Homeopathy and Anecdotes

In the Herald today, a letter to the editor from a Mr Barry Davis was published regarding an article about a recent scientific report on the evidence regarding homeopathy published by the Australian National Health and Medical Research Council: Effectiveness of Homeopathy for Clinical Conditions: Evaluation of the Evidence

The report evaluated the evidence regarding homeopathic treatment of several conditions, and drew the following conclusion:

The available evidence is not compelling and fails to demonstrate that homeopathy is an effective treatment for any of the reported clinical conditions in humans.

This letter to the editor, given the title “Homeopathic treatment”, mostly took the form of an anecdote. As far as I am aware letters to the editor are not published online, so here it is in its entirety:

I strongly disagree with your Saturday article on homeopathy. After having open-heart surgery for a faulty valve, I had a series of transient ischaemic attacks (mini strokes).

This resulted in seven visits to hospitals, totalling 42 days, numerous tests and scans, and two outpatient visits. The doctors told me they had no idea what was causing the strokes.

If the cause is not found, and treated, it could lead to a full stroke.

A relative, who has a PhD in chemistry and a diploma in homeopathy, took an interest in the problem. She recommended a homeopathic treatment, and in the last year, whenever I have felt an attack coming on, I have taken two of her pills and sat down, and the attack has stopped.

The only time in the last year that I have had an attack is when I twice failed to carry the pills.

Five years ago, I had a problem with recurring sore throats and congestion – this was also cured by homeopathic treatment.

I do not criticise the doctors or the hospitals – they tried and could not find the solution – but I firmly believe the medical profession and alternative medical practitioners should work in parallel, and each recognise the other.

Citing anecdotes seems to be a common way to defend modalities such as homeopathy, which are not supported by rigorous evidence. Unfortunately, personal stories can often be much more convincing than they should be. I am sending a letter of my own to the editor of the Herald in response to this one.

As I can’t be sure if it will be published, or if sections will be removed (although I’ve tried to keep it brief), I will publish it fully here as a rebuttal to the strategy of attempting to defend homeopathy against this report by citing personal experience.


There was once a time when medicine was based on personal anecdotes such as that of your correspondent Barry Davis. This philosophy gave rise to such false ideas as the four humours and ineffective and harmful treatments like bloodletting, for which there was no shortage of anecdotes.

It is only with the advent of medical science, particularly the randomised clinical trial, that we have become able to truly test medical interventions. Isolated cases such as Mr Davis’ still have a place in medical science, but they are considered the lowest form of evidence and best used in deciding where to allocate resources for testing treatments. There is good reason why our own Medicines Act prohibits their use in medical advertisements.

In order to provide safe and effective healthcare, doctors need to be able to accurately predict the outcomes of a treatment. Relying on poor evidence, like anecdotes, is likely to lead to inaccurate predictions and lower quality healthcare.

It is only by assessing high quality evidence, like in the recent report from the Australian National Health and Medical Research Council that looked at the best evidence regarding homeopathy, that we are able to reliably provide high quality healthcare.

If you really care about the truth then evidence trumps personal experience, not the other way around. If you really care about whether or not homeopathy is effective, then you need to follow the evidence where it leads, even if it does not line up with personal experience. Currently, as the aforementioned report concludes, that means:
“The available evidence is not compelling and fails to demonstrate that homeopathy is an effective treatment for any of the reported clinical conditions in humans.”


Update 2014/04/24 8:38 a.m.

My letter to the editor was published in the Herald this morning. It looks like it was kept pretty much intact, the only difference I noticed is that the very end was edited to appear as though the conclusion I quoted from the report was in my own words.

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Stargazing

As I mentioned in an earlier post, after looking up at the night sky through binoculars for the first time over my summer holiday, I decided to buy a telescope this year. On the 27th of January, I went to see a show at the local observatory, Stardome, and ended up talking to one of the staff about the telescopes they had on sale. I came home the excited new owner of a “Celestron Powerseeker 114EQ”.

