Asthma Risk Factors

Certain risk factors increase the chance that an individual will develop asthma. These risk factors include:

  • Low birth weight
  • Exposure to second hand smoke
  • Having a mother who smoked during pregnancy
  • Exposure to airborne pollution such as exhaust fumes
  • Black
  • Living in a low-income environment
  • Living in an urban environment
  • Having other allergies
  • Eczema
  • Hay fever
  • Parents or siblings with asthma
  • Occupational exposure to chemicals such as those used in hairdressing, manufacturing and farming

Other factors such as obesity and stress have been linked with higher rates of asthma.


  • Boys are more likely to get asthma than girls during childhood but this trend reverses during adulthood.
  • There are approximately 300 million asthma sufferers worldwide.
  • About 250,000 deaths are attributed to asthma each year with most of these deaths deemed to be avoidable.
  • Researchers predict that there will be 400,000 asthma sufferers worldwide by 2025.
  • More than 10% of asthma cases are a result of occupational exposure to fumes, gases or dust.
  • Asthma deaths are more likely to occur in low and lower-middle income countries with over 80% of deaths occurring in these countries.
  • Approximately 70% of asthmatics also have allergies.
  • Estimates suggest that approximately half of all asthma sufferers will have had an asthma attack in any given year.

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Back to: « Asthma

Risk Factors for Asthma

Risk factors for asthma currently being investigated include:

Asthma affects people of every race, sex, and age. However, significant disparities in asthma morbidity and mortality exist, in particular for low-income and minority populations. Populations with higher rates of asthma include:

  • Children
  • Women (among adults) and boys (among children)
  • African Americans
  • Puerto Ricans
  • People living in the Northeast United States
  • People living below the Federal poverty level
  • Employees with certain exposures in the workplace

Source: Healthy People (DHHS)1

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Who Is at Risk for Asthma?

Asthma affects people of all ages, but it most often starts during childhood. In the United States, more than 22 million people are known to have asthma. Nearly 6 million of these people are children.

Young children who often wheeze and have respiratory infections—as well as certain other risk factors—are at highest risk of developing asthma that continues beyond 6 years of age. The other risk factors include having allergies, eczema (an allergic skin condition), or parents who have asthma.

Among children, more boys have asthma than girls. But among adults, more women have the disease than men. It's not clear whether or how sex and sex hormones play a role in causing asthma.

Most, but not all, people who have asthma have allergies.

Some people develop asthma because of contact with certain chemical irritants or industrial dusts in the workplace. This type of asthma is called occupational asthma.

Source: NHLBI (NIH)2

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Children with a family history of allergies and asthma are more likely to have asthma. Exposure to triggers in the environment, including allergens, pollutants and viral infections, also play a role. “The rapid increase in asthma cases from the late 1970s cannot be attributed to genetics alone,” says Dr. Peter Gergen, medical officer at NIH’s National Institute of Allergy and Infectious Diseases. “Changes in the environment, home surroundings and exposure to infections have also contributed to the prevalence of asthma.”

Source: NIH News in Health (NIH)3

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Understanding what makes asthma worse can help asthma sufferers keep their disease in check. NIH research has shown that children who live in inner cities are exposed to higher levels of allergens from dust mites, dogs, cats, rodents, cockroaches and mold in their homes.

Source: NIH News in Health (NIH)4

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Research shows that asthma runs in families. When one or both parents have asthma, a child is more likely to develop it, too. This is known as genetic susceptibility.

However, environmental factors also contribute. Allergies and asthma are closely intertwined, and allergy-causing substances called allergens in the environment are a major cause of asthma.

Source: NIH News in Health (NIH)5

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Asthma Affects People of all Ages and Backgrounds

In most cases, we don't know what causes asthma, and we don't know how to cure it. Certain factors may make it more likely for one person to have asthma than another. If someone in your family has asthma, you are more likely to have it. Regular physical exams that include checking your lung function and checking for allergies can help your healthcare provider make the right diagnosis.

