Showing papers on "Menarche published in 2017"

Genomic analyses identify hundreds of variants associated with age at menarche and support a role for puberty timing in cancer risk

Abstract: The timing of puberty is a highly polygenic childhood trait that is epidemiologically associated with various adult diseases. Using 1000 Genomes Project-imputed genotype data in up to ∼370,000 women, we identify 389 independent signals (P < 5 × 10-8) for age at menarche, a milestone in female pubertal development. In Icelandic data, these signals explain ∼7.4% of the population variance in age at menarche, corresponding to ∼25% of the estimated heritability. We implicate ∼250 genes via coding variation or associated expression, demonstrating significant enrichment in neural tissues. Rare variants near the imprinted genes MKRN3 and DLK1 were identified, exhibiting large effects when paternally inherited. Mendelian randomization analyses suggest causal inverse associations, independent of body mass index (BMI), between puberty timing and risks for breast and endometrial cancers in women and prostate cancer in men. In aggregate, our findings highlight the complexity of the genetic regulation of puberty timing and support causal links with cancer susceptibility.

Mapping the knowledge and understanding of menarche, menstrual hygiene and menstrual health among adolescent girls in low- and middle-income countries

Abstract: Menstruation is a natural physiological process that requires proper management. Unlike other normal bodily processes, menstruation is linked with religious and cultural meanings that can affect the perceptions of young girls as well as the ways in which the adults in the communities around them respond to their needs. This review aims to answer the following questions: (1) how knowledgeable are adolescent girls in low- and middle-income countries about menstruation and how prepared are they for reaching menarche, (2) who are their sources of information regarding menstruation, (3) how well do the adults around them respond to their information needs, (4) what negative health and social effects do adolescents experience as a result of menstruation, and (5) how do adolescents respond when they experience these negative effects and what practices do they develop as a result? Using a structured search strategy, articles that investigate young girls’ preparedness for menarche, knowledge of menstruation and practices surrounding menstrual hygiene in LMIC were identified. A total of 81 studies published in peer-reviewed journals between the years 2000 and 2015 that describe the experiences of adolescent girls from 25 different countries were included. Adolescent girls in LMIC are often uninformed and unprepared for menarche. Information is primarily obtained from mothers and other female family members who are not necessarily well equipped to fill gaps in girls’ knowledge. Exclusion and shame lead to misconceptions and unhygienic practices during menstruation. Rather than seek medical consultation, girls tend to miss school, self-medicate and refrain from social interaction. Also problematic is that relatives and teachers are often not prepared to respond to the needs of girls. LMIC must recognize that lack of preparation, knowledge and poor practices surrounding menstruation are key impediments not only to girls’ education, but also to self-confidence and personal development. In addition to investment in private latrines with clean water for girls in both schools and communities, countries must consider how to improve the provision of knowledge and understanding and how to better respond to the needs of adolescent girls.

Association between Obesity and Puberty Timing: A Systematic Review and Meta-Analysis.

Abstract: This systematic review and meta-analysis examined the associations between obesity and puberty timing based on scientific evidence. Eight electronic databases were searched up to February 2017 for eligible studies, and two reviewers screened the articles and extracted the data independently. A total of 11 cohort studies with 4841 subjects met the inclusion criteria. Compared with the group of normal-weight girls, the obese group had more girls with menarche (RR: 1.87, 95% CI: 1.59–2.19, 2 studies). The number of girls with early puberty was significantly higher in the obese group than the normal weight group (RR: 2.44, 95% CI: 1.32–4.52, 5 studies). However, no differences were detected between girls who were obese or normal weight at age of menarche (WMD: −0.53 years, 95% CI: −1.24–0.19, 2 studies). There is no consistent result in the relationship between obesity and timing of pubertal onset in boys. Obesity may contribute to early onset of puberty in girls, while in boys, there is insufficient data. Given the limited number of cohort studies included in this meta-analysis, high-quality studies with strong markers of puberty onset, as well as standardized criteria for defining obesity are needed.

Menstrual hygiene management among Bangladeshi adolescent schoolgirls and risk factors affecting school absence: results from a cross-sectional survey.

