Association of estrogen-related polymorphisms with age at menarche, age at final menstrual period, and stages of the menopausal transition

Genetic determinants of age at menarche: does the LIN28B gene play a role? A narrative review

Menarche, the first menstrual period marking the onset of female reproduction, is a milestone of female puberty. The timing of menarche determines the timing of later phases of pubertal maturation in girls and has major implications for health later in life, including behavioral and psychosocial disorders during adolescence and fertility problems and increased risk for certain diseases in adulthood. Over the last few decades, a continuous decline in age at menarche has been noted, with environmental factors contributing to this change in the timing of menarche. However, a genetic component of age at menarche and pubertal onset has been strongly suggested by studies in families and twins wherein up to approximately 80% of the variance in puberty onset can be explained by heritability. Gene association studies have revealed several genetic loci involved in age at menarche, among which LIN28B has emerged as a key regulator of female growth and puberty. LIN28B, a human homolog of Lin28 of C. elegans, is a known RNA-binding protein that regulates let-7 microRNA biogenesis. Genome-wide association studies have identified the association of polymorphisms in the LIN28B gene with age at menarche in several population cohorts worldwide. In this paper, we review the genetic factors contributing to age of menarche, with particular focus on the identified polymorphisms in LIN28B gene.

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STUDY QUESTION

What is the scope of literature regarding women’s reproductive span in terms of definitions, trends and determinants?

SUMMARY ANSWER

The scoping review found a wide variation in definitions, trends and determinants of biological, social and effective women’s reproductive span.

WHAT IS KNOWN ALREADY

A woman’s reproductive span refers to her childbearing years. Its span influences a woman’s reproductive decisions.

STUDY DESIGN, SIZE, DURATION

A systematic scoping review was conducted. We searched MEDLINE, PubMed, JSTOR, CINAHL, Web of Science and Scopus electronic databases from inception to January 2021 without imposing language or date restrictions. We searched unpublished sources including the Global Burden of Disease, Demographic and Health Surveys, and National Health and Nutrition Examination Surveys. The list of relevant references was searched by hand. Sixty-seven reports on women’s reproductive span were included in this review.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This scoping systematic review followed an established framework. The reporting of this scoping review followed the reporting requirements provided in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, Extension for Scoping Reviews. Identified records were independently screened and data were extracted. We performed conceptual synthesis by grouping the studies by available concepts of reproductive span and then summarized definitions, measures used, temporal trends, determinants, and broad findings of implications on population demographics and assisted reproduction. Structured tabulation and graphical synthesis were used to show patterns in the data and convey detailed information efficiently, along with a narrative commentary.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 67 relevant reports on women’s reproductive span were published between 1980 and 2020 from 74 countries. Most reports (42/67) were cross-sectional in design. Literature on reproductive span was conceptually grouped as biological (the interval between age at menarche and age at menopause), effective (when a woman is both fertile and engaging in sexual activity) and social (period of exposure to sexual activity). We summarized the working definitions, trends and determinants of each concept. Few articles addressed implications on demographics and assisted reproduction.

LIMITATIONS, REASONS FOR CAUTION

A formal assessment of methodological quality of the included studies was not performed because the aim of this review was to provide an overview of the existing evidence base regardless of quality.

WIDER IMPLICATIONS OF THE FINDINGS

The review produced a comprehensive set of possible definitions of women’s reproductive span, trends, and potential determinants. Further advancement of these findings will involve collaboration with relevant stakeholders to rate the importance of each definition in relation to demography and fertility care, outline a set of core definitions, identify implications for policy, practice or research and define future research opportunities to explore linkages between reproductive spans, their determinants, and the need for assisted reproduction.

STUDY FUNDING/COMPETING INTEREST(S)

This work received funding from the UNDP-UNFPA-UNICEF-WHO-World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), a cosponsored programme executed by the World Health Organization (WHO). The authors had no competing interests.

STUDY REGISTRATION NUMBER

N/A.

Age at menarche and risk of vasomotor menopausal symptoms: a pooled analysis of six studies

OBJECTIVE

To examine the association between age at menarche and risk of vasomotor menopausal symptoms (VMS) and whether midlife body mass index (BMI) modified the association.

DESIGN

A pooled analysis of six cohort studies.

SETTING

The International collaboration on the Life course Approach to reproductive health and Chronic disease Events (InterLACE).

POPULATION

18 555 women from the UK, USA and Australia.

METHODS

VMS frequency data (never, rarely, sometimes and often) were harmonised from two studies (n = 13 602); severity data (never, mild, moderate and severe) from the other four studies (n = 4953). Multinominal logistic regression models were used to estimate relative risk ratios (RRRs) and 95% CIs adjusted for confounders and incorporated study as random effects.

MAIN OUTCOME MEASURES

Hot flushes and night sweats.

RESULTS

Frequency data showed that early menarche ≤11 years was associated with an increased risk of 'often' hot flushes (RRR 1.48, 95% CI 1.24-1.76) and night sweats (RRR 1.59, 95% CI 1.49-1.70) compared with menarche at ≥14 years. Severity data showed similar results, but appeared less conclusive, with RRRs of 1.16 (95% CI 0.94-1.42) and 1.27 (95% CI 1.01-1.58) for 'severe' hot flushes and night sweats, respectively. BMI significantly modified the association as the risk associated with early menarche and 'often' VMS was stronger among women who were overweight or obese than those of normal weight, while this gradient across BMI categories was not as strong with the risk of 'severe' VMS.

CONCLUSIONS

Early age at menarche is a risk factor for VMS, particularly for frequent VMS, but midlife BMI may play an important role in modifying this risk.

