Patients in Canada are dying while waiting their turn for obesity surgery, according to new research that says wait times for bariatric surgery are the longest of any surgically treated condition in the country.

In 2007, 6,783 patients were waiting for bariatric surgery in Canada. The wait time was just over five years, according to a report in the most recent issue of the Canadian Journal of Surgery.

At one Canadian centre — the McGill University Health Centre in Montreal — 12 patients died while on the waiting list. Researchers say the number of deaths underestimates the magnitude of the problem, because they were not actively looking to find them, and there was no formal callback of all 2,178 patients in the centre's queue as of the end of 2008.

The average age of those who died was 46.

"It is not surprising that prolonged waits of more than five years for bariatric surgery lead to deaths among patients on the waiting list, given the devastating obesity-associated diseases that afflict these patients," the McGill University researchers write. Those who died had underlying conditions such as diabetes, sleep apnea, heart disease, high blood pressure and deep vein thrombosis, or blood clots in the veins.

"Bariatric surgery cures or improves all these," says lead author Dr. Nicolas Christou, a professor of surgery at McGill University and director of the bariatric surgery program at the McGill University Health Centre.