racial/ethnic differences may exist in the association. Future studies are warranted to examine and confirm these findings.

Reproductive Health Disparities in the USA: Self-Reported Race/Ethnicity Predicts Age of Menarche and Live Birth Ratios, but Not Infertility.

Self-identified race/ethnicity and socioeconomic status (SES) contribute to disparities in several health domains, although research on their effects on women's reproductive function has largely focused on links between SES and age of menarche. Here, we assessed whether race/ethnicity, SES, and downstream correlates of SES such as food security and health-insurance security are associated with age of menarche, infertility, and live birth ratios (ratios of recognized pregnancies resulting in live births) in the USA. We used cross-sectional data from 1694 women aged 12-18 years for menarche (2007-2016), 974 women aged 23-45 for infertility (2013-2016), and 1714 women aged 23-45 for live birth ratios (2007-2016) from the National Health and Nutrition Examination Survey. We estimated multiple linear and logistic regressions with survey weights to test these associations. When controlling for lifestyle (activity levels, smoking, alcohol consumption) and physiological factors (diabetes, weight status), non-Hispanic (NH) black and Hispanic girls reported a significantly lower age of menarche by about 4.3 (standard error [SE] = 0.08, p < 0.001), and 3.2 months (SE = 0.09, p < 0.001), respectively, relative to NH white girls. NH black women reported live birth ratios 9% (SE = 0.02, p < 0.001) lower than NH white women. Women with unstable health insurance reported live birth ratios 6% (SE = 0.02, p = 0.02) lower than women with stable health insurance. Race/ethnicity, SES, and its downstream correlates were not associated with infertility. One hypothesized explanation for observed disparities in age of menarche and live birth ratios is the embodiment of discrimination faced by NH black women within the USA. Our findings also underscore the importance of health insurance access for favorable reproductive health outcomes. Future work should elucidate the role of embodied discrimination and other downstream correlates of SES in modulating women's reproductive health outcomes to inform strategies to mitigate health disparities.

Effect of age at menarche on the mother's weight status two and four years after delivery: a cohort study.

We aimed to estimate the effect of age at menarche on the risk of excess body weight in Brazilian women two and four years after delivery. This was a cohort study that used data from adult women of the Predictors of Maternal and Child Excess Body Weight (PREDI) Study obtained at baseline (2012) and at 1st(2014) and 2nd(2016) follow-up. A total of 435 women attending a public maternity hospital in Joinville-Brazil were initially included in the study (baseline) and 215 of them continued to participate in the 2nd follow-up carried out in the homes of the participants. Regression analysis was used to estimate the association between age at menarche (<12; ≥12 years) and excess body weight (≥25 kg/m2) trajectory during the follow-ups. Unadjusted analysis showed that mothers with age at menarche <12 years were 1.29 times (p = .018) more likely to be overweight/obese than those with age at menarche ≥12 years. After adjustment, age at menarche continued to exert an independent effect on the mother's body mass index (RR = 1.23; p = .037) four years after delivery. Strategies designed to attenuate the rising prevalence of maternal overweight and obesity, especially after pregnancy, could help improve the mother's health status in the future.

Menstrual and reproductive characteristics and breast cancer risk by hormone receptor status and ethnicity: The Breast Cancer Etiology in Minorities study.

We pooled multiethnic data from four population-based studies and examined associations of menstrual and reproductive characteristics with breast cancer (BC) risk by tumor hormone receptor (HR) status [defined by estrogen receptor (ER) and progesterone receptor (PR)]. We estimated odds ratios and 95% confidence intervals using multivariable logistic regression, stratified by age (<50, ≥50 years) and ethnicity, for 5,186 HR+ (ER+ or PR+) cases, 1,365 HR- (ER- and PR-) cases and 7,480 controls. For HR+ BC, later menarche and earlier menopause were associated with lower risk in non-Hispanic whites (NHWs) and Hispanics, and higher parity and longer breast-feeding were associated with lower risk in Hispanics and Asian Americans, and suggestively in NHWs. Positive associations with later first full-term pregnancy (FTP), longer interval between menarche and first FTP and shorter time since last FTP were limited to younger Hispanics and Asian Americans. Except for nulliparity, reproductive characteristics were not associated with risk in African Americans. For HR- BC, lower risk was associated with later menarche, except in African Americans and older Asian Americans and with longer breast-feeding in Hispanics and Asian Americans only. In younger African Americans, HR- BC risk associated with higher parity (≥3 vs. 1 FTP) was increased fourfold in women who never breast-fed, but not in those with a breast-feeding history, suggesting that breast-feeding may mitigate the adverse effect of higher parity in younger African American women. Further work needs to evaluate why menstrual and reproductive risk factors vary in importance according to age and ethnicity.

