The fundamental reason for what causes asthma is still not clear, and what it interesting is that the disease can strike one person with utmost severity while leaving another unaffected. A person’s predisposition to asthma is calculated by the presence or absence of certain risk factors that are now known to influence the respiratory disorder.
#1 Family History
Genes play a role in deciding who gets asthma and who does not. A child whose parent(s) have asthma is more likely to develop it too as compared to another child whose parents do not have asthma.
For reasons unknown, asthma is found to be more common among boys than girls, but this ratio shifts towards adulthood, where the ratio of male to female patients is almost same. It is hypothesized that this might be due to smaller airways in younger males.
Atopy refers to the genetic predisposition of a person towards developing certain allergies like allergic conjunctivitis, allergic rhinitis, eczema and asthma. Children with an existing eczema are found to also develop asthma later.
People can develop allergic reactions to common allergens like dust, animal proteins especially on cats and dogs, and certain household organisms like dust mites, fungi and cockroaches. This type of asthma is known as allergy asthma.
#5 Cigarette smoke
Studies show a link between smoking and an increased incidence of asthma, especially in young adults.
#6 Environmental factors
Air pollutants like nitrogen oxide and sulphur dioxide can increase the incidence of asthma, as can cold temperatures and high humidity. The haze seen on cold days, called smog, contains ozone, which is responsible for causing shortness of breath, cough and chest pain. Smog also contain sulphur dioxide that can irritate the airways and cause constriction.
#7 Hyper reactive airways
Some airways get inflamed easily when brought in contact with asthma allergens or triggers, causing asthma. People that show hyper-reactivity in their airways are at a higher risk of developing asthma.
Some studies point towards a link between body weight and non-allergic asthma. Overweight people (with BMI between 25 and 30) were seen more likely to develop asthma, and even more so if they were obese (with a BMI of 30 or higher).
#9 Pregnancy-related risks
Smoking by pregnant women is known to impair pulmonary function. Even babies born prematurely as an effect of maternal smoking are at a higher risk of developing asthma symptoms.
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“Am I at risk of an attack?” Asthma.org.uk, http://www.asthma.org.uk/advice-am-i-at-risk-from-an-attack
“Asthma risk factors,” WebMD.com, http://www.webmd.boots.com/asthma/guide/asthma-risk-factors
“Asthma Risk – Who & Why?” MedicineNet.com, Alan Szeftel, http://www.medicinenet.com/script/main/art.asp?articlekey=19453