Second Opinion: Chronically tired? Maybe it’s your genes
Second Opinion is a vital dose of the week’s news in health and medicine from reporter Kelly Crowe and CBC Health.
A 24½-hour clock
What if you’re genetically programmed with a natural body clock that’s longer than 24 hours? It’s been established that wake-sleep cycles are controlled by an intrinsic circadian rhythm that is genetically encoded.
Now, researchers at the Rockefeller University have found a gene variant in some people that interferes with their clock’s sleep trigger by about 30 minutes. So for those people, a perfect day would be 24½ hours long.
In the study, published in the journal Cell, the researchers report that one in 75 people in certain populations could be carriers of this “night owl” gene variant.
People who identify as night owls are often diagnosed with delayed sleep phase disorder (DSPD), which makes them energetic long after most people have hit the pillow.
If they could show up for work or school whenever they wanted, they would be able to get a healthy amount of sleep. But this gene variant could explain why some people are chronically sleep deprived in a society programmed around a 24-hour clock.
How Canada missed a chance to prevent thousands of heart attacks
If Canada had banned trans fats 10 years ago when New York City did, thousands of Canadian heart attacks could have been prevented, according to a new study. New York City banned trans fats in 2007. Eleven other counties in the state followed, creating the conditions for a natural experiment. Would the rate of heart attacks go down in the counties that banned trans fats compared with the ones that didn’t? Yes, researchers concluded this week. There were 6.5 per cent fewer heart attacks and strokes in the trans fat-free counties.
All of that raises an interesting question for Canada. What if Ottawa had banned trans fats in 2004 when all parties supported an NDP proposal to do just that? “We could have saved potentially thousands of heart attacks and strokes in Canada,” said Dr. Beth Abramson, Heart and Stroke cardiologist.
Last Friday, Health Canada quietly announced that trans fats will be banned from processed food here, 13 years after Parliament first agreed it should happen. The U.S. has a similar ban coming into effect at the same time.
Landmark challenge to medicare stalled for lack of funds
Far from the spotlight, in a nearly empty Vancouver courtroom, lawyers have been arguing over the future of Canada’s public health-care system. Karen Palmer is sometimes the only observer in the room. She’s a health policy analyst at Simon Fraser University, and she thinks it’s important that someone pay attention to the case, which has received scant media coverage. “I don’t think people understand what’s at risk,” she told us. “We are all enrolled in medicare. The outcome of this trial will affect all of us, across the country.”
Changing medicare is the whole point of the case, launched by Dr. Brian Day, the private health-care advocate behind the constitutional challenge. He’s arguing that lack of access to private health care violates the Charter of Rights. B.C.’s attorney general is fighting back, and the federal government is also intervening.
The case was supposed to last six months. It’s already gone over time, and Day’s lawyers still intend to call more than 50 additional witnesses. The defence hasn’t even started to present its case, and there are a series of interveners who also intend to weigh in.
And now the whole case has been put on hold because Day said he has run out of money to pay legal bills. The B.C. government lawyers have also asked for a pause in the proceedings. Both sides say they’re frustrated with the legal wranglings. Tentatively, the case is set to resume Sept. 5.
If a cancer drug slows the disease down but doesn’t extend life, is that enough?
Increasingly, new cancer drugs are being approved based on evidence that they slow down disease progression. It’s called “progression free survival.” But that same drug might not help a patient live longer.
How progression-free survival compares with overall survival is an increasingly controversial question, especially if the drug’s side-effects impair a patient’s quality of life. And the definition of “progression-free” varies depending on the type of cancer, and when it was first diagnosed.
French researcher Agnes Dechartres decided to take a closer look at how progression-free survival compared with overall survival in some of the newest immunotherapy drugs. In half the cases she studied, drugs that showed increases in progression-free survival did not extend life.
And because the benefit of some drugs appears greater when they’re evaluated using “progression-free” rather than “overall” survival, Dechartres concluded that caution must be taken when interpreting progression-free survival without knowing whether the drug extends life.
“It is important to measure and report both types of outcomes in clinical trials to be fully transparent about the treatment benefit,” Dechartres told us.
Ooops! Scientist accidentally discovers a major mosquito mistake
Nathan Burkett-Cadena didn’t set out to prove that the textbooks on mosquitoes are wrong. He was simply trying to grow some mosquitoes in his lab at the University of Florida so he could study them. He trapped pregnant females from a tropical mosquito species known to carry a virus that can cause human encephalitis. He put water dishes in the cages so they could lay their eggs. After all, his textbook on medical entomology said that Culex mosquitoes lay their eggs on the water surface.
But his Culex (Melanoconion) mosquitoes didn’t do that. In fact they died without laying their eggs at all, until he put upside down flowerpots in the cage, on a hunch. Immediately, they began laying clusters of eggs high and dry on the inside of the pots.
Burkett-Cadena calls it a “paradigm shift” in the understanding of mosquito biology. What are the implications of this for mosquito control? “It’s made the job harder, that’s the bottom line,” Burkett-Cadena told us. Although this particular subgenus is tropical, there are other Culex mosquitoes in Canada. Do the Culex mosquitoes found in Canada also lay their eggs out of the water? “We don’t know, it’s quite possible,” he said.
“It means a lot of the generalizations we make about egg-laying in mosquitoes needs a lot of re-examination. I suspect most species of Culex don’t conform to the textbook description of their egg-laying habits.”
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