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An Interview with Distinguished University Professor Gordon Guyatt, OC, FRSC (Part Five)


Author(s): Scott Douglas Jacobsen

Publication (Outlet/Website): In-Sight: Independent Interview-Based Journal

Publication Date (yyyy/mm/dd): 2017/08/01


An Interview with Distinguished University Professor Gordon Guyatt, OC, FRSC. He discusses: concerns about bogus medicine; big data and upper limits in health outcomes; coffee and randomized control trials; exciting research and health outcomes; ways the general public can avoid snake oil; possible examples of snake oil; antibiotic resistance; impressive research; vitamin fads; unsolved medical diseases; and cancer in Canada.

Keywords: Canada, coffee, Gordon Guyatt, medicine.

An Interview with Distinguished University Professor Gordon Guyatt, OC, FRSC (Part Five)[1],[2]

*Footnotes in & after the interview, & citation style listing after the interview.*

*This interview has been edited for clarity and readability.*

1. Scott Douglas Jacobsen: So, there are pervasive ideas in Canada, people with a functional healthcare system, a series of just bogus medical science and treatments. What is one of the main concerns with regards to them as a professional, a clinician?

It could be the whole gambit. It could be homeopathy; it could be crystals; it could be fake cancer therapies or private clinics giving stem cell therapies. You name it.

Dr. Gordon Guyatt: My familiarity with the magnitude of all of the things that you mentioned is limited. Some of the interventions are benign and not particularly costly, and of not much concern as a result. The interventions that might have harm associated with them, and would be more costly, would be a greater concern.

It has been speculated that homeopathy and alternative medicine and other interventions of that sort have a benefit because of the way medicine has evolved in terms of much more emphasis on technological aspects, and much less emphasis on caring and listening. I did not know the evidence if anyone has followed seriously over time, the use of alternative medicine.

I suspect the data may not be accurate, and so it is speculative whether their use has increased. Speculative on my part, but in the course of my 40 years in clinical practice, the emphasis on technological aspects has increased, and caring and listening to patients has decreased, and this might contribute to increased use of alternative interventions.

2. Jacobsen: We keep pushing into areas of bigger and bigger data, so we have more information about what the outcomes of certain treatments might be. Is there going to be an upper limit to how far we can take the health span of citizens for instance in Canada based on these advancements?

Guyatt: You’ve linked two things, but I would immediately be inclined to unlink. There is a great deal of excess optimism about what we can learn about treatments from large databases; large databases are essentially big observational studies that are terribly limited in making inferences about treatments because people who get treatment A are typically different than people who get treatment B.

As a result, one can make very easily spurious inferences about the effect of therapy. For an example, people who take antioxidant vitamins have less cancer and less cardiovascular disease than people who do not use antioxidant vitamins. Unfortunately, it has nothing to do with antioxidant vitamins.

In randomized trials, there is no difference in cancer or cardiovascular disease in those who do and do not use antioxidant vitamins. The reason people who take antioxidant vitamins do better is that different people take antioxidant vitamins than those who don’t, and those people are destined to do better in terms of cardiovascular disease and cancer.

This is the fundamental problem faced by large databases. It can record if people receive treatment or not. What they cannot do is ensure that the people who did and did not use the treatment were similar with respect to their prognosis, and likely outcomes had they not used treatment.

Indeed, the likelihood is that they were different, and that leads to a biased testament effect. So the large databases are going to provide some information, but we are still going to need randomized trials to sort out other treatments. So that’s one thing.

A completely separate issue is life span. Medical treatments have certainly contributed to that, but advances in nutrition and housing and poverty reduction had more influence on extending the life span than having medical treatments.

Once again, speculative as to what the limits of biology are, the life span in advanced industrial society, most advanced industrial societies, particularly those with low-income gradients keep going up, up, and up. I think it’s speculative as to what the limit of that would be.

3. Jacobsen: You have given another common example, which is one that shows up in the news quite often. It’s coffee, and statements about its health effects. Is it possible or has it been extended, the research about antioxidants, for instance, in improving health, in randomized control trial? It doesn’t necessarily show up. Is it the same for coffee?

Guyatt: It would be challenging to do randomized trials of coffee. I don’t know that they’ve been done, but again, any influences about the health effects of coffee are confounded by the fact that there are all sorts of differences between coffee drinkers and non-coffee drinkers. So until we have randomized trials, we’re going to have low quality evidence about the impact of coffee on various health outcomes.

4. Jacobsen: If we’re looking at the developments in medical research now, from a personal perspective, what is some of the more exciting research in development? From a professional perspective, what research has the most potential for improving health outcomes, especially for the aforementioned population such as the low income?

Guyatt: The best way to improve the health of low income folks is to decrease income gradients and that would have far more impact than any particular health interventions. If we could get everyone in society to stop smoking that would have a big impact: lifetime smokers have seven years shorter lifetimes than the lifespans of non-smokers, a far bigger gradient that can come from any particular health interventions.

So if we can persuade everyone to stop smoking, that would have an enormous impact on health. While medical innovations have made a big impact on both quality and quantity, there are other things like income gradients, like health habits – in particular, smoking – that have a bigger impact

Medical treatment has made a big impact on various areas, including cardiovascular disease and treatments and cancer. Those were made because those were the biggest sources of morbidity and mortality in society. That is where I see the biggest continuing potential: certainly, within the area of cancer, our understanding biology has advanced enormously.