TWEETABLE ABSTRACT

Overweight and obesity exacerbate the risk of vasomotor symptoms associated with early menarche.

Identification of Key Genes and Potential New Biomarkers for Ovarian Aging: A Study Based on RNA-Sequencing Data

Ovarian aging leads to reproductive and endocrine dysfunction, causing the disorder of multiple organs in the body and even declined quality of offspring's health. However, few studies have investigated the changes in gene expression profile in the ovarian aging process. Here, we applied integrated bioinformatics to screen, identify, and validate the critical pathogenic genes involved in ovarian aging and uncover potential molecular mechanisms. The expression profiles of GSE84078 were downloaded from the Gene Expression Omnibus (GEO) database, which included the data from ovarian samples of 10 normal C57BL/6 mice, including old (21-22 months old, ovarian failure period) and young (5-6 months old, reproductive bloom period) ovaries. First, we filtered 931 differentially expressed genes (DEGs), including 876 upregulated and 55 downregulated genes through comparison between ovarian expression data from old and young mice. Functional enrichment analysis showed that biological functions of DEGs were primarily immune response regulation, cell-cell adhesion, and phagosome pathway. The most closely related genes among DEGs (Tyrobp, Rac2, Cd14, Zap70, Lcp2, Itgb2, H2-Ab1, and Fcer1g) were identified by constructing a protein-protein interaction (PPI) network and consequently verified using mRNA and protein quantitative detection. Finally, the immune cell infiltration in the ovarian aging process was also evaluated by applying CIBERSORT, and a correlation analysis between hub genes and immune cell type was also performed. The results suggested that plasma cells and naïve CD4+ T cells may participate in ovarian aging. The hub genes were positively correlated with memory B cells, plasma cells, M1 macrophages, Th17 cells, and immature dendritic cells. In conclusion, this study indicates that screening for DEGs and pathways in ovarian aging using bioinformatic analysis could provide potential clues for researchers to unveil the molecular mechanism underlying ovarian aging. These results could be of clinical significance and provide effective molecular targets for the treatment of ovarian aging.

RANKL is a new Epigenetic Biomarker for the Vasomotor Symptom During Menopause

During menopausal transition, decreased level of estrogen brings a number of physiological problems and hormonal changes. In this study, promoter methylation of RANKL and FSHR genes were identified in 30 premenopausal and 35 postmenopausal women using methylation-specific high resolution melting (MS-HRM) analysis. The statistical analyses and their association with patient characteristics were performed by Pearson χ² and Fisher's exact test (p <0.05). The methylated RANKL gene was detected in 16 postmenopausal cases, and 12 (75.0%) of the RANKL methylated cases had hot flashes (p = 0.024). The methylated FSHR gene was detected in 18 postmenopausal cases, and 13 (75.0%) of the methylated cases had hot flashes (p = 0.028). In vitro studies demonstrated the association between RANKL expression, FSH level and hot flashes in the mouse. Although lack of epigenetic studies in this field proves our results crucial and therefore, our results showed magnitude of epigenetic profiles of Turkish Cypriot post-menopausal women. This was the first study which has investigated the RANKL and FSHR methylation and their relationship with hot flashes in postmenopausal women.

Polymorphisms in Estrogen Synthesis Genes and Symptom Clusters During the Menopausal Transition and Early Postmenopause: Observations From the Seattle Midlife Women's Health Study

During the menopausal transition and early postmenopause, participants in the Seattle Midlife Women's Health Study (SMWHS) experienced one of the three symptom severity clusters identified through latent class analysis: severe hot flashes with moderate sleep, mood, cognitive, and pain symptoms (high-severity hot flash); low-severity hot flashes with moderate levels of all other symptom groups (moderate severity); and low levels of all symptom groups (low severity). In an effort to determine whether gene polymorphisms were associated with these symptom severity classes, we tested associations between gene polymorphisms in the estrogen synthesis pathways (cytochrome P450 19 [CYP 19] and 17 beta hydroxysteroid dehydrogenase [ 17HSDB1]) and the three symptom severity clusters. SMWHS participants ( N = 137) recorded symptoms monthly in diaries and provided buccal smears for genotyping. Multilevel latent class analysis with multinomial regression was used to determine associations between gene polymorphisms and symptom severity clusters. Only the 17HSDB1 polymorphisms ( rs615942 and rs592389) were associated significantly with the high-severity hot flash cluster versus the low-severity symptom cluster. None of the polymorphisms was associated with the moderate-severity cluster versus the low-severity symptom cluster. Findings of associations of the 17HSDB1 polymorphisms with the high-severity hot flash symptom cluster are consistent with those of an association between 17HSDB1 polymorphisms and hot flashes in the Study of Women and Health Across the Nation population and our previous findings of associations between these polymorphisms with greater estrone levels.

Association of PvuII and XbaI polymorphisms on estrogen receptor alpha (ESR1) gene to changes into serum lipid profile of post-menopausal women: Effects of aging, body mass index and breast cancer incidence

