The World Health Organization says asthma affects about two hundred thirty-five million people worldwide. The WHO says asthma is the most common chronic disease among children. And it says the disease affects people in all countries around the world and at every development level. However, the WHO says eighty percent of asthma deaths happen in low and lower middle income countries.
Asthma affects not only millions of individuals, but families and economies alike. The yearly economic cost of the disorder is said to be close to twenty billion dollars. And the World Health Organization warns that asthma rates are increasing worldwide by an average of fifty percent every ten years.
SHIRLEY GRIFFITH: Asthma happens when tissue that lines the airways to the lungs begins to expand or swell. This swelling makes the airways smaller. The muscles in the airways tighten. Cells in the airways begin to produce a lot of mucous. This thick, sticky substance can cause the airways to close even more. This makes it difficult for air to flow in and out of the lungs.
This series of events is called an asthma attack. As asthma sufferers struggle to get air into their lungs, they may begin to cough. They also may experience wheezing -- breathing hard with a breathy, whistling sound.
Some asthma sufferers have tightness or pain in the chest. They say it feels as if someone is sitting on them. When asthma is most severe, the person may have extreme difficulty breathing. The disorder can severely limit a person's activity, and even lead to death.
最新
2013-11-25
2013-11-25
2013-11-25
2013-11-25
2013-11-25
2013-11-25