Should we all take aspirin? Not so fast.

I thought we'd put this one to bed. A large-scale study showed that low-dose aspirin (one quarter of a standard 325 mg pill, or about 81 mg) taken once a day can prevent heart attacks and some common types of cancer, including colon cancer.

I wrote about this topic just over a year ago, and I've followed my own advice, taking daily 81mg aspirins since then. The US Preventative Services Task Force recommends this too: regular, low-dose aspirin for people between the ages of 50 and 69 helps to prevent heart attacks, strokes and some types of cancer.

But now, a new study just published in The Lancet upends that advice. It's not that the previous study was wrong–it wasn't. It's just that the effects of aspirin vary significantly based on body weight. Essentially, the new study finds, almost all of the benefits accrue to people who weigh 70 kilograms (154 pounds) or less.

The study, a re-analysis by Peter Rothwell and colleagues of ten large trials that included 117,279 participants, is too long and complex to summarize here, so I'll just highlight a few key points. (Because the paper is open access, anyone can read it for free, just by clicking here.)

The good news, for people who weigh between 50 and 70 kg (110-154 lbs), is that the benefits of daily low-dose aspirin are quite good, possibly even better than we thought. The relative risk of a heart attack, stroke, or other major heart-related event is about 25% lower for people in this group.

The bad news, for the rest of us, is that we seem to get no heart-related benefits from taking a daily low-dose aspirin.

So perhaps those of us who weigh more than 70 kg just need a slightly larger daily aspirin pill. There is some good news here: Rothwell and colleagues found that, indeed, higher doses of aspirin are effective at reducing the risk of heart attacks for people who weigh more than 70 kg. This makes sense: adjusting the dosage based on weight is how most drugs are given. The problem is that aspirin generally comes in only 3 pill sizes: 81, 325, and 500 mg. So the studies have only looked at these 3 doses, and 325 mg is likely too large a dose for most people, because it increases the risk of bleeding events.

What about the cancer risk? As I wrote in 2017, the biggest benefit from daily low-dose aspirin is its reduction in the risk of colon cancer, breast cancer, and prostate cancer. Here, the new study doesn't quite give the whole picture, because it didn't look at breast cancer or prostate cancer. For colon cancer, low-dose aspirin reduces the risk significantly for people who weigh less than 70 kg. For heavier people, low-dose aspirin had little to no effect on colon cancer risk, but regular-sized aspirin (325 mg) worked for people up to 80 kg (176 lbs).

What to do now? The new study concludes that:
"The one-dose-fits-all strategy for daily aspirin use is unlikely to be optimal."
 In other words, you will probably benefit from daily aspirin, but the amount you should take depends on your weight. If you weigh less than 70 kg, the 81-mg tablets that you can find almost anywhere will do nicely. 

But what if you weigh more (as most men and many women do)? The science doesn't yet give us an answer: you could simply take 2 low-dose pills a day, but too much aspirin increases the risk of serious bleeding events. You could instead take a few extra pills per week, depending on your weight, which is what I'm going to do, at least until we get better data and more precise guidelines.

(Final note: as always, before you make any changes in your medication, ask your physician.)

Mosquito wars: what works to keep these little buggers away?

It's summer time, and with it comes outdoor dining, sports, and strolls through the neighborhood. But the loveliest evening can be spoiled by mosquitos, who torment us as they suck our blood and leave itchy welts behind.

How can we keep these pests away? Do citronella candles work? How about Victoria's Secret Bombshell perfume? (No, I'm not kidding. Read on.)

First, about mosquitos: they are more than just a nuisance. They also carry diseases, including West Nile virus, which now affects the entire U.S., and far more deadly diseases in other countries, including malaria, yellow fever, and Zika virus.

(Aside: West Nile virus first appeared in the U.S. in 1999, in New York, after a mosquito apparently hitched a ride on a plane from somewhere in the Middle East. A few years later it started spreading rapidly across the country, and now it's basically everywhere. West Nile fever usually manifests as a flu-like illness, but about 1 in 150 people get severe, life-threatening symptoms.)

