You'd think standard medical advice would be backed up by a lot of scientific research. But researchers recently found that nearly 400 routine practices completely contradict studies published in top journals.
Of more than 3,000 studies published in The JAMA and The Lancet journals from 2003 to 2017, and The New England Journal of Medicine from 2011 to 2017, more than a tenth constituted a "medical reversal" : a phenomenon that came to The opposite conclusion from what doctors generally believe.
在2003年到2017年发表在《美国医学会杂志》(JAMA)和《柳叶刀》(The Lancet)杂志，以及2011年到2017年发表在《新英格兰医学杂志》(The New England Journal of Medicine)上的3000多项研究中，超过十分之一构成是“医疗逆转”：一项结论与医生的普遍认知相反的现象。
You end up having a sense of shame, said Vinay Prasad of Oregon Health and Science University, who authored the study. "Smart people with good intentions have been doing this for years. But they are wrong."
“你到头来会有一种羞愧的感觉，”这项研究的构想者、俄勒冈健康与科学大学(Oregon Health and Science University)的维奈·普拉萨德(Vinay Prasad)说。“多少年来，一些怀着好心的聪明人一直在这么做。但他们是错的。”
Some of these ideas have been firmly rejected, but not all. Prasad and his colleagues are now trying to understand how common discredited practices and ideas are.
Here are 10 findings that contradict the once widely held theory.
Peanut allergies can occur regardless of whether a child has eaten peanuts before the age of 3.
Pediatricians have long advised parents not to let their babies eat peanuts until they are three. Even children who had eaten peanuts before the age of one were no more likely to develop peanut allergies.
Fish oil does not reduce the risk of heart disease.
The idea that fish fat could help prevent heart problems once seemed logical. People whose diets contain large amounts of fatty fish appear to have lower rates of heart disease. Fatty fish contains omega-3 fatty acids. Omega-3 supplements can reduce triglyceride levels, which have been linked to an increased risk of heart disease. Not to mention, omega-3 fatty acids seem to reduce inflammation, a key feature of heart attacks.
But a trial involving 12,500 people at risk of heart disease found that taking omega-3 supplements daily did not prevent heart disease.
The doll does not prevent pregnancy.
The dolls cry, need to be changed and hugged. The idea is that girls can learn how much care is needed to care for a baby. But a randomized study found that girls who were asked to carry "mock babies" actually had slightly higher rates of pregnancy than those who did not.
Ginkgo products do not prevent memory loss and dementia.
Such supplements made from ginkgo biloba were popular in ancient Chinese medicine and are still being promoted as a way to protect memory. A large federal study published in 2008 made it clear that the supplement had no such effect. But ginkgo still drives $249 million in sales. Don't people understand?
When treating acute pain patients in the emergency room, a dose of oral opioids is no better than drugs like aspirin and ibuprofen.
Yes, opioids are powerful. But a clinical trial suggests there are safer and equally effective alternatives for emergency room patients.
Testosterone treatment does not help older men retain their memory.
Some men have low testosterone levels and memory problems, and early studies suggest that middle-aged men with high testosterone levels appear to have better tissue protection in parts of the brain. Older men with higher testosterone levels also appear to do better on tests of psychological functioning.
But a rigorous clinical trial has shown that testosterone is no better at helping older men avoid memory loss than a sugar pill.
Keeping house away from dust mites, mice and cockroaches doesn't help prevent asthma attacks.
If you or your child has asthma, the advice of leading medical organizations has always been to remove these pests from your room. The theory is that an allergic reaction to them may cause an asthma attack. But researchers reported in 2017 that intensive pest management had no effect on asthma attacks among children in homes that were sensitive to mouse allergens.
Pedometers and calorie trackers don't help with weight loss.
In fact, dieters may be better off without digital help. After tracking 470 dieters for two years, those who carried step counts and calorie-tracking devices actually lost less weight than those who followed only standard recommendations.
Torn knee meniscus? Try physical therapy first, then surgery.
An estimated 460,000 patients a year in the United States undergo surgery to repair cartilage in their knees that is often torn by osteoarthritis. The tear is painful, and many patients worry that the pain will continue without surgery.
But when patients with torn meniscus and mild arthritis were randomized to six months of physical therapy or surgery, both groups improved, as much as they did.
If a pregnant woman's amniotic fluid breaks early, there is no need to deliver immediately.
Sometimes, a few weeks before the due date, the membranes burst and the amniotic fluid suddenly overflows. Obstetricians worry that bacteria could invade the fetus's alway sterile environment and cause an infection. The doctor thought it best to give birth at once.
But a clinical trial has found that if obstetricians carefully monitor fetuses while waiting for Labour to start naturally, the chances of infection are not greater. Babies born at the end of pregnancy are also healthier and less likely to suffer breathing difficulties or die than those born immediately after amniotic fluid ruptures.