Archive for the 'Science and Medicine' Category

May 17 2018

California Rules Coffee a Carcinogen

California Superior Court Judge Elihu Berle ruled, in accordance with Proposition 65 law, that coffee is a carcinogen and requires a warning label in the state of California. This ruling, however, is not in accord with science and rational medicine.

What went wrong are all the things that can go wrong when trying to assess health risk.

The ruling is based on the presence of acrylamide in coffee. There is evidence that acrylamide is a potential risk factor for certain cancers. This is based mostly on animal and in vitro studies.

How scientists determine that a substance is potentially a cancer risk is a little complex, since we cannot do direct clinical studies. It is unethical to expose a subject to a potential carcinogen to see if they get cancer. So we start with studies on cells and animals.


These types of pre-clinical studies, however, can only tell us about hazard, not risk. A hazardous substance is something which can theoretically cause harm depending on exposure, while risk is actual harm caused by exposure in a certain population to a certain dose over a certain period of time.

Think of it this way – sharks are hazardous, but a shark in a tank poses very little risk. Swimming with sharks in that tank, however, poses a high risk.

So how do we determine the risk to humans of a substance which is potentially hazardous based on pre-clinical studies? For that we rely on epidemiology and observational studies. If we, for example, ask people about their coffee drinking habits, and then track them over time for the development of cancer, we can then make comparisons and see if drinking coffee correlates with increased cancer risk.

There are many shortcomings from this type of data, however, specifically the potential for confounding factors. Drinking more coffee may correlate with more smoking, or consumption of other hazardous products, for example. You can try to control for possible confounding factors, but not the ones you are not aware of. So this limits the utility of such data.

Even still, it is possible to build a robust base of evidence clearly showing risk. If the observational studies all triangulate to only one plausible cause, then we can be highly confident of that interpretation of the correlations. Smoking, for example, correlates with risk of lung cancer every possible way you can look at the data. This is a solid causal link.

The same solid link does not exist for acrylamide in coffee. Therefore coffee is deemed only a probable cause of cancer by the IARC, which is a notoriously cautious body that errs on the side of calling substances “probable” carcinogens. Essentially, if some hazard shows up in pre-clinical studies, but there is no clinical evidence of actual risk, they still call it “probable.”

California law then takes the IARC “probable” and turns that into “coffee causes cancer.” In each step the precautionary principle ratchets up the warning, until we go from no clinical evidence of actual risk, to a required warning label that it does cause cancer.

This approach, however, is not without its own risk, turning the precautionary principle on its head.

As I reported previously on SBM, a 2013 study found that 72% of random ingredients from a cookbook had published data showing that they increased the risk of some cancer. What is the public supposed to do with this information?

There are two real risks here, the first of which is what is called alarm fatigue. If you set your threshold for warning alarms too low, then the alarms will always be going off, and people will learn to ignore them.

Do you think many people will stop drinking coffee because of the warning? I wonder what percentage will give up their daily coffee habit based on this decision. Most people will likely (and correctly) file this away as a manifestation of the overly cautious CYA nanny state and ignore the warnings. But this makes it more likely they will ignore more meaningful warnings about actual risk that they should be listening to.

If everything causes cancer, then perhaps nothing really does, and you should ignore all such warnings. The warnings themselves become useless.

There is also the opposite risk, that some people, in the sincere desire to be healthy or out of anxiety, will try to heed all such warnings. This can lead to what some are calling “orthorexia” (not currently a recognized clinical term), in which people excessively restrict their diet in the hopes of avoiding risky food.

If 72% or so of foods or ingredients can be linked to cancer, and you try to avoid them all, then what will you eat? What are the risks of such a highly restrictive diet? I strongly suspect that if you followed all the warnings about potential risks of foods, there would be net harm from poor nutrition.

There is also an opportunity cost to spending so much time and effort carefully vetting everything you eat for any possible risk. That time could be better spend on more fruitful healthy activities.

