BACKGROUND & AIMS: :We investigate the parity-time (PT) phase transition in photonic crystals with [Formula: see text] symmetry, with balanced gain and loss on dielectric rods in the triangular lattice. A two-level non-Hermitian model that incorporates the gain and loss in the tight-binding approximation was employed to describe the dispersion of the PT symmetric system. In the unbroken PT phase, the double Dirac cone feature associated with the [Formula: see text] symmetry is preserved, with a frequency shift of second order due to the presence of gain and loss. The helical edge states with real eigenfrequencies can exist in the common band gap for two topologically distinct lattices. In the broken PT phase, the non-Hermitian perturbation deforms the dispersion by merging the frequency bands into complex conjugate pairs and forming the exceptional contours that feature the PT phase transition. In this situation, the band gap closes and the edge states are mixed with the bulk states.

背景与目标： : 我们研究了具有 [公式: 参见文本] 对称性的光子晶体中的奇偶时间 (PT) 相变，在三角形晶格中的介电棒上具有平衡的增益和损耗。采用了在紧约束近似中包含增益和损耗的两级非Hermitian模型来描述PT对称系统的色散。在不间断的PT阶段，与 [公式: 参见文本] 对称性相关的双狄拉克锥特征得以保留，由于存在增益和损耗，其频移为二阶。对于两个拓扑上不同的晶格，具有真实本征频率的螺旋边缘状态可以存在于公共带隙中。在中断的PT相位中，非埃尔米特扰动通过将频带合并为复共轭对并形成具有PT相变特征的特殊轮廓来使色散变形。在这种情况下，带隙闭合，边缘状态与体状态混合。

BACKGROUND & AIMS: :Some adult human females show bone resorption (pitting) at the dorsal aspect of the pubis and preauricular area of the ilium. The etiology of pelvic bone resorption is attributed alternatively to reproduction and to pelvic anatomy. While most researchers infer that pelvic pitting is related to reproduction, only a few studies are based on women of known parity. Degree of pubic resorption is directly associated with both parity (Suchey et al.: Am. J. Phys. Anthropol. 51:517-539, 1979; Bergfelder and Hermann: J. Hum. Evol. 9:611-613, 1980) and age (Suchey et al.: Am. J. Phys. Anthropol. 51:517-539, 1979). The relationship between parity and degree of resorption of the preauricular area is equivocal, found to be significant by Dunlap (A Study of the Preauricular Sulcus in a Cadaver Population, Ph.D. dissertation, East Lansing, Michigan State University, 1981) but not by Spring et al. (Am. J. Phys. Anthropol. 79:247-252, 1989); both studies report that age is not associated with resorption of the preauricular area. Other mammals evidence public resorption, but the morphology of the preauricular area is less well known. This study addresses the issue on the etiology of pelvic bone resorption using a sample of Macaca mulatta (the free-ranging population from Cayo Santiago) for which parity and age at death are known for all specimens. The following results are reported. Resorption of the pubis is common among females but infrequent among males. Contrary to Rawlins (Am. J. Phys. Anthropol. 42:477-488, 1975), the degree of pubic resorption in female macaques is significantly related to both parity and age at death.(ABSTRACT TRUNCATED AT 250 WORDS)

背景与目标： : 一些成年女性在耻骨的背侧和the骨的耳前区表现出骨吸收 (点蚀)。骨盆骨吸收的病因可归因于生殖和骨盆解剖。虽然大多数研究人员推断骨盆凹陷与生殖有关，但只有少数研究是基于已知均等的女性。耻骨吸收的程度与宇称 (Suchey等人: Am. J. Phys. Anthropol. 51:517-539，1979; Bergfelder和Hermann: J. Hum. Evol. 9:611-613，1980) 和年龄 (Suchey等人: 上午。J. Phys. Anthropol. 51:517-539，1979)。地称与耳前区吸收程度之间的关系是模棱两可的，由Dunlap发现是显着的 (对尸体人群中的耳前沟的研究，博士学位论文，密歇根州立大学东兰辛，1981)，但不是Spring等人 (Am. J. Phys. Anthropol. 79:247-252，1989); 两项研究均报告年龄与耳前区域的吸收无关。其他哺乳动物证明公众吸收，但耳前区的形态鲜为人知。这项研究使用Macaca mulatta (来自Cayo Santiago的自由放养人群) 样本解决了骨盆骨吸收的病因学问题，所有标本都已知死亡年龄和死亡年龄。报告了以下结果。耻骨的吸收在女性中很常见，但在男性中很少。与罗林斯相反 (Am. J. Phys. Anthropol. 42:477-488，1975)，雌性猕猴的耻骨吸收程度与死亡时的同胎和年龄均显着相关。(摘要截短于250字)

