Association between Metal(loid)Exposure and Risk of Polycystic Ovary Syndrome Mediated by Anti-Müllerian Hormone among Women Undergoing In Vitro Fertilization and Embryo Transfer

Objective To investigate the relationship and potential pathways between metal(loid)exposure and the risk of polycystic ovary syndrome(PCOS)in women of childbearing age.Methods This case-control study included 200 patients with PCOS(cases)and 896 non-PCOS controls with the age of 25-37 years.The concentrations of 29 metal(loid)s in the follicular fluid(FF)and clinical indicators in the serum were measured in all participants.Logistic regression analysis and mediation analysis were conducted to evaluate the associations between metal(loid)exposure and PCOS risk and investigate the possible roles of clinical indicators,respectively.Results Logistic regression analysis revealed an association between high copper levels in FF and increased PCOS risk(highest vs.lowest quartile:adjusted odds ratio=2.94,95%confidence interval:1.83-4.72).A high luteinizing hormone/follicle-stimulating hormone ratio and elevated levels of testosterone and anti-Müllerian hormone(AMH)were strongly associated with increased PCOS risk induced by high copper exposure.The mediation analysis indicated a mediating effect of AMH in the association between copper exposure and PCOS risk.Conclusion Copper may affect PCOS risk through the hypothalamic-pituitary-ovarian axis,mediated by AMH.Copper exposure and internal AMH levels are important indicators for early warning of PCOS development.

Cohort-based long-term ozone exposure-associated mortality risks with adjusted metrics:A systematic review and meta-analysis

Long-term ozone(O_(3))exposure may lead to non-communicable diseases and increase mortality risk.However,cohort-based studies are relatively rare,and inconsistent exposure metrics impair the credibility of epidemiological evidence synthetization.To provide more accurate meta-estimations,this study updates existing systematic reviews by including recent studies and summarizing the quantitative associations between O_(3) exposure and cause-specific mortality risks,based on unified exposure metrics.Cross-metric conversion factors were estimated linearly by decadal observations during 1990-2019.

Contribution of Temperature Increase to Restrain the Transmission of COVID-19

The COVID-19 outbreak has already become a global pandemic and containing this rapid worldwide transmission is of great challenge.The impacts of temperature and humidity on the COVID-19 transmission rate are still under discussion.Here,we elucidated these relationships by utilizing two unique scenarios,repeated measurement and natural experiment,using the COVID-19 cases reported from January 23–February 21,2020,in China.The modeling results revealed that higher temperature was most strongly associated with decreased COVID-19 transmission at a lag time of 8 days.Relative humidity(RH)appeared to have only a slight effect.These findings were verified by assessing SARSCoV-2 infectivity under the relevant conditions of temperature(4
C–37
C)and RH(>40%).We concluded that temperature increase made an important,but not determined,contribution to restrain the COVID19 outbreak in China.It suggests that the emphasis of other effective controlling polices should be strictly implemented to restrain COVID19 transmission in cold seasons.