Tag: environmental health

Categories : Paediatrics Respiratory DiseasesTags :

Indoor Air Pollution Linked to Pneumonia in Children

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Streptococcus pneumoniae. Credit: CDC

A new study published in The Lancet Global Health, highlights the impact indoor air pollution can have on the development of child pneumonia, showing that increases in airborne particulate matter results in greater carriage of Streptococcus pneumoniae.

Streptococcus pneumoniae is a major human pathogen causing more than two million deaths per year; more than HIV/AIDS, measles and malaria combined, but it is also part of the normal microbial community of the nasopharynx. It is the leading cause of death due to infectious disease in children under five years of age; in sub-Saharan Africa, the burden of pneumococcal carriage and pneumonia is especially high.

Household air pollution from solid fuels increases the risk of childhood pneumonia. Nasopharyngeal carriage of S. pneumoniae is a necessary step in the development of pneumococcal pneumonia. More than 2.6 billion people are exposed to household air pollution worldwide. Inefficient indoor biomass burning is estimated to cause 3.8 million premature deaths annually and approximately 45% of all pneumonia deaths in children aged younger than five years. However, a causal pathway between household air pollution and pneumonia had not yet been identified.

In order to understand the connection between exposure to household air pollution and the risk of childhood pneumonia researchers from the UK, Malawi and the United States conducted the MSCAPE (Malawi Streptococcus pneumoniae Carriage and Air Pollution Exposure) study embedded in the ongoing CAPS (Child And Pneumonia Study) trial. The MSCAPE study assessed the impact of PM2.5, the single most important health-damaging pollutant in household air pollution, on the prevalence of pneumococcal carriage in a large sample of 485 Malawian children.

Through exposure-response analysis, a statistically significant 10% increase in risk of S. pneumoniae carriage in children was observed for a unit increase (deciles) of exposure to PM2.5 (ranging from 3.9 μg/m³ to 617.0 μg/m³).

Dr. Mukesh Dherani, the study principal investigator, indicated: “This study provides us with greater insight into the impact household air pollution can have on the development of child pneumonia. These findings provide important new evidence of intermediary steps in the causal pathway of household air pollution exposure to pneumonia and provide a platform for future mechanistic studies.”

Study author Professor Dan Pope said: “Moving forward further studies, particularly new randomized controlled trials comparing clean fuels (e.g. liquefied petroleum gas) with biomass fuels, with detailed measurements of PM2.5 exposure, and studies of mechanisms underlying increased pneumococcal carriage, are required to strengthen causal evidence for this component of the pathway from household air pollution exposure to ALRI in children.”

Professor Nigel Bruce, co-principal investigator, stated: “This study provides further important evidence that emphasises the need to accelerate to cleaner fuels, such as LPG, which are now being promoted by many governments across the continent in order to meet SDG7 by 2030.”

Source: University of Liverpool

Categories : Environmental EffectsTags :

Extreme Heat Health Risks Are Higher for Younger Adults

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Photo by Ketut Subiyanto on Pexels

A new study in the US has found that complications from extreme heat appear to be more pronounced among young and middle-aged adults than older adults.

Extreme heat poses an increasing threat to the public, due to the continued effects of climate change. Although the adverse health impacts of heat have been well documented among older adults, less is known about the potential impacts of heat on young and middle-aged adults.

Published in the BMJ, the study examined the relationship between extreme temperatures and emergency department (ED) visits, and found that days of extreme heat were associated with an increase risk of ED visits for any cause, heat-related illness, renal disease, and mental disorders among all adults, but the strongest association was found among adults ages 18-64.

Prior research on heat’s health impacts have mostly focused on mortality or hospital admissions among seniors. This study is the first national-scale assessment of extreme heat effects on adults of all ages, measured with ED visits.

“Many illnesses that lead to utilisation of the ED do not lead to hospitalisation because they can be treated in a short amount of time, particularly among the younger adult population,” said study senior author Gregory Wellenius, professor of environmental health and director of the Program on Climate and Health at SPH. “By looking at emergency room visits, we aimed to obtain a more comprehensive picture of the true burden of disease that might be attributed to the days of high heat.”

Prof Wellenius and colleagues analysed healthcare claims data to quantify the risk of ED visits for any cause and for heat-associated conditions during the warm season (between May and September) from 2010 to 2019.

For the study, the researchers analysed claims data among 74 million adults, including more than 22 million ED visits. They found that days of extreme heat (varying by location, but averaging about 34°C), were associated with a 66% greater risk of ED visits for heat-related illness, as well as a 30% increased risk for renal disease, compared to ED visits on cooler days. But the risk according to extreme heat varied by age. A day of extreme heat was associated with a 10.3% higher risk of ED visits among people ages 45 to 54 years old, compared to a 3.6% higher risk among those older than 75.

“Younger adults may be at greater risk of exposure to extreme heat, particularly among workers that spend substantial time outdoors,” says study lead author Shengzhi Sun, research scientist in the Department of Environmental Health at SPH. “Younger adults may also not realise that they too can be at risk on days of extreme heat.”

Prior studies had shown that people in US counties with lower warm-season temperatures still experience higher risks of heat-related complications.
“While extreme heat threatens everyone’s health, this study provides further evidence that it is especially dangerous in regions with cooler climates that may be less adapted to heat,” says study co-author Kate Weinberger, assistant professor at the University of British Columbia’s School of Population and Public Health. “As temperatures continue to rise due to climate change, the implementation of heat adaptation measures in these regions will be critically important.”

According to the researchers, many of these heat-related complications can be prevented through policy changes that reduce exposure to heat, or improve people’s susceptibility and adaptivity to heat.

“By looking at emergency department visits for different causes and for several age groups, we were able to characterise with accuracy the varying impact on health on different populations,” said study co-author, Professor Francesca Dominici. “An important goal of this study is to provide actionable information to clinicians and public health experts regarding how to prevent these emergency department visits, also considering that we can anticipate when these extreme heat events are likely to occur.”

Source: Boston University

Categories : Environmental EffectsTags :

Global Warming Drives a Third of Heat-related Deaths

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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.

Categories : Environmental EffectsTags :

How Air Pollution Causes Loss of Smell

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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