My new telescope
My new telescope

It’s a “Newtonian” telescope, also known as a “reflector”. It uses a mirror to gather light, as opposed to a “refractor” that uses a lens. The light comes in the front of my telescope and hits a concave mirror 114 mm in diamater at the other end of the tube, where it is bounced back up to a flat mirror near the opening that reflects the light out the side into the eyepiece. I have 3 eyepieces that give 45x, 90x, and 100x magnification.

My first target was Jupiter, which I’d got a brief glimpse of from one of Stardome’s much more expensive telescopes after the show I saw. When viewing it from home, I was thrilled to be able to make out its 4 Galilean moons, and tried taking a photo. It turns out, as you might be able to guess, that holding an iPhone 4 camera up against the eyepiece of a telescope in the dark, then holding it steady and pressing the “take a photo” button without bumping the phone, is actually pretty hard. I got very lucky though, and the first photograph I took clearly showed an overexposed Jupiter and its 4 largest moons:

Jupiter and the 4 Galilean moons. In no particular order: Io, Europa, Ganymede, and Callisto
Jupiter and the 4 Galilean moons. In no particular order: Io, Europa, Ganymede, and Callisto

Some time later, I was also lucky enough to take a recognisable photo of Saturn using the same technique:

Saturn. It appears on its side because of the angle I was viewing it from. Click through to see the full image.
Saturn. It appears on its side because of the angle I was viewing it from. Click through to see the full image.

That picture was taken with the highest magnification eyepiece, which has a lens only about 6 mm in diameter. It was really difficult to hold my phone steady for this, even with the trick I’d learned of using the iPhone headphones’ volume buttons as a remote for the camera app. After this, I decided I should look to see if I could buy an adapter to fit my iPhone directly onto my telescope, but while searching for one I found an article about how to make your own adapter. I didn’t follow the steps in that article, but I did decide to give it a shot. I found a piece of plastic, an old cover for part of a swimming pool pump, that fit perfectly over my telescope’s eyepiece, and put it together with a bunch of foamboard and glue to get the final product. Here are a few pictures of the process:

The first layer
The first layer
The plastic backing
The plastic backing
The second layer
The second layer
The 2 pieces combined
The 2 pieces combined
Trying it out. It was a bit heavy at this stage, and overbalanced my telescope
Trying it out. It was a bit heavy at this stage, and overbalanced my telescope
Cutting it down to size
Cutting it down to size
All trimmed down. After this I sanded the edges and it was good to go
All trimmed down. After this I sanded the edges and it was good to go

Using this new adapter and some astrophotography image processing software called Registax that lets me combine multiple images or frames of a video to form a single clean image, I’ve been easily able to take some clear images of Jupiter, the Moon, and Saturn:

Jupiter, with some of the cloud bands clearly visible. Click to see the full image.
Jupiter, with some of the cloud bands visible. Click to see the full image.
The waxing crescent Moon. Click to see the full image.
The waxing crescent Moon. Click to see the full image.
Saturn, rings and all. Click to see the full image.
Saturn, rings and all. Click to see the full image.

Registax also allows for a bit of processing to remove noise and sharpen the image. I’m not sure what I think of this yet, as I’m pretty much flailing blindly and to be honest it feels a bit like cheating, but here’s what came out the other end when I applied some of its filters to that Saturn image:

Processing image of Saturn to remove noise and sharpen it. Click to see the full image.
Processing image of Saturn to remove noise and sharpen it. Click to see the full image.

I also took some photos of Mars, but they’re all horribly overexposed and not really worth looking at. I’ve been having trouble seeing anything aside from just a circle of light when it comes to Mars. It’s tough using an iPhone 4 as a camera. It’s not possible to manually change settings like focus or exposure, and in order to take photos and videos of Jupiter that weren’t overexposed I had to lock the camera’s settings on the brightest part of the Moon (done not by tapping to focus like usual but by holding my finger on the spot for a second or so). Luckily Jupiter and the Moon are quite close in the sky at the moment so that wasn’t too much effort, but moving the telescope back and forth between the Moon and Mars was quite annoying. I’m sure there’s a better way that I’m yet to find. It possibly involves buying a decent camera.

