A Comparison of the Adjustment Methods for Assessing Urinary Concentrations of Cadmium and Arsenic: Creatinine vs. Specific Gravity

Kim, Dong-Kyeong; Song, Ji‐Won; Park, Jung-Duck; Choi, Byung-Sun

doi:10.5668/jehs.2011.37.6.450

“…If the increased Cd level in the body accumulates in the kidney, thus damaging the renal tubules, it increases the activity of urinary NAG and the excretion of β2-MG. Therefore, NAG and β2-MG are useful renal function indicators 16 , 29 , 30 . Thus, because the activity of urinary NAG shows a strong correlation with urinary Cd, it is often used as an indicator of the impact of Cd on the kidneys.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, because the activity of urinary NAG shows a strong correlation with urinary Cd, it is often used as an indicator of the impact of Cd on the kidneys. Additionally, an increase in the excretion of urinary β2-MG is considered as an important indicator of renal damage caused by Cd 29 , 31 – 33 . Therefore, several epidemiologic studies use urinary Cd as an environmental exposure indicator and NAG and β2-MG as indicators of renal tubular function disorders to investigate the impacts of environmental Cd exposure 33 – 35 .…”

Section: Discussionmentioning

confidence: 99%

Association between levels of exposure to heavy metals and renal function indicators of residents in environmentally vulnerable areas

Kwon

¹

,

Lee

²

,

Surenbaatar

³

et al. 2023

Sci Rep

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Abandoned metal mines and refineries are considered environmentally vulnerable areas owing to high levels of exposure to heavy metals. This study examined the association between heavy metal exposure and renal function indicators. We studied a total of 298 participants, of which 74 and 68 resided in low- and high-exposure abandoned metal mine areas, respectively, with 121 in the refinery area and 35 in the control area. Blood and urine samples were collected from the participants to analyze the levels of blood lead, cadmium, and creatinine and urinary cadmium, NAG, and β2-MG. The estimated glomerular filtration rate, which is calculated using the Chronic Kidney Disease Epidemiology Collaboration equation, was used for assessments. The study participants comprised more females than males, and their mean age was 70.3 years. The blood lead and cadmium as well as urinary cadmium levels were 2.12 μg/dL, 1.89 μg/L, and 2.11 μg/L, respectively, in the heavy metal-exposure areas, and 1.18 μg/dL, 0.89 μg/L, and 1.11 μg/L, respectively, in the control area. The odds ratio (OR) for exceeding the reference value showed that blood cadmium in the refinery area was 38 times higher than that in the control area. Urinary cadmium was seven times higher in the low-exposure abandoned metal mine area than in the control area. NAG showed a positive correlation with urinary cadmium in all areas. In the refinery area, correlations were observed between β2-MG and urinary cadmium levels and the eGFR and blood cadmium level; in the high-exposure abandoned metal mine area, correlations were observed between NAG, β2-MG, and the eGFR and blood cadmium. In this study, the association between Cd exposure and some renal function indicators was observed. This study’s findings and the obtained biological samples can serve as a basis for future molecular biological research.

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“…If the increased Cd level in the body accumulates in the kidney, thus damaging the renal tubules, it increases the activity of urinary NAG and the excretion of β2-MG. Therefore, NAG and β2-MG are useful renal function indicators 16,27,28 . Thus, because the activity of urinary NAG shows a strong correlation with urinary Cd, it is often used as an indicator of the impact of Cd on the kidneys.…”

Section: Discussionmentioning

confidence: 99%

Association between levels of exposure to heavy metals and renal function indicators of residents in environmentally vulnerable areas

Kwon

¹

,

Lee

²

,

Surenbaatar

³

et al. 2022

Preprint

1

0

View full text Add to dashboard Cite

Abandoned metal mines and refineries are considered environmentally vulnerable areas owing to high levels of exposure to heavy metals. This study examined the association between heavy metal exposure and renal function indicators. We studied a total of 298 participants, of which 74 and 68 resided in low- and high-exposure abandoned metal mine areas, respectively, with 121 in the refinery area and 35 in the control area. Blood and urine samples were collected from the participants to analyze the levels of blood lead, cadmium, and creatinine and urinary cadmium, NAG, and β2-MG. The estimated glomerular filtration rate, which is calculated using the Chronic Kidney Disease Epidemiology Collaboration equation, was used for assessments. The study participants comprised more females than males, and their mean age was 70.3 years. The blood lead and cadmium as well as urinary cadmium levels were 2.12 μg/dL, 1.89 μg/L, and 2.11 μg/L, respectively, in the heavy metal-exposure areas, and 1.18 μg/dL, 0.89 μg/L, and 1.11 μg/L, respectively, in the control area. The odds ratio (OR) for exceeding the reference value showed that blood cadmium in the refinery area was 38 times higher than that in the control area. Urinary cadmium was seven times higher in the low-exposure abandoned metal mine area than in the control area. NAG showed a positive correlation with urinary cadmium in all areas. In the refinery area, correlations were observed between β2-MG and urinary cadmium levels and the eGFR and blood cadmium level; in the high-exposure abandoned metal mine area, correlations were observed between NAG, β2-MG, and the eGFR and blood cadmium. In this study, the association between Cd exposure and some renal function indicators was observed. This study’s findings and the obtained biological samples can serve as a basis for future molecular biological research.