There is also an industry of self-help advice turning these public warning into marketable fearmongering. They have essentially been “weaponized” for either marketing or to promote various ideological agendas. The anti-GMO campaign is perhaps the best example.

The state should be trying to mitigate these counterproductive forces, not aid them. If anything they should be a mediating force, putting together panels of experts to create sober and useful bottom-line advice for the public, advice that people can plausibly used, and designed to minimize unintended consequences.

California’s approach, I think, is harmful. In an endeavor to protect the health of their citizens I think they are harming health. They are also potentially undercutting faith in experts an expertise itself, which has further downstream negative consequences.

This is the precautionary principle out of all control.

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May 15 2018

Homeopathic Nosodes

Homeopathy is bunk. Most people I encounter who disagree with this statement do not actually know what homeopathy is. They think it is some kind of herbalism or natural medicine. No – it is a prescientific superstition-based system of magic potions.

The basic idea is that you start with a fanciful treatment based on notions like sympathetic magic and incidental characteristics (like hair color). Then you dilute that fanciful treatment out of existence – so it doesn’t really matter anyway. Homeopathy is literally nothing, but homeopaths believe that the magical “essence” of the substance remains.

Unsurprisingly, clinical trials of homeopathic potions have convincingly shown that homeopathy works for nothing. So it can’t work, and in fact it doesn’t work.

So why is homeopathy still a thing? That is a fascinating question dealing with culture, human psychology, and political failure.

There is also an aspect of homeopathy that dovetails with another pseudoscience – the anti-vaccine movement. Homeopathic nosodes, which are just as useless as all other homeopathic potions, are offered as a substitute for vaccines. This way you not only waste money on a worthless health scam, you also forgo safe and effective medicine – a nice double whammy.

Nosodes are prepared by taking body fluid from a diseased person or animal and then diluting it so that you have – water. This water is then given to prevent the disease that the person or animal from which the fluid was taken had.

In addition to giving fake medicine instead of effective medicine to prevent a serious and communicable disease, there is some risk to the preparation process itself. Homeopaths are making nosodes of HIV, ebola, Hepatitis, and other serious infectious diseases. That’s right – their answer to the HIV epidemic in Africa, or to ebola outbreaks, is to give their fake medicine.

Are there any clinical trials of homeopathic nosodes that show they work? No. Homeopaths largely rely upon what they call a “homeopathic pathogenetic trials.” This is a great example of pseudoscience, because it follows some of the forms of real science, but isn’t doing actual science.

Here is one of an HIV nosode – they basically give 15 volunteers water, I mean an HIV nosode, and 7 volunteers water, I mean placebo. The volunteers are trained to record every symptom they experience. Over four weeks the HIV nosode water group recorded 130 symptoms, while the placebo water group recorded 60 symptoms. Those ratio’s are remarkably similar to the number of people in each group – twice as many people reported twice as many random symptoms. Shocking.

This is what passes for science in homeopathy. What they rarely do are actual efficacy trials designed to answer the real question – do the potions work? When high quality efficacy trials of homeopathy are done, they usually turn out negative, and systematic reviews have all been negative. So they mostly don’t bother with such trials, instead doing their HPTs, and observational trials, or looking at markers, so that they can pretend they are doing science.

This nonsense isn’t limited to humans. Recently there was outrage over homeopathic nosodes given to pets. These cats and dogs might get serious and preventable diseases because their owners relied on homeopathic nosodes they purchased on Amazon instead of real vaccines.

Opting for homeopathic remedies in favour of vaccines can be the cause of fatal viral diseases including parvovirus and herpes virus, the RSPCA said.

The former kills nine in 10 dogs who contract it, the latter can prompt a pregnant dog to abort her puppies or kill an entire litter of young puppies to die over 24 hours.

The British Veterinary Association said that skipping vaccinations can also be the cause of zoonotic diseases, such as canine leptospirosis, which can be infectious to humans.

Allowing people to die from fake vaccines is one thing, but you cross a line when you allow cats and dogs to die from preventable infections.

