The relationship between blood pressure and environmental exposure to lead and cadmium in Belgium

Public and occupational health risks related to lead exposure updated according to present-day blood lead levels

Lead is an environmental hazard that should be addressed worldwide. Over time, human lead exposure in the western world has decreased drastically to levels comparable to those among humans living in the preindustrial era, who were mainly exposed to natural sources of lead. To re-evaluate the potential health risks associated with present-day lead exposure, a two-pronged approach was applied. First, recently published population metrics describing the adverse health effects associated with lead exposure at the population level were critically assessed. Next, the key results of the Study for Promotion of Health in Recycling Lead (SPHERL; NCT02243904) were summarized and put in perspective with those of the published population metrics. To our knowledge, SPHERL is the first prospective study that accounted for interindividual variability between people with respect to their vulnerability to the toxic effects of lead exposure by assessing the participants' health status before and after occupational lead exposure. The overall conclusion of this comprehensive review is that mainstream ideas about the public and occupational health risks related to lead exposure urgently need to be updated because a large portion of the available literature became obsolete given the sharp decrease in exposure levels over the past 40 years.

Interpretation of Population Health Metrics: Environmental Lead Exposure as Exemplary Case

Our objective was to gain insight in the calculation and interpretation of population health metrics that inform disease prevention. Using as model environmental exposure to lead (ELE), a global pollutant, we assessed population health metrics derived from the Third National Health and Nutrition Examination Survey (1988 to 1994), the GBD (Global Burden of Disease Study 2010), and the Organization for Economic Co-operation and Development. In the National Health and Nutrition Examination Survey, the hazard ratio relating mortality over 19.3 years of follow-up to a blood lead increase at baseline from 1.0 to 6.7 µg/dL (10th–90th percentile interval) was 1.37 (95% CI, 1.17–1.60). The population-attributable fraction of blood lead was 18.0% (10.9%–26.1%). The number of preventable ELE-related deaths in the United States would be 412 000 per year (250 000–598 000). In GBD 2010, deaths and disability-adjusted life-years globally lost due to ELE were 0.67 million (0.58–0.78 million) and 0.56% (0.47%–0.66%), respectively. According to the 2017 Organization for Economic Co-operation and Development statistics, ELE-related welfare costs were $1 676 224 million worldwide. Extrapolations from the foregoing metrics assumed causality and reversibility of the association between mortality and blood lead, which at present-day ELE levels in developed nations is not established. Other issues limiting the interpretation of ELE-related population health metrics are the inflation of relative risk based on outdated blood lead levels, not differentiating relative from absolute risk, clustering of risk factors and exposures within individuals, residual confounding, and disregarding noncardiovascular disease and immigration in national ELE-associated welfare estimates. In conclusion, this review highlights the importance of critical thinking in translating population health metrics into cost-effective preventive strategies.

Relation of blood cadmium, lead, and mercury levels to biomarkers of lipid peroxidation in premenopausal women

Exposures to cadmium, lead, and mercury are associated with adverse health effects, including cardiovascular disease, which may be promoted by lipid peroxidation. The authors examined cadmium, lead, and mercury in relation to plasma levels of F(2)-8α isoprostanes (isoprostane), 9-hydroperoxy-10,12-octadecadienoic acid (9-HODE), 13-hydroxy-9,11-octadecadienoic acid (13-HODE), and thiobarbituric acid reactive substances (TBARS) in 252 women from western New York State (2005-2007). Healthy premenopausal women were followed for ≤2 menstrual cycles, with biomarkers of lipid peroxidation being assessed ≤8 times per cycle. Metals were measured at baseline in whole blood. Linear mixed models were used to estimate the association between cadmium, lead, and mercury and lipid peroxidation biomarkers. Median cadmium, lead, and mercury levels were 0.30 μg/L, 0.86 μg/dL, and 1.10 μg/L, respectively. Blood cadmium, lead, and mercury were not associated with increases in isoprostane, TBARS, 9-HODE, or 13-HODE levels. Isoprostane levels decreased 6.80% (95% confidence interval: -10.40, -3.20) per 1% increase in mercury. However, after adjustment for a simulated strong confounding factor, such as precisely measured fish consumption, the observed association was attenuated, suggesting that this unexpected association could be attributable to unmeasured confounding. In this population of healthy premenopausal women with low exposure levels, cadmium, lead, and mercury were not associated with elevated lipid peroxidation biomarkers.

