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Reprint | DOI: https://doi.org/10.31579/2693-2156/011
* Unidad de Posgrado de la Facultad de Medicina, Universidad Nacional de San Agustín de Arequipa Arequipa, Perú.
*Corresponding Author: Rocío Núñez, Unidad de Posgrado de la Facultad de Medicina, Universidad Nacional de San Agustín de Arequipa Arequipa, Perú.
Citation: Rocío Núñez (2020) El Mercurio producto de la Minería y su relación con Enfermedad Cardiovascular: Estado de Arte. J Thoracic Disease and Cardiothoracic Surgery, 1(3); DOI:10.31579/2693-2156/011
Copyright: © 2020 Rocío Núñez, This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Received: 26 July 2020 | Accepted: 04 August 2020 | Published: 07 August 2020
Keywords: mercury; mining; cardiovascular disease; state of the art; meta-analysis
It is clear, according to the literature, mercury from mining, in its methylmercury form, produces neurotoxicity and decreased IQ in fetuses; However, there are several reviews and studies on the association of mercury with cardiovascular diseases, because these are the cause of greater morbidity and mortality worldwide; it is necessary to clarify their relationship, as the purpose of this state of art. These documents were reviewed, analyzed and synthesized to define said association; within which, a meta-analysis was found that reviews 37 studies and concludes that there is no association of mercury with cardiovascular diseases and that on the contrary; lead, arsenic, cadmium and copper, if they have a strong relationship with cardiovascular disease.
There is no history of articles developed, such as State of Art, related to El Mercurio product of Mining and its association with Cardiovascular Disease, that is, the state of the question that is "creating a new field of research, not only with the of documentation, but rather the conversion of research into a phenomenon of research itself; consequently, one could speak of research on research ” [1]. And with this, break down the acquired information and build new information in order to produce a change that improves the standards of knowledge in order to transform a reality towards a solution that produces a positive impact in this case on the health of the person. What makes it an original article. The purpose of this State of the Art is to publicize the connection of Mercury product of Mining and Cardiovascular Disease and to answer the following question: Is Mercury product of Mining related to Cardiovascular Disease? In 2017, the World Health Organization ruled on Artisanal and Small-Scale Gold Mining (ASM) and its association with health and environmental problems, as a precedent is the Minimata Agreement on Mercury in October 2013 ; There are millions of people dedicated to this work in developing countries that consequently see their health affected [2] Diseases such as: Neurotoxicity and decreased IQ of children of pregnant mothers, exposed to this metal, in addition to particularly cardiovascular effects with one of the toxic forms of mercury: Methylmercury [3]. This is a public health problem because the World Health Organization stated that in 2012 17.5 million people died from cardiovascular diseases, which represents 30% of deaths registered in the world and predicts that by 2030 ; 23.6 million people will die from cardiovascular disease, and it also refers to the fact that it will continue to be the main cause of death [4]. In the United States, health policies to control mercury contamination have shown long-term economic benefits, more with global control policies determined in the Minimata Convention, in November 2013, than with domestic control policies, [5]. In Mojano (Colombia) there are several small-scale artisanal gold mines, where mercury is used as part of the process to obtain gold. A loss of 1 to 2 grams of mercury is calculated from obtaining 1 gram of gold. Mojano is comprised of four departments and is a crucial area for environmental regulation and ecological balance; 70% of the families in Mojano are poor; 57% of residents live in extreme poverty and of them 87% do not have basic needs and it has been shown that they have health problems due to exposure to mercury, both workers and the population living in the vicinity of the gold mines [6]. In the Wanshan mine (China); Children by consumption of rice that contains methylmercury product of these mines, are more exposed to mercury than adults and in them damage has been evidenced in the development of their Central Nervous System, another problem is intrauterine exposure due to the fact that methylmercury passes through the placental barrier and its passage through breastfeeding, which leads to a decrease in the IQ and it should be noted and emphasized that this neurotoxicity is irreversible [7]. If we know the population that will benefit, which according to the statistical data of the Global Mercury Assessment given in 2013: There are about 10 to 15 million people who extract gold from artisanal mines mainly in Africa, Asia and South America and 3 million women and children [6]. An efficient and effective intervention that produces a positive change in your health is a priority. This state of the art will provide new scopes to define the association of mercury from mining and cardiovascular disease.
