Blood chromium and lung function among Chinese young adults: A comprehensive analysis based on epidemiology and metabolomics.

Chromium (Cr) exposure is associated with various respiratory system diseases, but there are limited studies investigating its impact on lung function in young adults. The Cr exposure-related metabolomic changes are not well elucidated. This study recruited 608 students from a university in Shandong Province, China in 2019. We used cohort design fitted with linear mixed-effects models to assess the association between blood Cr concentration and lung function. In addition, we performed metabolomic and lipidomic analyses of baseline serum samples (N = 582) using liquid chromatography-mass spectrometry. Two-step statistical analysis (analysis of variance and mixed-linear effect model) was used to evaluate the effect of blood Cr exposure on metabolites. We found that blood Cr was associated with decreased lung function in young adults. Each 2-fold increase in blood Cr concentrations was significantly associated with decreased FEV1 and FVC by 35.26 mL (95 % CI: -60.75, -9.78) and 38.56 mL (95 % CI: -66.60, -10.51), respectively. In the metabolomics analysis, blood Cr exposure was significantly associated with 14 key metabolites. The changed metabolites were mainly enriched in six pathways including lipid metabolism, amino acid metabolism, and cofactor vitamin metabolism. Blood Cr may affect lung function through oxidative stress and inflammation related pathways.

Exposure to blue space surroundings and depressive symptoms in young Chinese adults: The mediating role of sleep.

OBJECTIVE: Existing evidence suggests that the natural environment can influence mental health. However, limited research has focused on the relationship between blue space and depressive symptoms in young adults. To investigate the association between blue space surroundings and depressive symptoms in young adults in China and explore the underlying mechanisms. METHODS: The study was conducted between September and November 2019, including 2,743 young adults from China. We assessed the exposure to blue space around participants' living environments during June, July, and August 2019 using the Modified Normalized Difference Water Index (MNDWI). Blue indexes were calculated for 300 m, 1000 m, and 3000 m circular buffer zones near residential environments. Logistic regression models were employed to explore the associations between blue space exposures (quartiles) and depressive symptoms, exploring potential mechanisms through structural equation modeling (SEM), while accounting for potential confounders. Stratification analysis was used to identify sensitive populations. RESULTS: Depressive symptoms were found in 148 (5.3%) of the 2,743 young adults in the study. We observed a negative correlation between depressive symptoms and average MNDWIs at participants' addresses (OR: 0.84; 95%CI: 0.72-0.98), within 300m (OR: 0.81; 95%CI: 0.70-0.95), 1000m (OR: 0.80; 95%CI: 0.69-0.93), and 3000m (OR:0.77; 95%CI: 0.66-0.89) buffer zones. Within the 1000m buffer zone, sleep was found to mediate 21% of the relationship between the presence of blue space and depressive symptoms. The stratified analysis revealed a stronger association between low MNDWI levels within the 1000m buffer zone and depressive symptoms in females (P < 0.05). Additionally, average MNDWI levels within the 3000m buffer zone were associated with depressive symptoms in both females and males. CONCLUSIONS: Blue space could improve depressive symptoms, particularly in females, with sleep playing a mediating role. Incorporating blue spaces into environmental planning is important for improving mental health.