Considering how much misinformation is currently floating around in the area of health and medicine, I thought it might be useful to write an article about how to read and understand scientific studies, so that you can feel comfortable looking at first hand data yourselves and making your own minds up.
Several people have contacted me over the last few weeks asking for my opinions on hydroxychloroquine. I’ve invariably answered that I don’t know, since I haven’t looked at the data myself. I felt that it was time to rectify that situation.
Most of us probably take fever lowering drugs, like paracetamol (a.k.a. acetaminophen, tylenol, panadol, alvedon), aspirin, or ibuprofen (a.k.a. advil, motrin, ipren), when we get a high temperature. The technical term for these drugs is antipyretics. After half an hour or so, we start to feel better and maybe don’t have to spend the whole day in bed. But it is well understood among researchers studying the immune system that the fever is in itself an important part of the body’s defence against infection. Our immune system works better at a higher temperature, and many pathogens have trouble replicating at a higher temperature. So, does taking antipyretics increase the risk of a more severe infection, or even of dying? And does it delay recovery?
“Try to cut down on the salt.”
I’m sure many people have gotten this well-meaning piece of advice from their doctor, especially if their blood pressure is a little bit high. It ranks up there with not smoking or drinking alcohol and avoiding red meat, saturated fat, and sugary drinks as one of those things we’re told to do if we don’t want to die prematurely. It is actively promulgated by government health authorities all over the world, including the NHS in the UK and the FDA in the US.
A new study has just been published in JAMA (the Journal of the American Medical Association) that seeks to answer this question definitively. This subject has been somewhat controversial, because observational studies have tended to show a positive effect, while randomised clinical trials have failed to show any effect. Usually you would trust the trial data more than the observational data, but these trials were all relatively short (generally a year or less), had relatively small study groups, and often used quite low doses of vitamin D.
This question has actually been pretty thoroughly researched, so it should be possible to come up with a conclusive answer. A systematic review and meta-analysis of the collected data was published in the British Journal of Medicine in 2017. The review was funded by the National Institutes of Health (NIH). No companies standing to benefit from the sale of vitamin D supplements were involved in funding the study and none of the authors had financial ties to any such companies. That makes me quite prone to trust the data.