Abstract: Background Many adolescent girls in low-income and middle-income countries lack appropriate facilities and support in school to manage menstruation. Little research has been conducted on how menstruation affects school absence. This study examines the association of menstrual hygiene management knowledge, facilities and practice with absence from school during menstruation among Bangladeshi schoolgirls. Methods We conducted a nationally representative, cross-sectional study in Bangladeshi schools from March to June 2013 among girls 11 to 17 years old who reached menarche. We sampled 700 schools from 50 urban and 50 rural clusters using a probability proportional to size technique. We interviewed 2332 schoolgirls and conducted spot checks in each school for menstrual hygiene facilities. To assess factors associated with reported school absence, we estimated adjusted prevalence difference (APD) for controlling confounders’ effect using generalised estimating equations to account for school-level clustering. Results Among schoolgirls who reached menarche, 41% (931) reported missing school, an average of 2.8 missed days per menstrual cycle. Students who felt uncomfortable at school during menstruation (99% vs 32%; APD=58%; CI 54 to 63) and who believed menstrual problems interfere with school performance (64% vs 30%; APD=27; CI 20 to 33) were more likely to miss school during menstruation than those who did not. School absence during menstruation was less common among girls attending schools with unlocked toilet for girls (35% vs 43%; APD=−5.4; CI −10 to –1.6). School absence was more common among girls who were forbidden from any activities during menstruation (41% vs 33%; APD=9.1; CI 3.3 to 14). Conclusion Risk factors for school absence included girl’s attitude, misconceptions about menstruation, insufficient and inadequate facilities at school, and family restriction. Enabling girls to manage menstruation at school by providing knowledge and management methods prior to menarche, privacy and a positive social environment around menstrual issues has the potential to benefit students by reducing school absence.

Early menarche, nulliparity and the risk for premature and early natural menopause

Abstract: Study question: How the timing of menarche and parity link with premature and early natural 42 menopause? Summary answer: Early menarche (≤11 years) is a risk factor for both premature menopause (final 44 menstrual period, FMP <40 years) and early menopause (FMP 40-44 years), a risk that is amplified for nulliparous women. What is known already: Women with either premature or early menopause face increased risk of chronic conditions in later life and of early death. Findings from some studies suggest that early menarche and nulliparity are associated with early menopause, however overall the evidence is mixed. Much of the evidence for a direct relationship is hampered by a lack of comparability across studies, adjustment for confounding factors, and statistical power. Study design, size, duration: This pooled study comprises 51,450 postmenopausal women from nine observational studies in the UK, Scandinavia, Australia, and Japan that contribute to the International collaboration for a Life course Approach to reproductive health and Chronic disease Events (InterLACE). Participants/materials, setting, methods: Age at menarche (categorised as ≤11, 12, 13, 14, and 15 56 or more years) and parity (categorised as no children, one child, and two or more children) were exposure of interest. Age at FMP was confirmed by at least 12 months of cessation of menses where this was not the result of an intervention (such as surgical menopause due to bilateral oophorectomy or hysterectomy) and categorised as premature menopause (FMP before age 40), early menopause (FMP 40-44 years), 45-49 years, 50-51 years, 52-53 years, and 54 or more years. We used multivariate multinomial logistic regression models to estimate relative risk ratio (RRR) and 95% confidence intervals (95%CI) for associations between menarche, parity and age at FMP adjusting for within-study correlation. Main results and the role of chance: The median age at FMP was 50 years (interquartile range 48 to 53 years), with 2% of the women experiencing premature menopause and 7.6% early menopause. Women with early menarche (≤11 years, compared with 12-13 years) were at higher risk of premature menopause (RRR 1.80, 95% CI 1.53 to 2.12) and early menopause (1.31, 1.19 to 1.44). Nulliparity was associated with increased risk of premature menopause (2.26, 1.84 to 2.77) and early menopause (1.32, 1.09 to 1.59). Women having early menarche and nulliparity were at over five folds increased risk of premature menopause (5.64, 4.04 to 7.87) and two folds increased risk of early menopause (2.16, 1.48 to 3.15) compared with women who had menarche at ≥12 years and two or more children. Limitations, reasons for caution: Most of the studies (except the birth cohorts) relied on retrospectively reported age at menarche which may have led to some degree of recall bias. Wider implications of the findings: Our findings support early monitoring of women with early menarche, especially those who have no children, for preventive health interventions aimed at mitigating the risk of adverse health outcomes associated with early menopause.

Duration of Reproductive Life Span, Age at Menarche, and Age at Menopause Are Associated With Risk of Cardiovascular Disease in Women

Abstract: BackgroundAlthough the timing of menarche and menopause may be associated with cardiovascular disease (CVD), the entire reproductive life span has not been considered comprehensively as risk for CV...

