Asthma: Definition and Incidence

According to the WHO:

Asthma attacks all age groups but often starts in childhood. It is a disease characterized by recurrent attacks of breathlessness and wheezing, which vary in severity and frequency from person to person. In an individual, they may occur from hour to hour and day to day.
This condition is due to inflammation of the air passages in the lungs and affects the sensitivity of the nerve endings in the airways so they become easily irritated. In an attack, the lining of the passages swell causing the airways to narrow and reducing the flow of air in and out of the lungs.

Other Definitions

Asthma is a medical condition that causes narrowing of the small airways in the lungs. Typically, asthma patients develop wheezing and have increased mucous production in their lungs. Asthma patients can have episodes of increased shortness of breath, often triggered by allergic reactions. Asthma sufferers often have the disease for many years, and the episodes of shortness of breath can be life-threatening.

Asthma is a chronic (long-lasting) inflammatory disease of the airways. In those susceptible to asthma, this inflammation causes the airways to narrow periodically. This, in turn, produces wheezing and breathlessness, sometimes to the point where the patient gasps for air. Obstruction to air flow either stops spontaneously or responds to a wide range of treatments, but continuing inflammation makes the airways hyper-responsive to stimuli such as cold air, exercise, dust mites, pollutants in the air and even stress and anxiety.

Incidence (Most common chronic respiratory illness in young children)

In the US: 6.4% USA; 17 million Americans (National Institute of Allergy and Infectious Diseases) including 5 million children; 8.1 million children, 51 per 1000; 14.5 million; 5% of population; 14.9 million in 1995 (National Heart, Lung and Blood Institute)

In Australia: Asthma affects 10-12% of adults in Australia. Asthma affects 14-16% of children in Australia (Australian Institute of Health and Welfare)

According to WHO estimates, 300 million people suffer from asthma and 255 000 people died of asthma in 2005.

Incidence in Malaysia:

Chan (1994) reported that 5 % of all outpatients in Ipoh General Hospital were
treated for asthma.

The Second National Health and Morbidity Survey (NHMS II) conducted in 1997
has shown that the estimated prevalence rate of asthma (self-reported) in
Malaysia was between 3.9 % to 4.4 % (mean 4.2 %). The age distribution based
on the Second National Health and Morbidity Survey shown that 4.5 % were
among age 0 1- 4 years and 4.1 % among adult.

Across all ages, the prevalence of asthma is between 8 - 10 %.
It is estimated that there are about 1.6 - 2.0 million of asthmatic cases in
Malaysia.