One other thing I was finally able to do last night is resolve the Alpha Centauri system (the outermost of the 2 “pointers” that show the way to the Southern Cross) as a binary star system. I wasn’t able to photograph it though, the stars still appear very close together and my phone overexposed them to look like a single star. I guess that’s a challenge for another night.

I’m also quite looking forward to the upcoming total lunar eclipse on the 15th of April. Although I’ve read that the Moon is meant to turn a dark red during the totality of the eclipse, I’m not really sure what to expect when it comes to viewing or photographing it, which I find pretty exciting.

Poor Science Reporting on the Paleo Diet

This morning I saw an article in the NZ Herald on the “paleo diet” that rather frustrated me. It seems like a great example of poor science reporting, trying its hardest to turn a study into a story instead of doing any actual science reporting. The role of a science reporter is not to sensationalise, it’s to accurately report on science, and that includes making the drawbacks of a study clear and not exaggerating the conclusions.

In this case though, it looks like the author chose to omit half the results of the study, presumably so as not to pollute the narrative they had chosen. The take-home message of the article can be found in the first paragraph:

the best way to lose weight is by copying our ancient ancestors, a study suggests.

I’m not even going to get into the problems with characterising the so-called “paleo diet” as “copying our ancient ancestors”, that’s been adequately covered elsewhere. The information used to support this weight loss conclusion is that the study in question found that:

Women who adopted the so-called Palaeolithic diet lost twice as much weight within six months as those who followed a modern programme based on official health guidelines.

Wow, that sounds impressive. Case closed, right? Except, if you look at the actual study (not open access, unfortunately), which of course is not linked to from the online article, you’ll find another result that is curiously omitted from the Herald article:

Both groups significantly decreased total fat mass at 6 months (−6.5 and−2.6 kg) and 24 months (−4.6 and−2.9 kg), with a more pronounced fat loss in the PD [Paleolithic-type diet] group at 6 months (P<0.001) but not at 24 months (P=0.095).

So there was a statistically significant difference in fat loss after 6 months, as mentioned in the article, but after 24 months there was no statistically significant difference in fat loss between the groups. That is a negative result.

Although there was still an observed difference in fat loss between the groups at 24 months, it wasn’t big enough for the researchers to be reasonably confident that it wasn’t just due to random variation. That’s partly due to the size of the difference observed, and also because the study was so small. 70 people split into 2 groups is very small for this kind of study, whereas a good sample size would be hundreds or even thousands of participants, not just a few dozen. Of course, such large studies are much more difficult and expensive to undertake, so a lot of smaller studies like this do happen. Sample size is very important though – small studies like this are not nearly as reliable as the much larger ones – so it’s important to remember to take the sample size into account when evaluating a study’s conclusions.

The Herald article does mention, way down near the bottom, that all of the participants in the study were obese postmenopausal women. Everywhere else, however, it avoids that caveat and seems to imply that the conclusions should be applicable to everyone, or at least to all women.

It’s also rather frustrating that the article says that the study “found [the “caveman diet”] more effective than some modern diets”, and that this study suggests it is “the best way to lose weight”, even though the study didn’t compare it with “some modern diets”. It compared it with a single other diet, one based on the Nordic Nutritional Recommendations.

If the Herald wants some tips on how to report on science, a great place to start would be to take another look at the science itself. The conclusion in the abstract of the study they’re writing about seems much more appropriate, even if it does seem a bit dismissive of the negative 24 month results:

A PD [Paleolithic-type diet] has greater beneficial effects vs an NNR [Nordic Nutritional Recommendations] diet regarding fat mass, abdominal obesity and triglyceride levels in obese postmenopausal women; effects not sustained for anthropometric measurements at 24 months. Adherence to protein intake was poor in the PD group. The long-term consequences of these changes remain to be studied.

Then again, perhaps I should be glad the Herald didn’t reprint the original headline from the Daily Telegraph:

Caveman diet twice as effective as modern diets

I’m not sure I could come up with a more misleading headline if I tried.

Despite the horrific headline, the original article does have a bit more information in its second half from the study’s primary author that was truncated from the Herald’s reprint.