The burden of chronic kidney disease associated with dietary exposure to cadmium in China, 2020

Cadmium (Cd) exposure increases the risk of chronic kidney disease (CKD). But the contribution of dietary Cd intake, the primary exposure route of Cd in humans, to the CKD burden remains to be evaluated in China. Concentrations of Cd in foods and population glomerular filtration rate (GFR) were retrieved from studies published between January 2000 and February 2023 in China. Daily food consumption in adults aged ≥35 years old was obtained from two nationwide Chinese surveys. Dietary Cd intake and its contribution rate among total Cd exposure from diet, inhalation, smoking and water were evaluated. Urinary Cd (UCd) was estimated using the toxicokinetic (TK) model based on dietary Cd intake. The effect of Cd on kidney function has been quantified with the previously published dose-response relationship between UCd and GFR. The incidence and disability-adjusted life years (DALYs) of CKD attributable to dietary Cd intake were derived considering the contribution rate of dietary Cd intake at the national and provincial levels. The national average dietary Cd intake was 0.6891 μg/kg bw/day, contributing 63.69% of total Cd exposure. The Cd exposure through foods resulted in 2.34 (95% uncertainty interval, UI: 1.54–3.40) stage 4 CKD and 0.37 (95% UI: 0.20–0.59) stage 5 CKD cases per 100,000 persons/year in mainland China, 2020. The corresponding DALYs loss associated with stage 4 and stage 5 CKD due to dietary Cd intake were 5.14 (95% UI: 3.24–7.67) and 4.78 (95% UI: 2.32–8.30) per 100,000 persons/year, together accounting for 2% of total DALYs of CKD. Greater dietary Cd intake and corresponding burden of late-stage CKD were observed in Southern areas than in Northern areas. Diet remains the primary exposure to Cd in Chinese adults. Efforts to reduce dietary Cd exposure would positively impact public health, especially in Southern provinces with high Cd exposure.