Category: Environmental Effects

Obesity Connection to Commonly-used Pesticide

Photo by Arjun MJ on Unsplash

A commonly-used pesticide could be contributing to the global obesity epidemic, according to a new study.

Researchers discovered that chlorpyrifos slows down the burning of calories in the brown adipose tissue of mice. Reducing this burning of calories, a process known as diet-induced thermogenesis, causes the body to store these extra calories, promoting obesity. Chlorpyrifos is banned for use on foods in Canada, and also now banned in the US and, as of last year, the EU, but widely sprayed on fruits and vegetables in many other parts of the world. In South Africa it is banned for residential use but is still used in agriculture.

Scientists made the discovery after studying 34 commonly used pesticides and herbicides in brown fat cells and testing the effects of chlorpyrifos in mice fed high calorie diets. Their findings were published in Nature Communications and could have important implications for public health.

“Brown fat is the metabolic furnace in our body, burning calories, unlike normal fat that is used to store them. This generates heat and prevents calories from being deposited on our bodies as normal white fat. We know brown fat is activated during cold and when we eat,” said senior author Gregory Steinberg, professor of medicine and co-director of the Centre for Metabolism, Obesity, and Diabetes Research at McMaster.

“Lifestyle changes around diet and exercise rarely lead to sustained weight loss. We think part of the problem may be this intrinsic dialling back of the metabolic furnace by chlorpyrifos.”

Steinberg said chlorpyrifos would only need to inhibit energy use in brown fat by 40 calories every day to trigger obesity in adults, which would translate to an extra 2kg of weight gain per year.

He said that while several environmental toxins including chlorpyrifos have been associated with increasing obesity rates in both humans and animals, these studies have mostly attributed weight gain to increases in food intake and not calorie burning.

“Although the findings have yet to be confirmed in humans, an important consideration, is that whenever possible consume fruits and vegetables from local Canadian sources and if consuming imported produce, make sure it is thoroughly washed,” said Steinberg.

Source: Medical Xpress

Heat Waves Increase Aggression in Mental Health Wards

Photo by Mary Taylor from Pexels

According to a new study from Germany, heatwaves may increase aggressive patient behaviour in mental health wards.

Studies have shown an association between increased temperature and the incidence of violent crimes, accounting for about 10% of the variance in one study in Finland. This effect has also been seen within the context of American Football games, with more penalties for aggressive behaviour given for visiting teams on hotter days.

Researchers from ZfP Südwürttemberg and Ulm University in Germany drew on local weather data and incident reporting data to examine the impact of hot weather on mental health inpatient wards.

They discovered that there were an average of 15% more aggressive incidents on days over 30°C (9.7 per day) compared to days under 30°C (8.4 per day).

A clear relationship was also seen between the temperature of hot days (those over 30°C) and the number of aggressive incidents. As the temperature increased, the higher the rate of incidents, which reached a peak of 11.1 on the very hottest days (over 33.5°C).

The findings suggest that temperature is the cause of the increase in incidents, rather than another factor. No equivalent correlation was found between temperature on hot days and the use of restrictive practices by hospital staff.

Staff recorded aggressive incidents according to a standardised protocol, documenting the nature of the aggression (eg physical, verbal), the target (eg staff, patients), the impact and any subsequent measures taken.

The data for the study came from six German mental health hospitals and covered 13 years (2007-2019), 1007 beds and 164 435 admissions. Over this period, there were a total of 207 days over 30°C. All six hospitals were built according to modern building standards, but all lacked air-conditioning.

Lead author Dr Hans Knoblauch said: “The climate emergency means that many areas of the world could experience significantly more hot weather in the future.

“While more research into the mental health consequences is needed, these findings could have practical implications for mental healthcare, particularly around hospital design and architecture.”

His colleague, Professor Tilman Steinert, from Ulm University, commented: “These findings highlight an underappreciated impact of the climate emergency on mental health services. Increased aggression is an indicator of increased distress and an environment that is failing to help patients recover.

“Urgent action is now needed, to replicate the findings of this study using more measurements within mental health hospitals, to invest in those hospitals, and to tackle the climate crisis. Mental health patients deserve better.”

Source: EurekaAlert!

