[Blood cadmium level and the change of cadmium exposure risk in Chinese urban school-age children in 2002 and 2012].

Objective: To investigate the blood cadmium concentrations and the related change in Chinese urban children derived from the China Nutrition and Health Survey 2002 and 2012(CNHS 2002 and CNHS 2012).

Methods: The Chinese urban children aged 6-11 years were selected according to gender, age and regional distribution using the multi-stage stratified cluster random sampling method, as well as the corresponding whole blood samples. The blood cadmium concentration was carefully determined by the quadrupole inductively coupled plasma mass spectrometry(ICP-MS) and the percentage of blood cadmium over 2 μg/L was subsequently estimated. In addition, the upper limit values of the 95%CI of the 95th percentiles of available blood cadmium data was assessed as the threshold of cadmium exposure.

Results: Totally, 2182 Chinese urban children were included, and of these, 1036 children were from the CNHS 2002 and 1146 children were from the CNHS 2012. From the CNHS 2002 to the CNHS 2012, the median blood cadmium concentration was increased from 0.28 μg/L to 0.95 μg/L, and the percentage of blood cadmium with over 2 μg/L was elevated from 1.45% to 10.47%. In addition, the new estimated threshold of blood cadmium was ascended from 1.24 μg/L up to 2.89 μg/L.

Conclusion: The risk of cadmium exposure in Chinese urban children aged 6-11 years was increasingly aggravated from the CHNS 2002 to the CNHS 2012.