Estrogen is a steroidal hormone involved in several physiological functions in the female body including regulation of serum lipid metabolism and breast cancer (BC). Estrogen actions on serum lipids mostly occur through its binding to intracellular Estrogen Receptor alpha (ERalpha) isoform, expressed in most of tissues. This gene (ESR1) exhibit many polymorphic sites (SNPs) located either on translated and non-translated regions that regulate ERalpha protein expression and function. This paper aimed to investigate the association of two intronic SNPs of ESR1 gene, namely c454-397T>C (PvuII) and c454-351A>G (XbaI) to alterations in serum levels of total cholesterol (T-chol), total lipid (TL), low density lipoprotein cholesterol (LDL), high density lipoprotein (HDL), and triglycerides (TG) in a cohort of post-menopausal women. In addition, we aimed to associate presence of these SNPs to development of BC along 5 years period. To do so, a group of healthy 499, highly miscigenated, post-menopausal Brazilian women, were carried using PCR-FRLP technique and further confirmed by automatic sequence analysis as well followed through 5 years for BC incidence. Measurements of serum lipid profile by standard commercial methods were carried individually whereas Dual Energy X-ray Absorciometry (DXA) measured Body Mass Indexes (BMI), Fat Mass (FM), Lean Body Mass (LBM), and Body Water Content (BWC). No effects of PvuII SNP on ESR1 gene were observed on patient´s serum T-chol, TL, LDL, HDL, and TG. However, c454-397T>C PvuII SNP is associated to lower body fat and higher levels of lean mass and body water and lower incidence of BC. On the other hand, statistically significant effect of XbaI c454-351A>G SNP on serum TG and TL levels. Patients homozygous for X allele were followed up from 2010–2015. They showed higher incidence of breast cancer (BC) when compared to either heterozygous and any P allele combination. Moreover, the increasing of TG and TL serum concentrations associated to SNP XbaI c454-351A>G on ESR1 gene is enhanced in both obese (higher BMI) and elder women. Taken together, these results suggested that XbaI c454-351A>G SNP is associated to changes in lipid profile, particularly in serum TG and TL, in this cohort of post-menopausal woman. Also, this paper shows another link between obesity and BC corroborating the current thesis that both diseases are interlinked.

The Seattle Midlife Women's Health Study: a longitudinal prospective study of women during the menopausal transition and early postmenopause

Background

The need for longitudinal, population-based studies to illuminate women’s experiences of symptoms during the menopausal transition motivated the development of the Seattle Midlife Women’s Health Study.

Methods

Longitudinal, population-based study of symptoms women experienced between the Late Reproductive stage of reproductive aging and the early postmenopause. Data collection began in 1990 with 508 women ages 35–55 and continued to 2013. Entry criteria included age, at least one period in past 12 months, uterus intact and at least 1 ovary. Women were studied up to 5 years postmenopause. Data collection included yearly health questionnaires, health diaries, urinary hormonal assays, menstrual calendars and buccal cell smears.

Results

Contributions of the study included development of a method for staging the menopausal transition; development of bleeding criteria to differentiate bleeding episodes from intermenstrual bleeding from menstrual calendars; identification of hormonal changes associated with menopausal transition stages; assessment of the effects of menopausal transition factors, aging, stress-related factors, health factors, social factors on symptoms, particularly hot flashes, depressed mood, pain, cognitive, sexual desire, and sleep disruption symptoms, and urinary incontinence symptoms; identification of naturally occurring clusters of symptoms women experienced during the menopausal transition and early postmenopause; and assessment of gene polymorphisms associated with events such as onset of the early and late menopausal transition stages and symptoms.

Conclusions

Over the course of the longitudinal Seattle Midlife Women's Health Study, investigators contributed to understanding of symptoms women experience during the menopausal transition and early postmenopause as well as methods of staging reproductive aging.

Electronic supplementary material

The online version of this article (doi:10.1186/s40695-016-0019-x) contains supplementary material, which is available to authorized users.

Estrogen receptors genes polymorphisms and age at menarche in idiopathic scoliosis

Background

The age at menarche (AAM) is commonly in use in patients with IS as one of the maturity indicator suggesting deceleration of the growth velocity. The AAM was suggested to be related to predisposition and curve progression potential of IS. The late age at menarche was reported to be associated with higher prevalence of adolescent idiopathic scoliosis. The age at menarche is determined by both genetic and environmental factors as well as their interactions. Estrogen receptors 1 and 2 polymorphism were reported to be associated with AAM: in ESR1 XbaI and PvuII site polymorphism and in ESR2 AluI site polymorphism.

The purpose of the study was to investigate associations of the ESR1 and ESR2 polymorphisms with AAM in IS patients and to evaluate association of AAM with IS severity.

Methods

208 females with IS Caucasian females from Central Europe underwent clinical, radiological and genetic examinations. Four SNPs were selected XbaI (A/Grs9340799) and PvuII (C/T rs2234693) in ESR1 and AluI (A/G rs4986938) and RasI (A/G rs1256049) in ESR2. Samples were analyzed with polymerase chain reaction followed by restriction fragments length polymorphism analysis (PCR-RFLP). The age of a menarche was established during personal interview with the patients and in case of children with their parents. The Cobb angle was measured.

Results

All genotypes followed HWE. Mean AAM for patients was 154.8 ± 14.7 months (12.9 ± 1.2 years). The earliest AAM was 121 and latest 192 months. There was no statistically significant difference between AAM mean values in each genotype, for the XbaI, PvuII, AluI and RsaI site polymorphisms the p values were p = 0.7141, p = 0.9774, p = 0.7973 and p = 0.2282, respectively. Patients divided according to Cobb into mild (<30°), moderate (30°-49°) or severe (≥50°) IS revealed tendency to delay AAM: 151.9 ± 14.7; 155.2 ± 14.8 and 157.9 ± 14.0 months, respectively. There was statistical significant difference between patients with mild <30° and severe ≥50° IS, p = 0.0267.

Conclusions

In IS patients estrogen receptors polymorphisms did not show association with the AAM. Patients with severe IS form revealed delayed AAM than patients with mild IS form.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2474-15-383) contains supplementary material, which is available to authorized users.