Early menarche: A systematic review of its effect on sexual and reproductive health in low- and middle-income countries

Abstract: Background Adolescent girls aged 15–19 bear a disproportionate burden of negative sexual and reproductive health outcomes in low- and middle-income countries. Research from several high-income countries suggests that early age at menarche is an important determinant of sexual and reproductive health. We conducted this systematic review to better understand whether and how early menarche is associated with various negative sexual and reproductive health outcomes in low- and middle-income countries and the implications of such associations. Methods We systematically searched eight health and social sciences databases for peer-reviewed literature on menarche and sexual and reproductive health in low- and middle-income countries. Two reviewers independently assessed all studies for inclusion, overall quality and risk of bias, and performed data extraction on all included studies. Results Twenty-four articles met all inclusion criteria–nine of moderate quality and fifteen with several methodological weaknesses. Our review of the minimal existing literature showed that early menarche is associated with early sexual initiation, early pregnancy and some sexually transmitted infections in low- and middle-income countries, similar to what has been observed in high-income countries. Early menarche is also associated with early marriage–an association that may have particularly important implications for countries with high child marriage rates. Conclusions Early age at menarche may be an important factor affecting the sexual and reproductive health of adolescent girls and young women in low- and middle-income countries. More research is needed to confirm the existence of the identified associations across different settings and to better understand the process through which early menarche and other markers of early pubertal development may contribute to the increased vulnerability of girls to negative sexual and reproductive health outcomes in low- and middle-income countries. Given the association of early menarche with early marriage, ongoing efforts to reduce child marriage may benefit from targeting efforts to early maturing girls.

Estrogen Effects on the Mammary Gland in Early and Late Life and Breast Cancer Risk.

Abstract: A woman has an increased risk of breast cancer if her lifelong estrogen exposure is increased due to an early menarche, a late menopause and/or an absence of childbearing. For decades it was presumed that the number of years of exposure drove the increased risk, however recent epidemiological data has shown that early life exposure (young menarche) has a more significant effect on cancer risk that late menopause. Thus rather than the overall exposure it seems that the timing of hormone exposure plays a major role in defining breast cancer risk. In support of this it is also known that aberrant hormonal exposure prior to puberty can also increase breast cancer risk, yet the elevated estrogen levels during pregnancy decrease breast cancer risk. This suggests that the effects of estrogen on the mammary gland/breast are age-dependent. In this review article we will discuss the existing epidemiological data linking hormone exposure and estrogen receptor positive breast cancer risk including menarche, menopause, parity and aberrant environmental hormone exposure. We will discuss the predominantly rodent generated experimental data that confirm the association with hormone exposure and breast cancer risk, confirming its use as a model system. We will review the work that has been done attempting to define the direct effects of estrogen on the breast, which are beginning to reveal the mechanism of increased cancer risk. We will then conclude with our views on the most pertinent questions to be addressed experimentally in order explore the relationship between age, estrogen exposure and breast cancer risk.

Disorders of puberty.

Abstract: Over the past 20 years, a clear secular trend toward the earlier onset of puberty has been described. A better knowledge should help clinicians attempting to define both precocious and delayed puberty (PP and DP, respectively). The definition of PP for girls is the appearance of secondary sex characteristics development before the age of 8 years, while DP is based on the absence of thelarche at the age of 13 years. Regarding PP, one should clinically distinguish between true precocious puberty, i.e., complete or central PP, and incomplete PP, which refers to premature thelarche, premature pubarche, and isolated menarche. Evaluation of girls of PP requires careful examination of the clinical expression, a GnRH test, and imaging of the central neurosystem. GnRH analog is considered the gold standard treatment of central precocious puberty. Peripheral PP should be managed according to the underlying causes. DP is suspected in girls with no breast development by the age of 13 years, or absence of menarche at 15 years with secondary sex characteristics. The clinical examination along with endocrine, radiological, and genetic investigation should be able to identify girls with permanent hypogonadism as opposed to those with transitory hypogonadism, who undergo spontaneous but DP. Estrogen therapy should be discussed according to the causes of DP. In all cases, emotional and psychosocial disorders should be considered for these girls with disorders of puberty.

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

Abstract: 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.

Disorders of Puberty: An Approach to Diagnosis and Management.

