A risk factor is something that increases your likelihood of getting a disease or condition.

It is possible to develop asthma with or without the risk factors listed below. However, the more risk factors you have, the greater your likelihood of developing asthma. If you have a number of risk factors, ask your doctor what you can do to reduce your risk.

Risk factors for asthma include:


It has been noted that asthma tends to run in families. People whose immediate blood relatives have asthma are more likely to develop the disease.

Genes and your environment play a role in the development of asthma. When asthma runs in families, genetic factors play a relatively large role. When asthma does not run in families, the genetic influence is not as significant as the environmental exposures.


People who have allergies (especially allergic rhinitis and severe food allergies) have a greater chance of developing asthma. Allergens that may be associated with asthma include:

  • Pollen
  • Animal dander
  • Mites
  • Molds
  • Dust and dust mites
  • Certain foods
  • Aspirin or other nonsteroidal anti-inflammatory drugs
  • Air pollution
  • Cigarette smoke

Medical Conditions

The following medical conditions increase your risk of developing asthma:


Although asthma can develop at any age, current statistics show that more than 50% of asthma cases are found in children between the ages of 2-17.

Exposure to Potential Allergens

Frequent exposure to the following potential allergens increases your risk of developing asthma:

  • Second-hand tobacco smoke
  • Pets
  • Molds
  • Dust mites
  • Occupational irritants, such as chemicals used in:
    • Farming
    • Beauty salons
    • Manufacturing plants of steel, plastics, and electronics
  • High levels of air pollution, particularly in an urban environment


Both males and females develop asthma. During childhood it is more common in boys; however, after the age of 20 the ratio is equal among the sexes.

Ethnic Background

Asthma affects people of all ethnic backgrounds. However, it is slightly more common in blacks and Hispanics than in whites.