The Risk Factors of Blood Cadmium Elevation in Chronic Kidney Disease

Abstract

Low-level cadmium exposure has adverse effects on chronic kidney disease (CKD); however, the risk factors for elevated blood cadmium levels (BCLs) have not been studied in CKD. We conducted a cross-sectional investigation in 200 CKD patients and stratified them by the tertiles of BCL to compare their demographic, environmental, and biochemical data. The factors associated with BCL were identified, and their effects were examined in subgroups. In the analyses, female sex, smoking, and CKD stage 5D were associated with high BCL, and statin was inversely correlated with BCL (odds ratio [95% confidence interval, CI], 6.858 [2.381-19.746], p < 0.001, 11.719 [2.843-48.296], p = 0.001, 30.333 [2.252-408.520], p = 0.010, and 0.326 [0.122-0.873], p = 0.026; deviations of BCL [nmol/L, 95% CI], 2.66 [1.33-4.00], p < 0.001, 3.68 [1.81-5.56], p < 0.001, 3.38 [0.95-5.82], p = 0.007, and -2.07 [-3.35--0.78], p = 0.002). These factors were also independently correlated with BCL in subgroups, including non-dialysis CKD, hypertensive patients, non-smokers, and male patients. In conclusion, female sex, smoking, and CKD stage 5D were the major risk factors for elevated BCL; additionally, statins were negatively associated with BCL in CKD.

Keywords: cadmium; chronic kidney disease; risk factors.

Figure 1

Forest Plots of BCL Associated Factors in CKD patients. (a) Middle BCL vs. Low BCL assessed by multinomial logistic regression analysis; (b) High BCL vs. Low BCL assessed by multinomial logistic regression analysis. Age, diabetes, and covariates with a p value ≤ 0.05 in univariate analyses were adjusted for analysis. Anti-HTN ≥ 3, antihypertensives ≥ 3 types; BCL, blood cadmium level; CKD, chronic kidney disease; CKD 5D, chronic kidney disease stage 5D; CKD 4–5, chronic kidney disease stage 4–5; CI, confidence interval; OR, odds ratio.

Figure 2

The Effects of BCL Associated Factors in Specific Subgroups. (a) Statin effects in subgroups; (b) CKD Stage 5D effects in subgroups; (c) female sex effects in subgroups; (d) smoking effects in subgroups. The numbers of specific subgroups were: ND-CKD (n = 179), male sex (n = 129), non-smokers (n = 174), and HTN (n = 171), respectively. HTN, hypertension; ND-CKD, non-dialysis CKD.