Mediation analysis of the alcohol-postmenopausal breast cancer relationship by sex hormones in the EPIC cohort.

Alcohol consumption is associated with higher risk of breast cancer (BC); however, the biological mechanisms underlying this association are not fully elucidated, particularly the extent to which this relationship is mediated by sex hormone levels. Circulating concentrations of estradiol, testosterone, their free fractions and sex-hormone binding globulin (SHBG), were examined in 430 incident BC cases and 645 matched controls among alcohol-consuming postmenopausal women nested within the European Prospective Investigation into Cancer and Nutrition. Mediation analysis was applied to assess whether individual hormone levels mediated the relationship between alcohol intake and BC risk. An alcohol-related hormonal signature, obtained by partial least square (PLS) regression, was evaluated as a potential mediator. Total (TE), natural direct and natural indirect effects (NIE) were estimated. Alcohol intake was positively associated with overall BC risk and specifically with estrogen receptor-positive tumors with respectively TE = 1.17(95%CI: 1.01,1.35) and 1.36(1.08,1.70) for a 1-standard deviation (1-SD) increase of intake. There was no evidence of mediation by sex steroids or SHBG separately except for a weak indirect effect through free estradiol where NIE = 1.03(1.00,1.06). However, an alcohol-related hormonal signature negatively associated with SHBG and positively with estradiol and testosterone was associated with BC risk (odds ratio [OR] = 1.25 [1.07,1.47]) for a 1-SD higher PLS score, and had a statistically significant NIE accounting for a mediated proportion of 24%. There was limited evidence of mediation of the alcohol-BC association by individual sex hormones. However, a hormonal signature, reflecting lower levels of SHBG and higher levels of sex steroids, mediated a substantial proportion of the association.

Hypertensive disorders of pregnancy and cardiovascular disease risk: a Mendelian randomisation study.

OBJECTIVE: Observational studies show that hypertensive disorders of pregnancy (HDPs) are related to unfavourable maternal cardiovascular disease (CVD) risk profiles later in life. We investigated whether genetic liability to pre-eclampsia/eclampsia and gestational hypertension is associated with CVD risk factors and occurrence of CVD events. METHODS: We obtained genetic associations with HDPs from a genome-wide association study and used individual participant data from the UK Biobank to obtain genetic associations with CVD risk factors and CVD events (defined as myocardial infarction or stroke). In our primary analysis, we applied Mendelian randomisation using inverse-variance weighted regression analysis in ever pregnant women. In sensitivity analyses, we studied men and nulligravidae to investigate genetic liability to HDPs and CVD risk without the ability to experience the underlying phenotype. RESULTS: Our primary analysis included 221 155 ever pregnant women (mean age 56.8 (SD 7.9) years) with available genetic data. ORs for CVD were 1.20 (1.02 to 1.41) and 1.24 (1.12 to 1.38) per unit increase in the log odds of genetic liability to pre-eclampsia/eclampsia and gestational hypertension, respectively. Furthermore, genetic liability to HDPs was associated with higher levels of systolic and diastolic blood pressure and younger age at hypertension diagnosis. Sensitivity analyses revealed no statistically significant differences when comparing the findings with those of nulligravidae and men. CONCLUSIONS: Genetic liability to HDPs is associated with higher CVD risk, lower blood pressure levels and earlier hypertension diagnosis. Our study suggests similar findings in ever pregnant women, nulligravidae and men, implying biological mechanisms relating to HDPs are causally related to CVD risk.

Sex Differences in the Primary Prevention of Cardiovascular Diseases in a Dutch Primary Care Setting.