Cadmium levels in urine and mortality among U.S. adults

BACKGROUND

Cadmium exposure has been associated with increased all-cause, cancer, and cardiovascular disease mortality. However, studies investigating this association have included participants with considerably higher levels of cadmium than those found in the general population.

OBJECTIVE

We aimed to evaluate the association of creatinine-corrected urinary cadmium levels with all-cause and cause-specific mortality in the U.S. general population.

METHODS

We analyzed the relationship between cadmium measured in 13,958 adults who participated in the Third National Health and Nutrition Examination Survey in 1988-1994 and were followed through 31 December 2000, and all-cause, cancer, cardiovascular disease, and coronary heart disease mortality.

RESULTS

The geometric mean levels of urinary cadmium per gram of urinary creatinine in study participants were 0.28 and 0.40 microg/g for men and women, respectively (p < 0.001). After multivariable adjustment, including smoking, a major source of cadmium exposure in nonoccupationally exposed populations, the hazard ratios [95% confidence interval (CI)] for all-cause, cancer, cardiovascular disease, and coronary heart disease mortality associated with a 2-fold higher creatinine-corrected urinary cadmium were, respectively, 1.28 (95% CI, 1.15-1.43), 1.55 (95% CI, 1.21-1.98), 1.21 (95% CI, 1.07-1.36), and 1.36 (95% CI, 1.11-1.66) for men and 1.06 (95% CI, 0.96-1.16), 1.07 (95% CI, 0.85-1.35), 0.93 (95% CI, 0.84-1.04), and 0.82 (95% CI, 0.76-0.89) for women.

CONCLUSIONS

Environmental cadmium exposure was associated with an increased risk of all-cause, cancer, and cardiovascular disease mortality among men, but not among women. Additional efforts are warranted to fully explain gender differences on the impact of environmental cadmium exposure.

Determination of Pb and Cd in road dusts over the period in which Pb was removed from petrol in the UK

It is commonly agreed that automobile exhaust has been the most important source of Pb pollution in urban areas, and that Cd may come from wear and tear of tyres. This study evaluates the fall in Pb concentrations in road dusts in Manchester as a consequence of the removal of Pb from petrol in January 2000. In the work presented here a slurry graphite furnace atomic absorption methodology for the determination of Pb and Cd in road dusts has been developed and is compared with an acid digestion method in terms of efficiency. The reproducibility and accuracy of the results obtained by acid digestion and the slurry method have been studied and a certified reference material CRM 038 was analysed to confirm the reliability of the proposed methods. Different factors were evaluated throughout this work including: (i) the effect of traffic density on Pb and Cd levels in road dust samples collected weekly during the period of May 1999 until September 2000; (ii) comparison between the Pb and Cd levels in a busy road and a residential street; (iii) the effect of distance from the source on Pb and Cd levels; The results of these experiments show a reduction in Pb levels over the sampling period. The relationship between road dust particle size and Pb and Cd concentration was also investigated in the 4-250 microns size range using the slurry method, showing that there is a relationship between metal concentration and particle size; the highest concentrations being for the smallest particle size.

Effects of chronic lead and cadmium exposure on blood pressure in occupationally exposed workers

An epidemiological study was performed to assess whether the occupational exposure to lead or cadmium is associated with an increase in blood pressure. Blood lead levels were determined in 36 male subjects who were occupationally exposed to lead, whereas urinary cadmium concentrations were determined in 40 male workers who were employed in cadmium pigment and resin factories from Barcelona (Spain). Blood lead and urine cadmium concentrations were also determined in 40 health volunteers who were not occupationally exposed to lead or cadmium (control group). The mean concentrations of blood lead were 9.8 micrograms/dL for controls and 39.5 micro/dL for lead-exposed workers, whereas 0.79 micrograms/g creatinine and 2.50 micrograms/g creatinine were the mean levels of urine cadmium for controls and for cadmium-exposed workers, respectively. After adjusting for age, body mass index, and drinking and smoking habits, a significant rise of blood pressure with the increases in blood lead levels was found in the group of lead-exposed workers, but not in the control group. In contrast, the results of this study did not corroborate the hypothesis that an increase in cadmium exposure implies a rise in blood pressure.