Publications by authors named "Katie M O'Brien"

Genome-wide association studies have identified approximately 200 genetic risk loci for breast cancer, but the causal variants and target genes are mostly unknown. We sought to fine-map all known breast cancer risk loci using genome-wide association study data from 172,737 female breast cancer cases and 242,009 controls of African, Asian and European ancestry. We identified 332 independent association signals for breast cancer risk, including 131 signals not reported previously, and for 50 of them, we narrowed the credible causal variants down to a single variant.

View Article and Find Full Text PDF

Background: Early-life trauma (before age 18) is hypothesized to increase risk for adverse pregnancy outcomes through stress pathways, yet epidemiologic findings are mixed.

Methods: Sister Study participants (U.S.

View Article and Find Full Text PDF
Article Synopsis
  • Elevated mammographic density increases the risk of breast cancer, and understanding how changes in density over time contributes to this risk is crucial, especially considering factors like family history and menopause.
  • In a study with 323 breast cancer cases and 899 controls, researchers found that cases had higher initial mammographic density and a slower decline in density compared to controls, suggesting that stable and increasing density levels are linked to a greater risk of breast cancer.
  • The stronger association between mammographic density changes and cancer risk was observed in pre-menopausal women and those with lower familial risk, indicating the relevance of monitoring density changes over time for assessing breast cancer risk.
View Article and Find Full Text PDF

A better understanding of the factors contributing to systemic concentrations of carotenoids is necessary given the weak correlations between circulating levels and dietary intake of carotenoids. Although genetic variation may play a key role in the interindividual variability in carotenoid concentrations, few genome-wide association studies (GWAS) have focused on carotenoids. We used a random sample ( = 519) of postmenopausal participants in the Sister Study with data on genotypes and plasma carotenoid levels to conduct GWAS for each of five carotenoids (mcg/mL): alpha-carotene, beta- carotene, cryptoxanthin, lycopene, and lutein/zeaxanthin.

View Article and Find Full Text PDF

Purpose: To determine the relationship between germline pathogenic variants (PV) in cancer predisposition genes and the risk of ductal carcinoma in situ (DCIS).

Experimental Design: Germline PV frequencies in breast cancer predisposition genes (ATM, BARD1, BRCA1, BRCA2, CDH1, CHEK2, PALB2, RAD51C, and RAD51D) were compared between DCIS cases and unaffected controls and between DCIS and invasive ductal breast cancer (IDC) cases from a clinical testing cohort (n = 9,887), a population-based cohort (n = 3,876), and the UK Biobank (n = 2,421). The risk of contralateral breast cancer (CBC) for DCIS cases with PV was estimated in the population-based cohort.

View Article and Find Full Text PDF
Article Synopsis
  • Pathogenic variants (PVs) in certain genes like BRCA1 and BRCA2 increase breast cancer risk, but it's unclear how risk varies based on the type and location of these variants.
  • This study analyzed breast cancer risks associated with different PV types and locations using data from 12 US studies and clinical cohorts involving over 64,000 women.
  • Results showed that women with specific exon PTVs had higher breast cancer risks, lower rates of ER-negative breast cancer, and were diagnosed at younger ages compared to those with other variants, with these patterns observed across multiple cohorts.
View Article and Find Full Text PDF
Article Synopsis
  • - The study aimed to enhance breast cancer risk modeling by integrating pathogenic variants (PVs) in specific genes, a polygenic risk score (PRS), and an epidemiologic risk score (ERS) using data from over 23,000 breast cancer cases and controls.
  • - The results showed that postmenopausal women with no PVs but high ERS had a 4.4-fold increase in breast cancer risk, while some CHEK2 PV carriers had a predicted lifetime risk below 20%, indicating potential over-screening in certain groups.
  • - The findings suggest that combining these risk factors can improve risk assessment and possibly lead to more tailored screening and prevention strategies for breast cancer.
View Article and Find Full Text PDF

Variable importance is a key statistical issue in exposure mixtures, as it allows a ranking of exposures as potential targets for intervention, and helps to identify bad actors within a mixture. In settings where mixtures have many constituents or high between-constituent correlations, estimators of importance can be subject to bias or high variance. Current approaches to assessing variable importance have major limitations, including reliance on overly strong or incorrect constraints or assumptions, excessive model extrapolation, or poor interpretability, especially regarding practical significance.

View Article and Find Full Text PDF

Uterine fibroids and endometriosis may be associated with an increased risk of ovarian cancer. Less is known about the role of hysterectomy in these associations. We estimated the independent and joint associations of hysterectomy, fibroids, and endometriosis with ovarian cancer incidence in the prospective Sister Study cohort (2003-2009).

View Article and Find Full Text PDF

Background And Aims: There are few known risk factors for inflammatory bowel disease (IBD), an autoimmune disease characterized by chronic intestinal inflammation. Use of specific pesticides has been associated with higher incidence of IBD among pesticide applicators and their spouses, but no study has examined pesticide exposure in early life, a period where the human immune system undergoes rapid changes. We evaluated pesticide use during childhood and adolescence and incidence of IBD among US women enrolled in the Sister Study.