One of the most popular ways to keep mosquitos off the backyard patio is easy to spot on a summer night in my neighborhood: burning citronella candles (such as this one from Cutter), which contain a natural oil made from grass whose scent is supposed to repel mosquitos. These are very popular and widely sold, but do they work?

Fortunately, the Journal of Insect Science published a study just last year, by Stacy Rodriguez and colleagues from the University of New Mexico, that gives us an answer. The scientists purchased a dozen different products, all from Amazon or local stores, and ran a very nice experiment to figure out how well each product worked.

Here's the setup: the scientists placed a cage full of mosquitos near a human volunteer, who sat 1-3 meters away, with a gentle breeze blowing from the humans towards the mosquitos. (This made it easier for the mosquitos to smell the humans, and also meant that they had to fly against the breeze if they wanted to bite the subjects.) The scientists applied each mosquito repellent (or device) to the volunteers, opened the cage, and counted how many mosquitos were attracted. They also ran controls where the subject had no protection.

So what worked? First off, with no protection, about 88% of the mosquitos were attracted to the human subjects. The three products that worked best at repelling mosquitos were:

  1. OFF!® Clip On™, where just 27% of the mosquitos were attracted
  2. Cutter® Lemon Eucalyptus, with 30%, and
  3. Ben’s® Tick & Insect Repellent, with 34%. 

Nothing else worked nearly as well as these, although several products reduced the proportion of mosquitos from 88% down to 60-70%.

Notably, some of the products did not work at all, including citronella: Cutter Citro Guard had no effect on the mosquito's attraction to the human volunteers. Other failures were Invisaband™ and Mosquitavert, wrist bracelets containing geraniol oil, and the PIC® Personal Sonic Mosquito Repeller, a clip-on ultrasonic device that emits a sound that mosquitos presumably don't like. Mosquitos basically ignored these devices.

So what's the secret in the products that do work? The OFF! device contains metofluthrin, which appears to be the most effective repellent on the market. Lemon eucalyptus oil is a natural product that is nearly as effective, and Ben's Tick & Insect Repellent contains DEET, which has long been known as an effective defense against mosquitos.

The only one of these products that purports to work on a whole area (like your backyard patio) rather than just one person is the citronella candle, which unfortunately just doesn't work. So if you want your garden party guests to be protected, you may have to keep on hand a basket full of products with metofluthrin, lemon eukalyptus oil, or DEET.

And what about Victoria's Secret Bombshell perfume? Well, the same scientists looked at Bombshell in a 2015 study, where they included the perfume thinking that it would attract (rather than repel) mosquitos. Surprisingly, it had the opposite effect: even though DEET and metofluthrin are more effective, the scientist found that:
"Victoria Secret Bombshell repelled mosquitoes quite effectively 120 min post application."
And what is the active ingredient? According to the same study, that's unknown.

Why is a university hosting a conference on a practice that may be an abuse of human rights?

Sometimes you think you've settled an issue, and you can move on. Demonstrating that a health practice is useless and sometimes harmful should be enough to squash it–but not always.

A few days from now, the University of Northern Iowa will host a conference on "facilitated communcation," a thoroughly debunked practice that harms patients and their families and that has been called unethical by leading medical societies.

For those who haven't heard of it, facilitated communication, or FC, is a method where a person (the "facilitator") sits next to someone and guides their hand over a keyboard. For example, a facilitator will hold the hand of a nonspeaking autistic child and guide her as she types out messages.

The problem is, scientific evidence going back 25 years shows that it doesn't work at all. All of the messages come from the facilitator–who might not even be aware that s/he is doing the actual communicating. Even worse, there are multiple documented instances where FC led to false charges of sexual abuse, invented by the facilitator, that severely damaged families and even led to imprisonment of innocent parents. Nonetheless, FC is still used today, and it is easy to find websites claiming that it can help parents communicate with their autistic children.

