The way that males and females react to environmental exposures and negative impacts on their neurological systems is often different. Although previous research has examined the cognitively impairing effects of solitary metal exposures, the relationship between metal mixtures and cognitive function, particularly when considering an individual’s sex, remains elusive. This study aimed to investigate the sex differences in the association between multiple metal combinations and cognitive function in older Americans. This research employed the 2011–2014 NHANES survey of elderly Americans. The association between five mixed metals and four cognitive tests (the animal fluency test (AFT), the digit symbol substitution test (DSST), the instant recall test (IRT), and the delayed recall test (DRT)) were investigated with generalized linear regression model (GLM), Bayesian kernel machine regression model (BKMR), weighted quantile sum regression model (WQS), and quantile g-computation regression model (Qgcomp). A total of 1833 people, including 883 males and 950 females, enrolled in this cross-sectional study. We discovered that blood lead and blood cadmium were negatively associated with cognitive performance, while blood selenium demonstrated a positive association with cognitive function in older people. The negative relationship of heavy metal combinations on cognitive function might be somewhat reduced or even reversed via selenium. The IRT, AFT, and DSST are three of the four cognitive tests where men had more dramatic positive or negative results. There was a sex-specific connection between blood metal ratios and cognitive function among older Americans, as evidenced by the more significant relationship between mixed metals and cognitive performance in men (either positively or negatively). These results emphasize the impacts of ambient heavy metal exposure on cognitive function by employing sex-specific methods.

Dioxin-like compounds (DLCs), which have anti-estrogenic properties that disturb estrogen equilibrium in women, have also been associated with increased mortality risk in relevant epidemiological studies. The purpose of this study was to evaluate the differences in the association between serum DLCs and all-cause mortality among non-menopausal and menopausal female populations. Adults who participated in the 1999–2004 National Health and Nutrition Examination Survey (NHANES) were included. In this study, serum concentrations of 9 DLCs (5 DL-PCBs, 2 PCDDs, and 2 PCDFs) were determined. Participants were observed until December 31, 2019. Stratified analyses were conducted based on sex to investigate sex differences in the association of DLCs with mortality risk. Menstrual stratified analyses were performed to evaluate the characteristics of changes in above association among women before and after menopause. Final analysis, 3,523 individuals participated in the study, including 1656 men and 1867 female. Out of the subsequent period of 55,650 person-years, 916 fatalities occurred. A group of seven compounds, namely PCB74, PCB105, PCB118, PCB156, HXCDD, OCDD, and PNCDF, exhibited a significant association with the overall mortality risk in the subject population. Both males and females were at higher risk of mortality from exposure to PCB74, PNCDF, with females being more susceptible. PCB156 and HXCDD were the DLCs that had a positive association with all-cause mortality risk in non-menopausal women.PCB074, PCB105, PCB118, PCB156, and OCDD were the DLCs that had a positive association with all-cause mortality risk in naturally menopausal women.PCB066, PCB074, PCB105, PCB118, PCB156, OCDD, and PNCDF were positively related with all-cause mortality risk in menopausal women who had undergone hysterectomy. Adult population exposure to DLCs corresponds to an increased risk of mortality; in truth, exposure at even low levels raises the probability of death. Women, particularly those who have gone through menopause, are more susceptible to DLCs exposure.