Is menarche occuring earlier among Lebanese girls?

BACKGROUND: Early menarche is associated with increased risks for several diseases such as cardiovascular diseases and breast cancer. This analysis aimed at generating evidence on a historical trend towards younger age at menarche among Lebanese girls. METHODS: A secondary analysis was conducted on data consolidated from three serial cross-sectional national surveys of women in Lebanon (2007, 2009 and 2012). A total of 6150 women were included in order to study the association between date of birth intervals and age at menarche. RESULTS: The mean age at menarche was 13.06 years, with a peak of the distribution at age 12. Women born before 1950 had a significantly higher mean age at menarche (13.21) compared to those born in 1970 and thereafter (12.95). A stratified analysis showed that women living outside the metropolitan Greater Beirut (GB) area were characterized by an older mean age at menarche (13.11) in all date of birth intervals compared to those in GB (12.89). However, age at menarche declined more significantly over the last two decades among women outside GB, compared to those living in GB. CONCLUSIONS: Epidemiological figures emerging from this study confirm that trends in Lebanon are in line with a global pattern of decreasing age at menarche. Urban-rural differences suggest that higher caloric content of diet and consequent early overweight, more evident in urban areas, are likely determinants of younger menarche. Evidence from this study calls for an urgent implementation of comprehensive multisectoral obesity prevention in children in Lebanon.

[The status of spermarche, menarche and corresponding relationships with nutritional status among students of 13 ethnic minorities in Southwest China in 2014].

Objective: To describe the current situation of spermarche/menarche of 13 ethnic minority groups in China in 2014, and analyze the association between spermarche/menarche and nutritional status among ethnic minority groups. Methods: The sample of 13 ethnic minorities (Bai, Hani, Dai, Lisu, Wa, Naxi, Miao, Shui, Buyi, Dong, Zhuang, Yao and Qiang) from Yunnan, Guizhou, Sichuan province and Guangxi Zhuang autonomous region were selected from Chinese National Survey on Students' Constitution and Healthy of 2014. A total of 25 964 students with completed records of height, weight, spermarche and menarche were selected, including 11 276 boys aged 11-18 years old and 14 688 girls aged 9-18 years old. Probit analysis was used to calculate the median age at spermarche or menarche. All subjects were classification into four nutritional status groups (normal, malnutrition, overweight and obesity) according to the Screening standard for malnutrition of school-age children and adolescents (WS/T 456-2014) and the Screening for overweight and obesity among school-age children and adolescent (WS/T 586-2018) of China. Binary logistic regression was used to analyze the association between spermarche, menarche and nutritional status. Results: The median age at spermarche (95%CI) of 13 ethnic minorities were ranged from 13.4 (13.1, 13.7) years old to 15.3 (15.1, 15.5) years old. In the 11 -year age group, all ethnic girls experienced menarche. The median age at menarche (95%CI) of 13 ethnic minorities were ranged from 12.1 (11.4, 12.7) years old to13.6 (13.4, 13.7) years old. Logistics regression analysis showed that students with malnutrition experienced spermarche or menarche later than normal weight students, the OR (95%CI) for boys about 0.49 (0.42, 0.56) and girls about 0.15 (0.12, 0.19), while overweight and obese students entered puberty at earlier age, the OR (95%CI) for boys about 1.37(1.10, 1.72) and girls about 3.21(2.51, 4.12). Conclusion: Boys from 13 ethnic minorities began to have spermatorrhea at the age of 13, and girls from 13 ethnic minorities began menstruating at the age of 9 in 2014. Nutrition status was closely related to spermarche and menarche.

Tending the 'monthly flower:' a qualitative study of menstrual beliefs in Tigray, Ethiopia.

