Incidence And Prevalence Of Asthma

The incidence of Asthma happens when a person is allergic to certain external factors in the environment which in medical terms are called as allergens. Allergens that cause asthma include pollen, animal dander, house dust or mold, kapok or feather pillows, food additives containing sulfites, and any other sensitizing substance. Asthma caused by these allergens is specifically called as extrinsic asthma. This asthma is more easily adaptable by children as compared to adults and it is followed by other problems as well including severe respiratory infection.

These asthma episodes triggered out mostly due to the following reasons:

Sometimes it occurs, if the person is emotionally stressed, fatigued, exposed to poisonous smokes or if temperature, and humidity changes.

Use of drugs and chemicals which are apparently useful such as aspirin, various nonsteroidal anti-inflammatory drugs (such as indomethacin and mefenamic acid), and tartrazine, a yellow food dye.

Heavy Exercise Routine may also provoke an asthma attack as bronchospasm may follow heat and moisture loss in the upper airways.

The asthma attack occurs eventually after the patient is exposed to an allergen. Immediately these sensitized IgE antibodies results in mast-cell degranulation in the lung interstitium, while releasing histamine, cytokines, prostaglandins, thromboxanes, leukotrienes, and eosinophil chemotaxic factors. The released Histamine then attaches to receptor sites in the larger bronchi, causing problems such as irritation, inflammation, and edema letting the inflammatory cells flow in. The influx of eosinophils provides additional inflammatory mediators and contributes to local injury.

Asthma can occur at any stage but medical histories and common observations of doctors and consultants have specified that more than 50 percent cases are from children below 10. Children lying in age-group below 10 years are so much vulnerable to asthma that every 13th child is having asthma symptoms in the world.



Prevalence of Asthma

According to the World Health Organization, asthma is now a serious public health problem with over 100 million sufferers worldwide. According to Statistics Canada, 8.4% of the population (aged 12 and over) has been diagnosed as having asthma (200-2001). Asthma is most common during childhood and affects at least 12% of Canadian children. Asthma continues to be a major cause of hospitalization of children in Canada.

According to the figures given by US Department for Lungs, prevalence of asthma statistics are as follows;

'6.4% USA (NIAID); 17 million Americans (NIAID) including 5 million children; 8.1 million children (NHIS-97), 51 per 1000 - NHIS95; 14.5 million; 5% of population (NWHIC); 14.9 million in 1995 (NHLBI)'

Prevalence Rates are;

Approx 1 in 15 or 6.40% or 17.4 million people in USA "6.4% USA (NIAID); 17 million Americans (NIAID) including 5 million children; 8.1 million children (NHIS-97), 51 per 1000 - NHIS95; 14.5 million; 5% of population (NWHIC); 14.9 million in 1995 (NHLBI)"



Asthma affects more than 5% of the population of the US, including children. Asthma affects an estimated 17 million Americans or 6.4 percent of the U.S. population. Children account for 4.8 million of the nation's asthma sufferers. Approximately 5% of the population has asthma, but the basic cause of asthma is not yet understood.

Asthma affects 14-15 million Americans, including almost 5 million children.