A polymorphism of the Nos3 gene and age at natural menopause

Prognostic significance of three endothelial nitric oxide synthase (eNOS) polymorphisms and metabolic syndrome (MetS) in patients with colorectal cancer

BACKGROUND

Polymorphisms of endothelial nitric oxide synthases (eNOS) have been associated with cancer susceptibility. Also, metabolic syndrome is associated with cancer malignancy. However, the effect of eNOS polymorphisms and metabolic syndrome on colorectal cancer (CRC) prognosis remains unclear.

OBJECTIVE

To investigated whether three genetic polymorphisms (- 786 T > C rs2070744, 4a4b rs869109213, and 894G > T rs1799983) in the eNOS and metabolic syndrome (MetS) were associated with CRC patient survival.

METHODS

We genotyped three polymorphisms of eNOS (- 786 T > C, 4a4b, and 894G > T) in 312 CRC cases from the Korean population by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis.

RESULTS

Although the three eNOS polymorphisms were not causative of MetS, the TT genotype of the 894G > T polymorphism was associated with a worse survival rate compared with the GG genotype in the CRC group with MetS than in the CRC group without MetS (5-years survival; adjusted HR = 54.777; 95% CI 5.073-591.487 and RFS; adjusted HR = 14.909; 95% CI 1.571-141.528).

CONCLUSIONS

The eNOS polymorphisms were not associated with metabolic syndrome prevalence in CRC patients. However, our findings suggest that the eNOS 894G > T polymorphism with MetS was associated with poor clinical outcomes.

OUP accepted manuscript

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 We searched unpublished sources including the Global Burden of Disease, Demographic and Health Surveys, and National Health and Nutrition Examination Surveys.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.

Genome-Wide Detection of Copy Number Variations and Their Association With Distinct Phenotypes in the World's Sheep

Copy number variations (CNVs) are a major source of structural variation in mammalian genomes. Here, we characterized the genome-wide CNV in 2059 sheep from 67 populations all over the world using the Ovine Infinium HD (600K) SNP BeadChip. We tested their associations with distinct phenotypic traits by conducting multiple independent genome-wide tests. In total, we detected 7547 unique CNVs and 18,152 CNV events in 1217 non-redundant CNV regions (CNVRs), covering 245 Mb (∼10%) of the whole sheep genome. We identified seven CNVRs with frequencies correlating to geographical origins and 107 CNVRs overlapping 53 known quantitative trait loci (QTLs). Gene ontology and pathway enrichment analyses of CNV-overlapping genes revealed their common involvement in energy metabolism, endocrine regulation, nervous system development, cell proliferation, immune, and reproduction. For the phenotypic traits, we detected significantly associated (adjusted P < 0.05) CNVRs harboring functional candidate genes, such as SBNO2 for polycerate; PPP1R11 and GABBR1 for tail weight; AKT1 for supernumerary nipple; CSRP1, WNT7B, HMX1, and FGFR3 for ear size; and NOS3 and FILIP1 in Wadi sheep; SNRPD3, KHDRBS2, and SDCCAG3 in Hu sheep; NOS3, BMP1, and SLC19A1 in Icelandic; CDK2 in Finnsheep; MICA in Romanov; and REEP4 in Texel sheep for litter size. These CNVs and associated genes are important markers for molecular breeding of sheep and other livestock species.

Relationship between some indicators of reproductive history, body fatness and the menopausal transition in Hungarian women

BACKGROUND

This paper analyzed the relationship between some indicators of reproductive history and body fatness in relation to the timing of the menopause transition in Hungarian women using survival analysis after controlling for birth cohort.

METHODS

Data on menstruation and reproductive history were collected during the personal interviews in a sample of 1932 women (aged 35+ years). Menarcheal age, the length of menstrual cycles and menstrual bleedings, regularity of menstrual cycles, number of gestations, lactation, the ever use of contraceptives, menopausal status and age at menopause were used as indicators of reproductive history. The body fat fraction was estimated by bioelectrical impedance analysis. Body fatness was also estimated by dividing women into obese and non-obese categories (considering body mass index and waist-to-hip ratio). Survival analyses were used to analyze the relationship between the indicators of reproductive history and body fatness during the menopausal transition.

RESULTS

Only the menarcheal age among the investigated reproductive life characteristics showed secular changes in the studied decades in Hungary; the mean age at menarche decreased by approximately 2.5 months per decade from the 1920s until the 1970s. Ever use of hormonal contraceptives, a relatively long cycle length in the perimenopausal transition and higher parity were all related with lower risk of early menopause. Later menarcheal age, normal length of menstrual cycle or bleeding in the climacterium, irregular bleeding pattern and postmenopausal status were associated with a higher amount of body fatness, while never use of contraceptives, regular menstruation, postmenopausal status and relatively early menopause were associated with a higher risk of abdominal obesity.

