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

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--d-glucosaminidase (NAG) and -2-microglobulin ((2)MG) 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 1.55g/g creatine in men and 1.59g/g creatine in women. Using (2)MG as the renal effect marker, BMDL10 of UCd was 1.58g/g and 1.53g/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.