Source: CDC Features6

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Who's at risk?

A number of things can increase your chances of getting asthma. These include:

Some people may also be at risk of developing asthma through their job.

Source: NHS Choices UK7

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Paint sprayers, bakers, pastry makers, nurses, chemical workers, animal handlers, timber workers, welders and food processing workers are all examples of people who may have a higher risk of being exposed to these substances.

Source: NHS Choices UK8

Risk Factors for Asthma

Air Pollution: Air pollution has been linked to a wide range of health problems, including breathing difficulties, cardiovascular disease, and even death. In Southern California—long known for its high levels of air pollution—public policies have helped to improve air quality over the past few decades.

Source: NIH News in Health (NIH)9

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Household endotoxins: Interestingly, early life exposure to household endotoxin protects children against the development of allergies. In contrast, this new research shows that adult exposure to endotoxin raises the risk of asthma.

Source: NIH News in Health (NIH)10

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Anxiety disorders: Asthma. Studies link asthma to anxiety disorders. Stress and anxiety can trigger asthma attacks while the shortness of breath and wheezing during asthma attacks can cause anxiety. Studies show that breathing retraining may help asthma control and ease anxiety.[14]

Source: OWH (DHHS)11

Exacerbating Factors for Asthma

Cold weather may also affect people with certain lung diseases. For example, asthma can be triggered in some people by physical activity in cold weather.

“If you have marginal breathing capacity and you compromise that in any way,” Gourley says, “cold winter air can make breathing worse.”

If you have difficulty breathing, try a face mask when you need to go out in the cold. Such masks, which can be found at many outdoor and sporting goods stores, cover your mouth and use the heat from your own breathing to warm the air before it enters your lungs.

Source: NIH News in Health (NIH)12

Exacerbating Factors for Asthma

Air pollution: Several studies have shown that air pollution and indoor allergens make asthma symptoms worse and can bring on an asthma attack. If you’re 1 of the 23 million Americans who suffer from asthma, you might get some relief by taking steps to reduce indoor allergen levels and modifying your lifestyle to avoid the ill effects of air pollution.

Source: NIH News in Health (NIH)13

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Air pollution: A new 2-year study supported by NIH and the Environmental Protection Agency (EPA) showed that even modestly increased levels of air pollution cause more frequent asthma symptoms and lower lung function in children who have persistent asthma and live in inner city areas of the United States. Even air pollution levels within EPA’s safety standards made asthma worse in vulnerable children.

High levels of nitrogen dioxide, a component of motor vehicle emissions, had the greatest effect in the study, leading to many asthma-related school absences. Past research has also shown that ozone and particle pollution can affect asthma. Ozone, which is found in smog, is worse on hot days, especially in the afternoons and early evenings. Particle pollution, found in smoke and dust, is bad near busy roads and factories or when there’s smoke in the air.

Source: NIH News in Health (NIH)14

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  1. Source: Healthy People (DHHS): 2020/ topics-objectives/ topic/ respiratory-diseases
  2. Source: NHLBI (NIH): health/ health-topics/ topics/ asthma/ atrisk
  3. Source: NIH News in Health (NIH): 2008/ May/ docs/ 01features_02.htm
  4. ibid.
  5. Source: NIH News in Health (NIH): 2006/ July/ docs/ 01features_01.htm
  6. Source: CDC Features: features/ AsthmaAwareness/ index.html
  7. Source: NHS Choices UK: conditions/ asthma/ causes/ 
  8. ibid.
  9. Source: NIH News in Health (NIH): issue/ apr2015/ capsule1
  10. Source: NIH News in Health (NIH): 2005/ October2005/ docs/ 02capsules.htm
  11. Source: OWH (DHHS): a-z-topics/ anxiety-disorders
  12. Source: NIH News in Health (NIH): 2009/ January/ feature1.htm
  13. Source: NIH News in Health (NIH): 2008/ May/ docs/ 01features_02.htm
  14. ibid.

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Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.