CONCLUSION

This report confirms that age of menarche is not significantly predictive of age at menopause but prior use of oral contraceptives, longer mean cycle length and smaller number of gestations all are. In addition, age of menarche, irregular bleeding pattern before the climacterium, length of menstrual cycles and bleedings during the climacterium and postmenopausal status were associated with obesity during the climacterium.

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 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.

The relationship between smoking and age at the menopause: A systematic review

CONTEXT AND OBJECTIVE

Increasing life expectancy has made it ever more important to study the factors that influence the age at the menopause, given that when it is reached outside of the normal range, it is associated with increased risk of osteoporosis and cardiovascular diseases, among other conditions. Among the factors studied in relation to early menopause, smoking is prominent. Destruction of the ovarian follicles is one of the mechanisms postulated for this effect. The aim of this study was to review and describe the associations between age at the menopause and the habit of smoking, its duration and its intensity.

METHOD

A systematic review of the literature indexed in the MEDLINE and LILACS databases was conducted, without restriction on publication date. After initially identifying 1325 articles and preselecting 161 articles for consideration of their complete texts, 96 articles reporting on the results from 109 studies were selected for analysis.

RESULTS

A great majority of the studies reported an association between the habit of smoking and early menopause, but there was no clear evidence that the duration of smoking and quantity of cigarettes smoked had any association with age at the natural menopause.

CONCLUSION

Additional studies are needed, preferably of prospective nature and with a large number of women, in order to deepen the knowledge of the effects of various aspects of smoking on age at the menopause. Experimental studies on animals may also contribute towards clarifying the physiopathological mechanisms through which smoking influences age at the menopause.

Polymorphisms of the endothelial nitric oxide synthase gene in premenopausal women with polycystic ovary syndrome

OBJECTIVES

To investigate the association of two common genetic polymorphisms of the gene encoding for endothelial nitric oxide synthase (Nos3), the enzyme catalyzing the production of nitric oxide (NO), with occurrence of the polycystic ovary syndrome (PCOS).

METHODS

In a prospective case-control study, we analyzed 2 polymorphisms of the Nos3 gene cluster (Nos 3 exon 7 Glu298Asp and 27-base pair repeat in intron 4 of Nos3) in a series of 210 premenopausal Caucasian women with PCOS and 171 healthy controls using pyrosequencing and PCR, respectively. Women completed a detailed questionnaire and underwent a peripheral venous puncture, ultrasonography, and a standardized oral glucose tolerance test (OGTT).

RESULTS

Genotype frequencies were not significantly different among women with PCOS and controls for the exon 7Nos3 and the intron 4Nos3 polymorphism (p=0.3 and 0.2, respectively).

CONCLUSIONS

In our series, two common polymorphisms of the Nos3 gene cluster were not associated with occurrence of PCOS.

Lack of consistent association between endothelial nitric oxide synthase gene polymorphisms, homocysteine levels and recurrent pregnancy loss in tunisian women

PROBLEM

Polymorphisms of the endothelial nitric oxide synthase (eNOS) gene have been associated with reduced vascular NO production or increased level of homocysteine, and evaluated as risk factors for recurrent pregnancy loss (RPL). Therefore, in this case-control study, we aimed to determine the effects of some eNOS functional polymorphisms: the 27-bp intron 4 repeat, the 894G/T of exon 7, and the promoter substitution -786T/C, in women with RPL.

METHOD OF STUDY

We genotyped 350 patients with RPL and 200 healthy women by polymerase chain reaction (PCR) and restriction fragment length polymorphism-PCR (RFLP-PCR). The homocysteine total plasma concentrations (tHcy) were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

None of the eNOS polymorphisms-related alleles, genotypes, and haplotypes were associated with RPL. The tHcy were similar between patients and controls; no significant association between tHcy levels and eNOS genotypes could be evidenced.

CONCLUSION

The present study identified a lack of association between eNOS gene polymorphisms, the risk of RPL and tHcy levels.

Polymorphisms associated with thrombophilia and vascular homeostasis and the timing of menarche and menopause in 728 white women

OBJECTIVE

Genetic factors have been proposed as modulators of the timing of natural menopause. Single nucleotide polymorphisms (SNPs) of genes associated with thrombophilia and vascular homeostasis may interfere with ovarian function and thus are candidate genes for early menopause. We attempted to assess the association of SNPs and the timing of menarche and natural and surgical menopause in an ethnically homogenous cohort of Middle European white women.