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“…Notably, the wealth of dilution correction methods currently in use contrasts with a relatively small number of comprehensive comparative studies, and the lack of consistent criteria for the most rational approach is challenging, as this choice may also depend on the specific causal relationships under study. 3,10,13,[32][33][34][35][36][37][38][39][40] Studies comparing diuresis correction methods have yielded contradictory results. In the exposure assessment of arsenic and other elements, several studies found adjustment by specific gravity to induce less bias than CRN.…”

Section: Variable Power Functional Dilution Adjustment Of Spot Urinementioning

confidence: 99%

“…In the exposure assessment of arsenic and other elements, several studies found adjustment by specific gravity to induce less bias than CRN. 3, 35,38,39 In a comparative study, both osmolality and CRN induced a comparably strong collider bias, conferring an erroneous association between arsenic and obesity. 36 Contrary to previous publications, in a recent study, CRN correction outperformed osmolality and specific gravity correction models.…”

Section: Introductionmentioning

confidence: 99%

Variable Power Functional Dilution Adjustment of Spot Urine

Carmine¹

2023

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1

0

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Background Dilution adjustment of spot-urinary biomarkers by conventional creatinine correction (CCRC) remains controversial. Apart from unaccounted confounders like age, sex, muscle mass, or diet, the misperception of constant mass ratios between analyte and creatinine (uCR) over a wide hydration range entails deceptive creatinine correction errors (CRCE), foremost at both ends of the uCR-spectrum. Mitigating CRCE by restricting uCR-ranges to 0.3(0.4)-3 g/L generates high numbers of sample rejects and allows for misleading fluctuations within presumably tolerable uCR-ranges. Methods The CRCE for exemplary total weight Arsenic (TWuAs) was analyzed in a large set of n= 5,599 unselected spot urine samples. After confining data to 14 - 80 years, uncorrected arsenic (uAsUC) < 500 mcg/l, and uCR < 4.5g/L, the remaining 5,400 samples were partitioned, and a calculation method to standardize uAsUC to 1 g/L uCR developed based on uAsUC-stratified power functional regression analysis (PFRA). Findings The obtained standardizing method of variable power-functional creatinine correction (V-PFCRC) represents a progression of reportedly proven simple power-functional modifications of CCRC (S-PFCRC). In contrast to CCRC and S-PFCRC, standardization to 1g/L uCR by V-PFCRC yielded constant uAsN-values over the entire uCR-range in all sextiles. Residual bias was largely neutralized in all sextiles of uAsN (R2 9E-06 - 0.04), compared to uAsUC (R2 0.93 - 0.99) and CCRC (R2 0.42 - 0.89). The efficacy of CRCE compensation was confirmed by simple PFRA in both sexes and seven age bands. The strongest %CRCEs were found in samples at low concentrations of uCR (SBC -0.96) and/or uAsUC (SBC -0.11). Interpretation Standardization to 1g/L uCR by V-PFRA allows for more reliable dilution adjustment of spot urinary results than CCRC and S-PFCRC. As an easily adoptable, novel approach, the calculation method developed in this study can minimize residual dilution bias in urinary biomarkers adjusted by uCR, SG, and osmolality. While minimizing sample rejects, V-PFCRC will improve the reliability and comparability, particularly of lower concentrated urinary biomarkers in both conventional results and multiple linear regression models. Funding Self-funded.

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A Comparison of the Adjustment Methods for Assessing Urinary Concentrations of Cadmium and Arsenic: Creatinine vs. Specific Gravity

Cited by 8 publications

References 33 publications

Association between levels of exposure to heavy metals and renal function indicators of residents in environmentally vulnerable areas

Association between levels of exposure to heavy metals and renal function indicators of residents in environmentally vulnerable areas

Association between levels of exposure to heavy metals and renal function indicators of residents in environmentally vulnerable areas

Variable Power Functional Dilution Adjustment of Spot Urine

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