Exposure to cadmium and lead is associated with diabetic kidney disease in diabetic patients

BACKGROUND

Cadmium (Cd) and lead (Pb) exhibit nephrotoxic activity and may accelerate kidney disease complications in diabetic patients, but studies investigating the relation to diabetic kidney disease (DKD) have been limited. We aimed to examine the associations of Cd and Pb with DKD in diabetic patients.

METHODS

3763 adults with blood metal measurements and 1604 adults with urinary ones who were diabetic from National Health and Nutrition Examination Survey (NHANES) 2007-2016 were involved. Multivariate logistic regression models were used to analyze the associations of blood Cd (BCd), blood Pb (BPb), urinary Cd (UCd), and urinary Pb (UPb) with DKD.

RESULTS

BPb, BCd, and UCd levels were higher among participants with DKD than diabetics without nephropathy, but UPb performed the opposite result. BPb and UCd were significantly associated with DKD in the adjusted models (aOR, 1.17 (1.06, 1.29);1.52 (1.06, 2.02)). Participants in the 2nd and 3rd tertiles of BPb and BCd levels had higher odds of DKD, with a significant trend across tertiles, respectively (all P-trend < 0.005). Multiplication interaction was also identified for BPb and BCd (P for interaction = 0.044).

CONCLUSION

BPb, BCd, and UCd were positively associated with the risk of DKD among diabetic patients. Furthermore, there were the dose-response relationship and multiplication interaction in the associations of BPb, BCd with DKD.

Biological monitoring of urinary lead: Preshift and postshift sampling detects efficiently recent lead exposure and signals the need to review and possibly improve controls at work

The objective of this study is to highlight the effectiveness of urinary lead as an index of recent lead exposure. In the past scientific literature urinary lead has been studied as a parameter for recent lead exposure. It is a reliable indicator for occupational lead exposure. But, strangely enough, nowadays is scarcely used in the Netherlands and worldwide. We performed six field biological monitoring studies of preshift and postshift urinary lead tests during tank maintenance and bridge repair work. Highest values occurred during bridge repair. Mean urinary values were postshift 1,6-5 times higher than preshift values, indicating clearly recent lead exposure and failing protective measures. This is so far we know the first study combining preshift and postshift sampling of urinary lead. We compared our studies with crossectional and follow-up studies in occupational medicine. Our conclusion is that preshift and postshift urinary lead testing is a worker friendly test, ideally for detecting recent lead exposures in the field. It signals the need to review or possibly improve controls at work. There are no safe lead levels, so we recommend to use a target value for urinary lead of <3 μg/g creatinine for all lead workers in the Netherlands.

Lead exposure and its interactions with oxidative stress polymorphisms on lung function impairment: Results from a longitudinal population-based study

Exposure to lead (Pb) and cadmium (Cd) were related to lung function impairment, and this association may be modified by genetic variants in oxidative stress response. Here we enrolled 1243 coke-oven workers in a prospective cohort who were followed up from 2010 to 2014, assessed the associations of Pb and Cd exposure with 4-year lung function impairment, and further explored the interaction effects of Pb with 2664 single nucleotide polymorphisms (SNPs) in 345 oxidative stress related genes. Urinary levels of Pb, Cd, and two oxidative stress biomarkers [8-iso-prostaglandin F2α (8-iso-PGF2α) for lipid peroxidation and 8-hydroxy-2'-deoxyguanosine (8-OHdG) for oxidative DNA damage] were measured at baseline only and their lung function levels were measured both at baseline and at the end of follow-up. Each 10-fold increase in urinary Pb was associated with -159 (95%CI: -254, -64.2) mL and -3.63% (95%CI: -6.48%, -0.78%) changes in FEV₁ and percent predicted FEV₁ (ppFEV₁), respectively. But none significant associations were observed for Cd. NQO1 rs2917670 showed significant interaction with Pb on elevated FEV₁ decline after multiple comparison (P_int=1.54 × 10^-5). In addition, urinary Pb increased with 8-iso-PGF2α and the rs2917670-C could significantly decrease NQO1 expression in normal lung tissues. These findings suggested the gene-environmental interaction of NQO1 rs2917670 and Pb exposure on the reduction of FEV₁. The effect of Pb exposure on elevated oxidative stress and the decreased expression of antioxidant enzyme NQO1 caused by rs2917670-C allele may partly explain the underlying biological mechanism.

A longitudinal study of an international panel

BACKGROUND

Urinary lead (Pb) is generally considered to have limited use in biomonitoring environmental exposure to lead. Carbon load in airway macrophages (AM BC) is an internal marker to assess long-term exposure to combustion-derived aerosol particles. In urban environments, atmospheric Pb and black carbon may have common sources. We aimed to study the temporal change of urinary Pb (U-Pb) when exposure to outdoor air pollution changes, and the relationship between U-Pb and AM BC.

METHODS

A panel of 50 young healthy adults [mean (SD) 26.7 (5.2) years], including 17 long-term (>1 year) residents in Leuven, Belgium (BE), 15 and 18 newcomers (arrived <3 weeks) from low- and middle-income countries (LMIC) and high-income countries (HIC), respectively, underwent 8 repeated measurements at 6 weeks intervals. In urine spot samples obtained at 5 time points (T1, T2, T4, T6, T8), 24 trace elements were quantified by inductively coupled plasma-mass spectrometry. At each time point, AM BC was quantified as the median surface of black inclusions (in μm²) by means of image analysis of 25 macrophages obtained by induced sputum. Changes in urinary metal concentrations (with and without creatinine correction) and the relationship between U-Pb and AM BC were estimated using linear mixed models adjusted for covariates and potential confounders.