The American Speech-Language-Hearing Association has recently written that
"FC is not an effective form of communication and does not provide access to communication... [it] has been associated with significant preventable harms arising through false allegations of sexual abuse and mistreatment. (Boynton, 2012; Chan & Nankervis, 2014; Wombles, 2014)"
Others have been even more blunt, writing that "FC is an abuse of human rights." And yet it has not disappeared.

Why do people still practice facilitated communication? Are they even aware that what they're doing is deeply harmful? A compelling case is made in this lengthy expose, published in 2012 by a former facilitator, Janyce Boynton, who admits that she was responsible for "graphic depictions of rape and sexual assault that had no bearing in reality." Her actions led to a family being split apart and the parents being charged with child abuse. 

Yet Boynton believed at the time that what she was doing was real–as she puts it, she simply "did not want to believe that FC was a hoax." She also makes it clear that many of the people she learned from sincerely believed that FC was real. Boynton herself was crushed when she realized that she–and not the severely autistic child who had been entrusted to her care–was typing all the messages. As Boynton eventually discovered: 
"By the mid-1990s, the scientific community had proved over and over again that it was the facilitator—not the disabled communication partner—who was typing the messages. Every time. Full stop."
Ms. Boynton is now leading the effort to try to convince the University of Northern Iowa to cancel its workshop promoting Facilitated Communication. She helped put together a letter, signed by dozens of doctors, scientists, and speech pathologists, urging the dean of the UNI's School of Education not to host the conference.

I wrote to the UNI dean as well, and she forwarded my questions to Christine Ashby, a faculty member at Syracuse University which is co-sponsoring the conference. Prof. Ashby declined to answer my questions, and instead sent me a document that "provides additional information about the method and the research pertaining to its use," as she wrote. I read the document and looked at the references, but I could find nothing that refuted the earlier double-blind studies (or other, more recent studies such as this one) that have shown that FC is ineffective.

The fight against dangerous pseudoscience never ends. As five professors of speech pathology and psychology wrote just a few weeks ago:
"It's time to stop exposing people to the dangers of Facilitated Communication."
And yet it is nearly certain that the University of Northern Iowa will proceed with its workshop on June 18-19, where attendees will not only get college credit, but they may emerge with the mistaken belief that they can unlock hidden thoughts in children who are unable to communicate. This can only cause harm.

Another anti-vax paper bites the dust

Anti-vaxxers learned a lesson from discredited, de-licensed former doctor Andrew Wakefield, who in 1998 published a badly flawed article in The Lancet pushing a link between vaccines and autism. Wakefield's study was eventually shown to be not only flawed but fraudulent, leading all of the co-authors except Wakefield himself to disavow it, and in 2010 the journal finally retracted it after Wakefield lost his medical license.

But it took The Lancet 12 years to retract the paper, and in that time the anti-vaccine movement flourished. Wakefield became a hero within that movement, and continues to push his anti-vaccine propaganda today, even making films presenting himself as a lone hero fighting for truth.

Other anti-vaxxers are very familiar with this saga, and they have followed Wakefield's recipe by writing scientific papers and attempting to get them published in reputable journals. Usually they fail, but now and then one slips through, which they then point to as "proof" that vaccines are harmful.

The latest example is a paper that appeared in Scientific Reports in November 2016 and that the journal just retracted last week. It has a title that sounds highly technical: "Murine hypothalamic destruction with vascular cell apoptosis subsequent to combined administration of human papilloma virus vaccine and pertussis toxin." (Wakefield's 1998 paper had a similarly obscure title.)

What that lengthy title hides is the paper's anti-vaccine message: that the HPV vaccine might cause neurological damage. The paper was quickly called out as pseudoscience by the scientific community, who reacted within days in the blogosphere and elsewhere, as described by a news article in Science that appeared just after the paper's publication.

