Association of blood mercury levels with nonmelanoma skin cancer in the U.S.A. using National Health and Nutrition Examination Survey data (2003-2016)

The preventive and carcinogenic effect of metals on cancer: a systematic review

BACKGROUND

Many studies have investigated the role of metals in various types of malignancies. Considering the wide range of studies conducted in this field and the achievement of different results, the presented systematic review was performed to obtain the results of investigations on the prevention and occurrence of various types of cancer associated with metal exposures.

METHODS

In this review, research was conducted in the three databases: Scopus, PubMed, and Web of Science without historical restrictions until May 31, 2024. Animal studies, books, review articles, conference papers, and letters to the editors were omitted. The special checklist of Joanna Briggs Institute (JBI) was used for the quality assessment of the articles. Finally, the findings were classified according to the effect of the metal as preventive or carcinogenic.

RESULTS

The total number of retrieved articles was 4695, and 71 eligible results were used for further investigation. In most studies, the concentration of toxic metals such as lead (Pb), chromium (Cr (VI)), arsenic (As), cadmium (Cd), and nickel (Ni) in the biological and clinical samples of cancer patients was higher than that of healthy people. In addition, the presence of essential elements, such as selenium (Se), zinc (Zn), iron (Fe), and manganese (Mn) in tolerable low concentrations was revealed to have anti-cancer properties, while exposure to high concentrations has detrimental health effects.

CONCLUSIONS

Metals have carcinogenic effects at high levels of exposure. Taking preventive measures, implementing timely screening, and reducing the emission of metal-associated pollutants can play an effective role in reducing cancer rates around the world.

Human exposure to heavy metals and related cancer development: a bibliometric analysis

As notifications on carcinogenicity of heavy metals increase, more and more attention is paid recently to heavy metals exposure. In our study, the human exposure to heavy metals and cancer knowledge epistemology was investigated using bibliometric analysis. The bibliometric data of the research articles were retrieved using following keywords: "heavy metal," "trace element", "cancer", "carcinogen", and "tumor" in the Scopus database. Specifically, 2118 articles published between 1972 and 2023 were found, covering a total of 1473 authors, 252 sources, and 2797 keywords. Retrospective data obtained from 251 documents and 145 journals were further analyzed by performance analysis and techniques of science mapping. The number of studies conducted in this field increased from one article published in 1972 to 18 articles published in 2022 in the study of Michael P Waalkes. The most impactful author regarding the number of published papers was Masoudreza Sohrabi with 7 publications. In the majority of the published papers, the most popular keywords were "cadmium" and "carcinogenicity". However, in recent 4 years, the emphasis has been placed more on epidemiology studies. Our study provides general knowledge about the trend of publication on the role of heavy metals in causing cancer. The leading researchers in the field of the effects of heavy metals on the development of cancer were identified in our studies. Our results might also create a better understanding of new and emerging issues and can be used as a comprehensive road map for future researchers.

Joint effect of whole blood metals exposure with dyslipidemia in representative US adults in NHANES 2011-2020

With little knowledge on the joint effects of metal exposure on dyslipidemia, we aimed to investigate the relationship between exposure to metal and dyslipidemia among US adults based on the National Health and Nutrition Examination Survey (NHANES). Based on the five NHANES waves (2011-2020), we selected five metals in blood as exposure, namely, cadmium (Cd), lead (Pb), total mercury (Hg), manganese (Mn), and selenium (Se), which were detected by inductively coupled plasma mass spectrometry. Survey-multivariable logistic regression, generalized weighted quantile sum (WQS), and Bayesian kernel machine regression (BKMR) were performed to determine whether dyslipidemia was associated with single metals or mixed metals. Our study included 12,526 participants aged from 20 to 80, representing 577.1 million non-institutionalized US adults. We found a positive association between several metals including Pb [adjusted odds ratio (AOR) = 1.332, 95%CI: 1.165, 1.522], total Hg (AOR = 1.264, 95%CI: 1.120, 1.427), Mn (AOR = 1.181, 95%CI: 1.046, 1.334), and Se (AOR = 1.771, 95%CI: 1.576, 1.992) and dyslipidemia. According to the WQS approach, metal mixtures were positively associated with dyslipidemia (AOR: 1.310, 95%CI: 1.216, 1.411) after a full-model adjustment. As is shown in the BKMR model, mixed metals tended to be positively associated with dyslipidemia ratios in a significant manner. Females, non-Hispanic White populations, people aged over 60, and those who did a little physical activity had a greater risk for dyslipidemia. Our findings suggest metals including Cd, Pb, Hg, Mn, and Se and their combinations may adversely affect dyslipidemia among US adults. Due to the cross-sectional nature of the study, it is possible that reverse causation may exist.

