March 14th, 2011 by GarySchwitzer in News, Research
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Here we go again. Headlines across America blaring lines like, “Coffee may reduce stroke risk.”
It was a big study, but an observational study. Not a trial. Not an experiment. And, as we say so many times on this website that you could almost join along with the chorus, observational studies have inherent limitations that should always be mentioned in stories. They can’t prove cause and effect. They can show a strong statistical association, but they can’t prove cause and effect. So you can’t prove benefit or risk reduction. And stories should say that.
USA Today, for example, did not explain that in its story. Nor did it include any of the limitations that were included in, for example, a HealthDay story, which stated:
“The problem with this type of study is that there are too many factors unaccounted for and association does not prove causality, said Dr. Larry B. Goldstein, director of the Duke Stroke Center at Duke University Medical Center.
“Subjects were asked about their past coffee consumption in a questionnaire and then followed over time. There is no way to know if they changed their behavior,” Goldstein said.
And, he noted, there was no control for medication use or other potential but unmeasured factors.
“The study is restricted to a Scandinavian population, and it is not clear, even if there is a relationship, that it would be present in more diverse populations. I think that it can be concluded, at least in this population, that there was not an increased risk of stroke among coffee drinkers,” he said.”
When you don’t explain the limitations of observational studies — and/or when you imply that cause and effect has been established — you lose credibility with some readers. And you should. Read more »
*This blog post was originally published at Gary Schwitzer's HealthNewsReview Blog*
March 8th, 2011 by GarySchwitzer in News, Opinion, Research
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We’re delighted to see that USA Today, Reuters, and WebMD were among the news organizations that included what an editorial writer said about an observational study linking ibuprofen use with fewer cases of Parkinson’s disease. All three news organizations used some version of what editorial writer Dr. James Bower of the Mayo Clinic wrote or said:
“Whenever in epidemiology you find an association, that does not mean causation.”
“An association does not prove causation.”
“There could be other explanations for the ibuprofen-Parkinson’s connection.”
Kudos to those news organizations. And some praise goes to the journal Neurology for publishing Dr. Bower’s editorial to accompany the study. His piece is entitled, “Is the answer for Parkinson disease already in the medicine cabinet? Unfortunately not.”
And unfortunately not all news organizations got that message. Because many don’t read the journals, so they certainly never get to the editorials. Instead, they rewrite quick hits off a wire service story. As a result, we end up with some of the following:
A FoxNews.com story was particularly deaf to Bower’s caveat, stating: “That bottle of ibuprofen in your medicine cabinet is more powerful than you may think.”
A CBSNews.com story never addressed the observational study limitation, instead whimsically writing: “Pop a pill to prevent Parkinson’s disease? A new study says it’s possible, and the pill in question isn’t some experimental marvel that’s still years away from drugstore shelves. It’s plain old ibuprofen.” Read more »
*This blog post was originally published at Gary Schwitzer's HealthNewsReview Blog*
February 12th, 2011 by RyanDuBosar in News, Research
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Enriched chicken feed may have resulted in eggs having less cholesterol and more Vitamin D than previously measured, reports the U.S. Department of Agriculture (USDA).
A large egg today has about 185 milligrams of cholesterol, down 14 percent from 215 milligrams in 2002, according to new research from the USDA’s Agricultural Research Service, reports USA Today. Also, an egg today has 41 international units (IUs) of Vitamin D, up 64 percent from 25 IUs measured in 2002. (That’s still only about 7 percent of the 600 IUs recommended per day.)
The agency regularly does nutrient checks on popular foods, this time analyzing eggs taken from store shelves in 12 locations around the country. The American Egg Board said in a press release that hen feed is made up mostly of corn, soybean meal, vitamins and minerals. Nutrition researchers at Iowa State University are also looking into reasons why cholesterol in eggs is decreasing.
The government’s “Dietary Guidelines for Americans” recommend that most people eat less than 300 milligrams of total dietary cholesterol a day, and people at a high risk of cardiovascular disease should eat less than 200 milligrams a day. The average American man consumes about 337 milligrams of cholesterol a day and the average woman consumes 217 milligrams, reports the Los Angeles Times.
One egg a day fits within the average, healthy American’s diet, reports WebMD, citing research funded by the Centers for Disease Control and Prevention and by the American Egg Board — owners of the slogan “the incredible, edible egg.”
*This blog post was originally published at ACP Internist*
February 3rd, 2011 by ChristopherChangMD in Health Tips, Research
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USA Today published a pretty accurate article regarding the rise of certain head and neck cancers with the increased popularity of oral sex and number of sexual partners.
The factor that creates this link is the human papillomavirus (HPV) which is associated with tonsil and tongue cancer. Alcohol and tobacco use is more highly linked with such oral cancers, but HPV does appear to be an independent risk factor.
A 2007 study in the New England Journal of Medicine found that younger people with head and neck cancers who tested positive for oral HPV infection were more likely to have had multiple vaginal and oral sex partners in their lifetime. Having six or more oral sex partners over a lifetime was associated with a 3.4 times higher risk for oropharyngeal cancer — cancers of the base of the tongue, back of the throat, or tonsils. Having 26 or more vaginal-sex partners tripled the risk. The association continued to increase as the number of partners in either category increased.
Of greater concern is that “French” kissing may also potentially be a mode of transmission.
The good news (if you’re a young non-smoker diagnosed with HPV-positive tumors) is that about 85 percent of non-smoking people with HPV-positive tumors survive. That number drops to 45 or 50 percent in people who smoke and are HPV-negative. Read more »
*This blog post was originally published at Fauquier ENT Blog*
January 10th, 2011 by KevinMD in Better Health Network, Opinion
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In a recent New England Journal of Medicine, a perspective piece on what to do with fatigued surgeons is generating debate. The issue of work-hour restrictions has been a controversial issue when it comes to doctors in training, something that I wrote about earlier in the year in USA Today. But once doctors graduate and practice in the real world, there are no rules.
As summarized in the WSJ’s Health Blog, the perspective piece argues for more regulation for tired surgeons:
… self-regulation is not sufficient. Instead, “we recommend that institutions implement policies to minimize the likelihood of sleep deprivation before a clinician performs elective surgery and to facilitate priority rescheduling of elective procedures when a clinician is sleep-deprived,” they write. For example, elective procedures wouldn’t be scheduled for the day after a physician is due to be on all-night call.
And the authors suggest that patients be “empowered to inquire about the amount of sleep their clinicians have had the night before such procedures.”
It’s a noble goal, and indeed, data does show that fatigued surgeons tend to make more errors. Patients, once confronted with a choice of being operated on by a tired surgeon, may choose to postpone surgery. Read more »
*This blog post was originally published at KevinMD.com*
