The effects of high altitude on age at menarche and menopause

The age at menarche and menopause of three groups of Bhotia females living at high altitude, Himalayan region — Uttar Pradesh, North India, were studied. The Johari Bhotia women had earliest menarche (¯X=15.1±1.1 years) as compared to Rang Bhotias, settled (¯X=15.6±0.9 years) and Rang Bhotias, migratory (¯X=16.0±1.0 years). The differences between all these three groups for age at menarche were significant. A trend towards increase in age at menarche with an increase in altitude has been observed, but the total fertility period in the three groups remained similar as early menarche has been found to be associated with early onset of menopause and late menarche with late menopause.     

Trisomic pregnancy and earlier age at menopause

We tested the hypothesis that the connection between advanced maternal age and autosomal trisomy reflects the diminution of the oocyte pool with age. Because menopause occurs when the number of oocytes falls below some threshold, our hypothesis is that menopause occurs at an earlier age among women with trisomic pregnancies than it does among women with chromosomally normal pregnancies. To determine their menstrual status, we interviewed women from our previous study of karyotyped spontaneous abortions who, in 1993, were age >/=44 years. Premenopausal women completed interviews every 4-5 mo, until menopause or until the study ended in 1997. The primary analyses compare 111 women whose index pregnancy was a trisomic spontaneous abortion with two groups: women whose index pregnancy was a chromosomally normal loss (n=157) and women whose index pregnancy was a chromosomally normal birth (n=226). We used a parametric logistic survival analysis to compare median ages at menopause. The estimated median age at menopause was 0.96 years earlier (95% confidence interval -0.18 to 2.10) among women with trisomic losses than it was among women with chromosomally normal losses and chromosomally normal births combined. Results were unaltered by adjustment for education, ethnicity, and cigarette smoking. Our results support the hypothesis that trisomy risk is increased with decreased numbers of oocytes. Decreased numbers may indicate accelerated oocyte atresia or fewer oocytes formed during fetal development.     

Distribution of age at menopause in two Danish samples

We analyzed the distribution of reported age at natural menopause in two random samples of Danish women (n = 176 and n = 150) to determine the shape of the distribution and to disclose any possible trends in the distribution parameters. It was necessary to correct the frequencies of the reported ages for the effect of differing ages at reporting. The corrected distribution of age at menopause differs from the normal distribution in the same way in both samples. Both distributions could be described by a mixture of two normal distributions. It appears that most of the parameters of the normal distribution mixtures remain unchanged over a 50-year time lag. The position of the distribution, that is, the mean age at menopause, however, increases slightly but significantly.     

Secular trend and intrapopulational variation in age at menopause in Spanish women

Menopause is associated with the general ageing process and marks the end of follicular depletion, a process that begins in the intrauterine stage and lasts throughout the lifetime of women until their reproductive senescence. Controversy persists about whether the age at menopause is sensitive to the ecological determinants prevailing during the lifecycle or whether it has a predominantly genetic component that would allow groups of women to be characterized with respect to particular menstrual characteristics manifested throughout their fertile life. By contrast, there is a definite secular trend in age at menarche in populations that have registered improvements in their environment: sexual maturation is closely associated with the general processes of growth and development. These aspects were analysed in a sample of Spanish women, mothers and daughters, born between 1883 and 1941. The results show (a) indications--although not conclusive--of a secular trend in the age at menopause, (b) a possible association between the age at menopause of mothers and their daughters, and (c) an association at the individual level between age at menarche, particular characteristics of ovarian function (fetal loss) and age at menopause. The reproductive ageing process therefore seems to result from the expression of the influence of ecological conditions in which the lifecycle of the women develops and of a degree of heritability that affects not only the age at menopause but also a range of characteristics of ovarian function.     

Migration,socio-economic status and age at menarche and age at menopause in the Yucatan,Mexico

The possible effects of migration and socio-economic status (SES) on age at menarche (MENA), age at menopause (MENO), potential reproductive period (PRP), and the correlation between MENA and MENO, were studied in 216 women in the Yucatan, Mexico. They were divided into three groups: migrant from the sisal-growing area on the coast, and sisal and coastal sedentary. Coastal sedentary women, living in the best socio-economic conditions, have the youngest MENA and the oldest MENO. Early migrant women have a significantly younger MENO (p.<0.05) and shorter PRP than Coastal sedentary women. There was no evidence of selective migration for MENA. When the Migrant, Sisal and Coastal sample were divided into cohorts by SES, it was impossible to obtain any clear picture. MENA increases with increased SES for the Coastal and Sisal cohorts, while the Migrant cohorts show an opposite trend. However, only the Low/Middle and High/Middle cohort differences for the Coastal sample are significant (p.<0.05, in both cases). It seems that migration has a limited affect on MENO and the PRP. Contrary to reports in the literature, the correlations between MENA and MENO and migrant status, and migrant socio-economic statuses, are negative, although these correlations were statistically significant in the Coastal sample.     

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).     

