Asthma is a chronic disease caused by inflammation of the airways that narrow, making breathing difficult and causing shortness of breath. Symptoms usually take the form of attacks (asthma attacks) that occur after exposure to triggers such as allergens, certain medications, viral infections or tobacco, among others. It is a major health problem worldwide, with a prevalence of between 5 and 14% of the population.

So far, no single direct cause of asthma has been identified, although many different risk factors related to the disease have been identified. Among them are:

  • Presence of other allergies. It has been shown that asthma is more frequent in people suffering from other allergies, eczema or rhinitis.
  • Urbanization: asthma is more frequent in people living in large cities, probably due to lifestyle factors.
  • Problems in lung development and maturation during childhood, associated with prematurity, exposure to tobacco smoke, underweight newborns or viral respiratory infections.
  • Exposure to allergens and environmental irritants such as dust mites, air pollution, chemicals, fumes or dust.
  • Overweight and obesity in children and adults.

Asthma is a genetically complex disease that affects more than 300 million people worldwide. An association study conducted in some 65,000 asthmatics and more than 300,000 controls has identified susceptibility genes including CD52 and regions of open chromatin in immune cells. These results allow a better understanding of the genetic architecture of the disease and provide information on possible therapeutic targets. The study also highlights the increased susceptibility of the male sex to the disease with markers specifically associated with men.


Asthma is a chronic disease that causes the lungs to swell and constrict causing a series of characteristic symptoms, which may vary from person to person. In most cases, asthma presents with attacks, lasting minutes or days, separated by symptom-free periods. During the acute period one may experience:

  • Cough with or without phlegm production.
  • Intercostal tightness (pulling of the skin between the ribs when breathing).
  • Shortness of breath that worsens with activity.
  • Wheezing when breathing.
  • Chest pain or stiffness.
  • Difficulty sleeping.
  • Abnormal breathing pattern.

Occasionally, more serious symptoms may occur that require immediate medical attention, such as blueness of the skin, decreased alertness, extreme shortness of breath, or rapid pulse.


To date there are no effective measures to prevent the onset of asthma, but it can be treated to prevent the main triggers and avoid new attacks.

  • Avoid breathing allergenic substances such as pollen, dust mites, fungi or animal hair (especially cat and dog hair). Avoid or reduce exposure to dust mites by avoiding carpets, rugs and stuffed animals in your home.
  • Avoid use of medications such as aspirin or other non-steroidal anti-inflammatory drugs.
  • Avoid exposure to irritants such as tobacco smoke, air pollution, cleaning products, hairspray, etc.
  • Avoid humid and warm environments such as indoor swimming pools, or intense physical exercise.

In addition to pharmacological treatments, which may be necessary to control asthma symptoms (mainly bronchial dilators and inhaled corticosteroids), immunotherapy, i.e. allergy vaccines, is available in some cases. This treatment is the only one that has been shown to reduce the natural course of allergic disease, although its potential benefit depends on the type of allergy and is not recommended for all patients with asthma.

Number of observed variants

13.5 million variants

Number of risk loci analyzed in the study

123 loci


Han Y, Jia Q, Jahani PS, et al . Genome-wide analysis highlights contribution of immune system pathways to the genetic architecture of asthma. Nature Communications. 2020 Apr;11(1):1776.

Papi A, Brightling C, Pedersen SE, Reddel HK. Asthma. Lancet. 2018 Feb 24;391(10122):783-800. doi: 10.1016/S0140-6736(17)33311-1. Epub 2017 Dec 19.

Centers for Disease Control and Prevention (CDC) [March 2022]

Word Health Organization (WHO) [March 2022]

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