We will keep seeing new therapies and prevention. Many cancers which were uniformly fatal have now been turned into chronic diseases. I expect that to continue.

5. Jacobsen: As a practical tip, how can the general public avoid snake oil, bogus remedies? Something simple.

Guyatt: What they can do is learn the basic principles of deciding what evidence is trustworthy and what is not.  That should be possible. A colleague of mine by the name of Andy Oxlan has completed a large randomized trial in Africa of teaching school age kids about recognizing, as you put it, snake oil from legitimate health claims.

His randomized trial showed that teaching the kids substantially improved their ability to make those distinctions. As a side effect, their parents’ ability to make those decisions improved. These are very low resource African settings. So there’s plenty of information that is potentially available to consumers about health claims.

Should people decide to educate themselves, they all would be in a position to make judgments themselves. They should certainly be in the position, even with quite limited knowledge, of asking their clinicians to justify what evidence there is to base what is being suggested and to challenge the physician or the clinician in explaining – to be made knowledgeable of the evidence that supports what they’re doing.

6. Jacobsen: Some of these fakes or snake oil sellers are predatory rather than true believers in it. Do any prominent examples come into mind?

Guyatt: I am maybe fortunately or unfortunately quite insulated from exposure to that. If I heard of anything, it would be through newspapers, and your knowledge would be as good as mine.

7. Jacobsen: There have been some international concerns about the effectiveness of antibiotics in the long term.

Guyatt: The concerns are multiple. There are many, many examples of antibiotics becoming ineffective as a result of bacteria developing resistance to the antibiotics. So that is a very real issue. It raises legitimate concern and suggestions that we should make sure that we’re only using the antibiotics when they are really warranted.

Efforts are ongoing to try and limit the use of unnecessary or inappropriate antibiotics; to the extent that we can limit their inappropriate use we can limit the emergence of resistance.

8. Jacobsen: Who is someone that’s combating or doing research to combat upcoming diseases that seem to be growing issues that really impresses you?

Guyatt: Oh gosh. I’m influenced by what I see immediately around me. So, efforts at, in terms of prevention, in low and middle-income countries reducing the increasing rates of motor vehicle accidents. As low and middle-income countries become higher income, it becomes a big problem in terms of motor vehicle accidents.

The efforts that can be made in terms of travel safety.  We have an emerging epidemic of motor vehicle accidents and the efforts to deal with that so far have not been made. There has been better medical management that the people have undergone, but the much bigger impact could be made in improving the safety of vehicular traffic.

That’s one major emerging threat where efforts to prevent it from growing would be public health, and regulatory efforts rather than simply medical interventions.

9. Jacobsen: In the past, vitamin E was a health fad. A more modern one, an ongoing one, is vitamin D. What is the research? What does it say?

Guyatt: The research does not support major health benefits for vitamin D for most people. Maybe for at least some sub-populations, there is a modest reduction in fractures. And perhaps in the elderly, a reduction in falls.  Very rarely, you have people who actually have serious vitamin d deficiency and they obviously need treatment, but those are few and far between. So that cancer prevention, for instance, evidence suggests that they do not have cancer preventing benefits and most of the other putative benefits that I have countered have not be substantiated. So maybe in subpopulations, at least a reduction in fractures and falls and that is really about all that’s been established.

10. Jacobsen: If you take into account instead of medical diseases around, and if you were to take into account your own personal fascination with one that’s unsolved, what is it and what are its characteristics?

Guyatt: So, one that occurs to me is an area investigation that one of the folks I work with by the name of PJ Devereaux is investigating is cardiovascular events after noncardiac surgery. Over the last 50 years, there’s been a huge increase in people undergoing noncardiac surgery – for conditions that we didn’t use to be able to treat surgically, e.g. joint replacements.

Associated with the increased number of people undergoing surgery, we’re operating on older and older people, and as the technology improves, we get to do that. The benefits are great, but it means that millions and millions of more people are undergoing noncardiac surgery. We have a substantial public health problem in terms of heart attacks and deaths from cardiovascular events following noncardiac surgery.

This has been a hugely under investigated area. Dr. Devereaux has been, as I said, leading the world in terms of starting to look at the magnitude of the problem, find out who is at risk, and start working towards developing strategies that would limit the heart attacks and deaths after noncardiac surgery.

11. Jacobsen: What is the general rate of cancer in the Canadian population?

Guyatt: I am a clinical epidemiologist in terms of investigating treatments and diagnosis and not somebody who follows the major Epidemiology trends.

The limited amount that I do know focuses on something I mentioned earlier in this conversation, which is lung cancer deaths decreasing as smoking has decreased but there could still be a greater reduction because many more Canadians continue to smoke than should. As long as that happens, lung cancer and some other cancers will continue to be a big problem.


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Appendix I: Footnotes

[1] Distinguished University Professor, Health Research Methods, Evidence and Impact, McMaster University.

[2] Individual Publication Date: August 1, 2017 at; Full Issue Publication Date: September 1, 2017 at

[3] B.Sc., University of Toronto; M.D., General Internist, McMaster University Medical School; M.Sc., Design, Management, and Evaluation, McMaster University.

[4] Credit: McMaster University.


In-Sight Publishing by Scott Douglas Jacobsen is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. Based on a work at


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