Exposure to arsenic, polycyclic aromatic hydrocarbons, metals, and association with skin cancers in the US adults

Worldwide, skin cancer affects millions of people yearly and is broadly classified into melanoma and nonmelanoma types of skin cancer. The toxicity of metals to human health is a public and clinical health problem due to their widespread use in tools, machinery, and appliances as well as their widespread distribution in the air, water, and soil. Arsenic is a carcinogenic metalloid and available in the Earth's crust. Polycyclic aromatic hydrocarbons (PAHs) are toxic to humans, and incomplete combustion of fossil fuels is the main source of PAHs. Human populations exposed to metals from various sources can lead to various diseases including cancer. Limited studies are conducted to simultaneously assess the correlation of multiple arsenic, PAHs, metals with the occurrence of skin cancer. This study aimed to analyze the association between six PAHs compounds, seven types of arsenic, and fourteen metals from urine specimen with skin cancer in US adults. We performed a cross-sectional analysis using data from a total of 14,716 adults from the National Health Examination and Nutrition Survey (NHANES) database for three cycles ranging from 2011-2012 to 2015-2016. Specialized weighted complex survey logit regressions were conducted. Linear logit regression models using only main effects were performed first to identify the correlation between the selected demographic and lifestyle variables and melanoma, nonmelanoma, and unknown types of skin cancer. A second set of linear, main-effects logit regression models were constructed to examine the correlation between melanoma, nonmelanoma, and other types of skin cancers and seven types of arsenic (arsenous acid, arsenic acid, arsenobetaine, arsenocholine, dimethylarsinic acid, monomethylacrsonic acid, and total arsenic), six PAHs (1-hydroxynaphthalene, 2-hydroxynaphthalene, 3-hydroxyfluorene, 2-hydroxyfluorene, 1-hydroxyphenathrene, and 1-hydroxypyrene), and fourteen metals (barium, cadmium, cobalt, cesium, molybdenum, manganese, lead, antimony, tin, strontium, thallium, tungsten, uranium, and mercury) when adjusted for the selected covariates. The statistical analysis was conducted using R software, version 4.0.4. A marginal positive significant correlation between total arsenic and nonmelanoma was observed. This study identified a significant positive association between barium, cadmium, cesium, mercury, tin, and melanoma development. Cesium showed a significant positive statistical association for nonmelanoma, and thallium showed a borderline significant statistical association for nonmelanoma. A statistically significant positive association was found between cadmium and an unknown type of skin cancer. The findings of this study indicated a statistically significant positive association between skin cancer and barium, cadmium, cesium, tin, mercury, and thallium. Further studies are recommended in humans to refute or confirm these findings.

Association between metal(loid)s in serum and leukemia: a systematic review and meta-analysis

Purpose

Heavy metals and metalloids are recognized as environmental threats, which are considered highly toxic and carcinogenic. Epidemiologically, their association with leukemia is under debate. We aim to clarify the association between the heavy metal(loid)s in serum and leukemia via a systematic review and meta-analysis.