Abstract: Disorders of puberty can profoundly impact physical and psychosocial well-being. Precocious puberty is pubertal onset before eight years of age in girls and before nine years of age in boys. Patients with early isolated pubertal changes, prepubertal linear growth, and no worrisome neurologic symptoms typically have a benign pattern of development and should be monitored in the appropriate clinical context. Among patients with true precocious puberty, or full activation of the hypothalamic-pituitary-gonadal axis, most girls have an idiopathic etiology, whereas it is commonly due to identifiable pathology on imaging in boys. History and physical examination should be followed by measurements of serum follicle-stimulating hormone, luteinizing hormone, and testosterone (boys) or estradiol (girls); thyroid function testing; and bone age radiography. Brain magnetic resonance imaging should be performed in girls younger than six years, all boys with precocious puberty, and children with neurologic symptoms. Delayed puberty is the absence of breast development in girls by 13 years of age and absence of testicular growth to at least 4 mL in volume or 2.5 cm in length in boys by 14 years of age. Constitutional delay of growth and puberty is a common cause of delayed puberty; however, functional or persistent hypogonadism should be excluded. History and physical examination should be followed by measurements of serum follicle-stimulating hormone, luteinizing hormone, and testosterone (boys) or estradiol (girls); and bone age radiography. Abnormal growth velocity necessitates assessment of serum thyroid function, prolactin, and insulinlike growth factor I. Boys 14 years and older and girls 13 years and older may benefit from sex steroid treatment to jump-start puberty. Referral to a pediatric endocrinologist may be warranted after the initial evaluation.

Association of timing of menarche with depressive symptoms and depression in adolescence: Mendelian randomisation study.

Abstract: Background Observational studies report associations between early menarche and higher levels of depressive symptoms and depression. However, no studies have investigated whether this association is causal. Aims To determine whether earlier menarche is a causal risk factor for depressive symptoms and depression in adolescence. Method The associations between a genetic score for age at menarche and depressive symptoms at 14, 17 and 19 years, and depression at 18 years, were examined using Mendelian randomisation analysis techniques. Results Using a genetic risk score to indicate earlier timing of menarche, we found that early menarche is associated with higher levels of depressive symptoms at 14 years (odds ratio per risk allele 1.02, 95% CI 1.005–1.04, n = 2404). We did not find an association between the early menarche risk score and depressive symptoms or depression after age 14. Conclusions Our results provide evidence for a causal effect of age at menarche on depressive symptoms at age 14.

Experiences and Constructions of Menarche and Menstruation Among Migrant and Refugee Women.

Abstract: Experiences and constructions of menarche and menstruation are shaped by the sociocultural environment in which women are embedded. We explored experiences and constructions of menarche and menstruation among migrant and refugee women resettled in Sydney, Australia, and Vancouver, Canada. Seventy-eight semistructured individual interviews and 15 focus groups comprised of 82 participants were undertaken with women from Afghanistan, Iraq, Somalia, South Sudan, Sudan, Sri Lanka, and varying South American countries. We analyzed the data using thematic decomposition, identifying the overall theme "cycles of shame" and two core themes. In "becoming a woman," participants constructed menarche as a marker of womanhood, closely linked to marriage and childbearing. In "the unspeakable," women conveyed negative constructions of menstruation, positioning it as shameful, something to be concealed, and polluting. Identifying migrant and refugee women's experiences and constructions of menarche and menstruation is essential for culturally safe medical practice, health promotion, and health education.

Childhood Social Disadvantage and Pubertal Timing: A National Birth Cohort From Australia

Abstract: BACKGROUND AND OBJECTIVES: Early pubertal timing is linked with a range of adverse health outcomes later Given recent trends of earlier pubertal maturation, there is growing interest in the factors influencing pubertal timing Socioeconomic disadvantage has been previously linked with reproductive strategies later in life In this study, we aim to determine the association between cumulative social disadvantages in early life and early puberty in a population-based birth cohort METHODS: Data are from the B (baby) cohort of The Longitudinal Study of Australian Children Children ( n = 5107) were aged 0 to 1 years when recruited in 2004 and 10 to 11 years ( n = 3764) at Wave 6 in 2015 Household socioeconomic position (SEP) and neighborhood socioeconomic disadvantage were collected at all 6 waves Trajectories of disadvantage were identified through latent class models Early puberty at Wave 6 was assessed from parental reports using an adaptation of the Pubertal Development Scale RESULTS: Cumulative exposure to extremely unfavorable household SEP in boys independently predicted a fourfold increase (odds ratio = 422, 95% confidence interval 227–786) in the rate of early puberty In girls, the increase was twofold (odds ratio = 196, 95% confidence interval 108–356) We found no effect from neighborhood disadvantage once family SEP was taken into account CONCLUSIONS: Cumulative exposure to household socioeconomic disadvantage in early life predicts earlier pubertal timing in both boys and girls This may represent 1 mechanism underpinning associations between early life disadvantage and poor health in later life

Ages at menarche and menopause and reproductive lifespan as predictors of exceptional longevity in women: the Women's Health Initiative.

