During an asthma attack, the airways become irritated and react by narrowing and constructing, causing increased resistance to airflow, and obstructing the flow of the air passages to and from the lungs. But what causes 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 “westernised” environment and lifestyle in developed countries has a lot to do with the chances of whether a person will develop asthma or not.

Are overweight people more likely to get asthma, as is often suggested?

According to a meta-analysis of seven studies on severe asthma, researchers found an increase in the odds for asthma in overweight and obese men and women.

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.

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 caused 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.

But what about colds, exercise, laughter, or tobacco smoke, which can give you an attack of asthma even if everything in the last paragraph is true for you ?

You can’t cure your asthma by not taking exercise, or by not laughing. Quite simply, these are not causes of the fact that you have asthma, though they can be causes of the fact that you have an attack.

The type of interior house paint can apparently make asthma worse. Glossy oil paints used for home decorating can bring on asthma attacks in asthma sufferers. The good news is that emulsion paints don’t seem to do this.

Polyurethane paints, usually recognisable because they come in two packs which need to be mixed together before use, can cause occupational asthma in people who use them regularly. However, they probably cause no great risk in people with asthma who use them infrequently. As always, when using chemicals and paints, it is surely a good idea to ventilate the area well during and after use.

For future updates, subscribe via Newsletter here or Twitter