(Aside: the HPV vaccine protects people from human papillomavirus, which causes many cases of cervical cancer as well as throat cancer. It's the first vaccine that prevents these cancers, which is an amazing breakthrough. Millions of doses have been administered with essentially zero cases of harm.)

What did the paper do? Basically, it was a setup. The authors–most of them from Tokyo Medical University–gave mice a huge dose of HPV vaccine plus (here's the kicker) a large dose of pertussis toxin. There's no valid reason to administer that toxin except to try to induce brain damage, which the authors could then blame on the HPV vaccine. The study design was clearly awful, and the paper should never have been published.

Just after the paper appeared, two groups of scientists wrote to the Nature publishing group (which publishes Scientific Reports) to protest, as reported in the Science story. One letter, from a group of HPV experts at the University of Antwerp, explained that:
"This experimental setup in no way mimics the immunization with HPV vaccines but is gross over-dosage and manipulation of membrane permeability."
This is putting it mildly. For a blunter assessment, see Orac's aptly titled "Torturing more mice in the name of antivaccine pseudoscience," which appeared in November 2016.

What was not publicly known before now was that I too wrote to the journal editors, asking them to "take action quickly, rather than waiting for over 10 years as The Lancet did." First I wrote to the immunology sub-editor, who forwarded my letter to the Editor-in-Chief, Richard White. Dr. White replied on 29 Nov 2016 that "We are looking into the specific issues raised regarding this paper."

That was the last I heard of it, until the journal announced last week that they have retracted the paper.

So in the end, the scientific record was corrected. But why did it take Scientific Reports 18 months to do it? Haven't they learned from the Wakefield debacle how much damage can be done while antivaccine articles like this one remain in the literature? The journal's editors had a responsibility to act more quickly, and they failed. The scientists who wrote those letters back in 2016 had the same complaint, as reported by Dennis Normile in Science last week. Not surprisingly, Scientific Reports refused to comment (when asked by Science) on any details of their review process.

That's not good enough. Scientific Reports is a "mega-journal," a new type of journal that publishes thousands of papers per year, with a relatively low bar for acceptance. The idea (not a bad one, in theory) is that any valid scientific study, even one that makes only a very small contribution, still merits publication somewhere.

What publishers have learned is that these mega-journals are very profitable, because they charge a publishing fee that more than covers their costs. In return for these profits, Nature Publishing has an obligation to remove harmful papers far faster than they did in this case. Otherwise, it's only a matter of time before anti-vaxxers do this again.

Finally, let me repeat something that can't be said often enough: vaccines are perhaps the single greatest medical advance in human history. They have saved millions of lives, and they continue to save lives today. Scourges such as smallpox and polio, which once swept through populations causing terrible pain, suffering, and death, have been conquered thanks to vaccines. Medical researchers continue to work on new vaccines against the infections that still plague us, and they are the real heroes.



How not to respond to the EPA's science denialism

You would think that the editors of the top science journals in the world would know how to write clearly. But if you read their joint statement in the journal Science last week, you might be forgiven for wondering what the heck they are talking about. It's not that complicated, really. Let me explain.

EPA Administrator Scott Pruitt, when he's not busy taking expensive trips, renting rooms at a deep discount from coal lobbyists, or building $48,000 soundproof booths for his office, is doing his best to make the U.S. a friendly place for fossil fuel industries. As part of his pollution-friendly mission, Pruitt denies the scientific consensus that climate change is real and is caused in part by human activities, especially by carbon dioxide emissions.

Pruitt has devised a clever new strategy to make science denialism part of official EPA policy, while pretending otherwise: he's issued a new proposed rule that requires the EPA to use only "transparent" science. (The official Federal Register entry is here.) In his press release, Pruitt stated
"The era of secret science at EPA is coming to an end. The ability to test, authenticate, and reproduce scientific findings is vital for the integrity of rulemaking process."
The press release, which is titled "EPA Administrator Pruitt Proposes Rule To Strengthen Science Used In EPA Regulations", seems to be all about science and openness. One thing I've got to give them credit for: the PR people at the EPA know how to obfuscate.