BACKGROUND & AIMS: BACKGROUND:Chargaff's rule of DNA base composition, stating that DNA comprises equal amounts of adenine and thymine (%A = %T) and of guanine and cytosine (%C = %G), is well known because it was fundamental to the conception of the Watson-Crick model of DNA structure. His second parity rule stating that the base proportions of double-stranded DNA are also reflected in single-stranded DNA (%A = %T, %C = %G) is more obscure, likely because its biological basis and significance are still unresolved. Within each strand, the symmetry of single nucleotide composition extends even further, being demonstrated in the balance of di-, tri-, and multi-nucleotides with their respective complementary oligonucleotides. RESULTS:Here, we propose that inversions are sufficient to account for the symmetry within each single-stranded DNA. Human mitochondrial DNA does not demonstrate such intra-strand parity, and we consider how its different functional drivers may relate to our theory. This concept is supported by the recent observation that inversions occur frequently. CONCLUSION:Along with chromosomal duplications, inversions must have been shaping the architecture of genomes since the origin of life.

背景与目标：

BACKGROUND & AIMS: UNLABELLED:The aims of the study were to determine: (1) the relationship between parity and bone mineral density (BMD); (2) the relationship between parity and osteoporotic peripheral fractures. MATERIAL AND METHODS:The group studied included 730 postmenopausal women. Patients were separated into four groups according to the number of fullterm pregnancies, group 1: nulliparae, group 2: one to three pregnancies, group 3: four to five pregnancies, and group 4: six and more pregnancies. Additionally, patients were separated into three groups according to their ages, as <50 years, 50-59 years and >or=60 years. RESULTS:The median parity was 4 [0-20]. All the patients with parity greater than six had spine and hip BMD values significantly lower than values in the other groups (p<0.001). After adjustment for age and body mass index (BMI), decreased lumbar and total hip BMD were still associated to increased parity (analysis of covariance (ANCOVA), p=0.04 and 0.023, respectively). The relation between parity and lumbar BMD was highly significant among women aged <50 years (age-adjusted p=0.022), while there was no parity-spine BMD association in the other age groups. The relation between parity and hip BMD was seen only in the group 50-59 years (age-adjusted p=0.042). A positive history for peripheral fractures was present in 170 (23%) patients. There was relationship between parity and peripheral fractures neither in the whole population nor in the sub-groups according to age. DISCUSSION:The present study suggests that the BMD of the spine and hip decreases with an increasing number of pregnancies, and this situation shows variations in different age groups. However, there was no correlation between parity level and peripheral fractures.

背景与目标：

BACKGROUND & AIMS: OBJECTIVES:To clarify the correlation between preeclampsia and parity and to identify protective factors against preeclampsia in multiparous women with systemic lupus erythematosus (SLE). METHODS:We conducted a single-center, retrospective chart review study of 85 pregnant women. We used multiple logistic regression analysis to assess the association between parity and preeclampsia in women with SLE, and described the detailed clinical courses and management of four women with a history of severe preeclampsia and of a woman who experienced preeclampsia during her latest pregnancy. RESULTS:Multiparity was significantly associated with a low risk of preeclampsia (adjusted odds ratio: 0.08; 95% confidence interval: 0.01-0.95). One multiparous woman without a history of preeclampsia developed preeclampsia during her latest pregnancy; she had critical risk factors for preeclampsia, including chronic kidney disease and hypertension, and was not administered aspirin. In contrast, four multiparous women with a history of severe preeclampsia received adequate medications; they did not develop recurrent preeclampsia and delivered live newborns. CONCLUSIONS:Multiparity and maintenance therapy for SLE before and during pregnancy and preventive treatment for preeclampsia may improve outcomes in subsequent pregnancies.