Background: Sex differences in the primary prevention of cardiovascular diseases (CVD) have been shown, but the evidence is mixed and fragmented. In this study, we assessed sex differences in cardiovascular risk factors assessment, risk factor levels, treatment, and meeting of treatment targets, within a Dutch primary care setting. Methods: Data were obtained from individuals aged 40 to 70 years old, without prior CVD, registered during the entire year in 2018 at one of the 51 general practices participating in the Julius General Practitioner's Network (JGPN). History of CVD was defined based on the International Classification of Primary Care (ICPC). Linear and Poisson regressions were used to investigate sex differences in risk factor assessment, risk factor levels, treatment, and meeting of treatment targets. Results: We included 83,903 individuals (50% women). With the exception of glycated hemoglobin (HbA1c), all risk factors for CVD were more often measured in women than in men. Lipid measurements and body mass index values were higher in women, while blood pressure (BP) and HbA1c levels were higher in men, along with estimated glomerular filtration rate (eGFR) levels. Among individuals with elevated BP or cholesterol levels, no sex difference was observed in the prescription of antihypertensive medications (RR 1.00, 95% CI: 0.94-1.06) but women were less likely than men to receive lipid-lowering medications (RR 0.87, 95% CI: 0.79-0.95). Among treated individuals, women were more likely than men to meet adequate levels of blood pressure (RR 1.17, 95% CI: 1.09-1.25) and less likely to meet target levels of cholesterol (RR 0.90, 95% CI: 0.83-0.98). Conclusion: While women were more likely to have their CVD risk factors measured, they were less likely to be prescribed lipid-lowering medications and to meet target levels. When treated, men were less likely to achieve adequate blood pressure control.

X chromosome inactivation skewing is common in advanced carotid atherosclerotic lesions in females and predicts secondary peripheral artery events.

BACKGROUND AND AIM: Sex differences in atherosclerosis have been described with female plaques being mostly perceived as stable and fibrous. Sex-specific mechanisms such as mosaic loss of the Y chromosome in men have been linked to cardiovascular health. In women, X-linked mechanisms such as X chromosome inactivation (XCI) skewing is common in several tissues. Yet, information on the role of XCI in female atherosclerotic plaques is lacking. Here, we investigated the presence of XCI skewing in advanced atherosclerotic lesions and its association with cardiovascular risk factors, histological plaque data, and clinical data. METHODS: XCI skewing was quantified in 154 atherosclerotic plaque and 55 blood DNA samples of women included in the Athero-Express study. The skewing status was determined performing the HUMARA assay. Then, we studied the relationship of XCI skewing in female plaque and cardiovascular risk factors using regression models. In addition, we studied if plaque XCI predicted plaque composition, and adverse events during 3-years follow-up using Cox proportional hazard models. RESULTS: XCI skewing was detected in 76 of 154 (49.4%) plaques and in 27 of 55 (67%) blood samples. None of the clinical risk factors were associated with plaque skewing. Plaque skewing was more often detected in plaques with a plaque hemorrhage (OR [95% CI]: 1.44 [1.06-1.98], P = 0.02). Moreover, skewed plaques were not associated with a higher incidence of composite and major events but were specifically associated with peripheral artery events during a 3-year follow-up period in a multivariate model (HR [95%CI]: 1.46 [1.09-1.97]; P = 0.007). CONCLUSIONS: XCI skewing is common in carotid plaques of females and is predictive for the occurrence of peripheral artery events within 3 years after carotid endarterectomy.

Sex-differences have been observed in the development of atherosclerosis between men and women. Women tend to have more stable and fibrous plaques compared to men. Sex-specific mechanisms such as mosaic loss of the Y chromosome in men, were associated with cardiovascular health. In women, despite X-linked mechanisms like X chromosome inactivation (XCI) skewing was identified in various tissues. However, its relationship with atherosclerosis has not yet been investigated. In our study, we explored if prevalence of XCI skewing in advanced atherosclerotic lesions related to cardiovascular risk factors, histological plaque data, and clinical information. We found that XCI skewing was present in approximately 50% of human plaques, particularly those with plaque hemorrhage. Interestingly, we did not find any notable relationship between plaque skewing and clinical risk factors. However, we found that XCI was more present in women with peripheral artery events during the 3 years period following carotid endarterectomy. In summary, our findings indicate that XCI skewing is commonly observed in carotid plaques among females and may serve as a predictive factor for the occurrence of peripheral artery events within 3 years after carotid endarterectomy.

Cigarette smoking and risk of histological subtypes of epithelial ovarian cancer in the EPIC cohort study.