Abstract: Objective:The aim of the present study was to investigate associations between reproductive factors and survival to age 90 years.Methods:This was a prospective study of postmenopausal women from the Women's Health Initiative recruited from 1993 to 1998 and followed until the last outcomes ev

Early Menarche and Menstrual Problems Are Associated with Sleep Disturbance in a Large Sample of Chinese Adolescent Girls.

Abstract: Study objectives Little is known about the association between menstruation and sleep disturbance in adolescent girls. This study examined sleep duration, insomnia symptoms, and sleep quality in relation to age at menarche and menstrual problems in a large sample of Chinese adolescent girls. Methods This report represents the baseline data of an ongoing longitudinal study of the Shandong Adolescent Behavior & Health Cohort in Shandong, China. A total of 5800 girls aged 12-18 years (mean age = 15.0, standard deviation = 1.4) participated in the baseline survey. A structured questionnaire was used to assess participants' age at menarche, menstrual cycle interval, menstrual flow length, period irregularity, period pain, body weight and height, and demographics. Internalizing and externalizing problems were measured by the Youth-Self Report of Child Behavioral Checklist. Sleep duration, insomnia symptoms, and sleep quality were assessed by the items adapted from the Pittsburgh Sleep Quality Index. Results After adjusting for age, school, body mass index, internalizing and externalizing problems, and family covariates, irregular periods (odds ratio [OR] = 1.46, 95% confidence interval [CI] = 1.06-2.02), period pain (OR = 1.99, 95% CI = 1.44-2.76), and menstrual flow length ≥7 days (OR = 1.21, 95% CI = 1.00-1.48) were significantly associated with insomnia symptoms. Irregular periods (OR = 1.72, 95% CI = 1.30-2.27) and period pain (OR = 1.78, 95% CI = 1.34-2.37) were significantly associated with poor sleep quality. Age at menarche ≤11 years (OR = 1.62, 95% CI = 1.05-2.50) was significantly associated with insomnia symptoms in 12- to 14-year-old girls. Conclusions Our results suggest that irregular periods and period pain appear to be associated with sleep disturbance and that early menarche may have short-term impact on sleep in adolescent girls.

Birth weight, early life weight gain and age at menarche: a systematic review of longitudinal studies.

Abstract: SummaryBackground and objective Adiposity in pre- and postnatal life may influence menarcheal age. Existing evidence is primarily cross-sectional, failing to address temporality, for which the role of adiposity in early life remains unclear. The current study sought to systematically review longitudinal studies evaluating the associations between birth weight and infant/childhood weight status/weight gain in relation to menarcheal age. Methods PubMed, EMBASE, Web of Science, Global Health (Ovid) and CINAHL were systematically searched. Selected studies were limited to English-language articles presenting multi-variable analyses. Seventeen studies reporting risk estimates for birth weight (n = 3), infant/childhood weight gain/weight status (n = 4) or both (n = 10), in relation to menarcheal age were included. Results Lower vs. higher birth weight was associated with earlier menarche in nine studies and later menarche in one study, while three studies reported a null association. Greater BMI or weight gain over time and greater childhood weight were significantly associated with earlier menarche in nine of nine and six of seven studies, respectively. Conclusions Studies suggested that lower birth weight and higher body weight and weight gain in infancy and childhood may increase the risk of early menarche. The pre- and postnatal period may thus be an opportune time for weight control interventions to prevent early menarche, and its subsequent consequences.

A descriptive cross-sectional study on menstrual hygiene and perceived reproductive morbidity among adolescent girls in a union territory, India.