Methods

We searched PubMed, Embase, Google Scholar, and CNKI (China National Knowledge Infrastructure) databases for all related articles. The standardized mean difference and its 95% confidence interval was used to evaluate the association of leukemia with heavy metal(loid)s in serum. The statistical heterogeneity among studies was assessed with the Q-test and I 2 statistics.

Results

Among 4,119 articles related to metal(loid)s and leukemia, 21 studies met our inclusion criteria, which are all cross-sectional studies. These 21 studies involved 1,316 cases and 1,310 controls, based on which we evaluate the association of heavy metals/metalloids in serum with leukemia. Our results indicated positive differences for serum chromium, nickel, and mercury in leukemia patients, while a negative difference for serum manganese in acute lymphocytic leukemia (ALL).

Conclusion

Our results suggested an elevated trend of serum chromium, nickel, and mercury concentrations in leukemia patients while descending trend of serum manganese concentration in ALL patients. The result of sensitivity analysis between lead, cadmium, and leukemia and publication bias of association between chromium and leukemia also needed attention. Future research work may focus on the dose-response relationship between any of these elements and the leukemia risks, and further elucidation of how these elements are related to leukemia may shed light on the prevention and treatment of leukemia.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40201-023-00853-2.

Use of Hand Creams during the Period of Frequent Disinfection in COVID-19 Pandemic-Preference Survey and Evaluation of Mercury Contamination

The skin is one of the ways the human body is exposed to toxic elements, including mercury (Hg). Hand creams are cosmetics that should be of high quality due to the fact that they can be used on irritated skin, which can facilitate the absorption of many ingredients. The study consisted of two stages: a consumer questionnaire was conducted regarding the preferences of the respondents, and then the Hg content in hand creams was determined. The survey covered 184 people with an age of 26.9 ± 7.8 years. Based on their preferences, 140 hand creams were selected for the study. The Hg content in the creams was determined by atomic absorption spectrometry with the amalgamation technique. The median content of this toxic element was 4.067 µg/kg. No influence of the country of origin, price, package size, main ingredients, and direction of action on the Hg content was shown. Noncarcinogenic risk assessment using the hazard quotient (HQ) indicated that the tested creams are safe. However, it should be emphasized that Hg has been shown in over 99% of the samples, which indicates that the content of this element in hand creams should be monitored.

Low-Level Environmental Mercury Exposure and Thyroid Cancer Risk Among Residents Living Near National Industrial Complexes in South Korea: A Population-Based Cohort Study

Background: Previous studies suggested that mercury may be linked to thyroid cancer due to its bioaccumulation in the thyroid gland, but no studies have evaluated the association between mercury exposure and thyroid cancer risk. We examined the relationship between mercury exposure and thyroid cancer risk, with the potential modification of hematological parameters. Methods: We performed a secondary analysis of a prospective cohort study among residents living near industrial complexes in South Korea (recruited from 2003 to 2011). Incident thyroid cancer cases (C73, ICD-10 code) were identified from the National Cancer Registry and Statistics Korea. Urinary mercury concentrations were measured using thermal decomposition amalgamation atomic absorption spectrometry (TDA-AAS). Cox proportional hazards regression models (adjusted for age, sex, educational level, smoking status, and employment) were used to estimate the hazard ratio (HR) and confidence interval [CI] between mercury exposure and the incidence of thyroid cancer. Results: We documented 69 cases of thyroid cancer in a total of 5213 participants during follow-up (median 8.7 years). The geometric mean of urinary mercury concentration was 1.8 μg/L for thyroid cancer cases and 1.2 μg/L for noncases (p for difference = 0.001). After adjusting for potential confounders, those in the highest tertile of urinary mercury levels had a twofold higher risk of thyroid cancer (HR = 1.97 [CI 1.03 - 3.80] in the highest tertile vs. the lowest tertile, p for trend = 0.043). This association was stronger for those with lower mean corpuscular volume and mean corpuscular hemoglobin status. Conclusions: Urinary mercury concentration was positively associated with the risk of thyroid cancer among residents living near national industrial complexes, and this association was influenced by red blood cell indices status. These results provide some evidence suggesting the adverse effects of environmental metal pollution in the development of thyroid cancer.