New data regarding a positive association between smoking and risk of epithelial ovarian cancer (EOC), especially the mucinous tumor type, has started to emerge. The purpose of this study was to examine the association between different measures of smoking exposures and subtypes of EOC in a large cohort of women from 10 European countries. The European Prospective Investigation into Cancer and Nutrition (EPIC) cohort is a multicenter prospective study initiated in 1992. The questionnaires included data about dietary, lifestyle, and health factors. Information about cigarette smoking was collected from individuals in all participating countries. We used Cox proportional hazard regression models to estimate hazard ratio (HR) of EOC overall and serous, mucinous, and endometroid histological subtypes, with 95% confidence intervals (CIs) associated with different measures of smoking exposures adjusting for confounding variables. Altogether 836 incident EOC cases were identified among 326,831 women. The tumors were classified as 400 serous, 83 mucinous, 80 endometroid, 35 clear cell, and 238 unspecified. Compared with never smokers, current smokers had a significantly increased risk for mucinous tumors [HR = 1.85 (95% CI 1.08-3.16)] and those smoking more than 10 cigarettes per day had a doubling in risk [HR = 2.25(95% CI 1.26-4.03)] as did those who had smoked less than 15 pack-years of cigarettes [HR = 2.18 (95% CI 1.07-4.43)]. The results from the EPIC study add further evidence that smoking increases risk of mucinous ovarian cancer and support the notion that the effect of smoking varies according to histological subtype.

A New Pipeline for the Normalization and Pooling of Metabolomics Data.

Pooling metabolomics data across studies is often desirable to increase the statistical power of the analysis. However, this can raise methodological challenges as several preanalytical and analytical factors could introduce differences in measured concentrations and variability between datasets. Specifically, different studies may use variable sample types (e.g., serum versus plasma) collected, treated, and stored according to different protocols, and assayed in different laboratories using different instruments. To address these issues, a new pipeline was developed to normalize and pool metabolomics data through a set of sequential steps: (i) exclusions of the least informative observations and metabolites and removal of outliers; imputation of missing data; (ii) identification of the main sources of variability through principal component partial R-square (PC-PR2) analysis; (iii) application of linear mixed models to remove unwanted variability, including samples' originating study and batch, and preserve biological variations while accounting for potential differences in the residual variances across studies. This pipeline was applied to targeted metabolomics data acquired using Biocrates AbsoluteIDQ kits in eight case-control studies nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Comprehensive examination of metabolomics measurements indicated that the pipeline improved the comparability of data across the studies. Our pipeline can be adapted to normalize other molecular data, including biomarkers as well as proteomics data, and could be used for pooling molecular datasets, for example in international consortia, to limit biases introduced by inter-study variability. This versatility of the pipeline makes our work of potential interest to molecular epidemiologists.

The MYO9B gene is a strong risk factor for developing refractory celiac disease.

BACKGROUND & AIMS: Celiac disease (CD) is associated with HLA-DQ2 and HLA-DQ8 and has been linked to genetic variants in the MYO9B gene on chromosome 19. HLA-DQ2 homozygosity is associated with complications of CD such as refractory celiac disease type II (RCD II) and enteropathy-associated T-cell lymphoma (EATL). We investigated whether MYO9B also predisposes to RCD II and EATL. METHODS: Genotyping of MYO9B and molecular HLA-DQ2 typing were performed on 62 RCD II and EATL patients, 421 uncomplicated CD patients, and 1624 controls. RESULTS: One single nucleotide polymorphism in MYO9B showed a significantly different allele distribution in RCD II and EATL patients compared with controls (P = .00002). The rs7259292 T allele was significantly more frequent in RCD II and EATL patients compared with CD patients (P = .0003; odds ratio [OR], 3.61; 95% confidence interval [CI], 1.78-7.31). The frequency of the haplotype carrying the T allele of this single nucleotide polymorphism was significantly increased in RCD II and EATL patients (11%), compared with controls (2%) and CD patients (3%) (OR, 6.76; 95% CI, 3.40-13.46; P = 2.27E-09 and OR, 4.22; 95% CI, 1.95-9.11; P = .0001, respectively). Both MYO9B rs7259292 and HLA-DQ2 homozygosity increase the risk for RCD II and EATL to a similar extent when compared with uncomplicated CD patients (OR, 4.3; 95% CI, 1.9-9.8 and OR, 5.4; 95% CI, 3.0-9.6, respectively), but there was no evidence for any interaction between these 2 risk factors. CONCLUSIONS: We show that both MYO9B and HLA-DQ2 homozygosity might be involved in the prognosis of CD and the chance of developing RCD II and EATL.

