Climate crisis seriously damaging human health, report finds
National academies say effects include spread of diseases and worse mental health
A report by experts from 27 national science academies has set out the widespread damage global heating is already causing to people’s health and the increasingly serious impacts expected in future.
Scorching heatwaves and floods will claim more victims as extreme weather increases but there are serious indirect effects too, from spreading mosquito-borne diseases to worsening mental health.
“There are impacts occurring now [and], over the coming century, climate change has to be ranked as one of the most serious threats to health,” said Prof Sir Andrew Haines, a co-chair of the report for the European Academies’ Science Advisory Council (Easac).
However, there were also great benefits from action to cut carbon emissions, the report found, most notably cutting the 350,000 early deaths from air pollution every year in Europe caused by burning fossil fuels. “The economic benefits of action to address the current and prospective health effects of climate change are likely to be substantial,” the report concluded.
The World Health Organization director general, Tedros Adhanom Ghebreyesus, warned in November that climate breakdown was already a health crisis. “We cannot delay action on climate change,” he said. “We cannot sleepwalk through this health emergency any longer.” In December, a WHO report said tackling the climate crisis would save at least a million lives a year, making it a moral imperative to act.
The new Easeac report, The Imperativeof Climate Action to Protect Human Health in Europe, assessed the scientific evidence of the effects of global heating on health. Extreme weather such as heatwaves, floods and droughts have direct short-term impacts but also affect people in the longer term. “Mental health effects include post-traumatic stress disorder, anxiety, substance abuse and depression,” the report said.
The scientists were also concerned by the effect of extreme weather on food production, with studies showing a 5-25% cut in staple crop yields across the Mediterranean region in coming decades. But the report said even small cuts in meat eating could lead to significant cuts in carbon emissions, as well as benefits to health.
The report anticipates the spread of infectious diseases in Europe as temperatures rise and increase the range of mosquitoes that transmit dengue fever and ticks that cause Lyme disease. Food poisoning could also rise, as salmonella bacteria thrived in warmer conditions, the report said. It even found research suggesting antibiotic resistance in E coli increases in hotter conditions.
“We are exposing the whole of the world population to changes in climate, and this is clearly very concerning as we are moving to some extent into uncharted territory,” said Haines, professor of environmental change and public health at the London School of Hygiene and Tropical Medicine.
“We are subjecting young people and future generations to these increasing [health] risks for many hundreds of years to come, if not millennia,” he said. “We have to try to minimise the effects and move towards a low-carbon economy.
“We think reframing climate change as a health issue can help to engage the public because most people are not just concerned about their own health, but about the health of their nearest and dearest and their descendants.
“We think this is a way of mobilising the public and raising concern in a constructive way and increasing the momentum for change.”
Global carbon emissions are still rising but scientists say rapid and deep cuts are needed to limit temperature rises to 1.5C above pre-industrial levels and avoid the worst impacts.
How Much Does Your Education Level Affect Your Health?
Education is associated with better health outcomes, but trying to figure out whether it actually causes better health is tricky.
People with at least some college education have mortality rates (deaths per 1,000 individuals per year) less than half of those without any college education, according to the Centers for Disease Control and Prevention.
In addition, people who are more educated exhibit less anxiety and depression, have fewer functional limitations, and are less likely to have a serious health condition like diabetes, cardiovascular disease or asthma.
But causality runs both ways. People in poor health from a young age may be unable to pursue education as much as those with better health. On the other hand, a person who tends to focus on long-term outcomes may be motivated to develop healthier habits like regular exercise — even if blocked from a pursuit of higher education.
Some clever studies have teased out the causal effects of education by exploiting natural experiments. One, by the U.C.L.A economist Adriana Lleras-Muney, relied on state compulsory education laws enacted between 1915 and 1939. These laws required some children to obtain more education than they might have otherwise, resulting in longer lives for those that did so. According to the study, having an additional year of education by 1960 increased life expectancy at age 35 by 1.7 years.
Studies that relied on inducements for greater education because of a poor labor market or as a way to avoid the Vietnam draft found that increased education led to better health and a lower likelihood of smoking. This finding is one clue about how education may improve health. It can reduce people’s engagement in risky behaviors, perhaps because those behaviors could threaten the higher income that greater education typically confersS
But health behaviors can explain only a portion of the relationship between education and mortality. Education may also provide skills to analyze information and tackle complex problems — precisely what’s needed to navigate the modern health system and attend to chronic diseases.
A higher level of education is also associated with higher income and greater wealth, which are also correlated with better health.
Again, causality goes both ways. You have to be reasonably healthy to keep a job or to work long hours, for example. But higher income also often comes with better health insurance and easier access to health care.