Journal information: Frank Eisele et al, Aggressive incidents in psychiatric hospitals on heat days, BJPsych Open (2021). DOI: 10.1192/bjo.2021.33

Global Warming Drives a Third of Heat-related Deaths

Photo by Kouji Tsuru on Unsplash

While the COVID pandemic will eventually die down, the health threat from global warming will only increase as long as countries fail to control their emissions. Between 1991 and 2018, more over of all deaths in which heat played a role were attributable to human-induced global warming, according to a groundbreaking new study.

Global warming is impacting human health in a number of ways, from direct effects linked to wildfires and extreme weather, to changes in the spread of vector-borne diseases. One of the most striking ways is in the increase in heat-associated mortality and morbidity. Climate projections predict a rise in average global temperature, with extreme events such as heatwaves adding to future health burden. However, until now no research has been conducted into what extent these impacts have already occurred in recent decades until now. Research to answer these questions was led by the London School of Hygiene & Tropical Medicine (LSHTM) and the University of Bern within the Multi-Country Multi-City (MCC) Collaborative Research Network. 

This new study focused on man-made global warming through a ‘detection & attribution’ study that identifies and attributes observed phenomena to weather and climate changes. Specifically, the team examined past weather conditions simulated under scenarios with and without anthropogenic emissions. This enabled the researchers to separate the warming and related health impact linked with human activities from natural trends. Heat-related mortality was defined as the number of deaths attributed to heat, occurring at exposures higher than the optimum temperature for human health, which varies across locations.

Published in Nature Climate Change, the study used data from 732 locations in 43 countries around the world. For the first time, it shows the actual contribution of man-made climate change in increasing mortality risks due to heat.

The study estimates that 37% of all heat-related deaths in the recent summer periods were attributable to the warming of the planet due to human activities. These deaths were highest in hot regions such as Central and South America (up to 76% in Ecuador or Colombia, for example) and South-East Asia (between 48% to 61%).

Estimates also showed the number of deaths from human-induced climate change that occurred in specific cities; 136 additional deaths per year in Santiago de Chile (44.3% of total heat-related deaths in the city), 189 in Athens (26.1%), 172 in Rome (32%), 156 in Tokyo (35.6%), 177 in Madrid (31.9%), 146 in Bangkok (53.4%), 82 in London (33.6%), 141 in New York (44.2%), and 137 in Ho Chi Minh City (48.5%).

The authors said their findings bolster evidence in favour of adopting strong mitigation policies to reduce future warming, and to implement interventions to protect populations from the adverse consequences of heat exposure.

First author Dr Ana M Vicedo-Cabrera, from the University of Bern, said: “We expect the proportion of heat-related deaths to continue to grow if we don’t do something about climate change or adapt. So far, the average global temperature has only increased by about 1°C, which is a fraction of what we could face if emissions continue to grow unchecked.”

While on average over a third of heat-related deaths are due to human-induced climate change, there is considerable regional variation. Climate-related heat casualties range from a few dozen to several hundred deaths each year per city, as shown above, depending on the local changes in climate in each area and the vulnerability of its population. Populations living in low and middle-income countries are those most affected yet produce the least global warming emissions.

Senior author Professor Antonio Gasparrini from LSHTM, and coordinator of the MCC Network, said: “This is the largest detection & attribution study on current health risks of climate change. The message is clear: climate change will not just have devastating impacts in the future, but every continent is already experiencing the dire consequences of human activities on our planet. We must act now.”

The authors acknowledge limitations of the study include a lack of empirical data from certain regions such as Africa.

Source: London School of Hygiene and Tropical Medicine

Journal information: Vicedo-Cabrera, A.M., et al. (2021) The burden of heat-related mortality attributable to recent human-induced climate change. Nature Climate Change. doi.org/10.1038/s41558-021-01058-x.

Lab Finds Benzene in Many Sunscreen Products

Some sunscreen products have been found to contain benzene, a known carcinogen. Photo by RF._.studio from Pexels

An online pharmacy company that also conducts independent testing of consumer products has detected benzene in several sunscreen products.

The company, Valisure LLC, has issued a petition to the Food and Drug Administration in the US to enact stricter rules regarding the presence of benzene in sunscreen products. 

Benzene is a colourless or light-yellow liquid chemical at room temperature. A widely used chemical, it has been used primarily as a solvent in the chemical and pharmaceutical industries and is a known carcinogen. Trace levels of benzene may be found in cigarette smoke, gasoline, glues, cleaning products, and paint strippers.

