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If you unwrap a gift next week and it turns out to be a genetic DNA test kit, what have you really opened? How much can that test tell you about your future health or who your parents really are?
Not as much as you might think, according to Timothy Caulfield, Canada Research Chair in health law and policy at the University of Alberta.
Caulfield has taken two direct-to-consumer genetic tests — 23andme and AncestryDNA. He learned he's Irish and that his earwax is wet, not dry. There was no information about which version is preferable.
Caulfield was also told that if he eats asparagus he will likely be able to smell the metabolite in his urine — something he presumably didn't need a genetic test to reveal.
He also learned he has a higher risk of heart disease and colorectal cancer. But even that doesn't tell him much, since his risk of both diseases is still very low.
What should he do with this information?
The personalized advice he received is what he already knows — eat a healthy diet, live a healthy lifestyle — advice most people won't take no matter what their DNA test results reveal.
"The whole idea is that this information is empowering," Caulfield said. "But research has shown that people don't change their behaviour based on this kind of information."
What about the risk of revealing dark family secrets, such as learning your real father is not who you thought? Caulfield said it would take some additional genetic sleuthing.
"It would have to be a bit of ancestry information that doesn't make sense based on the family story. It might be the start of an uncomfortable conversation, but it's not going to be definitive."
Other things to consider as you spit into the vial and send your genes through the mail: what is the company planning to do with the data? Some companies are transparent about their intention to share anonymized customer DNA data with researchers and pharmaceutical companies.
"I think people should be cautious, and they should look at the privacy rules, read what you're getting into," Caulfield said.
In May, Parliament passed the Genetic Non-Discrimination Act protecting Canadians from having to disclose results of genetic tests to insurance companies or to anyone else who tries to make genetic testing a condition of a contract.
"In other words, individuals are in no way obliged to disclose their genetic test results to any business or organization (including pharmaceutical companies, research groups, employers, insurers), nor should they feel any pressure to do so," a spokesperson for Canada's Privacy Commissioner told CBC News in an email.
"If an individual does wish for results to be disclosed (for example, for research purposes), consent must be in writing, fully informed and freely given."
The consumer DNA test kits are being advertised as holiday gifts and there are many variations, including testing for wine preference and even test kits for pets.
"So have fun with it maybe, but don't put too much stock in the results," Caulfield said.
The genetic information won't necessarily provide peace of mind by identifying what diseases you can stop worrying about. Knowing what diseases run in the family is a better barometer of future health risks, he said.
The Canadian College of Medical Geneticists has advised against making medical decisions based on direct-to-consumer genetic test results.
It's also the gift that might keep on giving whether you want it or not. Caulfield keeps getting updates from one company as the genetic analysis becomes more refined. And the updated analyses reveal that his Irishness is slipping.
"I used to be 100 per cent Irish. Now I'm 88.9 and I have a little bit of Welsh. I'm getting less Irish."
MRI dye warnings
There were new warnings this week about a dye used in MRI scans that could leave metal deposits in the brain.
The U.S. Food and Drug Administration issued a safety announcement about some gadolinium-based contrast agents injected intravenously during an MRI scan to improve the visibility of organs and tissues. Gadolinium is a heavy metal, and there is evidence that trace amounts can be retained in the body.
The health agencies stress that so far there is no evidence that the gadolinium deposits have caused any adverse neurological effects.
But the U.K. agency said, "Data on long-term effects of gadolinium deposition in brain, or other tissues, are very limited."
Last January Health Canada announced it was working with manufacturers to update the labelling on gadolinium contrast agents to include information about the evidence of gadolinium brain deposits after repeated use. Health Canada recommends using the lowest possible dose.
"To date, Health Canada has received no Canadian case reports suggesting gadolinium deposits in the brain associated with use of gadolinium contrast agents, nor any reports of negative health effects occurring in Canada due to gadolinium accumulation in the brain," said a spokesperson for Health Canada in an email to CBC News, adding that Health Canada is monitoring the situation.
Dogs face special holiday health risk
There's no need for a DNA test to know that chocolate is dangerous for dogs — but that risk is highest at Christmas.
A study in the BMJ's special Vet Edition warns of a "significant peak" in the risk of chocolate poisoning in dogs over the holidays.
Chocolate contains a chemical called theobromine, a stimulant similar to caffeine. Humans can handle it, but it's nasty stuff for our four-legged friends. It can cause vomiting, diarrhea, increased heart rate and even seizures.
"Humans process it very quickly, so we can eat chocolate with gay abandon," P-J Noble, a veterinarian at the Small Animal Teaching Hospital in Liverpool, U.K., and one of the authors of the study, told CBC's Kas Roussy.
"In dogs, they don't get rid of it very quickly. It hangs around and builds up to toxic levels very easily."
Researchers have known for some time that chocolate and dogs don't mix. But Noble and his team wanted to find out whether dog exposure to chocolate was tied to any of the big holidays — Christmas, Easter, Valentine's Day or Halloween.
After reviewing millions of electronic health records from 500 vet clinics in the U.K., they found Christmas beat them all when it came to chocolate exposure.
Santa Claus figurines, Advent calendars, and Christmas tree decorations made of chocolate were high on the doggy list of favourites.
But who can blame Fido for sticking his snout where it doesn't belong? Dogs like sugar, and when it's on display it's hard to resist.
One particular furry friend likely made Santa's naughty list. The study reports that the dog had ingested six Toblerones and six Terry's Chocolate Oranges.
"I would feel ill after that," says Noble.
None of the more than 300 cases of chocolate poisoning reported in this study was considered life-threatening, but too much of a good thing can be bad. When ingested in large amounts, chocolate can be fatal for dogs, especially if it's of the darker variety, Noble said.
So, Merry Christmas to all, say Noble and his colleagues, "but keep the chocolate away from your dog. Because no one wants to be going to the vet on Christmas Day."
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