TORONTO - With study after study touting the potential benefits of vitamin D, which could include staving off some cancers, requests for tests to check patients' blood levels have soared in the last year, swamping some medical labs.
LifeLabs, which provides a broad range of medical testing in British Columbia, Ontario and Quebec, saw demand for vitamin D tests skyrocket by 90 per cent between April 2007 and March of this year, said company spokesman Norm Berberich.
"And because of the way in which our business operates, we don't provide this test without a physician requisition," he said Thursday. "It means more physicians are requesting this test for their patients."
Berberich would not say how many vitamin D tests LifeLabs performs per year, but he said they are paid for by provincial health plans.
Although the company is managing to meet increased patient and physician demand, he conceded that "with the exceptional growth we've seen over the past year, turnaround times have also increased."
"I'd say that's the same for every provider of this test."
But not all labs are managing to keep up with the growing clamour for tests.
At the Health Sciences Centre in St. John's, N.L., endocrinologist Dr. Christopher Kovacs said burgeoning demand has created a huge backlog at the medical lab at the hospital, the province's largest.
"The increase is about 10-fold or more in the past 18 months or so -- from 200 to 2,500 per month," said Kovacs by e-mail, adding that similar increases are being experienced at labs across Canada.
Many of the requests to test blood levels of the so-called sunshine vitamin are unnecessary, he said, advising that patients concerned about whether they are getting adequate amounts of the nutrient should take a vitamin D supplement for several months.
"Most people are idly curious about their vitamin D levels, get several levels done to confirm that they really are that low, and then do nothing about it," Kovacs writes on a website blog. "Or some may take vitamin D for a few months and then stop, because most otherwise healthy people do not want to take any pills, period."
"Very few, extremely few, are the people who actually take vitamin D for a sustained interval, and for them another level will be done to see if they are getting enough."
Since studies have shown the majority of Canadians have inadequate levels of vitamin D -- primarily due to low sunlight during the fall and winter -- Kovacs suggests testing should be limited to the "few people who proactively take a vitamin D supplement for an extended period in order to determine if those people are getting enough."
But Dr. Gerry Schwalfenberg, an Edmonton family physician who specializes in environmental medicine and deficiencies, regularly orders the vitamin D test for his patients and recommends that other doctors do the same.
Preliminary findings of a yet-to-be-published study of more than 1,400 people in the region found 67 per cent of participants were deficient in vitamin D, said Schwalfenberg, one of the study's authors.
While some may argue that the increasing number of vitamin D tests -- which cost about $50 each -- is putting undue strain on an already overburdened health-care system, he argues that knowing patients' blood levels and treating them accordingly could lead to billion of dollars in savings in the long run.
Schwalfenberg said research strongly suggests that optimal levels of vitamin D may prevent certain cancers and Type 1 diabetes. It is already known to keep bones strong, reduce muscle pain and maintain good balance, helping to prevent falls in the elderly, he noted.
"I think people should know what their level is and I think they need to know how much they should take to replenish their vitamin D," he said. "And they will generally feel a lot better."
The Canadian Cancer Society recommends that adults consider taking a daily vitamin D supplement of 1,000 IUs during fall and winter, while darker-skinned and older people should think about taking the little white pills year-round.
Health Canada recommends 200 IUs for adults 19 to 50 years of age. In September, it said recommendations by various organizations to boost intake were premature and a comprehensive review is needed before it would revise its recommendations.