What I don’t get is the unwillingness to properly deal with homeopathy from a regulatory standpoint. Why is the political will lacking? It seems that part of the problem is that many politicians are not scientists or even minimally scientifically literate. But odds are most still realize that homeopathy is snake oil, or at least would listen to the overwhelming scientific consensus that homeopathy is snake oil.

There just doesn’t seem to be any political incentive to do so. This is a manifestation of a broken political system, where there is insufficient motivation to do something so obviously beneficial and correct like banning 100% fake medicine. But I also think this is a failure of the scientific and academic communities. There is a paucity of outrage at the infiltration of pseudoscience into our culture and our medical system. That is our fault. And if we lack proper outrage, how can we expect others to have it?

The underlying problem is that many snake oils like homeopathy fly under the radar. Many doctors don’t know what it is, do not know how much it has insinuated itself into the system, and don’t know the regulations. They are happy to ignore it and assume it is a small and benign fringe. They are wrong. This situation is easily remedied through education. Once properly informed, most health care professionals are properly outraged. Let’s have more of that.

 

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May 04 2018

Be Wary of Dubious Brain Cancer Study

We have yet another example of a scientifically complex study being mangled by the mainstream media, who simply do not have the chops to provide an adequate analysis. The Telegraph reports:

Fresh fears have been raised over the role of mobile phones in brain cancer after new evidence revealed rates of a malignant type of tumour have doubled in the last two decades.

They further report about the study:

They analysed 79,241 malignant brain tumours over 21 years, finding that cases of GBM in England have increased from around 1,250 a year in 1995 to just under 3,000.

This sounds alarming. The mainstream reporting was not horrible (unlike some of the fearmongering by advocacy groups) but was completely inadequate to really put this study into context. The Science Media Center put together analysis from various experts, and the entire page is worth a read. It is a good demonstration of how to really analyze a scientific paper.

The Telegraph article does point out that this new study is looking at brain cancer incidence only, and did not present any data that correlates the risk of brain cancer with any specific risk factor. The paper only speculates about possible causes, including the rise in cell phone use. But that is just scratching the surface.

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May 01 2018

A Healthy Lifestyle Matters

I see patients nearly every day who sincerely want to live a healthy lifestyle. Most people want to be healthy and I don’t know anyone who is looking forward to a premature death from a preventable disease. That is why health products and advice are a huge market.

For those looking to adopt healthy habits there is good news and bad news. The good news is that we are among the first generations to have comprehensive scientific data to tell us how to do that. The bad news is that we are also living at a time of massive misinformation, and so many people get distracted from the real scientific answers by slick marketing and ideology.

There is even more good news – you already know the answer to healthy living, and it is mostly simple (maybe not easy, but simple). A new study now confirms with the largest set of epidemiological data on the topic to date what previous studies have already shown. There are five basic lifestyle factors that have a dramatic effect on longevity and the risk of death from heart disease, cancer, or other causes.

The researchers used two datasets –  Nurses’ Health Study (1980-2014; n=78,865) and the Health Professionals Follow-up Study (1986-2014, n=44,354), which means they have data from 34 years with 123,219 subjects. That’s a powerful study. They tracked the correlation between five lifestyle factors – healthy diet, regular exercise, lean body mass, not smoking, and limited alcohol use – with longevity and risk of dying. They found:

We estimated that the life expectancy at age 50 years was 29.0 years (95% CI, 28.3-29.8) for women and 25.5 years (95% CI, 24.7-26.2) for men who adopted zero low-risk lifestyle factors. In contrast, for those who adopted all 5 low-risk factors, we projected a life expectancy at age 50 years of 43.1 years (95% CI, 41.3-44.9) for women and 37.6 years (95% CI, 35.8-39.4) for men. The projected life expectancy at age 50 years was on average 14.0 years (95% CI, 11.8-16.2) longer among female Americans with 5 low-risk factors compared with those with zero low-risk factors; for men, the difference was 12.2 years (95% CI, 10.1-14.2).

