Blood lead concentration and exposure related factors in Korea from the National Environmental Health Survey (KoNEHS) II (2012-2014)

The impact of metals on cognitive impairment in the elderly and the mediating role of oxidative stress: A cross-sectional study in Shanghai, China

Cognitive impairment (CI) is a prodrome of many neurodegenerative diseases with complex and unclear pathogenesis. Metal exposure has been found to be associated with CI, but existing population studies are scarce and have the limitations of single outcome and ignoring mixed exposures. This cross-sectional study was conducted in Shanghai, China, enrolling 836 seniors aged over 60 years to investigate the relationship between combined metal exposure (Lead (Pb), cadmium (Cd), and mercury (Hg)) and CI in the elderly and the mediating effect of oxidative stress. It was found that there were significant differences in urinary Pb, Cd, Hg and blood Pb levels between the CI and normal groups. Urinary Pb and Cd levels were significantly negatively correlated with Montreal Cognitive Assessment (MoCA) score, amyloid β42 (Aβ42), and Aβ42/40, while urinary Cd, Hg and blood Hg were significantly positively correlated with phosphorylated tau protein (P-tau). Weighted quantile sum (WQS) regression indicated that combined metal exposure had a more significant effect on CI than individual exposure. Mediation modeling revealed that plasma superoxide dismutase (SOD) was involved in the effects of urinary Cd on Aβ42/40 and P-tau, with mediation effects accounting for 20 % of the total effect. This study emphasized the combined exposure to metals, and the results can help to properly understand the association between mixed metals exposure and CI in the elderly, as well as provide population data and theoretical basis for identifying early environmental risk factors and discovering potential mechanisms of CI.

Lead in traditional and complementary medicine: a systematic review

Lead in the environment remains a matter of grave concern for public health. Lead has been associated with some traditional medicines and has been linked to cases of lead poisoning. A comprehensive compilation of these reports has not previously been conducted. The objective of this review is to explore how common is lead exposure after traditional medicine use, and which countries, systems and/or products are of most concern when it comes to lead contamination. A systematic search was conducted on PubMed, Ovid and EMBASE for studies published between 2005 and 2020. A grey literature search was conducted. Search terms related to lead and traditional medicine were developed for each database, and there were no limitations on language. Studies were included if they examined elevated lead in humans resulting from the use of traditional medicines reported in case reports, case-series, or observational studies. Of the papers discussing lead exposure, 85 case reports were identified and synthesized for the current review. Several themes were identified in the included studies. Traditional medicine has been used in the many parts of the world, however use is more common in South and Southeast Asian countries. The level of detectable lead in products varied widely by region and product types. Consumers of traditional medicines sought products for a wide variety of symptoms and ailments. The symptoms of lead poisoning from traditional medicine use reflected the typical symptom profile of lead poisoning, highlighting the need for awareness of traditional medicine products as a source of lead exposure. Traditional medicine usage remains an important part of health care in many regions, however there is a risk of lead exposure from several products. Health care practitioners in all regions of the world should be aware of the risk and explore the potential for traditional medicine use for patients presenting with elevated blood lead levels. Countries with a strong traditional medicine culture should explore policies for reducing lead exposure from traditional medicine products. JG, LO and MNBD are staff members of the World Health Organization. The authors alone are responsible for the views expressed in this publication and they do not necessarily represent the decisions, policy, or views of the World Health Organization.

Blood Pb levels are associated with prostate cancer prevalence among general adult males: Linking National Cancer Registry (2002-2017) and KNHANES (2008-2017) databases of Korea

BACKGROUND

Exposure to heavy metals may increase the risk of developing prostate cancer. However, these observations are often inconsistent and not based on clinically diagnosed cases.

OBJECTIVE

To investigate the association of lead (Pb), cadmium (Cd), and mercury (Hg) exposure with clinically determined prostate cancer cases among adult males in South Korea.

METHODS

Metal biomonitoring data and cancer information from the general Korean population were extracted by linking National Cancer Center (NCC) cancer registration data (2002-2017) with Korea National Health and Nutrition Examination Survey (KNHANES) data (2008-2017). Among them, 46 prostate cancer cases (designated as 'all-prostate'), including 25 diagnosed after heavy metal measurement (designated as 'post-prostate'), and 93 matching controls were chosen. Logistic regression analysis was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) between the heavy metal levels and prostate cancer.

