Asthma risk factors: who is more likely to get asthma

What asthma is

Asthma is a long-term condition that affects the airways, the tubes that carry air in and out of your lungs. With asthma, the airways can become inflamed and narrowed at times, which makes it harder for air to flow out when you breathe out. About 1 in 13 people in the United States have asthma, according to the CDC as cited by NHLBI. It affects people of all ages and often starts during childhood (NHLBI). There is no cure, but treatment and an asthma action plan can help you manage it (NHLBI).

What causes asthma

The exact causes are unknown and may differ from person to person (NHLBI). Genetics and your environment likely play a role (MedlinePlus). Asthma usually starts in childhood, when the body's defense system is still taking shape, but some people do not show signs until adulthood (adult-onset asthma) (NHLBI). NHLBI says many factors may work together, such as (NHLBI):

• things in the environment that affected you as a baby or young child, including cigarette smoke or certain germs
• viral infections that affect breathing
• family history, such as a parent who has asthma, especially your mother

Risk factors

NHLBI and MedlinePlus list these as raising the risk of asthma (NHLBI) (MedlinePlus):

• Family history and genes. You are more likely to have asthma if one of your parents has it, especially your mother (MedlinePlus).
• Allergies. Asthma is usually a type of allergic reaction, and people with asthma often have other allergies, such as food or pollen allergies (NHLBI).
• Secondhand smoke while your mother was pregnant with you or when you were a small child (MedlinePlus).
• Frequent viral respiratory infections as a young child (MedlinePlus).
• Obesity. Being overweight can raise your risk of asthma or make symptoms worse (NHLBI). The BMI calculator shows where your weight falls.
• Work exposures. Breathing in chemicals or industrial dust at work can raise your risk (NHLBI).
• Race or ethnicity. Puerto Rican people and Black or African American people have a higher risk than other groups. Black or African American and Hispanic children are more likely than non-Hispanic White children to die from asthma (NHLBI).
• Sex. More boys than girls have asthma as children. In teens and adults, it is more common in women (NHLBI) (MedlinePlus).
• Air pollution and changing weather patterns, which NHLBI says contribute to asthma onset and exposure to allergens (NHLBI).

Asthma in children

Viral infections and exposure to things such as cigarette smoke can raise a child's risk, and so can having a parent with asthma, especially a mother (NHLBI). Around 4 out of 10 children who wheeze when they get colds or respiratory infections are later diagnosed with asthma (NHLBI). Children may show asthma differently: coughing in their sleep or waking often, avoiding energetic play, or getting tired quickly (NHLBI).

Triggers

Triggers are things that set off or worsen symptoms in people who have asthma. They are not the same as risk factors, and they can differ from person to person and change over time (MedlinePlus). Common triggers include (NHLBI):

• indoor allergens such as dust mites, mold, and pet dander or fur
• outdoor allergens such as pollens and mold
• emotional stress
• physical activity, although with treatment you should still be able to stay active
• infections such as colds, the flu or COVID-19
• certain medicines, such as aspirin
• poor air quality or very cold air

Because infections can trigger attacks, see also flu high-risk groups, RSV risk factors and pneumonia risk factors. Asthma is on the flu and RSV high-risk lists.

Symptoms and emergency signs

Asthma symptoms include wheezing (a whistling sound when you breathe out), coughing especially at night or early morning, shortness of breath and chest tightness. Other conditions can cause these too, but in asthma they often come and go, start or get worse with colds, are set off by exercise, allergies or cold air, and are worse at night or in the morning (NHLBI).

Go to the emergency room if symptoms do not go away soon after your at-home medicines, or if you have a serious attack (NHLBI). For young children with asthma, NHLBI says to call 911 if they seem drowsy, confused or troubled, have a blue tint to the skin and lips, or have a fast heartbeat (NHLBI).

Common questions

Can asthma be prevented?

Because the exact cause is unknown, you may not be able to prevent it. NHLBI suggests steps that may help: keep your home free of dampness and mold, avoid air pollution as much as you can, and make a healthy lifestyle a priority, for example by eating more fruits and vegetables (NHLBI).

Can adults get asthma for the first time?

Yes. Some people do not show signs of asthma until adulthood; this is called adult-onset asthma (NHLBI). In adults, asthma is more common in women (NHLBI).

Is asthma the same as COPD?

No. They are different lung conditions. People with asthma have more risk of developing COPD than people without it, but most people with asthma will not get COPD (MedlinePlus). See COPD risk factors.

Also see sleep apnea symptoms and screening tests by age.