Are CYP1A1, CYP17 and CYP1B1 mutation genes involved on girls with precocious puberty? A pilot study

OBJECTIVES

To investigate three genes associated with puberty timing in girls with central precocious puberty by evaluating the association between polymorphism in the gene sequence codifying the enzymes participating in steroidogenesis, CYP1A1, CYP17, and CYP1B1 and central precocious puberty.

STUDY DESIGN

A total of 177 patients was included and divided into two groups: Case group with 73 girls diagnosed with central precocious puberty; Control group with 104 girls with puberty onset after 8 years of age who were followed at the Sector of Gynecology of Childhood and Adolescence, Division of Gynecology Clinic, HC-FMUSP. Polymorphism presence was assessed in the genes involved in estrogen metabolism (CYP1A1, CYP17, and CYP1B1) by the restriction fragment length polymorphism (RFLP) technique using DNA from peripheral blood.

RESULTS

No significant difference in the distribution of the CYP1A1 Mspl (p=0.86) and CYP17 (p=0.12) genotypes was detected between the two study groups. As for CYP1B1 Eco571, the mutated C/C genotype was found to be more frequent in the control group than in the case group (p=0.03).

CONCLUSION

Our data suggest the CYP1B1 Eco571 gene variant is associated with puberty timing.

Meta-analysis of loci associated with age at natural menopause in African-American women

Age at menopause marks the end of a woman's reproductive life and its timing associates with risks for cancer, cardiovascular and bone disorders. GWAS and candidate gene studies conducted in women of European ancestry have identified 27 loci associated with age at menopause. The relevance of these loci to women of African ancestry has not been previously studied. We therefore sought to uncover additional menopause loci and investigate the relevance of European menopause loci by performing a GWAS meta-analysis in 6510 women with African ancestry derived from 11 studies across the USA. We did not identify any additional loci significantly associated with age at menopause in African Americans. We replicated the associations between six loci and age at menopause (P-value < 0.05): AMHR2, RHBLD2, PRIM1, HK3/UMC1, BRSK1/TMEM150B and MCM8. In addition, associations of 14 loci are directionally consistent with previous reports. We provide evidence that genetic variants influencing reproductive traits identified in European populations are also important in women of African ancestry residing in USA.

Genome-wide association studies of age at menarche and age at natural menopause

Genome-wide association studies (GWAS) have been successful in uncovering genetic determinants of age at menarche and age at natural menopause. To date, more than 30 novel genetic loci have been identified in GWAS for age at menarche and 17 for age at natural menopause. These findings have stimulated a plethora of follow-up studies particularly with respect to the functional characterization of these novel loci and how these results can be translated into risk prediction. However, the genetic loci identified so far account for only a small fraction of the overall heritability. This review provides an overview of the current state of our knowledge of the genetic basis of menarche and menopause timing. It emphasizes recent GWAS results and outlines strategies for discovering the missing heritability and strategies to further our understanding of the underlying molecular mechanisms of the observed genetic associations.

A multigenic combination of estrogen related genes are associated with the duration of fertility period in the Spanish population

OBJECTIVE

The duration of the fertile period (FP) can be considered a complex parameter that depends on the interaction of multiple factors. In the present study, the role of interaction between genetic variants within estrogen synthesis and signaling pathways in the FP in Spanish women is studied.

MATERIAL AND METHODS

Nine single nucleotide polymorphisms (SNPs) located at different candidate genes related to the estrogen signaling pathway were analyzed in 1980 Spanish postmenopausal women.

RESULTS

Independently, none of the nine markers were significantly associated with age at menopause. In contrast, survival analysis techniques suggest several epistatic interactions including these markers in relation to age at menopause, especially between ESR2, NRIP1 and BMP15: women who showed the three markers ESR2 (AA), BMP15 (rs3897937) (TC) and NRIP1 (AA), the FP was shorter than the control group of women without any of these markers (32.36 ± 1.49 versus 34.94 ± 0.32 years; p = 0.026). The digenic BMP15 (rs3897937) (TC) and NRIP1 (AA) combination were also associated with a decreased duration of the FP (33.32 ± 0.96 years, p = 0.031).

CONCLUSIONS

The results suggest that interactions of estrogen-related alleles may contribute to variance in FP in Spanish women.

Genetic variation and reproductive timing: African American women from the Population Architecture using Genomics and Epidemiology (PAGE) Study

Age at menarche (AM) and age at natural menopause (ANM) define the boundaries of the reproductive lifespan in women. Their timing is associated with various diseases, including cancer and cardiovascular disease. Genome-wide association studies have identified several genetic variants associated with either AM or ANM in populations of largely European or Asian descent women. The extent to which these associations generalize to diverse populations remains unknown. Therefore, we sought to replicate previously reported AM and ANM findings and to identify novel AM and ANM variants using the Metabochip (n = 161,098 SNPs) in 4,159 and 1,860 African American women, respectively, in the Women's Health Initiative (WHI) and Atherosclerosis Risk in Communities (ARIC) studies, as part of the Population Architecture using Genomics and Epidemiology (PAGE) Study. We replicated or generalized one previously identified variant for AM, rs1361108/CENPW, and two variants for ANM, rs897798/BRSK1 and rs769450/APOE, to our African American cohort. Overall, generalization of the majority of previously-identified variants for AM and ANM, including LIN28B and MCM8, was not observed in this African American sample. We identified three novel loci associated with ANM that reached significance after multiple testing correction (LDLR rs189596789, p = 5×10⁻⁰⁸; KCNQ1 rs79972789, p = 1.9×10⁻⁰⁷; COL4A3BP rs181686584, p = 2.9×10⁻⁰⁷). Our most significant AM association was upstream of RSF1, a gene implicated in ovarian and breast cancers (rs11604207, p = 1.6×10⁻⁰⁶). While most associations were identified in either AM or ANM, we did identify genes suggestively associated with both: PHACTR1 and ARHGAP42. The lack of generalization coupled with the potentially novel associations identified here emphasize the need for additional genetic discovery efforts for AM and ANM in diverse populations.

