Asthma affects more than 25 million people in the US - surpassing the number of people with Parkinson's disease, Alzheimer's disease and cancer put together. But asthma is not as serious as these conditions, right? Wrong. Asthma kills 3,300 Americans annually and is responsible for more than a quarter of all emergency room visits each year.
The majority of asthma-related hospital visits and deaths are preventable. But it is partly down to lack of awareness that such incidents occur. Many sufferers do not view their symptoms as serious enough to warrant treatment or control. People whose asthma is not under control can potentially be thrown into a life-threatening situation by the condition.
It seems the assumption that asthma is not a serious condition is widespread, and this view is something that asthma charities and organizations worldwide are trying to quash.
Last year, leading charity Asthma UK wrote to the Daily Mail complaining about an article from the newspaper that suggested too many people claim the UK's Disability Living Allowance for asthma. According to Asthma UK, the article made a "dangerous assumption that asthma is not serious."
"People with very severe asthma have told us of problems doing even simple things like walking, dressing, caring for children, doing the shopping or getting a full night's sleep," Asthma UK wrote to the newspaper. "Let us be in no doubt; asthma is serious."
In an attempt to make people mindful of just how serious asthma is, May has been declared as National Asthma and Allergy Awareness Month. In line with this campaign, we use this spotlight feature to explore the triggers of asthma, how symptoms can be kept under control and what is contributing to increasing asthma prevalence and death rates.
Asthma and its triggers
Asthma is a chronic disease characterized by inflammation and narrowing of the airways - small tubes called bronchi - that carry air to and from the lungs. Its symptoms include shortness of breath, wheezing, chest tightness and coughing.
According to the Asthma and Allergy Foundation of America (AAFA), more than 50% of asthma cases in the US are caused by allergies. This is a form of the condition that is triggered by inhaled allergens, such as dust, pollen, mold and pet dander.
People who have allergic asthma are hypersensitive to such allergens. Once they get into the airways, the immune system overreacts. Muscles around the airways become tightened and cells in the airways produce a thick mucus.
Non-allergic asthma is a form of the condition that is not triggered by an allergic reaction. Instead, it can be brought on by other factors, such as anxiety, stress, exercise, cold air, dry air, hyperventilation and viruses.
Sudden and severe onset of asthma symptoms is referred to as an "asthma attack" - an episode that affects 44,000 Americans every day. In 2007, 165 children and 3,262 adults died from an asthma attack.
During an asthma attack, the lining of the airways becomes inflamed - similar to an allergy attack - and cells in the airways produce a thicker mucus than usual.
Signs of an approaching asthma attack include fatigue, an itchy neck, dark bags under the eyes and being short-tempered, irritable or nervous. Slow breathing or blue/gray lips or fingernails are signs of a serious medical emergency, and anyone experiencing such symptoms should call 911 (999 in the UK) immediately.
Although there is no cure for asthma, there are a number of ways the condition can be controlled in order to prevent asthma attacks.
Use of quick-relief medication - such as inhaled short-acting beta2-agonists - are recommended for asthma flare-ups.
First of all, it is recommended that asthma sufferers avoid triggers that encourage symptoms. For example, if pollen exposure sets off a person's asthma, they should avoid outdoor environments when pollen levels are high.
In case of asthma flare-ups or an asthma attack, quick-relief medicines - such as inhaled short-acting beta2-agonists - are recommended. These medicines are delivered by use of an inhaler and work by quickly opening up airways, allowing air to flow through.
According to the National Heart, Lung and Blood Institute (NHLBI), if symptoms of asthma occur more than twice a week, long-term control medicines - such as inhaled corticosteroids - may be recommended. Such medication reduces airway inflammation and helps prevent onset of asthma symptoms.
In order to keep full control of asthma, health professionals recommend that asthmatics should track their symptoms. The NHLBI state that a patient can work with their doctor to create an asthma action plan.
They note that asthma is well-controlled if:
- Symptoms occur no more than 2 days a week
- Symptoms do not wake the patient more than 1 or 2 nights a month
- The patient can carry out normal daily activities
- Quick-relief medicines are not required more than 2 days a week
- The patient has no more than one asthma attack a year that requires them to take corticosteroids by mouth
- Peak flow (the ability of air to move in and out of the lungs) does not fall below 80% of the patient's personal best.
Dr. Suzanne Beavers, of the Air Pollution and Respiratory Health Branch at the Centers for Disease Control and Prevention (CDC) and National Center for Environmental Health, told Medical News Today:
"CDC recommends people with asthma bear in mind that they can control their asthma. Developing a personal asthma action plan, avoiding asthma triggers, taking asthma medications as prescribed and seeing a health care provider regularly can help anyone control his or her asthma."
'People need to take asthma more seriously'
Given the increasing death rates from asthma, it seems that a good control of symptoms may be lacking.
According to the AAFA, asthma death rates have increased by more than 50% since the early 1980s, while death rates among children under the age of 19 years old have increased by almost 80%.
