Kidney disease
Is everyday low-level cadmium exposure linked to kidney damage?
Open access · cc by · source: Europe PMC
In ordinary US adults, higher cadmium levels well below occupational safety limits went along with more albumin leaking into the urine, though urinary cadmium was not linked to reduced kidney filtration.
Study at a glance
- Design
- Cross-sectional — Secondary analysis of four pooled NHANES cycles (1999-2006) in US adults; blood and urinary cadmium compared with eGFR-defined CKD and albuminuria using survey-weighted logistic regression adjusted for age, sex, race/ethnicity and BMI, plus ROC curves.
- N
- N=5426 · 5426 adults aged 20 or over from the NHANES urine subsample with both cadmium and kidney measures; pregnant or menstruating women excluded.
- Population
- Non-institutionalised US civilian adults aged 20 years and over in NHANES 1999-2006.
- Outcome
- Chronic kidney disease (eGFR below 60 mL/min/1.73 m2) and albuminuria (raised urinary albumin-to-creatinine ratio).
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
Blood cadmium above 1 mcg/L was linked to higher odds of both CKD (odds ratio 1.48) and albuminuria (odds ratio 1.41). Urinary cadmium above 1 mcg/g was linked to albuminuria (odds ratio 1.63) but not to CKD (odds ratio 0.70, not significant). Smokers had roughly double the cadmium levels of non-smokers, and cotinine correlated with blood cadmium. As a screening marker cadmium was weak: the area under the ROC curve for CKD was only 0.62 for urinary and 0.60 for blood cadmium.
Methodology
The authors pooled four cycles of the US National Health and Nutrition Examination Survey (1999-2006) and analysed 5426 adults who had cadmium measured in both blood (a marker of recent exposure) and urine (a marker of long-term body burden). They defined chronic kidney disease as an estimated glomerular filtration rate below 60 and albuminuria as a raised albumin-to-creatinine ratio in urine. Survey-weighted logistic regression adjusted for age, sex, race/ethnicity and body mass index compared people above and below 1 unit of cadmium, and ROC curves tested how well cadmium levels separated people with and without kidney problems.
Limitations
Because NHANES measures everyone once, the study cannot show that cadmium caused the kidney changes; reduced kidney function could itself alter cadmium handling, and albuminuria was usually measured only once so it may not be chronic. The regression did not adjust for smoking even though smoking is a major cadmium source, and there was no adjustment for diabetes or hypertension. Urinary cadmium levels were close to the detection limit, and classic markers of cadmium tubular damage such as beta-2-microglobulin were not available. The AUROC values around 0.6 mean cadmium is a poor individual-level predictor.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
Cadmium is a plausible kidney toxicant, but it predicts individual cases poorly.
Cadmium exposure is associated with kidney damage in two very different populations: in US NHANES adults, blood cadmium above 1 mcg/L went with higher odds of CKD (OR 1.48) and albuminuria (OR 1.41); in endemic Sri Lankan districts, urinary cadmium was higher in CKD of uncertain cause than in controls and rose with disease stage.
Evidence for the claim as stated.
Cadmium is a plausible kidney toxicant, but it predicts individual cases poorly.
Cadmium exposure is associated with kidney damage in two very different populations: in US NHANES adults, blood cadmium above 1 mcg/L went with higher odds of CKD (OR 1.48) and albuminuria (OR 1.41); in endemic Sri Lankan districts, urinary cadmium was higher in CKD of uncertain cause than in controls and rose with disease stage.
Scope note — Cross-sectional, not adjusted for smoking, diabetes or hypertension; ROC AUC about 0.6.
Limits the claim's scope: a different population, assay, or outcome.
Urinary cadmium behaves differently across settings: in NHANES it was linked to albuminuria but not to low-eGFR CKD (OR 0.70, not significant), while in Sri Lanka it rose with CKD stage. The populations, exposure levels and case definitions (eGFR-based versus albuminuria-based, with an eGFR equation not validated in South Asians) differ, so this is a difference of scope rather than a direct conflict.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
Urinary cadmium behaves differently across settings: in NHANES it was linked to albuminuria but not to low-eGFR CKD (OR 0.70, not significant), while in Sri Lanka it rose with CKD stage. The populations, exposure levels and case definitions (eGFR-based versus albuminuria-based, with an eGFR equation not validated in South Asians) differ, so this is a difference of scope rather than a direct conflict.
Related papers in this topic
Same topic cluster — not a recommendation engine.