Abstract: Introduction: Menstruation is a milestone event in a girl's life and the beginning of reproductive life. Lack of knowledge and poor sanitary practices during menstruation has been associated with serious ill-health ranging from genital tract infections, urinary tract infections, and bad odor. Aim: This study aims to explore the knowledge, attitude, and practices about menstrual hygiene and perceived reproductive morbidity among adolescent school girls in Puducherry. Materials and Methods: A school based cross-sectional study was conducted from June 2015 to July 2015 in Puducherry among 242 adolescent school girls in the age group of 12–18 years using multistage random sampling technique. Data were collected using a predesigned pretested, structured proforma by personal interview method after having informed written consent. Results: The mean age for menarche was 12.99 ± 0.9 years; 51.7% of respondents were not aware of menstruation before attaining menarche; 71.5% and 61.2% were not known about the cause and source of the menstrual bleeding, respectively; 78.1% used only sanitary pads whereas 21.9% used both old clothes and sanitary pads as the absorbents. Unsatisfactory cleaning of the external genitalia was practiced by 12% of respondents. Higher prevalence of dysmenorrhea (82.2%) was mentioned by the respondents; 25.2% reported excessive genital discharge. Statistically significant association was found between perceived reproductive morbidity and poor menstrual hygiene practices. About 88.4% of the study population reported any one of the reproductive morbidity, and only 37.4% sought for medical treatment from a health facility. Conclusion: The present study has underscored the necessity of adolescent girls to have adequate and precise knowledge about menstruation before menarche. Proper menstrual hygiene practices which could be imparted through appropriate interventions at earlier stages of life can prevent the girls and women from suffering reproductive morbidities.

The Effect of Bisphenol A on Puberty: A Critical Review of the Medical Literature

Abstract: Many scientific studies have revealed a trend towards an earlier onset of puberty and have disclosed an increasing number of children that display precocious puberty. As an explanation, some authors have considered the global socio-economic improvement across different populations, and other authors have considered the action of endocrine disrupting chemicals (EDCs). Among these, bisphenol A (BPA), an aromatic compound largely used worldwide as a precursor of some plastics and chemical additives, is well known for its molecular oestrogen-like and obesogenic actions. We reviewed the medical literature of the previous 20 years that examined associations between BPA exposure and the age of puberty in humans, considering only those referring to clinical or epidemiological data. Of 19 studies, only 7 showed a correlation between BPA and puberty. In particular, the possible disruptive role of BPA on puberty may be seen in those with central precocious puberty or isolated premature breast development aged 2 months to 4 years old, even if the mechanism is undefined. Some studies also found a close relationship between urinary BPA, body weight, and early puberty, which can be explained by the obesogenic effect of BPA itself. The currently available data do not allow establishment of a clear role for BPA in pubertal development because of the conflicting results among all clinical and epidemiological studies examined. Further research is needed to fully understand the potential role of exposure to EDCs and their adverse endocrine health outcomes.

Breastfeeding, ovulatory years, and risk of multiple sclerosis.

Abstract: Objective: To determine whether women who breastfeed their infants longer or have fewer ovulatory years are at lower risk of developing multiple sclerosis (MS). Methods: We recruited women with newly diagnosed MS or its precursor, clinically isolated syndrome (CIS) (n = 397), and matched controls (n = 433) into the MS Sunshine Study from the membership of Kaiser Permanente Southern California. A structured in-person questionnaire was administered to collect the behavioral (pregnancies, breastfeeding, hormonal contraceptive use) and biological (age at menarche and menopause, amenorrhea) factors to make up ovulatory years. Results: Among women who had live births, a cumulative duration of breastfeeding for ≥15 months was associated with a reduced risk of MS/CIS (adjusted odds ratio [OR] 0.47, 95% confidence interval [CI] 0.28–0.77; p = 0.003 compared to 0–4 months of breastfeeding). Being ≥15 years of age at menarche was also associated with a lower risk of MS/CIS (adjusted OR 0.56, 95% CI 0.33–0.96; p = 0.035). Total ovulatory years and the remaining factors that determine it, including gravidity, parity, episodes of amenorrhea, and hormonal contraceptive use, as well as age at first birth, showed no significant association with the risk of MS/CIS. Conclusions: Mothers who breastfeed longer may be at lower subsequent risk of developing multiple sclerosis. This is consistent with the other known maternal health benefits of breastfeeding and with our previous observation that women with MS who breastfeed exclusively are at lower risk of postpartum relapses.

The reproducibility of self-reported age at menarche: The Tromsø Study.