The FDA has forbidden the intentional introduction of the chemical into commercial products due to its toxic properties. The agency does, however, allow benzene-containing products to be sold if the product provides a “substantial therapeutic advance”, on the condition that levels in the product are at or below 2% and that the introduction of benzene into the product is unavoidable. Currently the agency has no guidelines regarding benzene levels in sunscreen products.

Over the past several years, Valisure has become a respected name in product testing—they were behind efforts to have the carcinogen NDMA removed from heartburn medications in 2018, and more recently led the effort to recall hand sanitizers that contained benzene. In 2020, they detected NDMA in metformin, leading to widespread product recalls.
In this new effort, the company tested 294 unique batches from 69 different companies. They found significant variability from batch to batch, even within a single company. Fourteen lots of sunscreen and after-sun care products from four different brands contained between 2.78 – 6.26 ppm of benzene; 26 lots from eight brands contained detectable benzene between 0.11 – 1.99 ppm; and 38 lots from 17 brands contained detectable benzene at < 0.1 ppm. 
There was no detection of benzene in an additional 217 batches of sunscreen from 66 different brands through initial analysis of at least one sample. 
The company also noted that some of the products they tested had levels that were higher than the 2% cap mandated by the FDA. They also noted that since most of the products they tested did not have any detectable amounts of benzene, it clearly is not an unavoidable byproduct of production. The FDA recently discovered that sunscreen chemicals can be readily absorbed through the skin, they added.

Their petition asks the FDA to ban any amount of benzene in sunscreen and after-tanning care products and issue a recall for those that have measurable levels of benzene that have already been sold. They have also published a table [PDF] that lists sunscreens brands with no detectable levels of benzene in them.

Source: Medical Xpress

How Air Pollution Causes Loss of Smell

Photo by Kouji Tsuru on Unsplash

Johns Hopkins Medicine researchers have studied how long-term exposure to air pollution causes loss of smell, or anosmia, to better understand how it can rob someone of the ability to smell and taste.

Anosmia can severely impact a person’s quality of life, making it extremely difficult to taste foods, detect airborne hazards in the environment, and other functions. People with anosmia may experience weight concerns, decreased social interaction, depression and general anxiety. Loss of smell has been linked in some cases to death in older adults. 

“We included participants from a variety of areas in our study; however, most lived in urban areas where pollution levels are highest,” says lead author Murugappan “Murray” Ramanathan, MD, rhinologist and associate professor of otolaryngology–head and neck surgery at the Johns Hopkins University School of Medicine. “We wanted to assess how their exposure to PM2.5 air pollution—inhalable, particulate matter less than 2.5 micrometers in size or about 30 times smaller than the diameter of a human hair—might cause them to lose their sense of smell.”

According to the US Environmental Protection Agency (EPA), PM2.5 (the PM stands for ‘particulate matter’) is the term for a mixture of solid particles and liquid droplets found in the air, and are smaller even than pollen grains. PM2.5 can be made of many materials depending on the location, such as dust, dirt, soot, smoke, organic compounds and metals. These particulated have been linked to cardiovascular disease, lung cancer, cognitive decline, chronic obstructive pulmonary disease, asthma and premature death. Previous studies have suggested PM2.5 is a likely culprit in loss of smell—a connection that Prof Ramanathan and his team decided to explore in greater detail.

In their study, the researchers examined data for 2690 people, aged 18 years and older, who were evaluated by otolaryngologists between January 2013 and December 2016. Of these, 538 were diagnosed with anosmia, with an average age of 54, the majority being men (63%).

The EPA’s Air Quality System provided air pollution data for the study. The researchers entered the data into a detailed computer simulation to estimate the PM2.5 pollution levels within the participants’ residential ZIP codes. The model was created by Zhenyu Zhang, a Johns Hopkins Medicine otolaryngology postdoctoral fellow.

The researchers found that long-term airborne exposure to PM2.5 nearly doubles (a 1.6- to 1.7-fold increase) the risk of losing one’s ability to smell. They believe this may occur due to the location of the olfactory nerve—which contains the sensory nerve fibres associated with the sense of smell—being directly in the path of inhaled PM2.5 materials.

