The exact cause of asthma is unknown, but it is believed to be the result of a genetic component, as well as environmental factors. Based on this understanding, the following are several key risk factors that are believed to increase the likelihood of an individual developing asthma-

• Being obese or overweight.
• Having an allergy, including hay fever or atopic dermatitis.
• A history of the disease in your family.
• Being a smoker.
• Exposure to secondhand smoke.
• Exposure to pollution or exhaust fumes.
• Exposure to chemicals in the workplace (a risk faced by factory workers, hairdressers etc.)
• Miscellaneous urban environmental factors.
• Frequent use of antibiotics during formative years.