Personal Science Week - 240613 Face Masks
The Cochrane report's final conclusion, plus microplastics and other links
Nobody wants to talk about face masks anymore, and even fewer of us want to wear them.
This week a new non-update from Cochrane reminds us to review the personal science approach to face masking. Plus: how effective is modern medicine in general?
We’re big fans of Cochrane Reviews, a library of extremely detailed analyses of the efficacy of various medical treatments. The authors are known for their very strict adherence to evidence-based medicine, where they carefully scrutinize all evidence for and against something and then write their conclusions. For more than a decade, they’ve been skeptical of face masks (“Physical interventions to interrupt or reduce the spread of respiratory viruses”) — there’s never been good evidence that they work — so when they updated their findings in early 2023, they endured a torrent of criticism and accusations of political bias. New York Times, the CDC, and many science publications ran unflattering takedowns that resulted in an apology from the Cochrane editor-in-chief, who promised a thorough investigation.
Well, the investigation quietly ended this week, with the editor-in-chief sheepishly reaffirming the original article. Despite the confident takedowns at the time by Zaynep Tufecki, Anthony Fauci, Scientific American and many others, ultimately the Cochrane Review couldn’t find a reason to change a word of its original conclusion.
Personal scientists are open-minded, so I’m not going to outright reject anything about the efficacy of masking. But it’s important to look carefully at your own experience. Everyone you know caught the virus, whether they diligently masked or not. Believers will argue that they “just didn’t wear it correctly that one time” or “it kept me safe longer than otherwise”. And of course some will argue that you’ve gotta have N95, or double-mask, or <insert your motivated reasoning excuse>.
Beyond that, there’s the common sense question about why, if face masks are really that useful, it took the COVID pandemic for such an important breakthrough to be widely known. After all, what a discovery! Think of all the needless suffering, the colds and flu we could have avoided over the decades!
In other words, you either have to believe that face masks are (1) the most important breakthrough in public health since antibiotics, or (2) pretty much useless.
Speaking of masks
There’s my favorite statistic, from Japan:
Why do so many women love masks? When asked why, the most common answer was surprisingly "Because wearing a mask keeps you warm" (51.8%), which was a very reasonable reason. However, "I don't have to worry about it even without makeup" (51.7%) came in second place by a small margin. It turns out that the reason given is that "you can hide your face".
Back in Fall ‘22 (PS Week 220923) we wrote about the Cochrane evidence on face masks as well as a few other evidence-based tips on supplements.
Does any medicine work?
Given the failures of professional science, Cochrane Reports Carl Heneghan and Tom Jefferson ask Is it time to hit the brakes on healthcare research?
Thirty years ago, Doug Altman wrote about the Scandal of Medical Research in the BMJ, “We need less research, better research, and research done for the right reasons.” Altman considered vast sums of money were wasted on seriously flawed research that suffered from “inappropriate designs, unrepresentative samples, small samples, incorrect methods of analysis, and faulty interpretation.”
In the intervening years, we have seen the opposite. As we write this, PubMed contains 36,914,967 indexed results. In 1994, just under 440,000 articles were indexed, growing to 1,775,913 million in 2022. A paltry 26 million articles have been indexed in the intervening thirty years.
In 2009, a Lancet series on avoidable waste in research estimated that 85% of research spending currently goes to waste.
Drug companies often hide evidence to the detriment of patient care. In 2004, an analysis of 102 randomised trials found that half of the efficacy and two-thirds of the harm outcomes were incompletely reported. The effects of reporting biases are widespread; they overestimate the benefits and underestimate the safety of treatments. For example, an analysis of 92 Cochrane reviews found that 86% did not include data from the primary harm outcome…
Before you give up
Sometimes it’s possible to be too skeptical about medical interventions, and Scott Alexander (from Astral Slate Codex) recently decided to push back against people who argue that mainstream medicine doesn’t work as well as we think. Economist and futurist Robin Hanson summarized the largest studies as evidence that attempts to expand medical care do very little:
In a late 1970s RAND Health Insurance Experiment on 7700 people over 3-5 years, those who randomly consumed 30-40% more medicine were no healthier.
In a 2008 Oregon Health Insurance Experiment, where for two years 8700 poor folk out of 35,200 eligible were randomly given Medicaid. This raised self-reported health, but mostly before they got any treatment. It cut medical debt.
In a 2021 Karnataka Hospital Insurance Experiment, half of 52,300 people were randomly given free (or cheap access) hospital insurance for 3.5 years, which increased their hospital insurance take-up from 60% to 79%. Again, no significant health difference.
In a 2019 US Taxpayer Experiment, 0.6 of 4.5 million were not sent a letter saying they faced a tax penalty for lacking insurance. Over the next two years those sent a letter got 0.23 more months of insurance. The headline result given is that the 45-64 year olds among them also had 0.06% lower mortality, at 1% significance.
Scott counters that these studies are at best, mild evidence that simply throwing general healthcare at a population isn’t effective, but dig deeper into the numbers and you’ll see significant, live-saving improvements in survival rates of cancer and many other conditions:
The odds of death within 30 days of a heart attack have fallen from 20% in 1995 to 12.4% in 2015 (source). You can see similar survival rate increases for other conditions like congestive heart failure (5-year survival rate went from 29% to 60% since 1970), multiple sclerosis (standardized mortality rate went from 3.1 to 0.7 since 1950), type 1 diabetes (survival rate at 50 from about 40% to 80% since 1950) and nearly any other condition you look up.
More on Microplastics
In PS Week 240523 we mentioned a new study on plastics by former Github CEO Nat Friedman, famous for sponsoring that prize to read ancient library scrolls. Trevor Klee follows up with a detailed summary about the toxicity of microplastics. The big chart at the end of the post goes into detail about what exactly is known and not known about different forms of microplastics.
Tldr; Trevor is unsure whether microplastics are a big threat or not. But he thinks Nat Friedman’s approach is unlikely to answer the question.
About Personal Science
Personal science is our word for the use of scientific techniques for personal, rather than professional reasons. Personal scientists are those of us who are curious about the world around us which we approach with an open mind. We’re also skeptical, so we tend not to believe things just because we read them somewhere or because a highly-credentialed “expert” says so. We prefer as much as possible to run our own experiments because even if a well-studied phenomenon works in lots of people, it only matters to you if it works in you.
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Wearing masks in crowded indoor spaces appears to have worked a bit too well for me: Never had as much as a sniffle during the pandemic, despite traveling more than usual. But as soon as I stopped wearing masks, I get sick 3 times within 4 months... Pre-pandemic, the only times I remember coming down with a full-blown cold was after long-distance flights (jetlag + lots of exposure?). So I'll keep wearing masks in airport terminals and when getting on or off airplanes.
I am not clear what is being said about the efficacy of masks. I have read a couple of articles recently. You might want to look up Don Milton's work at University of Maryland, College Park. I don't have a position because I don't know.
A small anecdote. I painted my kitchen cabinets and did some sanding with the doors off. Every opening had brown paper taped to cover the opening and many areas had plastic draped over it. Dust still got everywhere. Not a lot, but it still got everywhere.
One more thought. Physics is important. Many people reason about masks and viruses with the trying to "pickup sand with a tennis racket" model. But other forces are at play resulting from boundary conditions. To understand what I mean, think about how you light a match outside on windy day. You light it near a hard boundary because the wind speed there is zero. Masks do the same thing. So they can deflect a current of virus containing air even if they are porous.
My overall view is that stuff gets in with a typical mask but the goal is not to stop it but to lower it as much as possible: filtering some, deflection to even out density inhomogeneities. If there is a high average density, I don't think a mask will do much.