“Based on this result, we feel that long-term exposure to high levels of PM2.5 represents a common risk factor for the loss of sense of smell, especially in vulnerable populations such as older people—but also one that is potentially modifiable if sources of PM2.5 components can be better controlled,” says Ramanathan.

The researchers next steps are to study anosmia patients’ socioeconomic factors to find out if they affect the chances of exposure to PM2.5 air pollution. They also hope to evaluate other air pollution components that may contribute to loss of smell, such as ozone.

Source: Medical Xpress

Journal information: Zhenyu Zhang et al, Exposure to Particulate Matter Air Pollution and Anosmia, JAMA Network Open (2021). DOI: 10.1001/jamanetworkopen.2021.11606

Study Finds High Levels of ‘Forever Chemicals’ in Firefighters’ Bodies

A new study has shown that volunteer firefighters have higher levels of ‘forever chemicals‘, per- and polyfluoroalkyl substances (PFAS), in their bodies than the general population.

Volunteer firefighters—who comprise more than 65 percent of the U.S. fire service—monitored their exposure to PFAS. PFAS are synthetic organic substances with diverse structures, properties, uses, bioaccumulation potentials and toxicities. These chemicals do not break down easily and accumulate in human bodies and in the environment and are found in common items food packaging, electronics and carpeting. PFAS have been associated with a number health conditions that affect firefighters, including cardiovascular disease, and increasingly to cancer.

“The primary cause of line-of duty death among firefighters are heart attacks. They also get and die from many types of cancer more often than other people,” said lead author Judith Graber, an associate professor at Rutgers School of Public Health and a faculty member at the Environmental and Occupational Health Sciences Institute. “More than 95 percent of the U.S. population have these chemicals to some degree in their bodies, but firefighters have heightened exposure to PFAS through their protective gear and fire suppression foam and the burning materials they encounter that release particles, which can be inhaled or settle on gear and skin.”

The study surveyed 135 members of a volunteer fire department in New Jersey on their lifestyle and cancer risk factors. It compared traces of nine PFAS chemicals in their blood against the levels recorded in a 5000-strong nationally representative sample used by the CDC as a reference for the general population. Although over 4000 PFAS chemicals exist, the study looked at the nine chemicals commonly seen in the general population that the CDC has also tracked for the greatest length of time.

Two of thosee chemicals—perfluorododecanoic acid (PFDoA) and perfluorodecanoic acid (PFDA)—were found to be higher in volunteer firefighters. “Notably, we found PFDoA levels in 80 percent of the firefighters, but little in the general public,” Prof Graber said.

The number of years of firefighting was linked to higher levels of the chemicals; the average participant had 20 years of experience. Since they are constantly on call, volunteer firefighters may potentially have more years of firefighting-related exposures than their career counterparts, Graber said.

“The number one risk of a firefighter is being protected from the fire. The chemicals used in fire suppression foam and the protective clothing firefighters use came out 40 years ago when people thought they were safe, and they work well for what they are intended to do,” Prof Graber explained. “Further research is needed to better understand the sources of these chemicals and to design effective foam and protective clothing that do not use these chemicals.”

Source: Medical Xpress

Journal information: Judith M. Graber et al, Prevalence and Predictors of Per- and Polyfluoroalkyl Substances (PFAS) Serum Levels among Members of a Suburban US Volunteer Fire Department, International Journal of Environmental Research and Public Health (2021). DOI: 10.3390/ijerph18073730

Low-dose Radiation May be Beneficial to Humans

A study has found that cancer rates go down and life expectancy increases in areas of the US with high natural background radiation, flying in the face of decades of accepted theory that low-dose radiation is still harmful.

Natural background radiation exists from sources in the environment. This is the first large-scale study looking at terrestrial radiation (coming from radioactive elements in rocks, which vary across regions) and cosmic radiation (which increases with altitude). The Ben-Gurion University of the Negev (BGU) researchers found that life expectancy is approximately 2.5 years longer for those who live in areas of naturally high background radiation vs those who live in areas of low radiation.

The linear no-threshold (LNT) hypothesis has guided radiation protection policy in the US since the 1960s. This assumes that health risk from radiation is linear and incremental, meaning that there is no safe minimum dose – all ionising radiation is assumed to be harmful. However, numerous studies have contended that radiation at low doses initiates a protective hormesis effect.