背景与目标：

BACKGROUND & AIMS: :Chargaff's second parity rules for mononucleotides and oligonucleotides (CIImono and CIIoligo rules) state that a sufficiently long (> 100 kb) strand of genomic DNA that contains N copies of a mono- or oligonucleotide, also contains N copies of its reverse complementary mono- or oligonucleotide on the same strand. There is very strong support in the literature for the validity of the rules in coding and noncoding regions, especially for the CIImono rule. Because the experimental support for the CIIoligo rule is much less complete, the present article, focusing on the special case of trinucleotides (triplets), examined several gigabases of genome sequences from a wide range of species and kingdoms including organelles such as mitochondria and chloroplasts. I found that all genomes, with the only exception of certain mitochondria, complied with the CIItriplet rule at a very high level of accuracy in coding and noncoding regions alike. Based on the growing evidence that genomes may contain up to millions of copies of interspersed repetitive elements, I propose in this article a quantitative formulation of the hypothesis that inversions and inverted transposition could be a major contributing if not dominant factor in the almost universal validity of the rules.

背景与目标： : Chargaff的单核苷酸和寡核苷酸的第二个奇偶校验规则 (CIImono和CIIoligo规则) 指出，包含N个单核苷酸或寡核苷酸拷贝的足够长 (> 100 kb) 的基因组DNA链也在同一链上包含N个其反向互补的单核苷酸或寡核苷酸的拷贝。文献中非常支持规则在编码和非编码区域中的有效性，尤其是CIImono规则。由于对CIIoligo规则的实验支持还不那么完整，因此本文着重于三核苷酸 (三胞胎) 的特殊情况，研究了来自多种物种和王国的基因组序列的几个千兆字节，包括线粒体等细胞器和叶绿体。我发现，除某些线粒体外，所有基因组在编码和非编码区中都以非常高的准确性遵守CIItriplet规则。基于越来越多的证据表明基因组可能包含多达数百万个副本的穿插重复元素，我在本文中提出了一个定量的假设，即倒置和倒置转座可能是几乎普遍有效的主要因素，即使不是主导因素。规则。

BACKGROUND & AIMS: :Treatment options for gestational diabetes (GDM) are limited. In order to better understand mechanisms and improve treatments, appropriate animal models of GDM are crucial. Heterozygous db mice (db/+) present with glucose intolerance, insulin resistance, and increased weight gain during, but not prior to, pregnancy. This makes them an ideal model for GDM. However, several recent studies have reported an absence of GDM phenotype in their colony. We investigated several hypotheses for why the phenotype may be absent, with the aim of re-establishing it and preventing further resources being wasted on an ineffective model. Experiments were carried out across two laboratories in two countries (New Zealand and China), and were designed to assess type of control strain, diet, presence of the misty allele, and parity as potential contributors to the lost phenotype. While hyperleptinemia and pre-pregnancy weight gain were present in all db/+mice across the four studies, we found no consistent evidence of glucose intolerance or insulin resistance during pregnancy. In conclusion, we were unable to acquire the GDM phenotype in any of our experiments, and we recommend researchers do not use the db/+ mouse as a model of GDM unless they are certain the phenotype remains in their colony.

背景与目标： : 妊娠糖尿病 (GDM) 的治疗选择有限。为了更好地了解机制和改善治疗，合适的GDM动物模型至关重要。杂合子db小鼠 (db/) 在怀孕期间 (但不在怀孕之前) 表现出葡萄糖耐受不良，胰岛素抵抗和体重增加。这使它们成为GDM的理想模型。然而，最近的几项研究报告了其菌落中不存在GDM表型。我们调查了为什么表型可能不存在的几种假设，目的是重新建立表型并防止在无效模型上浪费更多资源。实验是在两个国家 (新西兰和中国) 的两个实验室中进行的，旨在评估对照菌株的类型，饮食，雾状等位基因的存在以及作为失去表型的潜在贡献者的胎次。尽管在这四项研究中，所有db/小鼠中都存在高瘦素血症和孕前体重增加，但我们没有发现怀孕期间葡萄糖耐受不良或胰岛素抵抗的一致证据。总之，我们在任何实验中都无法获得GDM表型，我们建议研究人员不要将db/小鼠用作GDM的模型，除非他们确定表型仍保留在其菌落中。