It turns out this is just a ruse. As Pruitt certainly knows, many of the EPA's rules are based on studies of human subjects, which are governed by strict privacy rules–which are necessary not only to get people to participate in the studies, but also because violating people's privacy can be highly unethical. This means that many studies showing the harms of pollution–for example, this massive study, which found that fine-scale particulate matter from coal plants increases the risk of lung and heart disease–are not "transparent" enough for the EPA, because the identities of the participants as well as all their health records are confidential.

In other words, the new EPA policy isn't about scientific transparency. It's a transparent (!) attempt to ignore the negative health effects of pollution, so that Pruitt can put in place new rules allowing polluters to dump more pollutants into our air and water. See how that works?

In response, the Editors-in-Chief of Science, Nature, the Public Library of Science, and the Proceedings of the National Academy of Sciences issued a joint statement. Alas, their statement is anything but clear. They spend about three-fourths of it explaining about how they support data sharing, and finally, in their last sentence, they write this:
"Excluding relevant studies simply because they do not meet rigid transparency standards will adversely affect decision-making processes."
That's it. Even the most sophisticated reader could be forgiven for not understanding what the issue is, not from this statement alone.

Here's what they should have said: the EPA wants to ignore the health consequences of pollution when creating policy. The EPA administrator, Scott Pruitt, has announced a new policy that pretends to be about scientific transparency, but is nothing of the sort. Instead, this policy is designed to undermine the EPA's mission, which is (and you can read this right on the EPA's website "to protect human health and the environment."

Since the EPA's creation in 1970, the U.S. has made tremendous strides in cleaning up our air and water. Let's not start backsliding just to enhance the profits of a few polluters.

[Note: I have written the EPA and asked for comment. I will update this article if they respond.]

Sniffle. It's allergy season again. Do those shots work?

Ah, spring is in the air. The flowers are blooming and the trees are bursting into leaf.

For many of us, this time of year means one thing: allergies. The price of going outside for any length of time is sneezing and itchy eyes that last for many hours, even after we return indoors. Rather than going out and enjoying the warm air and colorful vegetation, we close the doors and windows and stock up on antihistamines and eye drops. Studies show that 20–40% of people in the U.S. have allergies.

Your local pharmacy has shelf after shelf of allergy treatments, ranging from mildly effective (Zyrtec and its equivalents) to laughably ineffective (anything homeopathic). But even the best pills have side effects, and they only serve to suppress the symptoms. As one study put it:
"Patients struggle to alleviate their misery, frequently self-adjusting their treatment regimen of over-the-counter and prescription medications because of lack of efficacy, deterioration of efficacy, lack of 24-hour relief, and bothersome side effects."
Isn't there a way to tell your body to just stop it already? After all, pollen is not a pathogen. Our misery is caused by our own immune system's over-reaction: it ramps up in response to the foreign particles (pollen) in our eyes and airways and creates a histamine reaction, which is simply not necessary.

None of the over-the-counter pills prevent this reaction, but they can dampen it–hence the term "antihistamine." However, what if there were a way to tell your body to simply chill out and ignore the pollen?

Well, maybe. You can get allergy shots. This is a surprisingly simple procedure: your doctor takes a small, diluted amount of the allergen (pollen, cat dander, etc.) and injects it into your arm. Over the course of many months, your doctor will very gradually increase the amount being injected. You have to go for the shots every week, and continue them for several years.

The question is, do they work? The answer is a qualified yes.

