Your risk of asthma does increase with the number of risk factors you have, and asthma may develop even if you don't currently have any of the risk factors.

The following may increase your risk of asthma:

  • allergies (including conditions related to allergies such as eczema and allergic rhinitis)
  • age – although asthma can develop at any age, it is more common in childhood
  • family history
  • frequent exposure to potential allergens or irritants – these can include dust mites, exposure to tobacco smoke (even during fetal development), animal dander, and workplace irritants or chemicals
  • gender – during childhood, boys develop asthma more frequently than girls; however, this rate of occurrence changes after puberty so that more adult women than men develop asthma
  • multiple respiratory infections during childhood
  • obesity