Tag: heavy metals

Categories : Cardiovascular Disease Environmental EffectsTags :

Urinary Metal Exposure Linked to Increased Risk of Heart Failure, Landmark Study Finds

On By ModernMedia

In addition to cadmium, molybdenum and zinc found to have particularly high risk increases

Right side heart failure. Credit: Scientific Animations CC4.0

A new multi-cohort study at Columbia University Mailman School of Public Health, has found that exposure to certain metals, detected in urine, is associated with a higher risk of heart failure (HF). Published in the Journal of the American College of Cardiology, it is the largest investigation of its kind to date, reinforcing the importance of reducing environmental metal exposure to reduce heart failure risk. While environmental metals are recognised as cardiovascular disease risk factors, until now the role of metal exposure in heart failure risk had remained understudied.

“Most previous studies have assessed individual metals in isolation. By examining metals as a mixture, our analysis more closely reflects real-world exposure patterns,” said Irene Martinez-Morata, MD, PhD, postdoctoral research scientist in Environmental Health Sciences at Columbia Mailman School, and lead author. “In our analysis of over 10 000 adults across diverse geographic, racial, and ethnic backgrounds, we observed consistent associations between elevated urinary metal levels and increased HF risk over long-term follow-up after accounting for other established traditional risk factors for the disease such as diabetes and obesity.”

The study pooled data from three large cohorts with more than 20 years of follow-up:

  •  MESA (Multi-Ethnic Study of Atherosclerosis), U.S. adults aged 18–85 from six urban-suburban areas in Maryland, Illinois, North Carolina, California, Minnesota and New York.
  • SHS (Strong Heart Study), American Indian adults aged 18–65 in the U.S. from Oklahoma, Arizona, North Dakota and South Dakota.
  •  Hortega Study, a general population cohort in Spain

Among the 10 861 participants, a thousand people developed heart failure. In a subset, researchers assessed left ventricular function, which measures how effectively the heart pumps blood.

Metals were measured in urine samples, which can indicate how much metal is in the body and how much is being eliminated from it. Health and lifestyle data – including medication use, cholesterol levels, blood pressure, glucose, BMI, and more – were collected via questionnaires, lab tests, and physical exams. The team used advanced machine learning models to evaluate the combined effects of five urinary metals as a mixture.

Key findings included:

  •  Higher levels for the mixture of five metals in urine: arsenic, cadmium, molybdenum, selenium, and zinc, was associated with a 55% higher risk of heart failure in rural American Indian adults (SHS), a 38% higher risk in urban and suburban diverse populations (MESA) and a 8% increased risk in adults in Spain (Hortega).
  •  In the analysis of metals individually, a doubling in the levels of urine cadmium, a toxic metal found in tobacco products, foods and industrial waste, was associated with 15% higher risk of heart failure.
  • Similarly, a doubling in the levels of molybdenum and zinc was associated with 13% and 22% higher risk of heart failure across the three cohorts. These metals have an essential function in the body, but high levels can be toxic.

“The strongest association between the 5-metal mixture and HF risk was seen in the SHS cohort,” said Martinez-Morata. “This population faces a historically high burden of contaminant metal exposure and cardiovascular disease and public health action is urgently needed.”

The sources of exposure to these metals can vary from urban and rural environments. Toxic metals such as arsenic, cadmium, and tungsten can occur as a result of mining and industrial activity leading to contamination of drinking water, foods that grow in contaminated soils, and air pollution. Many of these metals are also present in smoking devices, consumer products, and certain foods, observes Martinez and her co-authors. “Essential metals such as zinc and selenium are needed for biological functions, but high levels can be toxic.”

“We consistently found higher urinary levels of cadmium, molybdenum and zinc linked to increased heart failure risk,” noted Ana Navas-Acien, MD, PhD, Columbia Mailman School professor and chair of the Department of Environmental Health Sciences. “Even after adjusting for diabetes – a known HF risk factor – the zinc association remained significant.”

These results support the relevance of metal exposures as contributors to heart failure risk. “In ongoing research, we aim to clarify biological mechanisms and to explore the role of environmental interventions in cardiovascular disease prevention,” said Navas-Acien, who also is senior author.

“This study’s strengths include its large, diverse sample size, high-quality data, and robust, long-term follow-up,” said Martinez-Morata. “Our findings underscore the importance of continuing efforts to monitor and reduce environmental metal exposures, particularly in communities with historically high exposure levels as an innovative approach to improve cardiovascular health.”

Source: Columbia University Mailman School of Public Health

Categories : Environmental EffectsTags :

Selenium Reduces Health Impact of Pollutant Mixtures

On By ModernMedia
Photo by Bill Oxford on Unsplash

A study in mice conducted by the University of Cordoba proves that exposure to mixtures of metals and drug residue exacerbates health impacts, and evaluates the positive effects of a diet enriched in selenium to reduce this harm.

People are exposed daily, through the environment and their diets, to external substances that can be harmful to their health. Metals and the residue of pharmaceuticals, for example, in high doses, contaminate water and food, creating mixtures where they can interact, with this increasing their individual toxicity.

Analysing the effects of environmental pollution on organisms is essential to develop regulations establishing maximum doses of these pollutants for people. But mixtures of pollutants pose unknown challenges as they may interact with each other.

