Sex and age disparities in multi-metal mixture exposure and cognitive impairment in urban elderly individuals: The mediation effect and biological function of metabolites.

Studies on the relationships between metal mixtures exposure and cognitive impairment in elderly individuals are limited, particularly the mechanism with metabolite. Few studies are available on the potential sex and age specific associations between metal exposure, metabolites and cognitive impairment. We examined plasma metal and blood metabolite concentrations among 1068 urban elderly participants. Statistical analysis included a battery of variable selection approaches, logistic regression for metal/metabolite associations, and Bayesian kernel machine regression (BKMR) to identify mixed effects of metals/metabolites on cognitive impairment risk. Our results showed that As was positively associated with cognitive impairment in the female (OR 95 % CI = 2.21 (1.36, 3.57)) and 60- to 70-year-old (OR 95 % CI = 2.60 (1.54, 4.41)) groups, Cr was positively associated with cognitive impairment in the male (OR 95 % CI = 2.15 (1.27, 3.63)) and 60- to 70-year-old (OR 95 % CI = 2.10 (1.24, 3.57)) groups, and Zn was negatively associated with cognitive impairment, especially in the female (OR 95 % CI = 0.46 (0.25, 0.84)), 60- to 70-year-old (OR 95 % CI =0.24 (0.12, 0.45)) and ≥ 80-year-old (OR 95 % CI = 0.19 (0.04, 0.86)) groups. Positive associations were observed between combined metals (Cr, Cu and As) and cognitive impairment, but Zn alleviated this tendency, especially in elderly individuals aged ≥80 years. Negative associations were observed between metabolites and cognitive impairment, especially in male, female and 60-70 years old groups. The mediation effects of metabolites on the association between metal exposure and cognitive impairment were observed, and the percentages of these effects were 15.60 % (Glu-Cr), 23.00 % (C5:1-Cu) and 16.36 % (Glu-Zn). Cr, Cu, and Zn could increase cognitive impairment risk through the "Malate-Aspartate Shuttle", "Glucose-Alanine Cycle", etc., pathways. Overall, we hypothesize that metabolites have mediation effects on the relationship between multi-metal exposure and cognitive impairment and that there are sex and age differences.

How Covid-19 impacts the financing in SMEs: Evidence from private firms.

The world economy, and SMEs in particular, have been hit hard by the COVID-19 epidemic. SME finance issues are becoming a significant focus of policymakers and academics. This research uses private companies as a sample to analyze how COVID-19 affected SME finance. We examine critical factors such as business size, leverage, profitability, liquidity, and the influence of COVID-19. Our research shows that the pandemic has had a significant, detrimental impact on funding for small and medium-sized businesses. Small and medium-sized enterprises (SMEs) have expanded their borrowing amid falling profits and cash flow. More specifically, smaller SMEs have been hit harder than their bigger counterparts. Implications for policymakers and the owners of SMEs are substantial. Governments should help small and medium-sized enterprises by providing incentives like tax credits and loan guarantees. Owners of small and medium-sized enterprises (SMEs) should prioritize sound financial management and stability. This research sheds light on SMEs' funding difficulties in the wake of COVID-19 and highlights the need to aid such businesses as rebuild.