A Mystery Solved?

Researchers at St. Joseph’s Healthcare have been studying a massive and previously unexplained peak in hospitalization of children for asthma that occurs each September.

The medical mystery was discovered after an analysis of five years of data, revealing that about 20 per cent of all annual hospitalizations for asthma in two to 15 year olds occur during September.

Epidemiologist at the Firestone Institute for Respirology Neil Johnston said, “Asthma remains the number one cause for emergency hospitalization for children in Canada. About 4,500 children with asthma were admitted to hospital in Ontario last year, almost 1,000 of them during September. And we had no real clue why until now.”

Reports of the surge in asthma hospitalizations have been found in many places in the Northern Hemisphere – not only in Ontario, but also in Saskatchewan, in some parts of the U.S., in Britain, Ireland, Scandinavia, and even Trinidad.

“There were asthma peaks in at exactly the same time in every region of Canada, although they were thousands of miles apart, in five different time zones and with different climates,” said Johnston. “That proved true north to south and east to west across the country. So we expanded the analysis to cover an 11-year period and brought in data from Australia and New Zealand to see if the findings would remain true over a longer period and for the changes of seasons in the Southern Hemisphere.”

The first discovery proved that the surge in asthma hospitalizations was not linked to a climactic change. “But…” said Johnston, “the data from Australia and New Zealand revealed several peaks, each of which occurred approximately two weeks after the return to school. And that happened repeatedly. The bottom line was that it had to be associated with school return – as it is in Canada. The same sort of occurrences across both the northern and southern hemispheres was definitely a smoking gun.”

That smoking gun motivated researchers to refine their study model further. As of this date data from the study is still being analyzed prior to publication, but they are convinced that they now know why come September hospital admissions for asthma jump.

“The data confirms it repeatedly,” said Johnston.

“Approximately two weeks after Labour Day five to 15-year-old kids hit that peak of hospitalization – the timing of the peak is in lock step with Labour Day. The analysis also found that two to four-year-olds have the same lock step relationship, but it’s exactly two days later.”

Researchers speculate that a combination of factors including stress, change of environment, broader exposure to viruses that are at their height in September, the closeness of kids in school and re-exposure to allergies bring on major asthma attacks.

“It’s a kind of whammy, whammy, whammy effect,” says Johnston. “We know that a number of different things can trigger an attack in asthmatic children. But in September they are faced with several things all at once. As for the two to four-year-olds the data is less conclusive. We need to do a further study – and we plan to do so – to be able to absolutely conclude they are related. The suspicion remains that older siblings who go to school pick up all this ‘soup’ and bring it home. Thus the two-day delay in a triggered attack for the younger kids.”

Research will continue. Last September emergency rooms and urgency care centres in Hamilton, and ERs in Brantford and Paris were staffed 24 hours a day with research nurses to conduct a study locally. That study looked into the link with viruses and allergens and is still in the early stages of analysis. However, results from the previous analysis are clear.

Kids with asthma need to get their condition under control before they head back to school.

“The important message,” says Johnston, “is that the huge jump in hospitalizations for asthma each and every September can be substantially prevented if children who are at risk get their asthma under control – are taking their asthma medication – before they go back to school. We need to get that message out to both parents of children who have or may have asthma and also to family physicians so that they can get children at risk into a management program”