So a 50 year old woman who drinks, smokes, is overweight, does not exercise regularly, and has a poor diet overall will die 14 years earlier than someone with none of those risk factors (and for men it is 12.2 years). That is significant. If you look at the full data, there is a fairly linear relationship between the number of risk factors and life expectancy – so each healthy lifestyle you adopt adds a couple years to your life expectancy.

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Apr 02 2018

Science and Pseudoscience of the Interstitium

Recently scientists published a study in which they present evidence for a new possible organ called the interstitium. The science here is interesting – the interstitium is a distributed system of fluid filled cavities in the connective tissue. The fluid is lymph, which means that these cavities likely play an important role in the immune system. They also give the skin and connective tissue a spongy structure, which would make them more flexible and durable.

It is also interesting how the existence of the interstitium was missed for so long. It was an artifact of the methods used to prepare tissue for slides. Fixing the tissue with chemicals would dry out the tissue, causing the cavities to collapse. It was therefore thought that these connective tissue layers were solid.

The science here seems solid, and will likely lead to further discoveries that might inform our understanding of certain diseases. However, the authors of the study decided to spread some pseudoscience along with the science.

Neil Theise, professor of pathology at NYU School of Medicine, and Rebecca Wells, professor of medicine and bioengineering at University of Pennsylvania, on a segment of Science Friday where they discuss their study, said that the interstitium might explain how acupuncture works. Some news outlets even decided to lead with the acupuncture angle. In an article for The Cut Theise digs deeper:

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Feb 26 2018

The Efficacy of Antidepressants

A new major study finds that antidepressants are effective for the acute treatment of major depression. The study is considered a definitive systematic review and meta-analysis including 522 trials comprising 116,477 participants. This includes unpublished data from pharmaceutical companies, to address the concern that some negative data was being hidden.

In the study all 21 antidepressants studied were more effective than placebo, ranging from 1.37 times as effective to 2.13 times as effective.

This is not surprising to anyone familiar with the evidence – it is, in fact, just a review of that evidence. However, many in the public might be confused because these results seem to contradict previously reported studies that purport to show that for many patient antidepressants are no more effective than placebo.

This confusion, however, is largely due to poor reporting. The key factor that is often missed is the severity of the depression. Often I hear people claim that, “Antidepressants have been shown not to work for depression.” But that is not a meaningful statement because you cannot scientifically refer to the evidence regarding “depression” without qualifying “mild to moderate” vs “severe” depression. That detail often gets dropped in mainstream reporting, and therefore the public consciousness.

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Feb 23 2018

More on Weight Loss

Whenever I post about the topic of diet or weight management, there is always a lively discussion in the comments. There are also always many comments that are based on ideology, rather than evidence, and the level of emotion is significantly higher than for many similar topics.

I think this is because the topics of food, eating, and weight management seem very personal. Also, everyone has a lifetime of experience with eating, and so everyone feels like their own anecdotal experience makes them an expert (even if they intellectually know they aren’t). The topic is also a setup for confirmation bias – we all have many friends, co-workers, and family with their own dieting experience, and we can even look around and see what strangers are doing and how they look. It is therefore really easy to see the evidence for whatever your opinions are, to have the illusion that your beliefs are confirmed.

To add further fuel to the confirmation bias fire, there are a host of gurus and fake experts out there, and even genuine experts but who only see a slice of the science. There are enough expert and pseudoexpert opinions out there to confirm whatever position we want to take.

For all these reasons dieting is one of the more challenging issues for the average person to find objective reliable information. That is all I am trying to do here, adding my perspective as an advocate for science-based medicine. Interpreting scientific medical data is complicated, and there are lots of opportunities to be mislead. The weight-management literature is particularly complex and heterogeneous, so again, you can support pretty much any position unless you take a really careful look at the literature.

So to follow up my post from yesterday, which prompted a flood of different opinions, let’s take a further look at the evidence.

