They were up to five times more likely to develop asthma or eczema.

In a study of 8 to 11-year-olds, those who ate oily fish were four times less likely to develop asthma than those who never ate it.

Around the age of fourteen he started to develop asthma.

However, it's possible you've developed asthma, which could result in a persistent, dry cough.

The rate of asthma increases as countries become more urbanized and in many parts of the world those who develop asthma do not have access to medication and medical care.