Reduced levels of a number of types of cancers were found when in areas of high background radiation levels as opposed to lower. In both sexes, there was a significant decrease in lung, pancreatic, colon and rectal cancers. Among men, there were additional decreases in brain and bladder cancers. However, no decreases in cervix, breast or prostate cancers or leukaemia were observed.

“Decades of scientific theory are potentially being disproven by the remarkable researchers at BGU. These findings might even provide a sense of relief for those who reside in areas in the U.S. with higher-than-average background radiation,” said Doug Seserman, Chief Executive Officer, American Associates, BGU.

Using the United States Environmental Protection Agency’s radiation dose calculator, the researchers retrieved data background radiation on all 3,29 US counties. Cancer rate data were retrieved from the United States Cancer Statistics, while life expectancy data were retrieved from the Institute for Health Metrics and Evaluation at the University of Washington Medical Center.

“It is reasonable to suggest that a radiation threshold does exist, yet it is higher than the upper limit of the natural background radiation levels in the US (227 mrem/year),” the researchers wrote. “These findings provide clear indications for re-considering the linear no-threshold paradigm, at least within the natural range of low-dose radiation.”

Source: News-Medical.Net

Journal information: David, E., et al. (2021) Background radiation impacts human longevity and cancer mortality: reconsidering the linear no-threshold paradigm. Biogerontology. doi.org/10.1007/s10522-020-09909-4.

Proximity to Deforested Areas Can Increase Outbreak Risk

Aerial view of logging activities. Photo by Pok Rie from Pexels

A new study has found that human proximity to deforested areas poses an increased risk of the outbreak of zoonotic viruses.  

This adds to a growing body of evidence that human encroachment on the natural environment is resulting in zoonotic disease outbreaks.

Deforested areas and even monocultures such as commercial forests planted by humans are linked to the outbreak of diseases, the researchers found.

The researchers explained that a forest’s healthy diverse ecosystem with a range of species, blocks and filters viruses. However, in the case of monocultures where single species of plants are cultivated, like a palm oil plantation, specialist species die off and are replaced by generalists such as rats which then spread pathogens on to humans.

“I was surprised by how clear the pattern was,” said one of the study authors, Serge Morand, of the French National Centre for Scientific Research. “We must give more consideration to the role of the forest in human health, animal health and environmental health. The message from this study is ‘don’t forget the forest’.”

Using a number of databases from sources such as the World Health Organization, the researchers analysed the relationship between changes in forest cover, plantations, population and disease around the globe.
Over 1990 to 2016, the study period covered 3884 outbreaks of 116 zoonotic diseases that crossed over into humans and 1996 outbreaks of 69 vector-borne infectious diseases, largely carried by mosquitoes, ticks or flies.

“Everyone in the field of planetary health is worried about what is happening to biodiversity, climate and public health in Brazil,” Morand emphasised. “The stress there is growing. The Amazon is near a tipping point due to climate change, which is not good at all for the world ecosystem. If we reach the tipping point, the outcomes will be very bad in terms of drought, fires and for sure in terms of disease.”

The rainforests of the Congo basin and south-east Asia, and monoculture afforestation projects around the world were also cause for concern. “Our results clearly suggest that it is not only forest clearance that is responsible for outbreaks of infectious diseases, but also reforestation or afforestation, particularly in countries outside the tropical zone,” the paper noted.

Morand’s next study involves examining forest cover with satellite imagery and exploring links with that to disease.

Source: The Guardian

Edible Food Film Packaging Developed as Alternative to Plastic

Researchers from India and Russia have created edible food films for packaging fruits, vegetables, poultry, meat, and seafood. 

These films are made up of natural ingredients, and as such are safe for health and the environment. In addition, these films are water-soluble and dissolve by almost 90% over 24 hours. A description of their research and the results of their experiments are published in the Journal of Food Engineering.

Using such films would help to reduce the problem of microplastics, micrometre-scale fragments of plastic which have been detected in human stools as well as inhaled through the lungs.Chemicals such BPAs, phthalates and flame retardants, as well as heavy metals included in plastics are of concern to human health. The increased surface area/volume ratio of microplastics in combination with their hydrophobicity, results in a high affinity with a broad range of hydrophobic and persistent organic pollutants, antibiotics, and heavy metals that could be introduced into the human body through the uptake of microplastics.