BACKGROUND & AIMS: OBJECTIVE:To define the prevalence of pelvic floor disorders in a non-institutionalised community and to determine the relationship to gender, age, parity and mode of delivery. DESIGN:A representative population survey using the 1998 South Australian Health Omnibus Survey. SAMPLE:Random selection of 4400 households; 3010 interviews were conducted in the respondents' homes by trained female interviewers. This cross sectional survey included men and women aged 15-97 years. RESULTS:The prevalence of all types of self-reported urinary incontinence in men was 4.4% and in women was 35.3% (P<0.001). Urinary incontinence was more commonly reported in nulliparous women than men and increased after pregnancy according to parity and age. The highest prevalence (51.9%) was reported in women aged 70-74 years. The prevalence of flatus and faecal incontinence was 6.8% and 2.3% in men and 10.9% and 3.5% in women, respectively. Pregnancy (> 20 weeks), regardless of the mode of delivery, greatly increased the prevalence of major pelvic floor dysfunction, defined as any type of incontinence, symptoms of prolapse or previous pelvic floor surgery. Multivariate logistic regression showed that, compared with nulliparity, pelvic floor dysfunction was significantly associated with caesarean section (OR 2.5, 95% CI 1.5-4.3), spontaneous vaginal delivery (OR 3.4, 95% CI 2.4-4.9) and at least one instrumental delivery (OR 4.3, 95% CI 2.8-6.6). The difference between caesarean and instrumental delivery was significant (P<0.03) but was not for caesarean and spontaneous delivery. Other associations with pelvic floor morbidity were age, body mass index, coughing, osteoporosis, arthritis and reduced quality of life scores. Symptoms of haemorrhoids also increased with age and parity and were reported in 19.9% of men and 30.2% of women. CONCLUSION:Pelvic floor disorders are very common and are strongly associated with female gender, ageing, pregnancy, parity and instrumental delivery. Caesarean delivery is not associated with a significant reduction in long term pelvic floor morbidity compared with spontaneous vaginal delivery.

背景与目标：

BACKGROUND & AIMS: :Pregnancy and childbirth are associated with hemodynamic changes and vascular remodeling. It is not known whether parity is associated with later adverse vascular properties such as larger arterial diameter, wall thickness, and lower distensibility. We used baseline data from 3283 women free of cardiovascular disease aged 45 to 84 years enrolled in the population-based Multi-Ethnic Study of Atherosclerosis. Participants self-reported parity status. Ultrasound-derived carotid artery lumen diameters and brachial artery blood pressures were measured at peak-systole and end-diastole. Common carotid intima-media thickness was also measured. Regression models to determine the association of carotid distensibility coefficient, lumen diameter, and carotid intima-media thickness with parity were adjusted for age, race, height, weight, diabetes mellitus, current smoking, blood pressure medication use, and total and high-density lipoprotein cholesterol levels. The prevalence of nulliparity was 18%. In adjusted models, carotid distensibility coefficient was 0.09×10−5 Pa−1 lower (P=0.009) in parous versus nulliparous women. Among parous women, there was a nonlinear association with the greatest carotid distensibility coefficient seen in women with 2 live births and significantly lower distensibility seen in primiparas (P=0.04) or with higher parity >2 (P=0.005). No such pattern of association with parity was found for lumen diameter or carotid intima-media thickness. Parity is associated with lower carotid artery distensibility, suggesting arterial remodeling that lasts beyond childbirth. These long-term effects on the vasculature may explain the association of parity with cardiovascular events later in life.

背景与目标： : 妊娠和分娩与血流动力学变化和血管重塑有关。尚不清楚奇偶性是否与后来的不利血管特性有关，例如较大的动脉直径，壁厚和较低的扩张性。我们使用了3283名年龄在45至84岁的无心血管疾病的女性的基线数据，这些女性参加了基于人群的多种族动脉粥样硬化研究。参与者自我报告的平价状态。在收缩期和舒张末期测量超声衍生的颈动脉管腔直径和肱动脉血压。还测量了颈总动脉内膜中层厚度。根据年龄，种族，身高，体重，糖尿病，当前吸烟，血压药物使用以及总和高密度脂蛋白胆固醇水平，调整了用于确定颈动脉扩张性系数，管腔直径和颈动脉内膜中层厚度与平价的关系的回归模型。nulliparity的患病率为18%。在校正模型中，产妇与未产妇相比，颈动脉扩张性系数低0.09 × 10-5 Pa-1 (P = 0.009)。在分娩妇女中，与2例活产妇女的最大颈动脉扩张系数和初产妇 (P = 0.04) 或较高胎次> 2 (P = 0.005) 的扩张系数存在非线性关联。对于管腔直径或颈动脉内膜中层厚度，未发现这种与奇偶性相关的模式。胎次与较低的颈动脉扩张性有关，表明动脉重塑持续到分娩后。这些对脉管系统的长期影响可能解释了胎次与以后生活中心血管事件的关联。