NIH and the Agency for Healthcare Research and Quality (AHRQ) have put together a long explainer of the evidence for and against allergy shots, which you can find at PubMed Health. The NIH study looked at 74 clinical studies of allergy shots. To save you some time, I'll cut to the chase: the evidence is quite good that shots work. Or, as the AHRQ study put it,
"we found high grade evidence that subcutaneous immunotherapy reduces rhinitis/rhinoconjunctivitis symptoms."
This might seem like pseudoscience, but it's not: what's happening is that your immune system is being de-sensitized to the allergen. It doesn't work for everyone, but in many people, this gradual de-sensitization trains their immune system not to react so badly. It's not necessarily permanent, either: after stopping the shots, allergies might re-appear after a few years.

So if you're looking out your window at the beautiful spring weather with a box of tissues by your side, maybe you have a way out. Talk to your doctor or visit the AAAAI site to find an allergy specialist. Don't expect miracles or a quick fix, but allergy shots are the best we've got, for now.


Anti-vaxxers use religious exemptions as false cover for their beliefs

History of measles in the 20th century.
For several years now, anti-vaxxers have been claiming that they have religious objections to vaccines. This is nonsense.

Just last month, the New England Journal of Medicine featured an article describing how the federal Equal Employment Opportunity Commission (EEOC) has been suing hospitals that deny employee requests for religious exemptions to the hospitals' vaccination requirements. The NEJM documented 14 cases where employees sued claiming that they had religious objections to the flu vaccine. Six of the cases were settled, and in the other cases, sometimes the hospital won, sometimes the employees. It's a mess.

The NEJM article focused on the legal perspective, advising hospitals on how they might avoid lawsuits. That's understandable, but it misses the broader point: there's virtually no such thing as a religious objection to vaccines. All of the world's major religions support vaccination, and only a few tiny, extremist sects teach their followers that vaccines are contrary to their faith.

What's really going on is that anti-vaxxers are using religious exemptions as cover for non-religious (and erroneous) objections to vaccines. The anti-vaxxers have convinced people that vaccines are harmful, or scary, or both. They are wrong.

Vaccines are the probably the greatest success story in the history of medicine. They've saved millions of lives. Consider that in the decade before the measles vaccine was introduced in 1963,
"3 to 4 million people in the United States were infected each year [and] an estimated 400 to 500 people died, 48,000 were hospitalized, and 1,000 suffered encephalitis (swelling of the brain) from measles." (Source: CDC)
And that's just measles. People no longer suffer and die from smallpox and polio, which have been eradicated worldwide (except for a few countries where polio still has a foothold). Vaccines protect us from multiple other formerly common childhood infections, and they've been so effective that people are no longer afraid of these diseases. That very success is the opening that the anti-vaxxers use to spread disinformation and fear.

It's not just the EEOC that has been enabling anti-vaxxers. Many U.S. states have passed laws that allow religious exemptions to vaccination. (Note that vaccines are required before children can enroll in public school systems, an incredibly important public health requirement. The exemptions refer to this requirement.)

Here, though, there are signs of hope. After suffering from repeated outbreaks of preventable diseases like measles, many states have recently awakened to the risks caused by unvaccinated children in public schools, and they are moving to remove or tighten these exemptions.

New Jersey is the latest state to act. While the bill introduced in the New Jersey legislature last week doesn't quite eliminate religious exemptions, it makes them harder to get, requiring considerably more documentation from parents claiming a religious exemption from vaccines for their children. NJ took action after realizing that these so-called "religious" objections had risen dramatically, from 3,865 in 2009 to 10,407 in 2016. That rise was fueled, apparently, by anti-vaxxers taking advantage of the loophole in the law, not by any genuine religious objection to vaccines.

It's worth noting that all states allow medical exemptions to childhood vaccination, which are legitimate and necessary. For example, a child undergoing leukemia treatment may have a severely weakened immune system, and a vaccine would be ineffective and possibly harmful. These children are precisely the ones who can only be protected by requiring all the other children in their school to be vaccinated.

Meanwhile, the EEOC should stop suing hospitals. Hospitals are filled with very sick and vulnerable people, and employees have an obligation not to expose patients to possibly deadly infections. If a hospital employee doesn't take that obligation seriously, then s/he should find another job.