Demographic, lifestyle, and other factors in relation to antimüllerian hormone levels in mostly late premenopausal women.

OBJECTIVE: To identify reproductive, lifestyle, hormonal, and other correlates of circulating antimüllerian hormone (AMH) concentrations in mostly late premenopausal women. DESIGN: Cross-sectional study. SETTING: Not applicable. PATIENT(S): A total of 671 premenopausal women not known to have cancer. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Concentrations of AMH were measured in a single laboratory using the picoAMH ELISA. Multivariable-adjusted median (and interquartile range) AMH concentrations were calculated using quantile regression for several potential correlates. RESULT(S): Older women had significantly lower AMH concentrations (≥40 [n = 444] vs. <35 years [n = 64], multivariable-adjusted median 0.73 ng/mL vs. 2.52 ng/mL). Concentrations of AMH were also significantly lower among women with earlier age at menarche (<12 [n = 96] vs. ≥14 years [n = 200]: 0.90 ng/mL vs. 1.12 ng/mL) and among current users of oral contraceptives (n = 27) compared with never or former users (n = 468) (0.36 ng/mL vs. 1.15 ng/mL). Race, body mass index, education, height, smoking status, parity, and menstrual cycle phase were not significantly associated with AMH concentrations. There were no significant associations between AMH concentrations and androgen or sex hormone-binding globulin concentrations or with factors related to blood collection (e.g., sample type, time, season, and year of blood collection). CONCLUSION(S): Among premenopausal women, lower AMH concentrations are associated with older age, a younger age at menarche, and currently using oral contraceptives, suggesting these factors are related to a lower number or decreased secretory activity of ovarian follicles.

Methylome analysis and epigenetic changes associated with menarcheal age.

Reproductive factors have been linked to both breast cancer and DNA methylation, suggesting methylation as an important mechanism by which reproductive factors impact on disease risk. However, few studies have investigated the link between reproductive factors and DNA methylation in humans. Genome-wide methylation in peripheral blood lymphocytes of 376 healthy women from the prospective EPIC study was investigated using LUminometric Methylation Assay (LUMA). Also, methylation of 458877 CpG sites was additionally investigated in an independent group of 332 participants of the EPIC-Italy sub-cohort, using the Infinium HumanMethylation 450 BeadChip. Multivariate logistic regression and linear models were used to investigate the association between reproductive risk factors and genome wide and CpG-specific DNA methylation, respectively. Menarcheal age was inversely associated with global DNA methylation as measured with LUMA. For each yearly increase in age at menarche, the risk of having genome wide methylation below median level was increased by 32% (OR:1.32, 95%CI:1.14-1.53). When age at menarche was treated as a categorical variable, there was an inverse dose-response relationship with LUMA methylation levels (OR(12-14 vs. ≤11 yrs):1.78, 95%CI:1.01-3.17 and OR(≥15 vs. ≤11 yrs):4.59, 95%CI:2.04-10.33; P for trend<0.0001). However, average levels of global methylation as measured by the Illumina technology were not significantly associated with menarcheal age. In locus by locus comparative analyses, only one CpG site had significantly different methylation depending on the menarcheal age category examined, but this finding was not replicated by pyrosequencing in an independent data set. This study suggests a link between age at menarche and genome wide DNA methylation, and the difference in results between the two arrays suggests that repetitive element methylation has a role in the association. Epigenetic changes may be modulated by menarcheal age, or the association may be a mirror of other important changes in early life that have a detectable effect on both methylation levels and menarcheal age.