Estimation of the reference level of urinary cadmium by using hybrid method in cadmium-polluted and non-polluted areas in China

ABSTRACT

This study investigated the reference level of urinary cadmium (UCd) of two Cd-polluted areas and one non-polluted area in China by applying the updated hybrid approach. Urinary N-acetyl-β-d-glucosaminidase (NAG) and β-2-microglobulin (β₂MG) were considered as indicators of early renal dysfunction. UCd was regarded as an indicator of the total internal Cd exposure. We recruited 3285 inhabitants for this investigation. Among them, 2106 were from polluted areas, while the other 1179 were from non-polluted areas. BMDL₁₀ (the lower 95% confidence limit of the benchmark dose (BMD)) of UCd for NAG was 1.55 μg/g creatine in men and 1.59 μg/g creatine in women. Using β₂MG as the renal effect marker, BMDL₁₀ of UCd was 1.58 μg/g and 1.53 μg/g in men and women, respectively. Our BMDL estimates accounting for age were lower than those reported in previous studies, suggesting that policies to control Cd exposure are warranted.

KEYWORDS:

• urinary cadmium
• NAG
• β₂MG
• renal dysfunction
• hybrid method

Conclusions

Our BMDL estimates accounting for age were lower than those reported in previous studies, suggesting that policies to control Cd exposure are warranted.

Funding

This study was financially supported by Special Funds of the State Environmental Protection Public Welfare Industry (201309049) and National Key Technology R&D Program of the Ministry of Science and Technology of China (2013BAI12B03). Ethical approval was obtained from the Ethical Committee in Beijing Jiaotong University.