Cadmium Burden of Residents in High and Low Age Groups in a District of Guangdong

Objectives The aim of this study was to evaluate the cadmium burden level of residents in a district of Guangdong province by using a benchmark dose method to evaluate the relevance of urinary cadmium with urinary β₂-microglobulin (MG) and N-acetyl-β-glucosaminidase (NAG), and to investigate the acceptable threshold for urinary cadmium level of residents in high ( > 50 years) and low (≤50 years) age groups.

Methods An environmental epidemiology study was conducted in a district of Guangdong province. The total number of valid subjects was 872 (375 men and 497 women). The cut-off value for renal dysfunction was defined as a discriminant standard for health hazard caused by environmental cadmium pollution. The benchmark dose was estimated by a BMDS software.

Results The BMDL for NAG was 4.25μg/g creatinine in low age group and 4.05 μg/g creatinine in high age group. The BMDL for β₂MG was 1.70 μg/g creatinine in low age group and 1.58 μg/g creatinine in high age group.

Conclusions In the risk assessment of renal dysfunction caused by cadmium, β₂MG would be a more sensitive biomarker than NAG, and the acceptable threshold for urinary cadmium in high age group was lower than that in low age group. The rate of renal dysfunction in high age group might be higher than that in low age group, which might be the result of long-term cadmium exposure.