RESULTS

Only U-Pb differed between groups and exhibited significant time trends. Participants from the LMIC group had significantly higher initial U-Pb (1.18 μg/g creat) than the HIC group (0.44 μg/g creat) and BE group (0.45 μg/g creat). In the LMIC group, U-Pb decreased significantly with time by 0.061 μg/g creatinine per 30 days [95% confidence interval (CI): 0.034, 0.088]. U-Pb remained unchanged in the other two groups. An increase in AM BC of 1 μm² was associated with an increase in U-Pb of 0.369 μg/g creat (95% CI: 0.145, 0.593).

CONCLUSION

This panel study demonstrates that U-Pb may be a valid alternative to blood Pb for biomonitoring changes in exposure to lead, at least at group level. In addition, we identified a positive association between U-Pb and AM BC, a biomarker of exposure to traffic-related air pollution, suggesting the existence of common sources of Pb and black carbon in urban environments.

Nutritional status and diet as predictors of children's lead concentrations in blood and urine

Lead exposure remains an important public health problem. Contaminated foods may act as a source of lead exposure, while certain nutrients may reduce lead absorption. We examined the cross-sectional associations of dietary patterns and the intake of several nutrients and foods with blood (Pb-B) and urinary (Pb-U) lead concentrations in children (5-8y) from Montevideo, Uruguay. From two 24-hour recalls completed by caregivers, we derived the mean daily intake of select nutrients and food groups (dairy, milk, fruit, root vegetables, foods rich in heme and non-heme iron), as well as "nutrient dense" and "processed" food patterns. Pb-B (n=315) was measured using atomic absorption spectrometry; Pb-U (n=321) using ICP-MS. Pb-U was adjusted for specific gravity and log-transformed to approximate a normal distribution. Iron deficiency (ID) and dietary variables were tested as predictors of Pb-B and log-Pb-U in covariate-adjusted regressions. Median [5%, 95%] Pb-B and Pb-U were 3.8 [0.8-7.8] μg/dL and 1.9 [0.6-5.1] μg/L, respectively; ~25% of Pb-B above current U.S. CDC reference concentration of 5μg/dL. ID was associated with 0.75μg/dL higher Pb-B, compared to non-ID (p<0.05). Consumption of root vegetables was not associated with Pb-B or log-Pb-U. Higher scores on the nutrient-dense pattern were related with higher Pb-Bs, possibly due to consumption of green leafy vegetables. Dietary intake of iron or iron-rich foods was not associated with biomarkers of lead. Conversely, children consuming more calcium, dairy, milk and yogurt had lower Pb-B and log-Pb-U. Our findings appear consistent with existing recommendations on including calcium-rich, but not iron- or vitamin-C-rich foods in the diets of lead-exposed children, especially where the consumption of these foods is low.

Urinary and blood cadmium and lead and kidney function: NHANES 2007-2012

BACKGROUND

Cadmium (Cd) and lead (Pb) are widespread environmental contaminants that are known nephrotoxins. However, their nephrotoxic effects at low-environmental exposure levels are debated.

OBJECTIVE

We examined the association of blood Pb (B-Pb), blood Cd (B-Cd), urinary Pb (U-Pb) and urinary Cd (U-Cd) with estimated glomerular filtration rate (eGFR) and urinary albumin (ALB).

METHODS

We used multivariate linear regression to analyze the association between B-Pb, B-Cd, U-Pb, and U-Cd with eGFR and ALB in adult participants (≥20 years of age) in NHANES 2007-2012. The dataset was limited to NHANES individuals with both blood and urinary metal measurements.

RESULTS

We found a statistically significant inverse association between eGFR and B-Cd and statistically significant positive associations between eGFR and both U-Cd and U-Pb, as well as statistically significant associations between ALB and the 3rd and 4th quartiles of U-Cd.

CONCLUSIONS

The inverse association between eGFR and B-Cd, in conjunction with positive associations between eGFR and ALB with U-Cd, suggest that U-Cd measurement at low levels of exposure may result from changes in renal excretion of Cd due to kidney function and protein excretion. However, renal effects such as hyperfiltration from Cd-mediated kidney damage or creatinine-specific Cd effects cannot be excluded with this cross-sectional design.

Levels and source apportionment of children's lead exposure: could urinary lead be used to identify the levels and sources of children's lead pollution?

As a highly toxic heavy metal, the pollution and exposure risks of lead are of widespread concern for human health. However, the collection of blood samples for use as an indicator of lead pollution is not always feasible in most cohort or longitudinal studies, especially those involving children health. To evaluate the potential use of urinary lead as an indicator of exposure levels and source apportionment, accompanying with environmental media samples, lead concentrations and isotopic measurements (expressed as (207)Pb/(206)Pb, (208)Pb/(206)Pb and (204)Pb/(206)Pb) were investigated and compared between blood and urine from children living in the vicinities of a typical coking plant and lead-acid battery factory. The results showed urinary lead might not be a preferable proxy for estimating blood lead levels. Fortunately, urinary lead isotopic measurements could be used as an alternative for identifying the sources of children's lead exposure, which coincided well with the blood lead isotope ratio analysis.