Although there have been many studies in laboratory conditions, on animal models, and in humans, the exact cause of asthma has not yet been identified. When scientists say this, it sounds awkward, because we all know some of the risk factors responsible for the development of asthma, such as allergy and stress. What they actually mean is that it is not certain what is that ultimate trigger, and why some people with all the risk factors never develop asthma, while there are patients with no risk factors who develop asthma.
However, the mechanism of immune system changes in asthma is very well researched, as well as the influence of certain risk factors, such as allergy, genetic predisposition, certain foods, heartburn, physical exercise, and stress.
There are some strong allergens which can induce asthma in sensitive persons. For example, birch pollen has been identified as a strong allergen, which can contribute to the development of adult-onset asthma.
However, the most common scenario involves persons with an atopic constitution (very prone to allergies) who often develop allergic reactions to multiple allergens during early childhood. These persons have a sort of a “shift” towards so-called th2 immune response, which stimulates an increased production of IgE antibodies and certain interleukins, specific for allergic reactions.
Due to these complicated mechanisms, prolonged reactions to multiple allergens can cause chronic inflammation of the airways, which eventually becomes self-sustaining and continues to exist even when allergens are absent. This is the most common way through which chronic inflammation of the airways turns to asthma and it usually happens in early childhood.
Genetic predisposition for asthma
Large studies have demonstrated many times that the children of people with asthma are at higher risk of developing asthma than others. This means that there is some sort of genetic predisposition to asthma. However, there is no single genetic mutation that we could blame. Instead, several different genes and their interactions, as well as the influence of environmental factors are responsible for the development of asthma. Such type of inheritance is called multifactorial inheritance and it is very hard to identify a specific genetic pattern in persons with asthma because of the presence of many interconnected factors. Still, genetic predisposition for asthma should be taken into account when making the diagnosis.
Food as a risk factor for asthma
Certain foods can provoke the immune system to develop an inflammatory reaction in the airways. Consequently, the symptoms of asthma may develop. However, the studies conducted on this subject did not come up with many conclusions as to which foods can trigger asthma. It seems that food allergies are at the basis of this mechanism, and, as you know, one can be allergic to basically any food. Another fact that scientists have noticed was that the lack of some necessary nutrients, such as vitamin D, is often found in asthma patients. These findings definitely need more backup from larger randomized controlled clinical studies.
Can heartburn induce asthma?
Heartburn manifests as lower chest or upper abdominal pain, often described as burning. It is a result of the reflux of the stomach content back into the esophagus. The condition may produce significant changes to the mucosa of the esophagus and cause Gastroesophageal Reflux Disease (GERD). But what does it have to do with asthma?
First of all, both conditions are very common, and if a person suffers from both heartburn and asthma, that is not a strong enough reason to conclude that their coexistence is related. However, scientists have noticed that GERD is more frequent in asthmatic patients than in the general population. Some researchers suggest that antacids (drugs for GERD treatment) should be applied in persons with severe asthma, even if they don’t have the symptoms of GERD. They think that due to a possible causative relationship between the two conditions, patients may have better chances of managing asthma symptoms by suppressing GERD. However, this is not recommended for mild or moderate cases of asthma.
Physical Exercise And Asthma
Most asthma patients experience worsening of their symptoms during some type of physical activity, but there are also those who only have symptoms while exercising. This type of asthma is called Exercise-induced Bronchoconstriction (EIB). Exercising especially worsens the symptoms of asthma if the air is dry and cold. Cold air, especially if inhaled by mouth tends to irritate the airways and causes their narrowing in asthmatic patients.
Patients should also avoid outdoor sports such as running if they have seasonal allergies.
This does not mean that persons with asthma should give up physical activity. On the contrary, exercise is good for the cardiovascular, respiratory, as well for the immune system. However, asthma patients should choose different types of activities that do not aggravate their symptoms. One of the best activities that are commonly recommended for patients with asthma is swimming. At swimming pools, the air is warm and humid, and it could even help to cough out the extra secret produced due to the inflammation of the respiratory mucosa. Other recommended activities include walking, hiking, and biking (moderate level).
More and more studies are showing evidence that asthma and psychological stress often occur together. Acute asthma attacks are also more common in asthma patients during the stressful periods in their life. Psychologists and psychiatrists have noticed a higher incidence of asthma in patients with Post Traumatic Stress Disorder (PTSD). From another viewpoint, stress is detrimental to human health in general, and it is highly probable that it could have a negative impact on patients with asthma. Furthermore, it can also play a significant role as a risk factor in the initiation of pathological mechanisms which contribute to the development of asthma.