BACKGROUND: Menstruation is a universal aspect of human female reproductive life. Management of menstrual flow presents hygiene challenges to girls and women in low-income countries, especially when they first start their periods. As part of a project to improve menstrual hygiene management in the Tigray Region of Ethiopia, we explored the local understanding of menstruation through focus-group discussions and individual interviews. METHODS: A detailed ethnographic survey of menstrual beliefs was carried out through 40 focus group discussions, 64 in-depth key informant interviews, and 16 individual case histories in the Tigray Region of northern Ethiopia. A total of 240 individuals participated in six types of focus groups (pre-menarchal girls, menstruating adolescents, married women of reproductive age, post-menopausal women, adolescent males, and married men). In-depth interviews were also carried out with 80 individuals, including Orthodox Christian priests, imams from the Muslim community, principals of primary and secondary schools, teachers and nurses, as well as menstruating schoolgirls and women. Audio data were transcribed and translated, then broken down into discrete codes using Atlas Ti software (version 7.5.4, Atlas.ti Scientific Software Development Mnbh, Berlin) and further grouped into related families and sub-families based on their content. The results were then synthesized to produce a cohesive narrative concerning menstruation in Tigray. RESULTS: Recurrent themes identified by participants included descriptions of the biology of menstruation (which were sometimes fanciful); the general unpreparedness of girls for menarche; cultural restrictions imposed by menstruation on females (particularly the stigma of ritual uncleanliness in both Christian and Muslim religious traditions); the prevalence and challenges of unmet menstrual hygiene needs at schools (including lack of access to sanitary pads and the absence of acceptable toilet/washing facilities); and the stigma and shame associated with menstrual hygiene accidents in public. CONCLUSIONS: Changes in the educational system in northern Ethiopia are required to improve student understanding of the biology of menstruation, to foster gender equity, to overcome the barriers to school attendance presented by poor menstrual hygiene management, and to create a society that is more understanding and more accepting of menstruation.

The genetic underpinnings of variation in ages at menarche and natural menopause among women from the multi-ethnic Population Architecture using Genomics and Epidemiology (PAGE) Study: A trans-ethnic meta-analysis.

Current knowledge of the genetic architecture of key reproductive events across the female life course is largely based on association studies of European descent women. The relevance of known loci for age at menarche (AAM) and age at natural menopause (ANM) in diverse populations remains unclear. We investigated 32 AAM and 14 ANM previously-identified loci and sought to identify novel loci in a trans-ethnic array-wide study of 196,483 SNPs on the MetaboChip (Illumina, Inc.). A total of 45,364 women of diverse ancestries (African, Hispanic/Latina, Asian American and American Indian/Alaskan Native) in the Population Architecture using Genomics and Epidemiology (PAGE) Study were included in cross-sectional analyses of AAM and ANM. Within each study we conducted a linear regression of SNP associations with self-reported or medical record-derived AAM or ANM (in years), adjusting for birth year, population stratification, and center/region, as appropriate, and meta-analyzed results across studies using multiple meta-analytic techniques. For both AAM and ANM, we observed more directionally consistent associations with the previously reported risk alleles than expected by chance (p-valuesbinomial≤0.01). Eight densely genotyped reproductive loci generalized significantly to at least one non-European population. We identified one trans-ethnic array-wide SNP association with AAM and two significant associations with ANM, which have not been described previously. Additionally, we observed evidence of independent secondary signals at three of six AAM trans-ethnic loci. Our findings support the transferability of reproductive trait loci discovered in European women to women of other race/ethnicities and indicate the presence of additional trans-ethnic associations both at both novel and established loci. These findings suggest the benefit of including diverse populations in future studies of the genetic architecture of female growth and development.

A cosmopolítica da gestação, do parto e do pós-parto: autoatenção e medicalização entre os índios Munduruku / The cosmopolitics of pregnancy, childbirth and postpartum: self-attention and medicalization among Munduruku Indians

A pesquisadora Raquel Paiva Dias-Scopel, do Instituto Leônidas e Maria Deane (ILMD/Fiocruz Amazônia), levanta questões sobre a valorização e respeito à diversidade étnica e cultural dos povos indígenas e a difícil interface com o processos de medicalização e do direito ao acesso aos serviços de saúde biomédicos. O livro é parte da Coleção Saúde dos Povos Indígenas, da Editora Fiocruz e partiu da tese de doutorado defendida em 2014 no Programa de Pós-Graduação em Antropologia Social da Universidade Federal de Santa Catarina (UFSC). Foi publicado pela primeira vez em 2015 pela Associação Brasileira de Antropologia com o título A Cosmopolítica da Gestação, Parto e Pós-Parto: práticas de autoatenção e processo de medicalização entre os índios Munduruku. No prefácio da primeira edição, sua orientadora, a doutora em antropologia e professora titular da UFSC, Esther Jean Langdon, ressalta que o conceito fundamental deste livro é da autoatenção, que aponta para o reconhecimento da autonomia e da criatividade da coletividade, principalmente da família, como núcleo que articula os diferentes modelos de atenção ou cuidado da saúde.

The Null Relation between Father Absence and Earlier Menarche.

