Background: Methylmercury (MeHg) is an environmental pollutant of global public health concern. MeHg is associated with immune dysfunction but the underlying mechanisms are unclear. The most common route of MeHg exposure is through consumption of fatty fish that contain beneficial n-3 polyunsaturated fatty acids (PUFA) that may protect against MeHg toxicity. Objectives: To better inform individual costs and benefits of fish consumption, we aimed to identify candidate epigenetic biomarkers of biological responses that reflect MeHg toxicity and PUFA protection. Methods: We profiled genome-wide DNA methylation using Illumina Infinium MethylationEPIC BeadChip in whole blood from N=32 individuals from Madre de Dios, Peru. Madre de Dios has high artisanal and small-scale gold mining activity, which results in high MeHg exposure to nearby residents. We compared DNA methylation in N=16 individuals with high (>10 μg/g) vs. N=16 individuals with low (<1 μg/g) total hair mercury (a proxy for methylmercury exposure), matched on age and sex. Results: We identified hypomethylated (i.e., likely activated) genes and promoters in high vs. low MeHg-exposed participants linked to Th1/Th2 immune imbalance, decreased IL-7 signaling, and increased marginal zone B cells. These three pathways are feasible mechanisms for MeHg-induced autoimmunity. In addition, we identified candidate epigenetic biomarkers of PUFA-mediated protection: hypomethylated enhancer binding sites for retinoid X receptor (RXR) and retinoic acid receptor α (RARα). Last, we observed hypomethylated enhancer and promoter binding sites for glucocorticoid receptor (GR), which is associated with developmental neurotoxicity, and transcription factor 7-like 2 (TCF7L2), which is associated with type 2 diabetes (T2D) risk. Discussion: Here, we identify a set of candidate epigenetic biomarkers for assessing individualized risk of autoimmune response and protection against neurotoxicity due to MeHg exposure and fish consumption. In addition, our results may inform surrogate tissue biomarkers of early MeHg exposure-related neurotoxicity and T2D risk.

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Background Brazil has a high burden of cervical cancer, even though it is preventable, traceable and treatable. Hence, this study evaluated levels of knowledge, attitudes and practices (KAP) related to cervical cancer screening and diagnosis and acceptance of self-screening techniques among women aged 24 and greater. Methods A cross-sectional KAP survey was administered to n = 4206 women and spanned questions relating to cervical cancer, HPV, speculum, Pap test and colposcopy. Questionnaire was disseminated through a major hospital’s social media platforms, intranet and gynecologic-oncology clinics. Logistic regressions evaluated associations between sociodemographic characteristics and knowledge, attitudes, and preventative behaviors against cervical cancer. Participants indicated willingness to try DNA-HPV self-sampling and cervix self-visualization (self-colposcopy). Findings Participants were mostly white individuals (70.5%) with higher education and from social classes A and B. They demonstrated superior levels of KAP than described in the literature, with over 57.8% having answered 80+% of questions correctly. KAP scores were predicted by social class, educational attainment, race, history of premalignant cervical lesions and geographic location. About 80% and 63% would be willing to try DNA-HPV self-sampling and cervix self-visualization, respectively. Interest in self-screening was associated with adequate attitude (OR = 1.85) and inadequate practice (OR = .83). Interpretation Adequate KAP are fundamental for the successful implementation of a self-screening program. Participants were interested in methods that provide them with greater autonomy, control and practicality. Self-screening could address barriers for under-screened women such as shame, discomfort, distance from clinics and competing commitments, enabling Brazil to reach the WHO’s cervical cancer elimination goals. It could also decrease excess medical intervention in over-screened populations by promoting shared decision-making.

Conclusions Although this reflects the correlation between poor performance status and likelihood of treatment, unresectability of disease may reflect geographical variation in timely diagnosis. Further work is needed to determine the impact of these factors on local 5-year survival rates.