RESULTS

Post-prostate patients exhibited higher blood Pb levels than controls (median 3.1 μg/dL vs. 2.38 μg/dL, p = 0.01). For all-prostate cancer, the OR of prostate cancer increased by 2.04-fold for every doubling of Pb levels (95% CI = 1.08-3.87, p = 0.03). The OR was also significantly elevated when comparing the third quartile (Q3) to the lowest quartile (Q1), with ORs ranging from 3.38 to 7.95, depending on model (p < 0.05). Blood Pb levels maintained a positive association with inconsistent significance for post-prostate cancer patients. For Cd and Hg, no statistically significant association was established.

SIGNIFICANCE

By linking two national health databases for the first time, we constructed an unbiased database of prostate cancer cases and matching controls. We found that blood Pb concentrations were associated with the risk of prostate cancer in Korean men at the current level of exposure.

Unveiling the metal mutation nexus: Exploring the genomic impacts of heavy metal exposure in lung adenocarcinoma and colorectal cancer

Mutations that activate oncogenes and deactivate tumor suppressor genes are widely recognized as significant contributors to cancer development. We investigated relationships between heavy metal exposure and the frequencies and types of gene mutations in patients with lung adenocarcinoma (LUAD) and colorectal cancer (CRC). Plasma concentrations of arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb) were measured using inductively coupled plasma mass spectrometry (ICPMS), and next-generation sequencing (NGS) of 1123 cancer-related genes was performed using the tumor tissues. Through Bayesian kernel machine regression (BKMR) analysis, we found associations between the integrated concentrations of the heavy metals and the number of gene mutations, especially insertions/deletions (indels), and Pb, As, and Cd were found to be the most significant contributors to the increased mutation rates. We extracted previously established mutational signatures and observed that they exhibit significant correlations with metal exposure. Moreover, we detected substantial shifts in the mutational landscape when comparing groups with high and low metal exposures. Several frequently mutated genes displayed positive correlations with metal exposure, whereas EGFR indels showed a negative association with Cd exposure. These findings suggest that heavy metal exposure can impact genomic stability in cancer-related genes, underscoring the importance of heavy metal exposure in cancer development.

Risk assessment of combined exposure to lead, cadmium, and total mercury among the elderly in Shanghai, China

Lead (Pb), cadmium (Cd) and total mercury (THg) are toxic heavy metals (THMs) that are widely present in the environment and can cause substantial health problems. However, previous risk assessment studies have rarely focused on the elderly population and have usually targeted a single heavy metal, which might underestimate the long-term accumulative and synergistic effects of THMs in humans. Based on the food frequency questionnaire and inductively coupled plasma mass spectrometry, this study assessed external and internal exposures to Pb, Cd and THg in 1747 elderly people in Shanghai. Probabilistic risk assessment with the relative potential factor (RPF) model was used to assess the neurotoxicity and nephrotoxicity risks of combined THMs exposures. The mean external exposures of Pb, Cd and THg in Shanghai elderly were 46.8, 27.2 and 4.9 μg/day, respectively. Plant-based foods are the main source of Pb and THg exposure, while Cd is mainly from animal-based foods. The mean concentrations of Pb, Cd and THg were 23.3, 1.1 and 2.3 μg/L in the whole blood, and 6.2, 1.0 and 2.0 μg/L in the morning urine, respectively. Combined exposure to THMs leading to 10.0 % and 7.1 % of Shanghai elderly at risk of neurotoxicity and nephrotoxicity. The results of this study have important implications for understanding the profiles of Pb, Cd and THg exposure in the elderly living in Shanghai and provide data support for risk assessment and control of nephrotoxicity and neurotoxicity from combined THMs exposure in the elderly.