Mercury is a heavy metal and one of the most toxic after lead and arsenic [8]. Mercury has an affinity for sulfhydryl groups of enzymes and antioxidants such as N acetylcysteine, α-lipoic acid, glutathione, which is the most powerful intracellular antioxidant [3]. Mercury induces greater oxidative stress with mitochondrial dysfunction, increases hydrogen peroxide, depletes mitochondrial glutathione, increasing lipid peroxidation and alteration of calcium homeostasis; the mercury-selenium complex reduces the amount of selenium, which is a precursor antioxidant in the formation of glutathione peroxidase that breaks down hydrogen peroxide [3].
Among the cardiovascular diseases that have been evidenced by mercury exposure, it is myocardial infarction, atherosclerosis, arterial hypertension, coronary disease [3]. Several mechanisms have been explained by which mercury determines these cardiovascular diseases, although it is not very elucidated; Increases the oxidation of low-density lipoproteins (LDL), destroying phospholipid plasma membrane, externalizes phosphatidylserine that modifies the mitochondrial membrane and generates apoptosis. Another mechanism is the inactivation of paraoxonase, an antioxidant enzyme related to high-density lipoproteins (HDL) in the transport of cholesterol. Mercury activates phospholipase A2 that generates severe inflammation that is correlated with coronary artery disease; in addition to inducing the formation of arachidonic acid metabolites such as prostaglandins, thromboxanes, and leukotrienes, which are mediators of more inflammation in the endothelium [3].
The effect of the dose response of Mercury has been evaluated, by means of its dosage in blood, hair and toenail samples. In atherosclerosis, methylmercury by oxidative stress promotes adhesion of molecules and inflammation that increases the thickness of the inner layer of blood vessels such as the carotid artery, a moderate association is evidenced. Heart rate variability due to an increase or decrease in sympathetic activity has been strongly related to a greater amount of methylmercury and in the case of Myocardial Infarctions, according to the EURAMIC and KIHD studies, this association has been moderate to strong [9].
Another mechanism that tries to explain the role of mercury in arterial hypertension is the inactivation of methyl or catecholamine transferase (COMT), which increases epinephrine, norepinephrine and dopamine in serum and urine; in addition to the relationship of mercury toxicity with cerebrovascular accident and carotid atherosclerosis, due to an increase in platelet aggregation, an increase in factor VIII and also endothelial dysfunction [10].
Currently in Korea, a study was published in May 2019, where about 7055 inhabitants were evaluated, between 2008 and 2011 and information was extracted from 6 hospitals in these areas; In some abandoned mines, about the relationship between the level of mercury in the blood of the inhabitants and arterial hypertension of these inhabitants, and a positive and significant correlation was found [11]. Despite the fact that in July 2018 a meta-analysis was presented where 37 articles were reviewed and it was found that mercury was not related to cardiovascular disease but instead; lead, arsenic, cadmium, and copper were associated with cardiovascular disease [12].
The objective of this state of the art is to define whether or not there is a relationship between mercury and cardiovascular disease, for which I have reviewed the current literature, sticking to the characteristics of the state of the question for this topic.
I proceeded to search for literature of the publications of the last 5 years in electronic databases, using Google Scholar and MEDLINE (via PubMed), with the use of keywords such as: Mercury, mining, cardiovascular disease and state of the art in the title and In summary, classify the documents found in order of importance and then analyze, synthesize and summarize their content to obtain the essence and purpose of a state of the art, answering the following questions: How much has been investigated? Who have investigated ? What gaps exist? What achievements have been achieved? From what dimensions has it been treated? and What aspects need to be addressed? [13].
In the United States, two policy models were projected, one global based on the Minimata Convention on mercury and another domestic model: Toxic, Aviation and Mercury Standards (MATS). This global model action policy to the year 2050 according to Minimata has a profit of $ 1.4 to 575 billion dollars with an average of 339 million dollars, while the domestic action policy (MATS) has a profit range of $ 6 million to $ 171 trillion in both humans and the ecosystem [5].
History has left us a lot of information about the toxic effect of mercury, such as the death of the Emperor of China Qin Shi Huang (260-210 BC), who underwent experiments to obtain eternal life. There are many routes by which mercury arrives, by air, water, food, cosmetics, pharmaceutical products, mining products [3]. Two major mercury disasters have been described; one in Japan (Minimata Bay and Agana Rivera) and the poisoning in Iraq with methylmercury immersed in a fungicide with devastating economic consequences [3].
