Asthma: Chronic, common and treatable

You're wheezing, you find it a struggle to take in enough oxygen or to catch your breath. You may be one of the estimated 300 million people around the world who suffer from asthma.

It is one of the world's most common chronic diseases and is normally more prevalent in heavily industrialized nations. According to the World Health Organization, Canada has one of the highest prevalence rates of clinical asthma in the world approximately 14 per cent but one of the lowest fatality rates from the disease, at 1.6 deaths per 100,000 asthmatics.

AStatistics Canada report released on Nov. 17, 2010, found that asthma rates for children between the ages of two and seven had fallen to 10 per cent in 2009, from 13 per cent in 2001. That's the lowestrate in more than a decade.

The Global Initiative for Asthma estimates that by 2025, world asthma rates will jump by a third, as rural populations continue to move to urban areas.

What are the symptoms of asthma?

Asthma is a chronic inflammation in the lungs, and can cause wheezing, difficulty breathing and chest pain. The symptoms can be severe enough to warrant a trip to a hospital. Respiratory disease in general is a leading cause of hospitalization of children in Canada.

Asthma symptoms can vary from one person to the next and even from one episode to the next. Symptoms can flare up suddenly and then not appear for a while.

Chronic asthma, especially in children, may require them to reduce their level of activity and to take medications to manage their symptoms. People with asthma can use inhalers or puffers containing drugs to help relax the airways and reduce inflammation. Other asthma drugs are used daily to prevent symptoms from occurring.

What causes asthma?

The cause of asthma is not known, but it is believed to be caused by an interaction between a genetic tendency for allergic reactions and environmental factors, such as second-hand smoke, household dust and outdoor air pollutants.

Asthma attacks can be triggered by certain pollutants, such as ground-level ozone, particulate matter, carbon monoxide, nitrogen dioxide, sulphur dioxide and lead. Other triggers include cigarette smoke, exercise, cold air, even intense emotions.

Cigarette smoke is less common in homes than it used to be, but it's still an important factor in triggering asthma. About 26 per cent of Canadians 15 to 19 and 14 per cent of children under age five must breathe second-hand smoke in their homes, according to a 2006 report by the Commission for Environmental Co-operation.

In the first in a series of seven articles, the Canadian Medical Association Journalsaid while it's clear that exposingchildren to tobacco smoke before they are born increases their risk of developing asthma and allergies, it's also possible that diet and nutrition, stress, use of antibiotics and birth by cesarean section may also play a role. The authors also suggest that breastfeeding may help protect babies from developing allergies and asthma, but prolonged breastfeeding may increase the risk.

Are some people more susceptible?

Asthma isn't directly genetic, so if a parent has asthma, it doesn't mean their child will have it, too. However, if one or both parents has asthma, the child is more likely to have it.

According to the Commission for Environmental Co-operation, people in North America who live in lower-income inner-city areas are at a higher risk for developing asthma. Their study says these people have poorer health care and higher exposure to indoor and outdoor air pollutants.

Belgian researchers suggest that kids who swim in pools that use chlorine to treat the water are at increased risk of asthma. Their study published in the journalPediatrics found teenagers who spent more than 1,000 hours swimming in chlorinated pools showed more than eight times the risk of having asthma as teens who mainly swam in pools disinfected with another method.

"This is an important factor, which might explain the epidemic of the disease in countries like Canada where you have a lot of swimming pools, indoors or outdoors," said the study's lead researcher, Alfred Bernard, a toxicology professor at Catholic University of Louvain in Brussels.

Some jobs that involve exposure to airborne chemical or organic triggers can result in what doctors call occupational asthma.

Are there sex differences?

Researchers have noticedthat, at early school age, the disease is more prevalent among boys,while during adolescence and adulthood, it affects girls and women more.

In August 2008, a study found boys were also more likely to grow out of it. The researchers speculate that hormonal factors may play a role.

How do I know whether I have it?

Coughing is a major feature of asthma, especially among children. Chronic coughing especially to the point of vomiting should be investigated.

Only a doctor can diagnose asthma. Other conditions like pneumonia, cystic fibrosis, heart disease and chronic obstructive pulmonary disease should be ruled out before a diagnosis of asthma can be made.

In November 2008, Canadian researchers found that 30 per cent of adults who received a diagnosis of asthma from a physician, in some cases based on symptoms alone,hadno evidence of the chronic disease when retested using clinical guidelines.

It is dangerous to stop taking asthma medications abruptly, cautioned study author Dr. Shawn Aaron of the Ottawa Health Research Institute. If someone thinks the medications aren't helping, then together with their physician, they should consider tapering off, if repeated lung function tests and symptoms suggest it is safe, he said.

At a minimum, asthma patients who have never had one should ask for spirometry tests, in which they blow through a tube to measure the rate and volume of airflow through the lungs.

Your chance of having asthma may also be higher if you have a history of:

• Wheezing, even though you did not have a cold.
• Inflammation in the nose (allergic rhinitis).
• Eczema, an allergic skin condition.

Can I live a normal life with asthma?

For the most part, yes. Several well-known athletes have not only lived with asthma but excelled at their sports despite asthma:

• Donovan Bailey won gold in the 100-metre sprint at theOlympics in Atlanta in 1996.
• Gary Robertshad a long NHLcareer.
• Haile Gebrselassie of Ethiopia ran the world's fastest marathon (two hours,three minutes and59 seconds) on Sept. 28, 2008, despite his asthma.

The key is to gain control of your asthma by avoiding the conditions that trigger it and to take the medication your doctor might have prescribed to control it.