Women's attractiveness is linked to expected age at menopause

A great number of studies have shown that features linked to immediate fertility explain a large part of the variance in female attractiveness. This is consistent with an evolutionary perspective, as men are expected to prefer females at the age at which fertility peaks (at least for short‐term relationships) in order to increase their reproductive success. However, for long‐term relationships, a high residual reproductive value (the expected future reproductive output, linked to age at menopause) becomes relevant as well. In that case, young age and late menopause are expected to be preferred by men. However, the extent to which facial features provide cues to the likely age at menopause has never been investigated so far. Here, we show that expected age at menopause is linked to facial attractiveness of young women. As age at menopause is heritable, we used the mother's age at menopause as a proxy for her daughter's expected age of menopause. We found that men judged faces of women with a later expected age at menopause as more attractive than those of women with an earlier expected age at menopause. This result holds when age, cues of immediate fertility and facial ageing were controlled for. Additionally, we found that the expected age at menopause was not correlated with any of the other variables considered (including immediate fertility cues and facial ageing). Our results show the existence of a new correlate of women's facial attractiveness, expected age at menopause, which is independent of immediate fertility cues and facial ageing.     

Effect of radiation on age at menopause among atomic bomb survivors

Exposure to ionizing radiation has been thought to induce ovarian failure and premature menopause. Proximally exposed female atomic bomb survivors were reported to experience menopause immediately after the exposure more often than those who were distally exposed. However, it remains unclear whether such effects were caused by physical injury and psychological trauma or by direct effects of radiation on the ovaries. The objective of this study was to see if there are any late health effects associated with the exposure to atomic bomb radiation in terms of age at menopause in a cohort of 21,259 Life Span Study female A-bomb survivors. Excess absolute rates (EAR) of natural and artificial menopause were estimated using Poisson regression. A linear threshold model with a knot at 0.40 Gy [95% confidence interval (CI): 0.13, 0.62] was the best fit for a dose response of natural menopause (EAR at 1 Gy at age of 50 years = 19.4/1,000 person-years, 95% CI: 10.4, 30.8) and a linear threshold model with a knot at 0.22 Gy (95% CI: 0.14, 0.34) was the best fit for artificial menopause (EAR at 1 Gy at age of 50 years for females who were exposed at age of 20 years = 14.5/1,000 person-years, 95% CI: 10.2, 20.1). Effect modification by attained age indicated that EARs peaked around 50 years of age for both natural and artificial menopause. Although effect modification by age at exposure was not significant for natural menopause, the EAR for artificial menopause tended to be larger in females exposed at young ages. On the cumulative incidence curve of natural menopause, the median age at menopause was 0.3 years younger in females exposed to radiation of 1 Gy compared with unexposed females. The median age was 1 year younger for combined natural and artificial menopause in the same comparison. In conclusion, age at menopause was thought to decrease with increasing radiation dose for both natural and artificial menopause occurring at least 5 years after the exposure.     

Breast cancer susceptibility loci in association with age at menarche,age at natural menopause and the reproductive lifespan

Background: Genome-wide association studies have identified single nucleotide polymorphisms (SNPs) associated with breast cancer risk. Some of these loci have unknown functional significance and may mediate the effects of hormonal exposures on breast cancer risk. We examined relationships between breast cancer susceptibility variants and menstrual/reproductive factors using data from two population-based studies. Methods: The first analysis was based on a sample of 1328 women age 20–74 who participated as controls in a case–control study of breast cancer conducted in three U.S. states. We evaluated the associations between age at menarche, age at natural menopause and the reproductive lifespan with 13 previously identified breast cancer variants. Associations were also examined with a genetic score created as the sum of at-risk alleles across the 13 variants. For validation, significant results were evaluated in a second dataset comprised 1353 women age 43–86 recruited as part of a cohort study in Wisconsin. Results: Neither the genetic score nor any of the 13 variants considered individually were associated with age at menarche or reproductive lifespan. Two SNPs were associated with age at natural menopause; every increase in the minor allele (A) of rs17468277 (CASP8) was associated with a 1.12 year decrease in menopause age (p = 0.02). The minor allele (G) of rs10941679 (5p12) was associated with a 1.01 year increase in age at natural menopause (p = 0.01). The results were not replicated in the validation cohort (B = −0.61, p = 0.14 and B = −0.01, p = .0.98, respectively). Conclusions: The evaluated variants and reproductive experiences may work through separate pathways to influence breast cancer risk.     

Coronary heart disease in relation to age,sex, and the menopause.

Examination of the Registrar General''s mortality data suggested that women do not lose protection from coronary heart disease (CHD) after the menopause. Apparently, at around the age of 50 men begin to lose a factor that had previously put them at increased risk of developing CHD compared with women. Male sex hormones may be risk factors for CHD, and further studies are needed to clarify their role in the aetiology of CHD in men.     

The vascular flora of Rome

The aim of this paper is to document plant diversity in the metropolitan area of Rome (Italy) by providing a comprehensive inventory of the present-day vascular flora and an overview of its composition and species diversity. We compiled the floristic catalogue by including all vascular plant entities that occur spontaneously within the administrative boundaries of the Rome municipality. The data, which were gathered from extensive field surveys, from a broad review of the literature and from herbaria records, were updated and integrated in a comprehensive account. The inventory of the flora of metropolitan Rome lists 1649 entities, from 139 families and 677 genera. The flora contains 228 taxa that are non-native to the Italian flora, 81 of which are established in the study area. The overview of flora reveals a remarkable species diversity and outlines the main characteristics of the flora of Rome, which may be summarized as (1) a large number of taxa of high conservation value which occur in remnants of near-natural vegetation, (2) the loss or decline of some species, particularly of native freshwater plants, (3) a remarkably high native species richness within the urban area, which includes many native woody species and (4) a rich ruderal flora, prevalently composed of native species that are well adapted to human disturbance, along with a variety of taxa of non-native or uncertain origin. The large set of data and the overview presented in this paper represent a fundamental framework for future research and for the conservation of plant diversity in metropolitan Rome.