In 2011, cystic fibrosis researchers noticed something weird. Patients with this deadly genetic disorder were living longer and longer — but those in Canada seemed to be living significantly longer than those in the United States.
The researchers wondered if the Canadian patients were actually more likely to survive longer, or if something else was going on. Were there differences in the way each country gathered its data? “Perhaps Canada collected data on mild cystic fibrosis patients more than the US,” said Dr. Anne Stephenson, a physician-researcher specializing in cystic fibrosis at St. Michael’s Hospital in Toronto.
But that didn’t turn out to be true. Six years and plenty of statistical analyses later, Stephenson and her colleagues found that the median age of survival for Canadians was 50, and only 40 for Americans. The gap persisted even when they looked only at data from the most severe cases.