DESIGN

In the present cross-sectional study, eight SNPs of six genes involved in vascular function and homeostasis were analyzed by sequencing-on-chip using solid-phase polymerase chain reaction on oligonucleotide microarrays in 728 white women: factor V (F5) Leiden G1691A, factor II (F2) prothrombin G20210A, plasminogen activator inhibitor1 (PAI-1) 4G/5G, angiotensinogen (AGT) Met235Thr, endothelial nitric oxide synthase (NOS3) T768C and NOS3 Glu298Asp, apolipoprotein E-1 (APOE-1) Cys112Arg, and APOE-2 Arg158Cys. The women's reproductive and medical histories were correlated to genotypes.

RESULTS

In a univariate analysis, current smoking (P = 0.01) and the presence of at least one mutant allele of F5 Leiden (P = 0.03) and APOE-2 (P = 0.03) were significantly associated with a reduced age at natural menopause. The presence of at least one mutant allele of F5 Leiden (P = 0.02) and a body mass index above 25 kg/m (P = 0.009) were significantly associated with an increased risk for surgical menopause by premenopausal hysterectomy (odds ratio = 2.6, 95% CI, 1.2-5.6; odds ratio = 1.9, 95% CI, 1.2-3.0, respectively). Age at menarche was not affected by the carriage of any of the investigated SNPs. Applying stepwise linear regression models considering all two-way interactions, no interactions were found among different SNPs or between SNPs and environmental and lifestyle parameters.

CONCLUSION

We identified various genetic and personal history parameters influencing age at natural menopause and the risk of undergoing premenopausal hysterectomy. To the best of our knowledge, we present the largest study to date determining SNPs as contributors to the genetic control of the timing of natural and surgical menopause.

Polymorphisms of the Nos3 gene and unexplained late intrauterine fetal death

OBJECTIVE

Genetic polymorphisms associated with vascular diseases have been proposed to be involved in the pathogenesis of late unexplained intrauterine fetal death (IUFD). The Nos3 gene is known to regulate vascular tone via the endothelial nitric oxide synthase/nitric oxide pathway.

STUDY DESIGN

In a multicenter case-control study, we evaluated two Nos3 polymorphisms (exon 7 Glu298Asp and a 27bp-repeat in intron 4) in 92 women with IUFD and 92 healthy control women.

RESULTS

The investigated Nos3 polymorphisms were not associated with the occurrence of IUFD. In the subgroup of pregnancies affected by IUFD, women with at least one mutant allele of the Nos3 intron 4 polymorphism were diagnosed with IUFD at a significantly earlier gestational age (31.8 [standard deviation (S.D.) = 4.9] weeks versus 34.6 [S.D. = 4.8] weeks, p = 0.02) and showed a significantly reduced birth weight (2113 g [S.D. = 1028] versus 1571 g [S.D. = 568], p = 0.03).

CONCLUSION

We are the first to report on Nos3 polymorphisms and IUFD. While not being associated with the incidence of IUFD overall, the intron 4 Nos3 polymorphism might modulate the timing of IUFD in affected pregnancies.

The influence of a Vitamin D receptor gene polymorphism on the timing of female reproductive functions in humans

OBJECTIVE

To evaluate the association between a common polymorphism of the Vitamin D receptor gene (VDR) and the timing of female reproductive functions in humans.

METHODS

One thousand fifty-eight consecutive women were included in this cross-sectional study. We analyzed the intron 8 Bsm I restriction fragment length polymorphism (RFLP) of VDR on chromosome 12q using a microarray-based system.

RESULTS

The presence of the VDR polymorphism did not influence the timing of menarche and natural menopause and was not associated with the number of spontaneous abortions, full term pregnancies (FTP) as well as the total number of pregnancies. Of note, women with at least one mutant allele of VDR were at a significantly decreased risk for experiencing surgical menopause (odds ratio [OR] 0.65, 95% confidence interval [CI], 0.46-0.92, P = 0.02). Smoking and a body mass index (BMI) > 25 were associated with an earlier natural menopause and an increased risk for surgical menopause, respectively.

CONCLUSIONS

While no association of a common polymorphism of VDR with the timing of menarche and menopause was ascertained, we found the presence of at least one mutant allele of VDR to be associated with a decreased risk of experiencing surgical menopause, i.e., premenopausal hysterectomy, in a large series of Caucasian women.

Estrogen-metabolizing gene polymorphisms and age at natural menopause in Caucasian women

BACKGROUND

Lifestyle parameters, personal history and genetic factors are thought to affect the timing of natural menopause in humans. Based on their biological function, estrogen-metabolizing gene polymorphisms have been regarded as candidate genes for early menopause.