To understand the health effects of exposure to these ‘cocktails of contaminants’, a team at the University of Cordoba, evaluated, in mice, the toxicity of a mixture of contaminants that is very common in the environment and that accumulates along the food chain: a combination of metals (arsenic, cadmium, mercury) and drugs (diclofenac, flumequine).

In order to determine how these compounds interacted with each other, “we studied the controlled exposure of mice to this mixture and analysed how it affects the proteins in the liver; that is, how their liver proteostasis changes when ingesting these mixtures of contaminants for two weeks,” explained Professor Nieves Abril, senior author of the paper published in Science of the Total Environment.

Their conclusion is negative: the cocktail effect synergises these compounds, doing increased damage to health when the compounds act together.

“We used a massive protein detection technique (shotgun proteomic), which allowed us to compare how the proteins of the group exposed to the mixture of contaminants were altered compared to the control group,” April explained.

Of the proteins affected, they selected 275 as sentinels to verify what was changing and, after computer analysis, they were able to determine the metabolic pathways that were altered and their consequences for health. These analyses revealed a disproportionate defence response having a contrary and harmful effect on the system.

The researcher stressed that “although these pollutants generated oxidation in the cells separately too, when they acted together we found that the oxidation was so intense that all the antioxidant defence responses were activated continuously, without deactivating them, which ends up doing damage and causing many proteins to stop working.” The analyses showed a sustained expression of the response mediated by NRF2, which is the regulator that sets in motion a good part of the antioxidant defences, which caused a reducing stress.

Selenium as hope

It’s not all bad news in the study, as selenium could be a way to reduce the damage caused by exposure to these pollutants. A third group of mice were given doses of selenium, a mineral often found in vitamin supplements found in pharmacies, and proteomic analyses showed relief from the molecular damage done by the pollutants.

Selenium itself is an oxidant, but in low doses it activates responses in a controlled manner, predisposing the body to better defence.

Source: University of Córdoba

Categories : Environmental Effects Substance UseTags :

High Levels of Metal In Blood and Urine of Exclusive Marijuana Users

On By ModernMedia
Photo by Rodnae Productions on Pexels

Researchers have detected significant levels of metals in the blood and urine among marijuana users, concluding that marijuana may be an important and under-recognised source of lead and cadmium exposure. This is among the first studies to report biomarker metal levels among marijuana users and most likely the largest study to date, that links self-reported marijuana use to internal measures of metal exposure, rather than just looking at metal levels in the cannabis plant. The results are published online in the journal Environmental Health Perspectives.

Measurements reported by participants for exclusive marijuana use compared to nonmarijuana-tobacco had significantly higher lead levels in blood (1.27ug/dL) and urine (1.21ug/g creatinine). 

“Because the cannabis plant is a known scavenger of metals, we had hypothesised that individuals who use marijuana will have higher metal biomarker levels compared to those who do not use,” said first author Katelyn McGraw, postdoctoral researcher. “Our results therefore indicate marijuana is a source of cadmium and lead exposure.”

The researchers, from Columbia University Mailman School of Public Health, combined data from the National Health and Nutrition Examination Survey for the years 2005-2018, a biannual programme of studies designed to assess the health and nutritional status of adults and children in the U.S.

McGraw and colleagues classified the 7254 survey participants by use: non-marijuana/non-tobacco, exclusive marijuana, exclusive tobacco, and dual marijuana and tobacco use. Five metals were measured in the blood and 16 in urine. 

The researchers used four NHANES variables to define exclusive marijuana and tobacco use: current cigarette smoking, serum cotinine levels, self-reported ever marijuana use, and recent marijuana use. Exclusive tobacco use was defined as individuals who either answered yes to ‘do you now smoke cigarettes, or if individuals had a serum cotinine level >10ng/mL.

The study found higher levels of cadmium (Cd) and lead (Pb) in blood and urine among participants reporting exclusive marijuana use compared to non-smokers. Cd and Pb levels were also higher in exclusive marijuana users who reported using marijuana within the last week. Cd biomarker levels were higher in those who smoked only marijuana than , either because of differences in frequency of use or differences in Cd levels in the tobacco and cannabis plants themselves. However, blood and urinary Pb levels among exclusive marijuana users and exclusive tobacco users were similar. Dual marijuana and tobacco users also had higher levels of Cd and Pb compared with non-smokers.

These observations marijuana use is an important and underrecognised source of Cd and Pb exposure independent of tobacco use, the researchers concluded.

Marijuana is the third most commonly used drug in the world behind tobacco and alcohol. As of 2022, 21 states and Washington D.C., covering more than 50 percent of the U.S. population, have legalised recreational use of marijuana; and medical marijuana is legal in 38 states and Washington D.C. However, because marijuana is still illegal at the federal level, regulation of contaminants in all cannabis-containing products remains piecemeal and there has been no guidance from federal regulatory agencies like the FDA or EPA. As of 2019, 48.2 million people, or 18% of Americans, report using marijuana at least once in the last year.

While 28 states regulate inorganic arsenic, cadmium, lead, and total mercury concentrations in marijuana products, regulation limits vary by metal and by state. 

“Going forward, research on cannabis use and cannabis contaminants, particularly metals, should be conducted to address public health concerns related to the growing number of cannabis users,” said Tiffany R. Sanchez, PhD, assistant professor of environmental health sciences at Columbia Public Health, and senior author.