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The Causes of Asthma

What are the causes of asthma?  Why do some people develop asthma?  Why is asthma more common in the western world?

Asthma is not contagious.  You cannot catch asthma from another person. However, you can inherit the asthma tendency from your parents, although people with asthma should not worry about their future children on this score.

Studies show that children whose parents smoke are twice as likely to develop asthma as children of non-smoking parents.  Also, children whose mothers smoked during pregnancy tend to be born with smaller airways, which greatly increases their chances of developing the disease.

The "westernized" environment and lifestyle in developed countries has a lot to do with the chances of whether a person will develop asthma or not.

Many people believe air pollution has something to do with asthma, although the evidence, at this stage, is surprisingly very weak.

Causes of asthma include allergies to house dust mites, cats, dogs, and moulds. These are all environmental causes of asthma.

Childhood infections and exposure to substances from bacteria in a dirty environment seem to protect against allergies, and this seems to be the main reason why richer populations have more allergic disease.

So the causes of asthma are complicated.  They include our genes, our exposure to things we become allergic to, and a general effect of our environment on the chance that these genes and the things we become allergic to will cause trouble at some time during our lives.   But it is not quite as complicated as it sounds.

Almost all asthma in young people is cause by allergies.  This means that if you have asthma you probably have inherited genes which make it possible for you to get asthma, plus allergy-producing things in your environment, such as house dust mites, cats, or dogs.  The allergies and the genes are the causes for developing asthma, because if either of them were not present you would not developed asthma.