Rationale, Study Design, and Cohort Characteristics for the Markers for Environmental Exposures (MEE) Study

Abstract

Environmental factors have been linked to many diseases and health conditions, but reliable assessment of environmental exposures is challenging. Developing biomarkers of environmental exposures, rather than relying on self-report, will improve our ability to assess the association of such exposures with disease. Epigenetic markers, most notably DNA methylation, have been identified for some environmental exposures, but identification of markers for additional exposures is still needed. The rationale behind the Markers for Environmental Exposures (MEE) Study was to (1) identify biomarkers, especially epigenetic markers, of environmental exposures, such as pesticides, air/food/water contaminants, and industrial chemicals that are commonly encountered in the general population; and (2) support the study of potential relationships between environmental exposures and health and health-related factors. The MEE Study is a cross-sectional study with potential for record linkage and follow-up. The well-characterized cohort of 400 postmenopausal women has generated a repository of biospecimens, including blood, urine, and saliva samples. Paired data include an environmental exposures questionnaire, a breast health questionnaire, dietary recalls, and a food frequency questionnaire. This work describes the rationale, study design, and cohort characteristics of the MEE Study. In addition to our primary research goals, we hope that the data and biorepository generated by this study will serve as a resource for future studies and collaboration.

Association of Glyphosate Exposure with Blood DNA Methylation in a Cross-Sectional Study of Postmenopausal Women

“…Recruitment, questionnaires, and specimen collection were described in detail previously. 65 Briefly, women were recruited from 2017 to 2019 via two recruitment arms: targeted mailings to members of the Athena Breast Health Network (a cohort of women receiving screening mammograms at University of California, Irvine health facilities), and untargeted recruitment from the broader community via flyers, social media, events, and word of mouth. The study was designed to identify epigenetic markers for factors potentially related to breast cancer risk; thus, women with a personal history of breast cancer or mastectomy were excluded from the study.…”

“…Specimens were collected and processed as previously described. 65 Briefly, participants self-collected first-morning urine samples on 2 d within a 10-d period not known to them in advance to capture their typical behaviors and exposures. Urine samples were stored in a freezer ( ) until they could be transported to the laboratory.…”

Association of mammographic density with blood DNA methylation

“…Study participants were postmenopausal women between the ages of 45–66 with no personal history of breast cancer or mastectomy and for whom a mammogram report indicating mammographic density was available within the last 3 years (N = 385). Recruitment, questionnaires, and specimen collection and processing were described previously [ 32 ]. Women were considered postmenopausal if they had not had a menstrual cycle for 1 year or more.…”