Updated 16 August 2018

Who gets asthma? (Prevalence)

Asthma affects one in ten children (10%) and one in twenty adults (5%), and mostly presents before the age of five.


Asthma is one of the most common respiratory diseases in the world today. The Global Initiative for Asthma (GINA) claimed in 2010 that more than 300 million people are affected by asthma worldwide.

It affects one in ten children (10%) and one in twenty adults (5%). It occurs for the first time at any age, even in adulthood, although it usually begins before the age of five.

Roughly 80% of all childhood asthma occurs before the age of five.

It’s more common in boys and is seen predominantly in children who are allergic or come from allergic families. It tends to run in families, as do related allergic conditions, such as hay fever and eczema.

Approximately 50% of childhood asthma, particularly if it’s mild, goes into remission during the teenage years, but don’t be fooled into thinking this means you have "outgrown" asthma. As many as 30% of “teenagers-in-asthma-remission” go on to re-develop asthma during adulthood. Asthma usually persists if contracted during adulthood.

Ethnic variations

For decades it was accepted that allergic diseases were infrequent among black people and in people who live in rural communities.

This may be because living in the country protects people from developing asthma, even if they have the genetic potential to be asthma sufferers. Recent studies have confirmed that black people with asthma are much less likely to have parents or older siblings who suffer from asthma (positive family history) than other asthma sufferers.

However, if a black person does have a positive family history of asthma, they are much more likely to have asthma than black people without a family history, and even people from other races with a family history! In patients who have moved from rural to urban areas, either the early exposure to foreign allergens from the newly adopted western lifestyle or the loss of protection from the rural lifestyle, contributes to a higher degree of allergic sensitisation recorded among African infants than in other races. These factors account for the increased number of black children who have asthma.

Exposure to urban living

Studies conducted on people living in rural areas in Transkei have shown that migration to urban and peri-urban settlements has resulted in a 20-times increased risk of developing asthma symptoms. The incidence of asthma in rural areas has also increased.

Read more: 

What are the mechanisms of asthma?

Reviewed and updated by Prof Eugene Weinberg, Paediatrician Health24, April 2015.


Read Health24’s Comments Policy

Comment on this story
Comments have been closed for this article.

Ask the Expert

Asthma Expert

Professor Keertan Dheda has received of several prestigious awards including the 2014 Oppenheimer Award, and has published over 160 peer-reviewed papers and holds 3 patents related to new TB diagnostic or infection control technologies. He serves on the editorial board of the journals PLoS One, the International Journal of Tuberculosis and Lung Disease, American Journal of Respiratory and Critical Medicine, Lancet Respiratory Diseases and Nature Scientific Reports, amongst others.Read his full biography at the University of Cape Town Lung Institute

Still have a question?

Get free advice from our panel of experts

The information provided does not constitute a diagnosis of your condition. You should consult a medical practitioner or other appropriate health care professional for a physical exmanication, diagnosis and formal advice. Health24 and the expert accept no responsibility or liability for any damage or personal harm you may suffer resulting from making use of this content.

* You must accept our condition

Forum Rules