Past research has indicated that it is down to people's attitude toward asthma that causes lack of symptom control.
A 2002 study published in the journal Respiratory Medicine found that patients fail to recognize warning symptoms of asthma, do not believe there will ever be a permanent cure, and therefore fail to undergo the treatment they need.
The American Academy of Allergy, Asthma Immunology (AAAAI) state that in 2008, less than half of people with asthma knew how to avoid triggers of the condition, while almost half of those who knew how to avoid triggers did not do so.
"People do need to take asthma and allergic conditions more seriously. People die from complications linked to these diseases more often than they should," Talissa White, external affairs manager of the AAFA told Medical News Today.
Many health care professionals argue that asthmatics need better tools to control their asthma.
Earlier this year, researchers from the Cincinnati Children's Hospital in Ohio focused on helping 322 teenagers better manage their asthma symptoms by providing them with a "care bundle of tools."
"These included standardized and evidence-based care; self-management support, such as self-monitoring by using diaries and journals; care coordination and active outreach among health care providers; linking these teens to community resources; and following-up with patients whose chronic asthma is not well-controlled," explained senior study author Dr. Maria Britto.
At study baseline, only 10% of participants had good control of their asthma symptoms. By the end of the study, this increased to 30%. The researchers said their study showed that supported self-management programs may be effective in preventing asthma-related hospitalizations.
Given the increasing prevalence of asthma, some health professionals believe that because the condition is so widespread, many people underestimate its seriousness. After all, it is human nature that the more common something is, the less important it is perceived to be.
The hygiene hypothesis
"Over the last decade, we have seen an increase in the number of Americans with Asthma," White added. "In fact, between 2001 and 2011, the number of Americans with asthma grew by 28%."
Research has indicated that the "hygiene hypothesis" may be a cause of asthma - the idea that certain populations are not exposed to "healthy microbes" in rural areas that supposedly protect against the condition.
And it seems asthma prevalence is increasing globally. At present, approximately 300 million people around the world have asthma. This number is expected to grow by more than 100 million by 2025.
But why are we seeing such a rapid rise in asthma prevalence?
Exactly what causes asthma is unclear. It is known that there is a genetic risk involved in asthma development; a person is at high risk for the condition if a relative has it.
Research has also shown that use of antibiotics in children, cigarette smoke exposure and viral infections in early life may increase asthma risk.
However, one widely studied potential cause of asthma development is the "hygiene hypothesis." This is the idea that certain populations are not exposed to "healthy microbes" that supposedly protect against asthma, allergies and other inflammatory disorders.
Medical News Today recently reported on a study that builds on the hygiene hypothesis. Led by Christopher Lowry of the Department of Integrated Physiology at the University of Colorado Boulder, the study suggests that populations in urban areas are more prone to asthma and allergies because these healthy microbes reside in more rural areas.
Lowry told us he believes that this theory may partly explain the increase in asthma and allergies:
"We believe that cases of asthma and allergic disease are on the rise in part because, in modern urban societies, people have reduced exposure to environmental organisms that co-evolved with humans; organisms that induce anti-inflammatory responses.
Studies in animal models have shown that just a few immunizations with a single heat-killed environmental bacterium can reduce asthma symptoms."
Dr. Mark Holbreich, a fellow of the AAAAI and an allergy and asthma consultant in Indianapolis, IN, has also conducted research that supports the idea that certain environmental exposure can protect against asthma and allergies. He led a 2012 study that found Amish children who were raised on rural farms were much less likely to have asthma and allergies, compared with farm children from Switzerland.
"There is increasing information in medical literature that certain populations have a very low prevalence of allergies and asthma. These are populations that have an exposure to a rich microbial environment," Dr. Holbreich told us.
Lowry believes that the hygiene hypothesis is a useful tool for finding ways to prevent and treat asthma and allergies, and given the rapid increase in prevalence of such conditions, more research in this area is needed.
"On a larger scale, we should be investing in research to identify novel approaches for the prevention and treatment of allergies and asthma," said Lowry. "We should also consider rational design of urban spaces to maximize exposure to health-promoting environmental microorganisms."
The quest for asthma intervention
Aside from the hygiene hypothesis, scientists are in the process of investigating other areas in an attempt to find new treatments for asthma.
Medical News Today recently reported on a study published in the Proceedings of the National Academy of Sciences (PNAS), which detailed the discovery of a molecule that could treat allergic asthma.
Other research has found that a high-fiber diet could protect against asthma, while a 2013 study found that when children are exposed to dogs regularly in early infancy, their risk of developing asthma and allergies decreases.
But while many of these suggested interventions require further investigation and may take many years to confirm, Dr. Holbreich said that there are prevention strategies for asthma that can be actioned immediately:
"Two things that can be of immediate benefit for decreasing the prevalence and risk of this disease is decrease in cigarette smoke exposure in all families and reduction in childhood obesity."