Abstract: Previous studies of the reproducibility of self-reported age at menarche have been limited because of small study samples, short follow-up and the limited age span of the women included. The present study assessed the reproducibility of age at menarche in 6731 women with a wide variation of age when giving the information about age at menarche. The women reported age at menarche in a self-administered questionnaire, both in 1986–1987 and 1994–1995. They were all residents of Tromso, Norway, and aged 25–73 in 1994–1995. In order to investigate the agreement between self-reported age at menarche at the two points in time, Pearson’s correlation coefficient was applied to assess the linear correlation between the reported menarcheal age at the two occasions. Analyses were stratified for age. A Bland-Altman plot was produced and limits of agreement computed. We found a high correlation and a strong agreement between self-reported age at menarche in 1986–1987 and 1994–1995. The overall Pearson’s correlation coefficient was 0.84 and was not attenuated by increasing age of the women. The Bland-Altman plot showed a strong agreement in self-reported age at menarche. The mean difference between self-reported age at menarche was 0.01 years with limits of agreement −1.52 to 1.54. We found high reproducibility of self-reported age at menarche. The mean menarcheal age in the two surveys was identical (13.2 years) with 95% of the women reporting the same age at menarche or with a difference of 1 year. Only 0.7% of the women reported age at menarche with a difference of more than 2 years in 1986–1987 and 1994–1995.

Age at menarche and lung function: a Mendelian randomization study

Abstract: A trend towards earlier menarche in women has been associated with childhood factors (e.g. obesity) and hypothesised environmental exposures (e.g. endocrine disruptors present in household products). Observational evidence has shown detrimental effects of early menarche on various health outcomes including adult lung function, but these might represent spurious associations due to confounding. To address this we used Mendelian randomization where genetic variants are used as proxies for age at menarche, since genetic associations are not affected by classical confounding. We estimated the effects of age at menarche on forced vital capacity (FVC), a proxy for restrictive lung impairment, and ratio of forced expiratory volume in one second to FVC (FEV1/FVC), a measure of airway obstruction, in both adulthood and adolescence. We derived SNP-age at menarche association estimates for 122 variants from a published genome-wide meta-analysis (N = 182,416), with SNP-lung function estimates obtained by meta-analysing three studies of adult women (N = 46,944) and two of adolescent girls (N = 3025). We investigated the impact of departures from the assumption of no pleiotropy through sensitivity analyses. In adult women, in line with previous evidence, we found an effect on restrictive lung impairment with a 24.8 mL increase in FVC per year increase in age at menarche (95% CI 1.8–47.9; p = 0.035); evidence was stronger after excluding potential pleiotropic variants (43.6 mL; 17.2–69.9; p = 0.001). In adolescent girls we found an opposite effect (−56.5 mL; −108.3 to −4.7; p = 0.033), suggesting that the detrimental effect in adulthood may be preceded by a short-term post-pubertal benefit. Our secondary analyses showing results in the same direction in men and boys, in whom age at menarche SNPs have also shown association with sexual development, suggest a role for pubertal timing in general rather than menarche specifically. We found no effect on airway obstruction (FEV1/FVC).

Menstrual and reproductive factors and lung cancer risk: A pooled analysis from the international lung cancer consortium.

Abstract: Many clinical features of lung cancer are different in women and men. Sex steroid hormones exert effects in nonreproductive organs, such as the lungs. The association between menstrual and childbearing factors and the risk of lung cancer among women is still debated. We performed a pooled analysis of eight studies contributing to the International Lung Cancer Consortium (4,386 cases and 4,177 controls). Pooled associations between menstrual or reproductive factors and lung cancer were estimated using multivariable unconditional logistic regression. Subgroup analyses were done for menopause status, smoking habits and histology. We found no strong support for an association of age at menarche and at menopause with lung cancer, but peri/postmenopausal women were at higher risk compared to premenopausal (OR 1.47, 95% CI 1.11-1.93). Premenopausal women showed increased risks associated with parity (OR 1.74, 95% CI 1.03-2.93) and number of children (OR 2.88, 95% CI 1.21-6.93 for more than 3 children; p for trend 0.01) and decreased with breastfeeding (OR 0.54, 95% CI 0.30-0.98). In contrast, peri/postmenopausal subjects had ORs around unity for the same exposures. No major effect modification was exerted by smoking status or cancer histology. Menstrual and reproductive factors may play a role in the genesis of lung cancer, yet the mechanisms are unclear, and smoking remains the most important modifiable risk factor. More investigations in large well-designed studies are needed to confirm these findings and to clarify the underlying mechanisms of gender differences in lung cancer risk.