“We have created three types of food films based on the well-known naturally occurring seaweed biopolymer sodium alginate. Its molecules have film-forming properties. Sodium alginate is an auspicious carbohydrate macromolecule that has the potential film-forming properties upon hydrolysis and abundantly existed in cell walls as a mixture of various salts. The greatest advantage of sodium alginate is that it performs as liquid-gel in an aqueous medium.”

Rammohan Aluru, Study Co-Author and Senior Researcher of Organic Synthesis Laboratory, Ural Federal University

The researchers cross-linked alginate molecules with a natural antioxidant ferulic acid, resulting in a strong and homogeneous film that is more rigid and prolongs the life of the products. However, being able to produce edible, naturally sourced films also has other benefits.

“Food stays fresh longer due to the antioxidant components that slow down the oxidation processes,” said Grigory Zyryanov, professor of the Department of Organic and Biomolecular Chemistry at Ural Federal University. “In addition, we can add to the films natural antiviral agents that will also extend the shelf life of food. Garlic, turmeric, and ginger contain compounds that may prevent the spread of the viruses.”

No special equipment for the production of films is required, the authors claim, and can be scaled up to an industrial scale by manufacturers of  food products and films.

“It can also be produced at a polymer production plant. The only condition is that it must meet the standards that apply to food production. And if an inexhaustible source of algae the ocean is nearby it will be quite simple to create such films,” said Prof Zyryanov.

Source: News-Medical.Net

Journal information: Yerramathia, B. B., et al. (2021) Structural studies and bioactivity of sodium alginate edible films fabricated through ferulic acid crosslinking mechanism. Journal of Food Engineering. doi.org/10.1016/j.jfoodeng.2021.110566.

Brominated Flame Retardants May Raise Breast Cancer Risk

Brominated flame retardants (BFRs) are present in a wide variety of household fixtures and furniture, and particles of this may increase the risk of breast cancer through prolonged exposure at critical times in a woman’s life.

BFRs are endocrine disruptors, and since they are not tightly bound to the substances they are included into, they are able to escape into the household environment. Endocrine disruptors can be problematic to protect against since they can exert harmful effects even at low doses. Exposure to endocrine disruptors is most disruptive in the foetal stage and during infancy; these compounds also easily cross the placental boundary and are found in breast milk. At high exposures, cells have a toxic response, but at a low dose, similar to the levels of naturally occurring hormones, endocrine dysregulation is the outcome.

Exposure to these compounds can cause problems for organs such as mammary glands, which are sensitive to hormones, which BFRs can mimic. “BFRs pose a significant risk, particularly during sensitive periods, from intrauterine life to puberty and during pregnancy,” said Professor Plante, co-director of the Intersectoral Centre for Endocrine Disruptor Analysis and environmental toxicologist.

The researchers exposed female rodents to a mixture of BFRs, similar to that found in house dust, prior to mating, during gestation and during lactation. Biologists were able to observe the effects on the offspring at two stages of development and on the mothers.

Early development of mammary glands was seen in prepubertal rats. For pubescent rats, the results, published in 2019, showed a deregulation of intercellular communication. Similar effects were observed in female genitors in a 2017 study. All of these effects are associated with an increased risk of breast cancer.

In the early 2000s, observation showed that human exposure to BFRs peaked, Professor Isabelle Plante pointed out. “Young women exposed to BFRs in utero and through breastfeeding are now in the early stages of fertility. Their mothers are in their fifties, a period of increased risk for breast cancer,” said Prof Plante. This is why the team is currently studying endocrine disruptors related to a predisposition to breast cancer, funded by the Breast Cancer Foundation and the Cancer Research Society.

In all three studies, most of the effects were observed at a low dose, raising questions about the current legislation for endocrine disruptors. “To evaluate the ‘safe’ dose, experts give an increasing dose and then, when they observe an effect, identify it as the maximum dose. With endocrine disruptors, the long-term consequences would be caused by lower doses,” reported Prof Plante.

Source: Medical Xpress

Journal information: Rita-Josiane Gouesse et al, In Utero and Lactational Exposure to an Environmentally Relevant Mixture of Brominated Flame Retardants Induces a Premature Development of the Mammary Glands, Toxicological Sciences (2020). DOI: 10.1093/toxsci/kfaa176