METHODS

In the present cross-sectional, multi-centre study, we analysed nine single nucleotide polymorphisms of six estrogen-metabolizing genes [three estrogen-synthesizing genes, i.e. 17-beta-hydroxysteroid dehydrogenase type 1 (17-beta HSD), cytochrome P-450 (CYP) 17 and CYP19; and three estrogen-inactivating genes, i.e. catechol-O-methyltransferase (COMT), CYP1A1 and CYP1B1] by sequencing-on-chip-technology in 1360 Caucasian women with natural menopause. Women's lifestyle parameters, reproductive and personal histories were ascertained.

RESULTS

Carriage of at least one mutant allele of the CYP1B1-4 Asn453Ser A--> G polymorphism (P = 0.004) and the number of full-term pregnancies (P < 0.001) were found to be independently associated with age at natural menopause. Women with at least one polymorphic allele of CYP1B1-4 experienced natural menopause earlier than non-carriers of the polymorphism [mean (SD) 48.6 (5.0) versus 49.4 (4.3) years]. Women with no, one, two and three or more full-term pregnancies experienced natural menopause at 48.5 (5.0), 48.8 (4.8), 49.5 (4.2) and 49.6 (4.6) years, respectively.

CONCLUSION

We present the most comprehensive data on estrogen-metabolizing gene polymorphisms and timing of natural menopause to date. The number of full-term pregnancies and the CYP1B1-4 polymorphism are significant predictors of timing of natural menopause in Caucasian women.

The influence of Nos3 polymorphisms on age at menarche and natural menopause

OBJECTIVE

Deficiency of the gene encoding endothelial nitric oxide synthase, i.e. Nos3, has been reported to be associated with late menarche, reduced ovulation rates, fewer deliveries, and earlier onset of menopause in a mouse model.

METHODS

We assessed the Glu298Asp and the T-786C polymorphisms of Nos3 in 87 consecutive healthy postmenopausal women by pyro- and capillary-sequencing, respectively. Results were correlated with age at menarche and natural menopause, number of miscarriages and live births, as well as body mass index (BMI) and smoking habits.

RESULTS

Allelic frequencies of the Glu298Asp polymorphism of Nos3 were 121 (69.5%) and 53 (30.5%) for the wild-type G allele and the mutant T allele, respectively. Forty-one women (47.1%) were homozygote wild-type (G/G), 39 (44.9%) were heterozygote (G/T), and 7 (8.0%) were homozygote mutant (T/T). Allelic frequencies of the T-786C polymorphism of Nos3 were 105 (60.6%) and 69 (39.4%) for the wild-type T allele and the mutant C allele, respectively. Thirty-three women (38.0%) were homozygote wild-type (T/T), 39 (45.1%) were heterozygote (T/C), and 15 (16.9%) were homozygote mutant (C/C). Presence of at least one mutant allele of the Glu298Asp or the T-786C polymorphisms of Nos3 were not associated with age at menarche, natural menopause, and number of miscarriages and deliveries. BMI above 27 kg/m2 and smoking were associated with earlier onset of natural menopause (47.8 years versus 50.2 years (P = 0.01) and 46.8 years versus 49.8 years (p = 0.02)).

CONCLUSIONS

Our data show that smoking and increased BMI, but not Glu298Asp or the T-786C polymorphisms of Nos3, are associated with an early onset of natural menopause.

Vasoconstrictively acting AT1R A1166C and NOS3 4/5 polymorphisms in recurrent spontaneous abortions (RSA)

PROBLEM

Inadequate uteroplacental perfusion is one of the main reasons for recurrent spontaneous abortions (RSA). Coagulation, fibrinolysis, and vasoconstriction affect tissue perfusion. These systems are regulated by different gene products. Polymorphisms can modulate the expression levels of the respective genes and can thereby affect perfusion. Vasoconstriction is influenced by the expression of endothelial nitric oxide synthase (eNOS) and of the angiotensinogen II type 1 receptor (AT1R).

METHOD

The aim of our study was to investigate, whether two polymorphisms in the AT1R and NOS3 genes shown to result in maternal vasoconstriction are associated with an increased risk for RSA.

RESULTS

Our data indicate that the vasoconstrictively acting genotypes AT1R C/C and NOS3 4/4 are of similar prevalence in RSA patients and in controls.

CONCLUSION

Results do not show any influence of the polymorphisms studied on early pregnancy development. This is in concordance with the concept of an independent regulation of placental perfusion.