There is an important precedent following the publication of the National Council of Researchers in 2011. Regarding the dose-response between mercury and its cardiovascular effects. Where the mercury measurement was done in different types of samples: The mercury in a blood sample in people who ate fish regularly: in red blood cells, in that to measure organic mercury in dental amalgams and with low exposure to methylmercury and in hair and Toenail in exposed to organic and inorganic mercury with long-term exposure [9].
Myocardial infarction was found to have a moderate to strong relationship with mercury and was a function of four studies: 1. (EURAMIC; Guallar et al. 2002); 2. (KIHD; Virtanen et al. 2005); 3. (HPES; Yashizawa et al. 2002) and 4. (NSHDS; Hallgren et al. 2001). Of these were EURAMIC and KIHD with positive association with mercury, with significant results, (0.45 - 0.80) according to RR, OR and 95% CI. Atherosclerosis and decreased heart rate variability had an intermediate relationship with mercury [9].
In Korea, in a period of time from 2008 to 2011. Published in 2019; The relationship between blood mercury concentration and its relationship with arterial hypertension was studied in residents who lived in fields of an old mine, the sample was 7,055 people, a questionnaire was administered and data from 6 hospitals in these areas were reviewed , people with high levels of mercury in their blood were significantly correlated with high blood pressure than with patients with low levels. The first ones with Odds Ratio (OR): 1,277; 95% (CI): 1,135-1,436 [11].
Chowdhury et al. In his meta-analysis, he conducted a systematic review, where he identified 37 studies; that included the relationship of arsenic, lead, cadmium, mercury and copper with cardiovascular disease. There were 348 259 participants; with 13033 coronary disease; Cardiovascular accident 4205 and 15274 with cardiovascular disease [12].
The relative risk (RR) for arsenic and lead was 1.3 and 1.4 for cardiovascular disease; 1.23 and 1.85 for coronary heart disease and 1.15 and 1.63 for cerebrovascular accident. The RR for cadmium and copper was 1.33 and 1.81 for cardiovascular disease; 1.29 and 2.22 for coronary heart disease, plus 1.72 and 1.29 for cerebrovascular accident. Mercury had no association with cardiovascular disease [12].
The mechanisms by which this involvement occurs by the other components that have an association is not well understood but: arsenic accelerates and exacerbates atherosclerosis mediated by apolipoproteins in mice, produces reactive oxygen species in endothelial cells, generates inflammation or high blood pressure. Lead has two pathways, one, it accelerates systolic pressure, damages kidney function and the other is atherosclerosis, it induces oxidative stress, inflammation and inflammation. Copper is a natural part of essential trace elements for the human being but in an excessive way it induces oxidative stress, through the copper-homocysteine complex it produces endothelial dysfunction and vascular injury. Cadmium generates oxidative stress, inflammation, endothelial damage resulting in atherosclerosis [12].
Analysis of results
The latest studies conducted to determine the association between mercury and cardiovascular disease, discussed as antecedents, are old; However, they are part of the review carried out by the Meta-analysis of Chowdhury et al. already described, which has allowed us to define this state of the art; This relationship between mercury and cardiovascular disease, whose approach leads to greater benefits in these most vulnerable populations, with the installation of global policies based on the Minimata Convention in October 2013, in those countries, where the incidence and prevalence of mercury toxicity and decrease morbidity and mortality due to neurotoxicity and decrease of the IQ, which is its most recognized association.
There are several confounding factors, in the reviewed studies, one of them is the risk-benefit of fish consumption, because they contain: omega 3, polyunsaturated fatty acids and selenium. Also, the toxic effect of methylmercury [3].
It would be good to analyze in subsequent studies whether the decrease in exposure to methylmercury and quantification of cases of cardiovascular disease; also dose-response of methylmercury with fatal or non-fatal myocardial infarction: make the conversion, in the type of sample where mercury is dosed, which corresponds to 2.44 ug Hg / g hair per ug Hg / g of toenail, to standardize the results [9].
There are several studies that have followed populations for long periods and in this long-term exposure it would have been ideal to perform repeated measurements and see individual variations; Another point to take into account are the roads or routes: The Environment and occupation, all adjusted to other confusing factors such as smoking. Also reduce the heterogeneity of the results of the meta-analysis of different study populations [12]
Mercury is a toxic heavy metal, also coming from mining activity and in its organic form, methylmercury is an important cause of neurotoxicity and decreased IQ, but it is not related to cardiovascular disease.
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