BACKGROUND & AIMS: BACKGROUND:Forkhead box protein A1 (FOXA1) promotes luminal differentiation, and hypermethylation of the gene can be a mechanism of developing estrogen receptor-negative (ER-) breast cancer. We examined FOXA1 in breast tumor and adjacent normal tissue in relation to reproductive factors, particularly higher parity and no breastfeeding, that are associated with ER- tumors. METHODS:We performed IHC for FOXA1 in breast tumors (n = 1,329) and adjacent normal tissues (n = 298) in the Women's Circle of Health Study (949 Blacks and 380 Whites). Protein expression levels were summarized by histology (H) scores. Generalized linear models were used to assess FOXA1 protein expression in relation to reproductive factors by ER status. RESULTS:ER-positive (ER+) versus ER- tumors had higher FOXA1 protein expression (P < 0.001). FOXA1 expression was higher in tumor versus paired adjacent normal tissue in women with ER+ or non-triple-negative cancer (both P < 0.001), but not in those with ER- or triple-negative cancer. Higher number of births (1, 2, and 3+) was associated with lower FOXA1 protein expression in ER+ tumors [differences in H score, or β = -8.5; 95% confidence interval (CI), -15.1 to -2.0], particularly among parous women who never breastfed (β = -10.4; 95% CI, -19.7 to -1.0), but not among those who breastfed (β = -7.5; 95% CI, -16.9 to 1.8). The associations for ER- tumors were similar, although they were not statistically significant. CONCLUSIONS:In this tumor-based study, higher parity was associated with lower FOXA1 expression in ER+ tumors, and breastfeeding may ameliorate the influence. IMPACT:These findings contribute to our understanding of FOXA1 methylation and breast cancer etiology.

背景与目标：

BACKGROUND & AIMS: OBJECTIVES:The purpose of the study was to determine whether there exists a positive correlation between the mother's parity and the child's weight on delivery. MATERIALS AND METHODS:A retrospective study has been conducted on a selected group of 86 multiriparas with three deliveries. Only in term babies of healthy mothers were taken into consideration. Data derived from cases has been analyzed by means of Microsoft Excel and Statistica 6.0 software. RESULTS:In 65.1% of the cases, the birth weight of the second neonate exceeded the weight of the first one. The rate diminishes to 51.2% when we compare the third child with the second. In 2.3% of the records no changes have been observed. The abovementioned criteria enabled us to form three groups out of the initial cohort and perform further analysis. CONCLUSIONS:Significant correlation between birth weight of the first and second newborn has been found. No such correlation was found in the case of the second compared to the third delivery.

背景与目标：

BACKGROUND & AIMS: :Daily stress and sleep deprivation can influence the diurnal pattern of cortisol, which normally consists of high morning levels and a gradual decline throughout the day. While most individuals have consistent declining cortisol concentrations over days, others display either flat or inconsistent profiles. Postpartum mothers experience considerable home demands and sleep deprivation, yet, breastfeeding mothers perceive lower stress and reduced negative mood states compared to bottlefeeders. On the other hand, multiparity (having more than one child) is associated with reduced steepness in diurnal cortisol decline. Interestingly, no study to date has investigated the diurnal cortisol pattern and its stability across days in postpartum women as a function of their choice of infant feeding and parity. In this study, we measured salivary cortisol at four different time points during the day, on two non-consecutive days in first-time (primiparous) and second-time (multiparous) mothers at 5-20 weeks postpartum who were exclusively breastfeeding or bottlefeeding, and in non-postpartum mothers of young children (1-6 years). Among multiparous mothers, we found that cortisol levels in those who were bottlefeeding were higher than in breastfeeding mothers at both awakening and 1600 h. This effect remained significant after controlling for individual differences related to infant feeding choice, such as estradiol levels, education and income. No effect of infant feeding choice on cortisol concentrations was observed in primiparous mothers. While a consistent decline across days was common, some mothers presented a flat or inconsistent profile, a profile that was not associated with infant feeding choice or parity. Importantly, mothers with consistent declining profiles had the highest household income. Our findings suggest that although breastfeeding might promote a tighter regulation of diurnal basal cortisol secretion, in particular for multiparous mothers who are likely to be exposed to greater home demands and maternal responsibilities, some aspects of socioeconomic status such as income can also play a significant role in the stability of diurnal cortisol secretion across days.