Molecular profiling of postnatal development of the hypothalamus in female and male rats

Reproductive function is highly dynamic during postnatal developmental. Here, we performed molecular profiling of gene expression patterns in the hypothalamus of developing male and female rats to identify which genes are sexually dimorphic, to gain insight into a more complex network of hypothalamic genes, and to ascertain dynamic changes in their relationships with one another and with sex steroid hormones during development. Using a low-density PCR platform, we quantified mRNA levels in the preoptic area (POA) and medial basal hypothalamus (MBH), and assayed circulating estradiol, testosterone, and progesterone at six ages from birth through adulthood. Numerous genes underwent developmental change, particularly postnatal increases, decreases, or peaks/plateaus at puberty. Surprisingly, there were few sex differences; only Esr1, Kiss1, and Tac2 were dimorphic (higher in females). Cluster analysis of gene expression revealed sexually dimorphic correlations in the POA but not the MBH from P30 (Postnatal Day 30) to P60. Hormone measurements showed few sex differences in developmental profiles of estradiol; higher levels of progesterone in females only after P30; and a developmental pattern of testosterone with a nadir at P30 followed by a dramatic increase through P60 (males). Furthermore, bionetwork analysis revealed that hypothalamic gene expression profiles and their relationships to hormones undergo dynamic developmental changes that differ considerably from adults. These data underscore the importance of developmental stage in considering the effects of hormones on the regulation of neuroendocrine genes in the hypothalamus. Moreover, the finding that few neuroendocrine genes are sexually dimorphic highlights the need to consider postnatal development from a network approach that allows assessment of interactions and patterns of expression.

CYP17 and CYP19 genetic variants are not associated with age at natural menopause in Polish women

The aim of the study was to investigate associations between two common polymorphisms of CYP17 and CYP19, encoding key enzymes of estrogen biosynthesis, and age at menopause in Polish women. One hundred fifty women after menopause (49.5±3.8 years), with no previous history of hormone replacement therapy took part in the study. The genetic control group consisted of 150 newborns from the same population. We investigated an association between the age at menopause and the single nucleotide polymorphism T→C in the 5' untranslated region (promoter) of the CYP17 gene (c.-34T>C; rs743572 - MspA1) or the number of tetranucleotide repeats [TTTA](n) (rs60271534) including deletion/insertion (D/I) of a 3 bp sequence in intron 4 of the CYP19 gene. CYP17 polymorphism was analyzed by PCR-RFLP and CYP19 by PCR and capillary electrophoresis. In the case of CYP17 polymorphism, 28.7% and 36.7% wild homozygous (TT), 50.7% and 46.0% heterozygous (TC), as well as 20.6% and 17.3% mutated homozygous (CC) types were identified in the subjects and controls, respectively. The frequency of mutated alleles (C) was 46.0% vs. 40.3% (p=0.19). In the case of CYP19 polymorphism, 34.0% and 32.0% of homozygotes (1_1), 50.7% and 51.3% of heterozygotes (1_2), 15.3% and 16.7% of homozygotes (2_2) were identified in the subjects and controls, respectively. No association between the studied CYP17 or CYP19 polymorphisms and age at menopause was found in Polish women.

Variants in CYP17 and CYP19 cytochrome P450 genes are associated with onset of Alzheimer's disease in women with down syndrome

CYP17 and CYP19 are involved in the peripheral synthesis of estrogens, and polymorphisms in CYP17 and CYP19 have been associated with increased risk of estrogen-related disorders. Women with Down syndrome (DS) have early onset and high risk for Alzheimer's disease (AD). We conducted a prospective community-based cohort study to examine the relationship between SNPs in CYP17 and CYP19 and cumulative incidence of AD, hormone levels and sex hormone binding globulin in women with DS. Two hundred and thirty-five women with DS, 31 to 67 years of age and nondemented at initial examination, were assessed for cognitive and functional abilities, behavioral/psychiatric conditions, and health status at 14-20 month intervals over five assessment cycles. We genotyped these individuals for single-nucleotide polymorphisms (SNPs) in CYP17 and CYP19. Four SNPs in CYP17 were associated with a two and one half-fold increased risk of AD, independent of APOE genotype. Four SNPs in CYP19 were associated with a two-fold increased risk of AD, although three were significant only in those without an APOE ε4 allele. Further, carrying high risk alleles in both CYP17 and CYP19 was associated with an almost four-fold increased risk of AD (OR = 3.8, 95% CI, 1.6-9.5) and elevated sex hormone binding globulin in postmenopausal women. The main effect of the CYP17 and CYP19 variants was to decrease the age at onset. These findings suggest that genes contributing to estrogen bioavailability influence risk of AD in women with DS.

Genetics of age at menarche: a systematic review

BACKGROUND

Menarche is the first menstrual period of a girl at puberty. The timing of menarche is important for health in later life. Age at menarche is a complex trait and has a strong genetic component. This review summarizes the results of the genetic studies of age at menarche conducted to date, highlights existing problems in this area and outlines prospects of future studies on genetic factors for the trait.

METHODS

PubMed and Google Scholar were searched until May 2011 using the keywords: 'menarche', 'puberty' and 'age at menarche' in combination with the keywords 'polymorphism', 'candidate gene', 'genome-wide association study' and 'linkage'.