View Article and Find Full Text PDF
Article Synopsis
  • Scientists looked at the timing of when girls start their periods (called menarche) and how it can affect their health later in life.
  • They studied about 800,000 women and found over a thousand genetic signals that influence when menstruation starts.
  • Some women have a much higher chance of starting their periods too early or too late based on their genetic makeup, suggesting that genes play a big role in this process!
View Article and Find Full Text PDF

Background: Hair products may be a source of harmful chemicals and have been linked to age-related health outcomes. We investigated whether the use of hair products is related to epigenetic age in a sample of Black (both Hispanic and non-Hispanic) and non-Hispanic White women.

Methods: In a subset of 4358 participants aged 35-74 years from the Sister Study, we estimated cross-sectional associations between self-reported use of four chemical hair products (permanent dye, semipermanent dye, straighteners/relaxers, and hair permanents/body waves) in the year before enrollment (2003-2009) and three DNA methylation-based measures of epigenetic age (DunedinPACE, GrimAge age acceleration [GrimAgeAccel], and PhenoAge age acceleration [PhenoAgeAccel]) using survey-weighted multivariable linear regressions.

View Article and Find Full Text PDF
Article Synopsis
  • The study examined the relationship between tea and coffee consumption and the incidence of biliary tract cancer (BTC) using data from 15 studies.
  • Drinking tea was linked to a lower risk of gallbladder cancer (GBC) and possibly intrahepatic bile duct cancer (IHBDC), while coffee consumption was associated with a higher risk of GBC.
  • The findings suggest that tea might be protective against certain types of BTC, whereas coffee could increase the risk of GBC, warranting further investigation into these associations.
View Article and Find Full Text PDF

Purpose: Intimate care products may contain substances associated with increased risk of hormone-related cancers. The relationship between genital talc use and ovarian cancer, in particular, has been well studied, but concerns about recall bias and exposure misclassification have precluded conclusions. We examined the association between intimate care products and female hormone-related cancers, accounting for potential biases, using data from a US-based cohort study.

View Article and Find Full Text PDF
Article Synopsis
  • - The study analyzed genetic factors linked to breast cancer in a diverse sample of 18,034 African ancestry cases and 22,104 controls, identifying 12 genetic variants tied to increased risk.
  • - Key findings included a rare variant (rs61751053) associated with overall breast cancer risk (odds ratio 1.48) and a common variant (rs76664032) connected to triple-negative breast cancer (odds ratio 1.30).
  • - A polygenic risk score (PRS) showed a predictive capability (0.60 area under the curve) for breast cancer risk, illustrating improved accuracy compared to PRS based on European data and highlighting the significance of diversity in genetic research.
View Article and Find Full Text PDF

African-ancestry (AA) participants are underrepresented in genetics research. Here, we conducted a transcriptome-wide association study (TWAS) in AA female participants to identify putative breast cancer susceptibility genes. We built genetic models to predict levels of gene expression, exon junction, and 3' UTR alternative polyadenylation using genomic and transcriptomic data generated in normal breast tissues from 150 AA participants and then used these models to perform association analyses using genomic data from 18,034 cases and 22,104 controls.

View Article and Find Full Text PDF

Purpose: Higher pre-diagnosis physical activity (PA) is associated with lower all-cause mortality in breast cancer (BCa) patients. However, the association with pathological complete response (pCR) is unclear. We investigated the association between pre-diagnosis PA level and chemotherapy completion, dose delay, and pCR in BCa patients receiving neoadjuvant chemotherapy (NACT).

View Article and Find Full Text PDF
Article Synopsis
  • The study investigates how seasonal changes may affect the accuracy of toenail measurements of various metals and trace elements, which is important for epidemiological research on long-term health effects.
  • Conducted with participants from the Sister Study, the research analyzed toenail clippings for elements like iron, aluminum, and lead, finding significant seasonal trends, particularly peaking around mid-August for many elements.
  • The findings emphasize the need to adjust for these seasonal variations in future studies to enhance the precision of health outcome associations linked to trace element exposure.
View Article and Find Full Text PDF

Background: A high body mass index (BMI, kg/m) is associated with decreased risk of breast cancer before menopause, but increased risk after menopause. Exactly when this reversal occurs in relation to menopause is unclear. Locating that change point could provide insight into the role of adiposity in breast cancer etiology.

View Article and Find Full Text PDF

Importance: Changes in leukocyte composition often precede chronic disease onset. Patients with a history of breast cancer (hereinafter referred to as breast cancer survivors) are at increased risk for subsequent chronic diseases, but the long-term changes in peripheral leukocyte composition following a breast cancer diagnosis and treatment remain unknown.

Objective: To examine longitudinal changes in peripheral leukocyte composition in women who did and did not develop breast cancer and identify whether differences in breast cancer survivors were associated with specific treatments.

View Article and Find Full Text PDF

Background: Outdoor air pollution is a ubiquitous exposure that includes endocrine-disrupting and carcinogenic compounds that may contribute to the risk of hormone-sensitive outcomes such as uterine cancer. However, there is limited evidence about the relationship between outdoor air pollution and uterine cancer incidence.

Methods: We investigated the associations of residential exposure to particulate matter less than 2.

View Article and Find Full Text PDF

Background: Some personal care products (PCPs) contain endocrine-disrupting chemicals that may affect breast cancer (BC) risk. Patterns of use vary by race and ethnicity. Use often starts in adolescence, when rapidly developing breast tissue may be more susceptible to environmental carcinogens.

View Article and Find Full Text PDF