Association of blood cadmium levels and all-cause mortality among adults with rheumatoid arthritis: The NHANES cohort study

Background: The potential impact of environmental cadmium exposure on the prognosis of patients with rheumatoid arthritis (RA) remains unclear, despite its known association with various adverse health outcomes. Methods: In this study, a total of 1285 RA patients were included in the National Health and Nutrition Examination Survey (NHANES) conducted between 2003 and 2016. The Cox regression model was employed to investigate the relationship between blood cadmium levels and the risk of all-cause mortality in RA patients. Results: During a mean follow-up duration of 105.9 months, 341 patient deaths were recorded. After adjusting for multiple factors, elevated blood cadmium was strongly correlated with an increased risk of all-cause mortality in patients with RA. With one unit rise in natural logarithm-transformed blood cadmium concentrations, the risk of patient death increased by 107%. The adjusted hazard ratios for each quartile of blood cadmium demonstrated a significant upward trend (P < 0.001). A linear dose-response relationship of blood cadmium concentrations with all-cause mortality was also distinctive (P < 0.001). Consistent findings were ascertained when conducting stratified analyses by age, gender, race, education level, body mass index, smoking status, and drinking status. Conclusions: Elevated blood cadmium levels may serve as a risk factor for increased death risk in RA patients.