Researchers have claimed that the absence of a biological father accelerates the daughter's menarche. This claim was assessed by employing a large and nationally representative sample of Indonesian women. We analyzed 11,138 ever-married women aged 15+ in the Indonesian Family Life Survey 2015. We regressed age at menarche on the interaction of father absence (vs. presence) and mother absence (vs. presence) at age 12 with or without childhood covariates. For robustness checks, we performed a power analysis, re-ran the same specification for various subgroups, and varied the independent variable of interest. All results produced a null relation between father absence and age at menarche. The power analysis suggests that a false negative was unlikely. Our review of the literature indicates that the claim of the relation between father absence and earlier menarche was based on weak statistical foundations. Other studies with higher-quality datasets tended to find no relation, and our results replicated this tendency. Therefore, the influence of father absence does not appear to be universal.

The meaning of menarche: A cross-cultural semantic network analysis.

The psychological meaning of menarche was explored in 102 college students from Mexico and the United States. The Natural Semantic Networks Technique was used and participants were asked to respond to the prompt "My first period was …" The strongest components of the Mexican women's semantic network were scary, confusing, and unexpected; the strongest components of the American women's semantic network were unexpected, annoying, and painful. Only the Americans listed positive words (i.e., nice). The Mexicans' network contained the most negative words (i.e., dirty). The results suggest a need for better education and greater social support, especially in Mexico.

Negotiating Discourses of Shame, Secrecy, and Silence: Migrant and Refugee Women's Experiences of Sexual Embodiment.

In Australia and Canada, the sexual health needs of migrant and refugee women have been of increasing concern, because of their underutilization of sexual health services and higher rate of sexual health problems. Previous research on migrant women's sexual health has focused on their higher risk of difficulties, or barriers to service use, rather than their construction or understanding of sexuality and sexual health, which may influence service use and outcomes. Further, few studies of migrant and refugee women pay attention to the overlapping role of culture, gender, class, and ethnicity in women's understanding of sexual health. This qualitative study used an intersectional framework to explore experiences and constructions of sexual embodiment among 169 migrant and refugee women recently resettled in Sydney, Australia and Vancouver, Canada, from Afghanistan, Iraq, Somalia, South Sudan, Sudan, Sri Lanka, India, and South America, utilizing a combination of individual interviews and focus groups. Across all of the cultural groups, participants described a discourse of shame, associated with silence and secrecy, as the dominant cultural and religious construction of women's sexual embodiment. This was evident in constructions of menarche and menstruation, the embodied experience that signifies the transformation of a girl into a sexual woman; constructions of sexuality, including sexual knowledge and communication, premarital virginity, sexual pain, desire, and consent; and absence of agency in fertility control and sexual health. Women were not passive in relation to a discourse of sexual shame; a number demonstrated active resistance and negotiation in order to achieve a degree of sexual agency, yet also maintain cultural and religious identity. Identifying migrant and refugee women's experiences and constructions of sexual embodiment are essential for understanding sexual subjectivity, and provision of culturally safe sexual health information in order to improve well-being and facilitate sexual agency.

Puberty Experiences of Low-Income Girls in the United States: A Systematic Review of Qualitative Literature From 2000 to 2014.

PURPOSE: Puberty is a critical period of development that lays the foundation for future sexual and reproductive health. It is essential to learn about the puberty experiences of low-income girls in the United States given their increased vulnerability to negative sexual and reproductive health outcomes. To understand the present-day puberty experiences of this population, we conducted a qualitative systematic review. METHODS: We systematically searched the peer-reviewed literature published between 2000 and 2014 on the puberty experiences of low-income girls in the United States. Reviewers screened titles, abstracts, and the full texts of articles. Using standardized templates, reviewers assessed the methodologic quality and extracted data. Data were synthesized using thematic analysis. Confidence in each finding was assessed using Confidence in the Evidence from Reviews of Qualitative research. RESULTS: Twenty qualitative articles were included. They described the experiences of mostly African-American, Caucasian, and Hispanic girls living primarily in urban areas of Northeastern United States. Five overarching themes emerged: content of girls' puberty experiences, quality of girls' puberty experiences, messages girls receive about puberty, other factors that shape girls' puberty experiences, and relationships that shape girls' experiences of puberty. CONCLUSIONS: The limited existing evidence suggests that low-income girls in the United States are unprepared for puberty and have largely negative experiences of this transition.

Early Puberty, School Context, and Delinquency Among South Korean Girls.