Much of income’s effect on health may originate in childhood. Many studies demonstrate that children of wealthier parents are in better health, perhaps because of better access to prenatal care and nutrition, or because they live in less polluted environments. A healthier childhood often means a healthier adulthood. And children born to higher-income parents are more likely to obtain more education and have higher incomes themselves. That’s how the income-health relationship may propagate across generations.
Greater education and wealth can also confer greater social status or rank, which has also been linked to health. A landmark studypublished in 1978 found that higher-ranking British civil servants (like administrators) had lower rates of mortality due to coronary heart disease than lower-ranking ones (like messengers). Lower-ranked civil servants tended to be heavier; they had higher blood pressure and blood sugar, and smoked more. Many investigations have replicated this relationship between social rank and health.
An intriguing hypothesis that links social standing and health is that people of lower status lead more stressful lives. Stress is known to alter blood flow and release hormones damaging to tissue, suppressing the immune system and raising risks of cardiovascular disease and mortality. One study linked childhood poverty to chronic stress and subsequent reductions in memory, which could affect education, wage attainment and health. Even stress endured in pregnancy can affect the health of the fetus in ways that endure throughout life, research suggests.
Health also varies by racial and ethnic identity, which also tend to play a big role in social standing.
For example, African-Americans have higher rates of mortality than white Americans, even after adjusting for income and education. Here too, there are childhood origins — African-American infants are more likely to be born preterm and with lower birth weights.
One reason may be less access to prenatal care. African-American patients are also less likely to receive preventive health care and more likely to live in areas with lower-quality hospitals and doctors. Disadvantages and stress stemming from a history of discrimination and community segregation underlie these and other disparities.
Hispanics tend to be healthier than comparable non-Hispanic white Americans, despite being poorer on average. The Hispanic paradox, as it’s known, could be because Hispanic immigrants are typically in better health than native U.S. residents (people who are healthier in the first place may be more likely to migrate). Or it could be because of health behaviors. For example, Hispanics are less likely to smoke or drink frequently than their non-Hispanic white counterparts.
In this century, there has been a sharp rise in so-called deaths of despair — suicides, drug overdoses or alcohol abuse — for middle-aged white Americans without a college degree. Even as mortality rates for the poorly educated have risen, the rates among those with some college education have held nearly steady or gone down since 2007.
In 2012, researchers found that life expectancy for white women without a high school diploma was 73.5 years compared with 83.9 years for white women with a college degree or more. For white men, it was 67.5 years for those without a diploma compared with 80.4 for those with a college degree or better.
Just as our health is affected by lifestyle, genes, the environment and the health system, education has a role, too. We can’t yet say exactly how much or exactly why. But a decrease in longevity associated with lower education levels may help explain why overall American life expectancy has declined slightly in recent years.
Menopause and heart health: Why timing hormone therapy is key
Researchers already know that menopause affects the heart, but a new study suggests that changes start to take place in the years leading up to this phase. The study findings could change how doctors administer hormone replacement therapy.
The older a person gets, the more likely they are to develop heart disease. However, the risk of the condition — which is the biggest killer of women in the United States — increases even more during menopause.
Experts believe that this is due to a drop in the levels of estrogen, as this hormone helps the arteries function properly.
Hormone replacement therapy (HRT) is one way to treat the symptoms that this decline causes, but the fears surrounding this treatment have not subsided since decades-old research suggested a link to heart issues and cancer.
A 2017 JAMA study found that women who took HRT tablets were no more likely to die of cardiovascular disease, cancer, or another cause within 18 years than women who did not take them. Despite this, people are still reluctant to try the treatment.
Mimicking the perimenopausal period
New findings suggest that HRT may be effective in protecting the heart, but not when people take it after the menopause, as is currently the norm.
The new study, which appears in Acta Physiologica, focused on what happens to the heart during the years leading up to menopause. This period is called perimenopause.
Previously, researchers only studied menopausal or postmenopausal hearts because scientists were unable to replicate the perimenopausal stage in mice.
That changed when a team from the University of Guelph in Ontario, Canada found a way to achieve this.
“We could induce instant menopause in lab mice by removing their ovaries, but that doesn’t recapture the gradual change of menopause,” says senior author Prof. Glen Pyle. “We now have a lab animal model in which we can make a mouse’s ovaries fail slowly over time to mimic the gradual transition to menopause seen in women.”
Testing ‘the timing hypothesis’
As a result, a group of mice entered menopause slowly over 4 months. Their hearts appeared to look normal and function in the same way, but “markers of stress” appeared.
“So, it’s like a house that looks fine, but there’s a leak in the foundation. The changes are hidden, but they are there,” notes Prof. Pyle.
The team administered drugs mimicking estrogen to the mice during perimenopause.
Prof. Pyle states, “We wanted to test the timing hypothesis: the idea that there’s a window of opportunity for taking estrogen so that we could see if we could identify that window and determine how menopause impacted the response to estrogens.”