背景与目标： : 每天的压力和睡眠不足会影响皮质醇的昼夜模式，皮质醇通常由高早晨水平和全天逐渐下降组成。尽管大多数人的皮质醇浓度在几天内持续下降，但其他人则显示出平坦或不一致的轮廓。产后母亲经历了相当大的家庭需求和睡眠不足，然而，与喂奶瓶者相比，母乳喂养的母亲感觉到较低的压力和减少的负面情绪状态。另一方面，多胎 (有多个孩子) 与昼夜皮质醇下降的陡度降低有关。有趣的是，迄今为止，还没有研究调查产后妇女的昼夜皮质醇模式及其在不同天内的稳定性，这取决于她们对婴儿喂养和胎次的选择。在这项研究中，我们在一天中的四个不同时间点测量唾液皮质醇，在产后5-20周的第一次 (初产) 和第二次 (多产) 母亲的两个非连续天，这些母亲完全母乳喂养或瓶装喂养，在非产后母亲的幼儿 (1-6岁)。在多胎母亲中，我们发现在觉醒和1600小时，喂瓶的母亲的皮质醇水平均高于母乳喂养的母亲。在控制了与婴儿喂养选择有关的个体差异 (例如雌二醇水平，教育程度和收入) 之后，这种影响仍然显着。在初产妇中没有观察到婴儿喂养选择对皮质醇浓度的影响。虽然几天内持续下降是常见的，但一些母亲的情况是平坦或不一致的，这种情况与婴儿的喂养选择或均等无关。重要的是，状况持续下降的母亲的家庭收入最高。我们的研究结果表明，尽管母乳喂养可能会促进昼夜基础皮质醇分泌的更严格调节，特别是对于可能面临更大家庭需求和孕产妇责任的多胎母亲而言，但社会经济地位的某些方面 (例如收入) 也可以发挥重要作用在昼夜皮质醇分泌的稳定性中跨天。

BACKGROUND & AIMS: OBJECTIVE:To determine whether a reported positive association between parity and the development of non-insulin-dependent diabetes mellitus (NIDDM) and impaired glucose tolerance (IGT) is reproducible in other populations. RESEARCH DESIGN AND METHODS:We investigated the relationship in data from population-based surveys in four Pacific and Indian Ocean island nations. Women greater than or equal to 40 yr of age at the time of the survey, excluding those in whom diabetes developed before 40 yr of age, were included in this study of Micronesians from Nauru (n = 204) and Kiribati (n = 562), Fiji Melanesians (n = 390), Fiji Indians (n = 247), and mixed-ethnic Mauritians (n = 1333). Subjects in each survey underwent a 75-g oral glucose tolerance test, and glucose tolerance status was ascertained with 1985 World Health Organization criteria. Obstetric information and family history of diabetes were determined by interview. RESULTS:Age and body mass index (BMI)-adjusted mean parity increased slightly with worsening glucose tolerance in only two groups, decreased in one group, and was inconsistent in the other two (none were statistically significant). We also found an inconsistent relationship between the number of full-term pregnancies and the prevalence of IGT and NIDDM, although in each population, there was a higher prevalence of NIDDM in the highest parity group (greater than or equal to 10 pregnancies) compared with the lowest parity group (1-3 pregnancies). In logistic regression analyses accounting for age, BMI, and family history of diabetes, odds ratio estimates for NIDDM and IGT associated with each pregnancy were not significantly greater than unity. CONCLUSIONS:The results indicate that there is little if any independent association between parity and the development of abnormal glucose tolerance in these populations.

