Long-term inhalation exposure to manganese (Mn) metal or its inorganic compounds can result in manganism or subclinical neurofunctional deficits. Studies have described affected workers in Mn dioxide mining, Mn-containing ore crushing and milling facilities, manufacturing of dry-cell batteries, Mn steel and alloy production plants, and in welders. The objective of this study was to critically review existing evidence on the reliability of potential biomarkers of Mn exposure, specifically the relationship between inhalation exposure to Mn particulates in different occupational settings and Mn concentrations in blood and other biological fluids and tissues, with a particular focus on whole blood as a potentially useful medium for measuring internal tissue dose. We also examined available evidence on the relationship between Mn levels in blood and adverse clinical and subclinical neurotoxic outcomes. Three bibliographic databases were searched for relevant studies and identified references were screened by two independent reviewers. Of the 6338 unique references identified, 76 articles were retained for data abstraction. Findings indicate that the relationships between Mn in blood and both external Mn exposure indices and neurofunctional impairments are limited and inconsistent. Different sources of exposure to Mn compounds, heterogeneity in the methodological approaches, and inadequate reporting of essential information limited direct comparison of the reported findings. Among the Mn-exposure biomarkers considered in this review – including biomarkers in blood, plasma, serum, erythrocytes, urine, bone, toenails, fingernails, hair, saliva – biomarkers in whole blood may provide to be most useful in Mn biomonitoring and risk assessment.

Over the past four decades, there has been increasing concern that perineal use of talc powder, a commonly used personal care product, might be associated with an increased risk of ovarian cancer. To critically review all available human epidemiological data on the relationship between perineal use of talc powder and ovarian cancer, with consideration of other relevant experimental evidence. We identified 30 human studies for qualitative assessment of evidence, including 27 that were retained for further quantitative analysis. A positive association between perineal use of talc powder and ovarian cancer was found [OR: 1.28 (95% CI: 1.20-1.37)]. A significant risk was noted in Hispanics and Whites, in women applying talc to underwear, in pre-menopausal women and in post-menopausal women receiving hormonal therapy. A negative association was noted with tubal ligation. Perineal use of talc powder is a possible cause of human ovarian cancer.

We conducted a critical review on biomarkers of environmental manganese (Mn) exposure to answer the following questions: 1) are there reliable biomarkers of internal Mn exposure (Mn in biological matrices) associated with external metrics of Mn exposure (Mn in environmental media)? and 2) are there accurate reference values (RVs) for Mn in biological matrices? Three bibliographic databases were searched for relevant references and identified references were screened by two independent reviewers. Of the 6342 unique references identified, 86 articles were retained for data abstraction. Our analysis of currently available evidence suggests that Mn levels in blood and urine are not useful biomarkers of Mn exposure in non-occupational settings. The strength of the association between Mn in environmental media and saliva was variable. Findings regarding the utility of hair Mn as a biomarker of environmental Mn exposure are inconsistent. Measurements of Mn in teeth are technically challenging and findings on Mn in tooth components are scarce. In non-occupationally exposed individuals, bone Mn measurements using in vivo neutron activation analysis (IVNAA) are associated with large uncertainties. Findings suggest that Mn in nails may reflect Mn in environmental media and discriminate between groups of individuals exposed to different environmental Mn levels, although more research is needed. Currently, there is no strong evidence for any biological matrix as a valid biomarker of Mn exposure in non-occupational settings. Because of methodological limitations in studies aimed at derivation of RVs for Mn in biological materials, accurate RVs are scarce.

The potential association between major adverse cardiovascular events (MACE) and concomitant treatment with proton pump inhibitors (PPIs) and clopidogrel has been debated since 2009. Recent reports, however, suggest that PPIs may increase the risk of MACE independently of clopidogrel. This review evaluates epidemiological findings relevant to the association between PPIs, taken alone or concomitantly with antiplatelets, and the risk of MACE. A systematic review and meta-analysis were conducted. Relevant studies were identified from MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials and then screened. Included studies were categorized into three groups: Group A: PPIs versus no PPIs; Group B: combined PPIs and clopidogrel versus clopidogrel alone; Group C: combined PPIs and other drugs versus other drugs. Pooled risk ratios (RRs) were calculated for each outcome of interest in each comparison group. Of the 1667 studies identified, 118 were included in the systematic review, of which 66 were included in the meta-analyses. Among Group A observational studies, RRs for MACE outcomes were statistically significant for some patient populations but not others. Pooled RRs from Group A RCTs were not statistically significant for any outcome. Pooled RRs for Group B observational studies were statistically significant for all-cause mortality and MI, but were diminished in magnitude when pooling was restricted to propensity score matched studies or post hoc analyses of RCTs. Group C studies did not demonstrate an association with MACE. Findings do not consistently support an association between MACE and PPIs when taken alone, or concomitantly with antiplatelets.