Tag: climate change

Categories : Environmental EffectsTags :

Extreme Heat Health Risks Are Higher for Younger Adults

On By ModernMedia
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 : Cardiovascular Disease Environmental EffectsTags :

Extreme Heat Threatens Cardiovascular Health

On By ModernMedia
Photo from Olivier Collett on Unsplash
Photo from Olivier Collett on Unsplash


With South Africa’s summer being expected to be both wetter and hotter this year, there is a greater risk of adverse cardiovascular incidents, especially for adults with pre-existing cardiovascular diseases. Experts writing in the Canadian Journal of Cardiology discuss how extreme heat affects cardiovascular health, why health professionals should care and what recommendations they can make to minimise consequences.

Extreme heat events are predicted to become longer, more common and more severe. Some 70 000 heat-related deaths occurred during the 2003 European heatwave. Risk factors for heat-related hospitalisation include age, chronic illnesses, social isolation, some medications, and lack of access to air conditioning. Among chronic illnesses, cardiovascular diseases are often identified as a risk factor for heat-related hospitalisation and death.

The Intergovernmental Panel on Climate Change (IPCC) recently reported that global temperatures are rising at a greater rate than previously projected, and that the number of extreme heat days will significantly increase across most land regions,” said senior author Daniel Gagnon, PhD, University of Montreal. “Although we don’t yet fully understand the reasons, people with cardiovascular disease are at greater risk of hospitalisations and death during extreme heat events.”

The researchers reviewed studies and noted a consistent association between extreme heat and increased risk of adverse cardiovascular outcomes. An examination of reviews and meta-analyses on the effect of extreme heat on adverse cardiovascular outcomes showed that heatwaves significantly increase mortality risk from ischaemic heart disease, stroke, and heart failure.

“Although the effects of extreme heat on adverse cardiovascular events have been explained in the context of heatstroke, many events occur without heatstroke, and the mechanisms of these events in the absence of heatstroke remain unclear,” observed Dr Gagnon. “It is likely that heat exposure increases myocardial oxygen needs.”

One possibility is that heat exposure puts excessive strain on the heart for individuals with heart disease and that heat exposure increases the risk of blood clots forming within cardiac blood vessels.

The authors propose that preventive strategies should aim to reduce the extent of hyperthermia and dehydration. In Canada, heat-health warnings systems act as a first line of defence by raising awareness of upcoming heat events and recommending strategies to minimise possible heat complications. For example, heat warnings are issued 18-24 hours before a heat event in Ontario and Québec, when ambient temperature will remain above 30°C for a minimum of two days. Public advisories include identifying the signs of heat stress, ensuring people drink adequate amounts of cold fluid or seeking an air-conditioned environment – though for many people, this is not an option.

Recent research supports electric fan use, skin wetting and immersing the feet in tap water as simple methods to stay cool during extreme heat events. “Air conditioning is the most effective strategy that can be recommended since it effectively removes the heat stimulus and minimises the risk of adverse cardiovascular outcomes,” commented Dr Gagnon. “However, less than one third of global households own air conditioning.”

More studies are needed to explain why extreme heat is linked to increased risk of adverse cardiovascular outcomes; the effect of cardiovascular medication on the human body’s physiological responses during heat exposure; the best cooling strategies in heat waves for individuals with CVD; and safe environmental limits for outdoor exercise in individuals with heart disease.

“Cardiovascular health professionals need to be aware of the negative consequences of extreme heat on cardiovascular health. A better awareness and understanding of the cardiovascular consequences of extreme heat, and of the measures to take to prevent and mitigate adverse events, will help us all assess the risk and optimize the care of patients exposed to an increasingly warm climate,” concluded Dr Gagnon.

Source: Elsevier

Categories : Environmental EffectsTags :

Tropical Areas Approaching Upper Limits for Survivable Heat

On By ModernMedia
Photo by Jordan Opel on Unsplash

Some people living in tropical regions are already living under conditions of heat stress that are approaching the upper limits of human survivability, a study has found.

In this study published in iScience, researchers noted that climate models used to predict heat conditions around the world are generally based on data from weather stations in relatively populated areas. Such data, they note, excludes conditions for people living in what they describe as informal settlements. To find out more about the conditions for people living in areas expected to be hit by the worst global warming effects, the researchers placed heat sensors in and around 100 houses in Makassar, Indonesia, a settlement in a tropical part of the country. The observed conditions are likely representative of many such settlements in the tropics, the researchers suggested.

Analysing the data, the researchers discovered that, during the rainy season, 80% of the sensors recorded temperatures in excess of established health thresholds. At such temperatures and humidity levels, adverse health impacts are said to be felt by people living there. In a few instances, they found that the sensors recorded temperatures that are believed to represent the upper limit of human survivability.

These findings are alarming for several reasons, they noted. For one, millions of people living in many parts of the world are already living under heat conditions that are harmful to their health. Another is the fact that many such people engage in physical labour for their livelihoods, and doing so in extreme heat can be fatal. Perhaps most alarming is the near certainty that conditions in such places are going to get worse as the planet continues to warm from fossil fuel burning and climate change. An analysis of the agreements reached at the COP26 summit found that the Earth was on course for a 2.4°C increase in temperature, well above the 1.5°C increase suggested by scientists to avoid the worst effects of climate change. For most such places, there are no relocation plans, and little chance that heat-mitigating technology such as air-conditioning will be installed. This suggests that a disaster of massive proportions is on the way.

Source: Phys.Org

Categories : Environmental Effects Neurodegenerative DiseasesTags :

With Climate Change, Heat May Worsen Multiple Sclerosis Symptoms

On By ModernMedia

As average global temperatures increase due to climate change, multiple sclerosis (MS) patients can experience worsening symptoms resulting in an increase in hospital visits.

Some 60% to 80% of MS patients experience heat sensitivity. Increased body temperature slows or stops nerve signals in damaged nerves, which has a number of impacts such as blurred vision and other neurological effects. Heat sensitivity is also correlated with fatigue. Together with fatigue, divided attention from heat sensitivity can contribute to falls.

“We know that heat sensitivity is common in multiple sclerosis, and climate scientists expect that periods of anomalously warm weather will become more frequent with climate change,” said study author Holly Elser, PhD. of Stanford University School of Medicine. “Our study suggests that warming trends could have serious health implications over the long term for people living with MS.”

The study defined anomalously warm weather as a month in which local average temperatures were higher than the long-term average temperature for that month by at least 1.5C.

The researchers drew data on insurance claims for 106 225 people with MS living in the US, and then calculated the estimated effect of anomalously warm weather on MS-related emergency department, inpatient and outpatient visits. Then, the number of medical visits for each person during anomalously warm weather periods was compared to those for periods of normal weather periods.

During anomalously warm weather periods, there was a 4% increased chance of an emergency department visit compared to periods of normal weather. Participants had a 3% increased chance of having an inpatient visit and a 1% increased chance of having an outpatient visit during anomalously warm periods compared to periods of normal weather.

Researchers estimate that during the follow-up period, anomalously warm weather periods were linked to an estimated excess of at least 592 emergency department visits, 1260 inpatient visits and 1960 outpatient visits related to MS.

“While the relative increase in risk of visits is small, the associated absolute effect on people with MS and the health care system is meaningful,” concluded Dr Elser.

Source: Medical Xpress