Fish intake and risk of melanoma in the NIH-AARP diet and health study

PURPOSE

Prior epidemiological studies evaluating the association between fish intake and melanoma risk have been few and inconsistent. Few studies distinguished different types of fish intake with risk of melanoma.

METHODS

We examined the associations between intake of total fish and specific types of fish and risk of melanoma among 491,367 participants in the NIH-AARP Diet and Health Study. We used multivariable-adjusted Cox proportional hazards regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

During 6,611,941 person-years of follow-up with a median of 15.5 years, 5,034 cases of malignant melanoma and 3,284 cases of melanoma in situ were identified. There was a positive association between higher total fish intake and risk of malignant melanoma (HR = 1.22, 95% CI = 1.11-1.34 for top vs. bottom quintiles, ptrend = 0.001) and melanoma in situ (HR = 1.28, CI = 1.13-1.44 for top vs. bottom quintiles, ptrend = 0.002). The positive associations were consistent across several demographic and lifestyle factors. There were also positive associations between tuna intake and non-fried fish intake, and risk of malignant melanoma and melanoma in situ. However, fried fish intake was inversely associated with risk of malignant melanoma, but not melanoma in situ.

CONCLUSIONS

We found that higher total fish intake, tuna intake, and non-fried fish intake were positively associated with risk of both malignant melanoma and melanoma in situ. Future studies are needed to investigate the potential biological mechanisms underlying these associations.

Dietary components and the risk of non-melanoma skin cancer: A systematic review of epidemiological studies

Non-melanoma skin cancer (NMSC) is the most common cancer among white-skinned people. The main environmental risk factor for all types of skin cancer is ultraviolet (UV) exposure to the sun. However, significant modifiable risk factors, such as diet, have been studied about NMSC risk. Several original studies have been conducted on the link between various dietary components and the risk of NMSC in the past decade, but have not been systematically reviewed. This review focuses on the potential impact of dietary components in the prevention of NMSC and evaluates the findings of epidemiologic evidence for dietary factors. We conducted a systematic search of three databases, including Scopus, ISI Web of Science, and PubMed, to identify relevant epidemiological studies published between 2000 and July 6, 2021. Finally, forty-three articles were included. Because of the inherent limitations of epidemiological studies, no definitive conclusions can be drawn; however, the links between folate, citrus, caffeine, and alcohol with BCC are notable; thus, high dietary folate intake, as well as citrus and alcohol consumption, are associated with an increased risk of basal cell carcinoma (BCC), whereas caffeine is associated with a lower risk. More research is required to reach a definitive conclusion.

Influence of the Levels of Arsenic, Cadmium, Mercury and Lead on Overall Survival in Lung Cancer

The effects of heavy metals on cancer risk have been widely studied in recent decades, but there is limited data on the effects of these elements on cancer survival. In this research, we examined whether blood concentrations of the heavy metals arsenic, cadmium, mercury and lead were associated with the overall survival of lung cancer patients. The study group consisted of 336 patients with lung cancer who were prospectively observed. Blood concentrations of heavy metals were measured to study the relationship between their levels and overall survival using Cox proportional hazards analysis. The hazard ratio of death from all causes was 0.99 (p = 0.94) for arsenic, 1.37 (p = 0.15) for cadmium, 1.55 (p = 0.04) for mercury, and 1.18 (p = 0.47) for lead in patients from the lowest concentration quartile, compared with those in the highest quartile. Among the patients with stage IA disease, this relationship was statistically significant (HR = 7.36; p < 0.01) for cadmium levels in the highest quartile (>1.97–7.77 µg/L) compared to quartile I (0.23–0.57 µg/L, reference). This study revealed that low blood cadmium levels <1.47 µg/L are probably associated with improved overall survival in treated patients with stage IA disease.