Whole blood cadmium levels and depressive symptoms in Chinese young adults: A prospective cohort study combing metabolomics

To investigate the association between Cd exposure and depressive symptoms in Chinese young adults. And to investigate the potential metabolic changes associated with high blood Cd concentrations. We conducted a cohort study in 2019 and 2021. Blood Cd and depressive symptoms were collected during baseline and follow-up. The nine-item Patient Health Questionnaire (PHQ-9) scores were used to assess depressive symptoms. We used the generalized linear mixed model to estimate the association between blood Cd levels and depressive symptoms. A metabolomic and lipidomic analysis based on liquid chromatography-mass spectrometry was conducted on a total of 679 blood samples. The metabolomic data were analyzed using variance analysis and linear mixed effects models. Blood Cd concentrations were significantly associated with increased severity of depression symptoms [odds ratio (OR) 2.07, 95% confidence interval (CI) 1.04–4.11]. Metabolomics analysis found 93 metabolites with significant statistical differences between the lowest blood Cd level group and the highest Cd level group. Among the 93 differential metabolites, 17 were enriched in 7 differential metabolic pathways. Blood Cd was associated with increased severity of depression symptoms in Chinese young adults. Cd exposure may affect depressive symptoms by inducing oxidative stress, and inflammation, and disrupting amino acid metabolism. Our study evaluated the health effects of Cadmium (Cd). Cd is being discarded in our water, soil, and into the atmosphere due to the rapidly growing agriculture and metal industries. Cd in the environment can enter the human body through inhalation, skin contact, and ingestion of Cd-rich food and water. Cd has an extremely long biological half-life in the body, lasting approximately 20-30 years, and it has various adverse effects on the human body. Even though strict environmental pollution legislations have been implemented in China, the blood Cd exposure levels remain unclear.