背景与目标：

BACKGROUND & AIMS: :The 10-item Pregnancy-Related Anxiety Questionnaire-Revised (PRAQ-R) is a widely used instrument to assess and identify pregnancy-specific anxiety in nulliparous women. It has good psychometric values and predictive validity for birth and childhood outcomes. Nonetheless, the PRAQ-R is not designed for use in parous women, as particularly one item of the questionnaire is not relevant for women who gave birth before. We tested the factorial and scalar invariance of a modified PRAQ-R2 across nulliparous and parous women with an adapted item to fit both groups of pregnant women. A longitudinal study among 1144 pregnant women (n = 608 nulliparous and n = 536 parous) with two repeated measures of the PRAQ-R2 was used to test for measurement invariance of the instrument. Results show metric and scalar invariance, indicating that the PRAQ-R2 measures similar constructs on the same scale for all pregnant women at two different times during pregnancy. We conclude that the PRAQ-R2 can be used, compared, or combined in a sample of nulliparous and parous women.

背景与目标： : 经修订的10项妊娠相关焦虑问卷 (praq-r) 是一种广泛使用的工具，可评估和识别未产妇的妊娠特异性焦虑。它对出生和儿童结局具有良好的心理计量学价值和预测效度。尽管如此，praq-r并非设计用于生育妇女，因为调查表中的一项与以前分娩的妇女无关。我们用适合两组孕妇的适应项目测试了未生育和生育妇女的改良PRAQ-R2的阶乘和标量不变性。对1144例孕妇 (n = 608例未产孕妇和n = 536例孕妇) 进行了纵向研究，并对PRAQ-R2进行了两次重复测量，以测试仪器的测量不变性。结果显示了度量和标量不变性，表明该PRAQ-R2在怀孕期间的两个不同时间对所有孕妇在相同规模上测量相似的构建体。我们得出的结论是，该PRAQ-R2可以在未生育和生育妇女的样本中使用，比较或组合。

BACKGROUND & AIMS: :The association between parity and endometrial cancer risk is inconsistent from observational studies. We aimed to quantitatively assess the relationship by summarizing all relevant epidemiological studies. PubMed (MEDLINE), Embase and Scopus were searched up to February 2015 for eligible case-control studies and prospective studies. Random-effects model was used to pool risk estimations. Ten prospective studies, 35 case-control studies and 1 pooled analysis of 10 cohort and 14 case-control studies including 69681 patients were identified. Pooled analysis revealed that there was a significant inverse association between parity and risk of endometrial cancer (relative risk (RR) for parous versus nulliparous: 0.69, 95% confidence interval (CI) 0.65-0.74; I(2) = 76.9%). By evaluating the number of parity, we identified that parity number of 1, 2 or 3 versus nulliparous demonstrated significant negative association (RR = 0.73, 95% CI 0.64-0.84, I(2) = 88.3%; RR = 0.62, 95% CI 0.53-0.74, I(2) = 92.1%; and RR = 0.68, 95% CI 0.65-0.70, I(2) = 20.0% respectively). The dose-response analysis suggested a nonlinear relationship between the number of parity and endometrial cancer risk. The RR decreased when the number of parity increased. This meta-analysis suggests that parity may be associated with a decreased risk of endometrial cancer. Further studies are warranted to replicate our findings.

背景与目标： : 从观察性研究中，产次与子宫内膜癌风险之间的关联是不一致的。我们旨在通过总结所有相关的流行病学研究来定量评估这种关系。对PubMed (MEDLINE)，Embase和Scopus进行了长达2015年2月的搜索，以进行合格的病例对照研究和前瞻性研究。采用随机效应模型进行风险估计。确定了10项前瞻性研究，35项病例对照研究和10项队列研究和14项病例对照研究 (包括69681名患者) 的汇总分析。汇总分析显示，奇偶性与子宫内膜癌风险之间存在显着的负相关 (相对危险度 (RR) 对于非产妇: 0.69，95% 置信区间 (CI) 0.65-0.74; I(2) = 76.9%)。通过评估奇偶校验的数量，我们确定了1、2或3的奇偶校验与未发生时显示出显着的负关联 (RR = 0.73，95% CI 0.64-0.84，I(2)  = 88.3%; RR = 0.62，95% CI 0.53-0.74，I(2)  = 92.1%; 和RR = 0.68，分别95% CI 0.65-0.70，I(2) = 20.0%)。剂量反应分析表明，胎次数与子宫内膜癌风险之间存在非线性关系。当奇偶校验数量增加时，RR降低。这项荟萃分析表明，平价可能与子宫内膜癌的风险降低有关。需要进一步的研究来复制我们的发现。