RESULTS

Our search yielded 170 papers, 35 of which were selected for further analysis. Several large-scale genome-wide association studies along with a powerful meta-analysis of their aggregated data identified about 50 candidate genes for the trait. Some genes were replicated in different studies of Caucasians (e.g. LIN28B, TMEM38B) or in different ethnicities (e.g. SPOCK, RANK and RANKL). However, despite the large volume of results obtained, there is a huge gap in relevant data on ethnic groups other than Caucasians.

CONCLUSIONS

The reviewed studies laid a solid basis for future research on genetics of age at menarche. However, as yet specific genes for this trait have not been identified consistently in all ethnicities and types of studies. We suggest expanding the research to different ethnicities and propose several methodologies to increase the efficiency of studies in this area, including a systems approach, which combines existing high-throughput methods in a single pipeline.

Environmental and genetic pathways between early pubertal timing and dieting in adolescence: distinguishing between objective and subjective timing

BACKGROUND

Early pubertal timing in girls is associated with elevated risk for dieting and eating pathology. The relative importance of biological versus socio-environmental mechanisms in explaining this association remains unclear. Moreover, these mechanisms may differ between objective measures of pubertal development and girls' subjective perceptions of their own maturation.

METHOD

The sample comprised 924 sister pairs from the National Longitudinal Study of Adolescent Health. Objective pubertal timing (menarcheal age), girls' perceptions of pubertal status and timing relative to peers, dieting and disordered eating behaviors were assessed during a series of confidential in-home interviews.

RESULTS

Behavioral genetic models indicated that common genetic influences accounted for the association between early menarcheal age and increased risk for dieting in adolescence. In contrast, girls' subjective perceptions of their timing relative to peers were associated with dieting through an environmental pathway. Overall, subjective and objective measures of pubertal timing accounted for 12% of the variance in dieting.

CONCLUSIONS

Genetic differences in menarcheal age increase risk for dieting among adolescent girls, while girls' perceptions of their maturation represent an environmentally mediated risk.

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.

Searching for the noninvasive biomarker holy grail: are urine proteomics the answer?

Recently, biobehavioral nursing scientists have focused their attention on the search for biomarkers or biological signatures to identify patients at risk for various health problems and poor disease outcomes. In response to the national impetus for biomarker discovery, the measurement of biological fluids and tissues has become increasingly sophisticated. Urine proteomics, in particular, may hold great promise for biobehavioral focused nursing scientists for examination of symptom-and syndrome-related research questions. Urine proteins are easily accessible secreted proteins that provide direct and indirect windows into bodily functions. Advances in proteomics and biomarker discovery provide new opportunities to conduct research studies with banked and fresh urine to benefit diagnosis, prognosis, and evaluation of outcomes in various disease populations. This article provides a review of proteomics and a rationale for utilizing urine proteomics in biobehavioral research. It addresses as well some of the challenges involved in data collection and sample preparation.

Reported early family environment covaries with menarcheal age as a function of polymorphic variation in estrogen receptor-α

Age at menarche, a sentinel index of pubertal maturation, was examined in relation to early family relationships (conflict, cohesion) and polymorphic variation in the gene encoding estrogen receptor-α (ESR1) in a midlife sample of 455 European American women. Consistent with prior literature, women who reported being raised in families characterized by close interpersonal relationships and little conflict tended to reach menarche at a later age than participants reared in families lacking cohesion and prone to discord. Moreover, this association was moderated by ESR1 variation, such that quality of the family environment covaried positively with menarcheal age among participants homozygous for minor alleles of the two ESR1 polymorphisms studied here (rs9304799, rs2234693), but not among women of other ESR1 genotypes. In addition, (a) family relationship variables were unrelated to ESR1 variation, and (b) genotype-dependent effects of childhood environment on age at menarche could not be accounted for by personality traits elsewhere shown to explain heritable variation in reported family conflict and cohesion. These findings are consistent with theories of differential susceptibility to environmental influence, as well as the more specific hypothesis (by Belsky) that girls differ genetically in their sensitivity to rearing effects on pubertal maturation.

Gonadal hormones and cognitive aging: a midlife perspective

Gonadal steroids affect a variety of brain processes. Cognitive consequences of hormonal changes associated with menopause are of scientific interest and of relevance to public health. Natural menopause is a normal physiological process that can only be directly studied through observational research. Similarly, surgical menopause in humans is rarely directly amenable to experimental research. Causality with respect to cognitive outcomes is, therefore, difficult to infer. Cross-sectional and longitudinal findings from the Melbourne Women's Midlife Health Project, the Study of Women's Health Across the Nation and other midlife cohorts suggest that cognitive consequences of the natural menopausal transition are probably small, at least during midlife and at least for episodic memory, which is a key cognitive domain. The data for episodic memory are the most robust. Midlife episodic memory performance is similar both shortly before and after natural menopause, and serum estradiol concentration in midlife is not associated with episodic memory performance. Effects of natural menopause on other cognitive domains, cognitive consequences of surgical menopause and late-life cognitive consequences of midlife hormonal exposures are less well understood and merit continued study.

Evaluation of PvuII and XbaI polymorphisms in the estrogen receptor alpha gene (ESR1) in relation to menstrual cycle timing and reproductive parameters in post-menopausal women

OBJECTIVE

To evaluate the association of -397T>C and -351A>G single nucleotide polymorphisms (SNPs) - also called PvuII and XbaI, respectively - located on estrogen receptor alpha (ERS1) gene with age at menarche, menopause onset, fertility and miscarriage in a population of post-menopausal women.