Compared with chronological age, criminologists have paid less attention to the biological sense of age typically expressed by pubertal development. Studies that have examined pubertal timing's effects on delinquency have almost exclusively been conducted in Western countries using mostly White samples. To our knowledge, no study has ever examined this issue in the Asian context. The current study is the first attempt to bridge this research gap by examining the association among menarcheal timing, the sex composition of schools, and delinquency in a representative sample of 1,108 ninth-grade girls in South Korea. The results show that significant association between early menarche and delinquency exists only in mixed-sex schools but not in all-girls schools. In addition, the significant linkage between early menarche and delinquency in mixed-sex schools is mediated by delinquent peer associations.

Early puberty in 11-year-old girls: Millennium Cohort Study findings.

OBJECTIVE: Early puberty in girls is linked to some adverse outcomes in adolescence and mid-life. We address two research questions: (1) Are socioeconomic circumstances and ethnicity associated with early onset puberty? (2) Are adiposity and/or psychosocial stress associated with observed associations? DESIGN: Longitudinal data on 5839 girls from the UK Millennium Cohort Study were used to estimate associations between ethnicity, family income, adiposity and psychosocial stress with a marker of puberty. MAIN OUTCOME MEASURE: Reported menstruation at age 11 years. RESULTS: All quoted ORs are statistically significant. Girls in the poorest income quintile were twice as likely (OR=2.1), and the second poorest quintile nearly twice as likely (OR=1.9) to have begun menstruation compared with girls in the richest income quintile. Estimates were roughly halved on adjustment for Body Mass Index and markers of psychosocial stress (poorest, OR=1.5; second poorest, OR=1.5). Indian girls were over 3 times as likely compared with whites to have started menstruation (OR=3.5) and statistical adjustments did not attenuate estimates. The raised odds of menstruation for Pakistani (OR=1.9), Bangladeshi (OR=3.3) and black African (OR=3.0) girls were attenuated to varying extents, from about a third to a half, on adjustment for income and adiposity. CONCLUSIONS: In contemporary UK, excess adiposity and psychosocial stress were associated with social inequalities in early puberty, while material disadvantage and adiposity were linked to ethnic inequalities in early puberty among girls.

Age at menarche and risk of major cardiovascular diseases: Evidence of birth cohort effects from a prospective study of 300,000 Chinese women.

BACKGROUND: Previous studies of mostly Western women have reported inconsistent findings on the association between age at menarche and risk of cardiovascular disease (CVD). Little is known about the association in China where there has been a large intergenerational decrease in women's mean age at menarche. METHODS: The China Kadoorie Biobank recruited 302,632 women aged 30-79 (mean 50.5)years in 2004-8 from 10 diverse regional sites across China. During 7years follow-up, 14,111 incident cases of stroke, 14,093 of coronary heart disease (CHD), and 3200 CVD deaths were reported among 281,491 women who had no prior history of CVD at baseline. Cox regression yielded adjusted hazard ratios (HRs) relating age at menarche to CVD risks. RESULTS: The mean (SD) age of menarche was 15.4 (1.9)years, decreasing from 16.2 (2.0) among women born before 1940 to 14.7 (1.6) for those born during the 1960s-1970s. The patterns of association between age at menarche and CVD risk appeared to differ between different birth cohorts, with null associations in older generations but U-shaped or weak positive associations in younger women, especially those born after the 1960s. After minimizing the potential confounding effects from major CVD risk factors, both early and late menarche, compared with menarche at age 13years, were associated with increased risk of CVD morbidity and mortality, which was more pronounced in younger generations. CONCLUSION: Among Chinese women the associations between age at menarche and risk of CVD differed by birth cohort, suggesting other factors may underpin the association.

Associations of urinary phthalate and phenol biomarkers with menarche in a multiethnic cohort of young girls.

To study potential environmental influences on puberty in girls, we investigated urinary biomarkers in relation to age at menarche. Phenols and phthalates were measured at baseline (6-8 years of age). Menarche was ascertained over 11 years for 1051 girls with menarche and biomarkers. Hazards ratios were estimated from Cox models adjusted for race/ethnicity and caregiver education (aHR, 95% confidence intervals [CI] for 5th vs 1st quintile urinary biomarker concentrations). 2,5-Dichlorophenol was associated with earlier menarche (aHR 1.34 [1.06-1.71]); enterolactone was associated with later menarche (aHR 0.82 [0.66-1.03]), as was mono-3-carboxypropyl phthalate (MCPP) (aHR 0.73 [0.59-0.91]); the three p-trends were <0.05. Menarche differed by 4-7 months across this range. Enterolactone and MCPP associations were stronger in girls with below-median body mass index. These analytes were also associated with age at breast development in this cohort. Findings from this prospective study suggest that some childhood exposures are associated with pubertal timing.