Association of blood lead exposure with frailty and its components among the Chinese oldest old

Lead (Pb) is a widespread environmental contaminant, associated with a higher risk of functional impairment that can lead to frailty in older adults. However, few studies focused on the association of Pb exposure with frailty among the oldest old (aged ≥ 80 years). In this study, we aimed to assess the associations of Pb with frailty and its components in the oldest old. The included individuals were the oldest old aged ≥ 80 years who participated in a 2017 cross-sectional survey of the Healthy Aging and Biomarkers Cohort Study. Frailty was ascertained by the frailty index, which was created based on health deficits. We used logistic regression models to estimate the association of blood Pb with frailty and its components. The geometric mean and median of blood Pb were 38.51 μg/L and 36.27 μg/L among the oldest old, respectively. Compared with the first quartile of blood Pb, participants in the fourth quartile had higher risk of frailty and its components, the ORs are 1.71 (1.22-2.41), 1.99 (1.35-2.94), 1.91 (1.25-2.93), 1.57 (1.13-2.17) and 1.43 (1.05-1.96), for frailty, ADL disability, IADL disability, functional limitations, and hearing loss in the oldest old, respectively. There was a significant interaction between blood Pb and frailty in different age groups. In conclusion, our findings provide preliminary evidence that higher blood Pb may increase the risk of frailty among the oldest old by increasing the risk of disability in four physical functions: disability in ADL, disability in IADL, functional limitations, and hearing loss.

Effect of exposures to mixtures of lead and various metals on hypertension, pre-hypertension, and blood pressure: A cross-sectional study from the China National Human Biomonitoring

We aimed to explore the effects of mixtures of lead and various metals on blood pressure (BP) and the odds of pre-hypertension (systolic blood pressure (SBP) 120-139 mmHg, and/or diastolic blood pressure (DBP) 80-89 mmHg) and hypertension (SBP/DBP ≥140/90 mmHg) among Chinese adults in a cross-sectional study. This study included 11,037 adults aged 18 years or older from the 2017-2018 China National Human Biomonitoring. Average BP and 13 metals (lead, antimony, arsenic, cadmium, mercury, thallium, chromium, cobalt, molybdenum, manganese, nickel, selenium, and tin) in blood and urine were measured and lifestyle and demographic data were collected. Weighted multiple linear regressions were used to estimate associations of metals with BP in both single and multiple metal models. Weighted quantile sum (WQS) regression was performed to assess the relationship between metal mixture levels and BP. In the single metal model, after adjusting for potential confounding factors, the blood lead levels in the highest quartile were associated with the greater odds of both pre-hypertension (odds ratio (OR): 1.56, 95% CI: 1.22-1.99) and hypertension (OR:1.75, 95% CI: 1.28-2.40) when compared with the lowest quartile. We also found that blood arsenic levels were associated with increased odds of pre-hypertension (OR:1.31, 95% CI:1.00-1.74), while urinary molybdenum levels were associated with lower odds of hypertension (OR:0.68, 95% CI:0.50-0.93). No significant associations were found for the other 10 metals. WQS regression analysis showed that metal mixture levels in blood were significantly associated with higher SBP (β = 1.56, P < 0.05) and DBP (β = 1.56, P < 0.05), with the largest contributor being lead (49.9% and 66.8%, respectively). The finding suggests that exposure to mixtures of metals as measured in blood were positively associated with BP, and that lead exposure may play a critical role in hypertension development.

Effects of Exposure to Lead and Cadmium on Health of Inhabitants of Abandoned Metal Mine Area in Korea

People living near abandoned mines are at increased risk of exposure to toxic metals. We surveyed 4500 inhabitants with the mean age of 68.5 years old (male: 1768, female: 2732) living near 104 abandoned metal mines from 2013 to 2017 (the 2nd phase health survey in Korea). We conducted personal interviews, blood and urine sampling, and analyzed the concentrations of lead (Pb) and cadmium (Cd) in whole blood and Cd in urine using a graphite furnace atomic absorption spectrometer. The geometric means of blood Pb, blood Cd, and urine Cd were 2.27 μg/dL, 1.42 μg/L, and 1.66 μg/g creatinine, respectively. The level of metal exposure was lower than that reported from the first phase health survey in Korea (2008‒2011) but was higher than in the general population of Korea. Blood Pb was higher in males while blood Cd and urine Cd were significantly higher in females. Blood Pb was highest in the 40‒59 age group, while blood and urine Cd levels continuously increased until age 80 or older. The Cd levels in blood and urine were affected by consumption of locally produced rice and duration of residence near abandoned mines. Furthermore, negative correlations were observed between blood Pb and blood and urine Cd levels. Additionally, 252 of the 4500 subjects exceeded the thresholds of blood Cd or urine Cd levels. Together, these findings suggest that Cd has more sustainable and adverse health effects on the abandoned mine inhabitants, who are mostly aged. Therefore, continuous biomonitoring and risk assessment to environmental health risks are necessary for environmental pollution control and health promotion.