STUDY DESIGN

Cross-sectional study with 273 healthy, high miscegenated, post-menopausal women (mean age of 63.1±9.7 years old). Subjects were genotyped for PvuII and XbaI SNPs by PCR-RFLP and confirmed by automatic sequencing. Reproduction informations (age at menarche, age at menopause, number of pregnancies, fertility rate and miscarriages) were obtained by retrospective study using a questionnaire.

RESULT(S)

Age at menarche, menopause onset, number of pregnancies, total fertility rate, and parity did not seem to be influenced by any of the studied genotypes (chi-square, p>0.05). However, women carrying the xx genotype showed a 44% higher chance of miscarriage, whereas this value did not trespass 16% for any other genotype analyzed. It has been also observed a higher occurrence of miscarriage in association with combined xxpp genotype of ERS1 gene (chi-square, p<0.01).

CONCLUSION(S)

The present data indicate that the studied SNPs on ERS1 gene do not influence the menstrual cycle timing and parity but there is a strong relationship between the xx ERS1 SNP genotype and the incidence of miscarriage in the post-menopausal population analyzed.

Longitudinal, epidemiologic studies of female reproductive aging

Human female reproductive aging consists of multiple processes and interacts with other physiological systems in unique ways. Here we discuss eight recent longitudinal, epidemiologic studies of female reproductive aging that include endocrine data to highlight their contributions to our understanding of these various aging processes and their interactions. Specifically, we review data on ovarian and nonovarian reproductive aging processes and reproductive staging. We consider these data in the context of longitudinal research design and research goals, identify limitations of the studies but also ways in which existing longitudinal data can further our understanding of aging processes, and make recommendations for future studies of female reproductive aging.

TNFRSF11A and TNFSF11 are associated with age at menarche and natural menopause in white women

OBJECTIVE

Menarche and menopause mark the lower and upper limits of the female reproductive period. The timing of these events influences women's health in later life. The onsets of menarche and menopause have a strong genetic basis. We tested two genes, TNFRSF11A (RANK) and TNFSF11 (RANKL), for their association with age at menarche (AM) and age at natural menopause (ANM).

METHODS

Nineteen single nucleotide polymorphisms (SNPs) of TNFRSF11A and 12 SNPs of TNFSF11 were genotyped in a random sample of 306 unrelated white women. This sample was analyzed for the association of the SNPs and common haplotypes with AM. Then, a subsample of 211 women with natural menopause was analyzed for the association of both genes with ANM. Smoking, alcohol intake, and duration of lactation were applied as covariates in the association analyses.

RESULTS

Three polymorphisms of TNFSF11 were associated with AM: rs2200287 (P = 0.005), rs9525641 (P = 0.039), and rs1054016 (P = 0.047). Two SNPs of this gene, rs346578 and rs9525641, showed an association with ANM (P = 0.007 and P = 0.011, respectively). Two SNPs of TNFRSF11A were associated with AM (rs3826620; P = 0.022) and ANM (rs8086340; P = 0.015). Multiple SNP-SNP and SNP-environment interaction effects on AM and ANM were detected for both genes. One polymorphism of TNFRSF11A, rs4436867, was not directly associated with either trait but indicated significant interactions with four TNFSF11 polymorphisms on ANM. Two other TNFRSF11A polymorphisms, rs4941125 and rs7235803, showed interaction effects with several TNFSF11 polymorphisms on AM. Both genes manifested significant interaction with the duration of breast-feeding in their effect on ANM.

CONCLUSIONS

The TNFRSF11A and TNFSF11 genes are associated with the onset of AM and ANM in white women.

A large-scale candidate gene association study of age at menarche and age at natural menopause

Recent genome-wide association (GWA) studies have identified several novel genetic loci associated with age at menarche and age at natural menopause. However, the stringent significance threshold used in GWA studies potentially led to false negatives and true associations may have been overlooked. Incorporating biologically relevant information, we examined whether common genetic polymorphisms in candidate genes of nine groups of biologically plausible pathways and related phenotypes are associated with age at menarche and age at natural menopause. A total of 18,862 genotyped and imputed single nucleotide polymorphisms (SNPs) in 278 genes were assessed for their associations with these two traits among a total of 24,341 women from the Nurses' Health Study (NHS, N = 2,287) and the Women's Genome Health Study (WGHS, N = 22,054). Linear regression was used to assess the marginal association of each SNP with each phenotype. We adjusted for multiple testing within each gene to identify statistically significant SNP associations at the gene level. To evaluate the overall evidence for an excess of statistically significant gene associations over the proportion expected by chance, we applied a one-sample test of proportion to each group of candidate genes. The steroid-hormone metabolism and biosynthesis pathway was found significantly associated with both age at menarche and age at natural menopause (P = 0.040 and 0.011, respectively). In addition, the group of genes associated with precocious or delayed puberty was found significantly associated with age at menarche (P = 0.013), and the group of genes involved in premature ovarian failure with age at menopause (P = 0.025).

Human studies on genetics of the age at natural menopause: a systematic review

BACKGROUND Timing of natural menopause has great implications for fertility and women's health. Age at natural menopause (ANM) is largely influenced by genetic factors. In the past decade, several genetic studies have been conducted to identify genes in ANM, which can help us unravel the biological pathways underlying this trait and the associated infertility and health risks. After providing an overview of the results of the genetic studies performed so far, we give recommendations for future studies in identifying genetic factors involved in determining the variation in timing of natural menopause. METHODS The electronic databases of Pubmed and Embase were systematically searched until September 2009 for genetic studies on ANM, using relevant keywords on the subject. Additional papers identified through hand search were also included. RESULTS Twenty-eight papers emerged from our literature search. A number of genetic regions and variants involved in several possible pathways underlying timing of ANM were identified, including two possible interesting regions (9q21.3 and chromosome 8 at 26 cM) in linkage analyses. Recent genome-wide association studies have identified two genomic regions (19q13.42 and 20p12.3), containing two promising candidate genes (BRKS1 and MCM). In the candidate gene association studies on ANM, very few consistent associations were found. CONCLUSION A number of genetic variants have been discovered in association with ANM, although the overall results have been rather disappointing. We have described possible new strategies for future genetic studies to identify more genetic loci involved in the variation in menopausal age.

