Gannan rare earth elements cohort: study design, methods, and baseline characteristics of the cohort.

OBJECTIVE: The Gannan region, known as the "Kingdom of Rare Earths", supplies over 70% of the global demand for medium and heavy rare earth elements (REEs). However, large-scale mining has led to environmental REEs contamination, posing potential health risks to residents. The Gannan REEs Cohort (GREEC) was established to investigate the long-term health effects of REEs exposure. METHODS: GREEC is an ongoing community-based prospective cohort study conducted in two counties of Ganzhou, China. We enrolled 1062 residents aged 18–80 years who had lived in the area for at least five years. At baseline, we collected comprehensive data via questionnaires, physical examinations, and biological samples. Urinary concentrations of 15 REEs were measured using inductively coupled plasma mass spectrometry. Follow-up surveys, including repeated physical examinations and validation of chronic disease endpoints, are planned every three years. RESULTS: The mean age of participants was 50 years, with 78.81% being female. The prevalence of hypertension, dyslipidemia, and diabetes were 34.09%, 31.26%, and 6.40%, respectively. Detectable rates of all rare earth elements in urine were over 75%, with median concentrations ranging from 0.20 ng/L (Tm) to 28.54 ng/L (Nd). Light REEs (La, Ce, Pr, Nd) showed strong positive correlations (e.g., La and Ce: ρ = 0.85), whereas heavy REEs exhibited more complex correlation patterns. CONCLUSION: As the first community-based cohort focusing on residents in heavy REE mining areas, GREEC provides critical baseline data on REEs exposure and cardiometabolic risk profiles. Its longitudinal design and comprehensive data offer a unique platform for elucidating REEs-related health effects and underlying mechanisms.