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Feb 22 2018

Low Fat vs Low Carb – No Difference

There is a legitimate scientific debate about the optimal proportion of macronutrients (fat, carbohydrates, protein) for weight loss and maintenance. Although I do think there is a strong consensus that the scientific evidence supports the conclusion that the proportion does not ultimately matter (within a range of healthy balance), and that all that really matters is calories in-calories out.

Since weight loss is extremely challenging, even a small edge might be worth knowing about. There are also many basic science reasons to suspect there might be a difference in hunger for different diets, and this will translate into behavior. There are further many health considerations other than just weight and it would be good to know what effect different types of diet have on cardiac and diabetic risk factors.

Unfortunately there is a great deal of confusion and misinformation out there (common for any topic of public interest). One main drivers of this, as I see it, is a self-help industry looking to make billions on the challenge of weight loss by selling one fad diet after the other. Another main driver is the media reporting basic science or preliminary studies without putting them into proper context.

That is why one of the main goals of my science blogging is to emphasize that you cannot reliably make conclusions about interventions from basic or preliminary research. Most new ideas do not work out, and extrapolating from such data is not likely to lead to conclusions which are true. We need the research to develop to the point where we have rigorous clinical trials, testing the ultimate effect in actual people.

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Feb 16 2018

More Victims of Alternative Cancer Treatments

Every doctor who treats cancer patients can tell you stories of patients who present with cancers too advanced to treat because they were spending their time pursuing alternative treatments. This has also been studied – last year a Yale team published a study showing higher rates of death among cancer patients who choose alternative treatments.

There is now a recent story of a YouTuber who produced videos claiming that a vegan diet and prayer cured her stage 4 cancer, except now she has died from her cancer. Of course, I am sad for her death and that the treatments she sought at the end were not enough to save her. It’s likely that everyone knows someone affected by cancer – it is a scary and often tragic disease. At the same time, we can’t miss the lessons in this story. It is so typical it can serve as an archetype.

What typically happens is that when some people are diagnosed with cancer they search for any possible salvation from their situation. That is understandable. Often there is an initial treatment, such as removal of a solid tumor, or shrinking the tumor with drugs. Some patients may also seek additional intervention, such as alternative treatments or faith healing. At that point they are in the honeymoon phase of the illness – no matter what their ultimate prognosis, their symptoms were likely improved by the initial treatment. They can imagine that they are cured. This is usually the point at which they claim that whatever alternative or faith-based treatment they underwent healed them.

Depending on the type of cancer, some of these patients may have been essentially cured by their initial surgery or treatment. For those who weren’t, a recurrence of symptoms is inevitable. We then may or may not hear about them when the cancer returns and leads to their death.

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Feb 09 2018

Ontario College Plans Program in Homeopathy

Here we go again.

If you are in a decision-making position at an institution of higher learning than you have a responsibility to understand and protect the academic reputation of that institution. Further, such institutions (many of which, as in this case, are publicly funded) have a responsibility to society, to promote academic standards and legitimacy. At the very least such institutions should not be promoting pseudoscience, or dressing up any nonsense as if it were real.

Georgian College in Ontario has approved funds and plans to open a program that will teach homeopathy as if it is real medicine. Teaching any pseudoscience is an outrage, but when it is medical pseudoscience there is also arguably another layer of malfeasance because the connection to real harm is more direct.

I know this is old territory here, but for review: Homeopathy is a prescientific philosophy-based system based on magical thinking. Its core ideas were never valid, and have never been supported by science. Essentially, homeopathy uses fanciful treatments that are based on silly ideas, such as the personality of the patient, but also “sympathetic magic.” The belief is that homeopathic remedies contain the magical essence of symptoms and can be used to cure those same symptoms.

Then, doubling down on the idea of magical essence, all actual substances are diluted out of existence, so that only the essence remains. Therefore, in reality, only water remains. Homeopathy is literally treating people with magic water created with rituals resembling witchcraft, and without the tiniest bit of scientific legitimacy.

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