Association analyses suggest multiple interaction effects of the methylenetetrahydrofolate reductase polymorphisms on timing of menarche and natural menopause in white women

OBJECTIVE

This study aimed to investigate whether polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) gene are associated with age at menarche and age at natural menopause in white women.

METHODS

In a cross-sectional study, a total of 305 randomly selected unrelated white women were genotyped for six single nucleotide polymorphisms (SNPs) of the MTHFR gene (including one common replacement, rs1801133). This sample was comprehensively analyzed for the association of the SNPs with age at menarche. Then a subsample of 210 women who experienced natural menopause was analyzed for the association of the MTHFR gene with age at natural menopause.

RESULTS

Duration of breast-feeding was a significant predictor of earlier natural menopause (P < 0.05). No individual SNPs were associated with either age at menarche or age at natural menopause. However, three significant (P < 0.05) SNP-SNP interaction effects (rs2066470/rs1476413, rs2066470/rs4846049, and rs17037390/rs4846049) on the onset of menarche were determined. Three haplotypes were significantly associated with age at menopause (P < 0.05). Four SNPs (rs2066470, rs17037390, rs1801133, and rs4846048) indicated significant interaction effects with various lifestyle factors on age at natural menopause.

CONCLUSIONS

The results of our study suggest that the MTHFR gene may influence the onset of menarche and natural menopause. This effect is probably due to the multiple SNP-SNP and SNP-environment interactions. More independent studies are needed to further clarify the possible contribution of this gene to the timing of menarche and menopause.

Ovarian aging: mechanisms and clinical consequences

Menopause is the final step in the process referred to as ovarian ageing. The age related decrease in follicle numbers dictates the onset of cycle irregularity and the final cessation of menses. The parallel decay in oocyte quality contributes to the gradual decline in fertility and the final occurrence of natural sterility. Endocrine changes mainly relate to the decline in the negative feedback from ovarian factors at the hypothalamo-pituitary unit. The declining cohort of antral follicles with age first results in gradually elevated FSH levels, followed by subsequent stages of overt cycle irregularity. The gradual decline in the size of the antral follicle cohort is best represented by decreasing levels of anti-Mullerian hormone. The variability of ovarian ageing among women is evident from the large variation in age at menopause. The identification of women who have severely decreased ovarian reserve for their age is clinically relevant. Ovarian reserve tests have appeared to be fairly accurate in predicting response to ovarian stimulation in the assisted reproductive technology (ART) setting. The capacity to predict the chances for spontaneous pregnancy or pregnancy after ART appears very limited. As menopause and the preceding decline in oocyte quality seem to have a fixed time interval, tests that predict the age at menopause may be useful to assess individual reproductive lifespan. Especially genetic studies, both addressing candidate gene and genome wide association, have identified several interesting loci of small genetic variation that may determine fetal follicle pool development and subsequent wastage of his pool over time. Improved knowledge of the ovarian ageing mechanisms may ultimately provide tools for prediction of menopause and manipulation of the early steps of folliculogenesis for the purpose of contraception and fertility lifespan extension.

Polymorphisms in estrogen metabolism and estrogen pathway genes and the risk of miscarriage

PURPOSE

This study investigated genetic variations in the estrogen pathway and their association with miscarriages.

METHODS

A total of 483 patients were recruited from a comprehensive control group for case-control studies. Three variants of the CYP19A1 gene (rs10046, rs4646 and rs700519) and one variant each of the estrogen (ESR1) and progesterone (PGR) receptor genes (rs3020314 and rs1042838) were investigated using polymorphism genotyping. The chi-squared test and one-way analysis of variation (ANOVA) were used for statistical analysis.

RESULTS

For rs10046 (CYP19A1), the C/C genotype was associated with a greater frequency of miscarriages (P = 0.017). The other genotypes were not found to be associated with recurrent miscarriage.

CONCLUSIONS

This is the first study that has identified a single-nucleotide polymorphism in the aromatase gene that suggests a significant association between genotypes and miscarriage. As aromatase is an essential enzyme in the estrogen pathway, it may be speculated that variations in the aromatase gene in some way give rise to different conditions in the endocrine environment that can lead to impaired fertility.

CYP17 polymorphism and hot flushes in postmenopausal women

OBJECTIVE

To investigate the association between the CYP17alpha gene polymorphism and hot flushes in postmenopausal women.

METHODS

Ninety-three non-hysterectomized, postmenopausal women were enrolled in this study. Vasomotor symptoms were assessed at the baseline visit and based on information provided by each participant. The genotypic polymorphism of CYP17alpha gene was analyzed by PCR-RFLP assay using genomic DNA isolated from peripheral blood lymphocytes.

RESULTS

Thirty-six women reported hot flushes of mild intensity, 25 reported hot flushes of moderate intensity and 32 of severe intensity. There was no significant difference between the severity of hot flushes and the CYP17 genotype or allele frequencies, 0.58 and 0.67 respectively. No association was found between hot flush severity and the CYP17 allele (odds ratio = 1.17, p = 0.61).

CONCLUSION

The results of this study suggest that the CYP17 MspAI polymorphism was not significantly associated with an increased risk of reporting hot flushes.