Association of blood cadmium concentration with chronic obstructive pulmonary disease progression: a prospective cohort study

Prior studies in patients with chronic obstructive pulmonary disease (COPD) had indicated a potential correlation between cadmium (Cd) exposure and reduction in lung function. Nevertheless, the influence of Cd exposure on the progression of COPD remained unknown. Exploring the relationship between Cd exposure and the progression of COPD was the aim of this investigation. Stable COPD patients were enrolled. Blood samples were collected and lung function was evaluated. Regular professional follow-ups were conducted through telephone communications, outpatient services, and patients' hospitalization records. Each additional unit of blood Cd was associated with upward trend in acute exacerbation, hospitalization, longer hospital stay, and death within 2 years. Even after adjusting for potential confounding factors, each 1 unit rise in blood Cd still correlated with a rise in the frequencies of acute exacerbation, longer hospital stay, and death. Moreover, COPD patients with less smoking amount, lower lung function and without comorbidities were more vulnerable to Cd-induced disease deterioration. Patients with COPD who have higher blood Cd concentration are susceptible to worse disease progression.