Sometimes being in the top spot isn't a good thing. A new study shows that Canada has one of the highest -- possibly the highest -- rates of inflammatory bowel disease in the world.
An estimated one in every 300 Canadians suffers from the painful condition, in which the lining of the intestinal tract becomes red and raw and is prone to bleeding.
IBD, which includes ulcerative colitis and Crohn's disease, is also very common in other northern countries.
"There is a genetic component to this disease -- it does tend to run in families," said lead researcher Charles Bernstein of the University of Manitoba.
However, environmental factors also seem to play a role and scientists are at a loss to explain why Canada is such a hot spot. (Scientists can't even say for sure that Canada has the highest rate because there are not a lot of reliable statistics from other countries.)
The researchers came up with their Canadian estimate by examining medical records from five provinces -- British Columbia, Alberta, Saskatchewan, Manitoba and Nova Scotia. They then made a projection for the rest of Canada.
Dr. Bernstein said scientists are toying with several theories to explain why people living in some lands -- especially developed countries such as Canada -- seem especially prone to IBD. One is the so-called hygiene hypothesis, which relates to our obsession with cleanliness.
Some scientists argue that young children need to be exposed to a lot of common germs for the normal development of their immune systems.
Still, why should Canadians be more prone to IBD than other developed countries?
A clue might lie in Dr. Bernstein's new study, published in the American Journal of Gastroenterology.
One of its findings is that IBD rates are significantly lower in British Columbia than other provinces. Possibly the climate of balmy British Columbia somehow mitigates the disease. Dr. Bernstein says it will be "fascinating" to watch what happens to the children of recent immigrants who come from areas of the world where the disease is less common.
"Will their rates of IBD be as high as other Canadians?" he wondered.
Solving this mystery could pay big dividends.
"If you understand what causes it, you can develop treatments for it," he said.