Wednesday, June 25, 2008

Real and Apparent Danger

By Angry Doc

There is a real and apparent danger in Singapore.

(emphasis mine)

Toxins in dish-washing detergent?

I WOULD like to ask why dish-washing liquid detergents do not carry ingredient labels. This is perhaps an oversight since such detergents leave traces on utensils, even after washing.

The danger is even more apparent in foodcourts where mass-washed utensils are coated with unknown ingredients.

Recently, there were reports about the danger of methylisothiazolinone, a neurotoxin that is found increasingly in shampoos, except some old, trusted brands. Methylisothiazolinone is possibly found in dish-washing detergent, especially those that tout 'anti-bacteria' formula since methylisothiazolinone is also a biocide.

Likewise, can the authorities clarify why formaldehyde is found increasingly in shampoos? The dangers of formaldehyde are already known, such as autism, eyesight degeneration and high carcinogenic effect on contact with water molecules. In addition, there are no standards as to how much formaldehyde is added to shampoo since it is considered a non-food item. But the danger is real and apparent.

Michael Yee

angry doc won't address the first part of Mr Yee's letter, since he too does not want detergent in his food. But the second part of the letter gets to him.

Formaldehyde is a widely used form of preservative. No doubt it can be fatal when ingested, and causes irritation of the eyes and skin when in vapour form (angry doc had personal experience of that back in medical school, he does - ah, sweet, gross anatomy!). But is it as dangerous as Mr Yee described?

Does formaldehyde cause eyesight degeneration? Well, yes, if it is splashed into your eye or injected into an eyeball.

Does it have high carcinogenic effect? Well, yes, it has been shown to cause some forms of cancers in mice, but it has not been shown to cause more cancers in people who are exposed to it at work (and who presumably use shampoo when they are off work).

Does it cause autism? angry doc couldn't find any evidence for that.

Mr Yee has given misleading information about the dangers of formaldehyde in the first part of that paragraph, but the penultimate sentence in that paragraph is simply untrue.

Shampoos are classified as cosmetic products, and come under the purview of the Cosmetics Control Unit of the Health Products Regulation Group of the Health Sciences Authority. The amount of formaldehyde permitted in shampoos is regulated by the ASEAN Cosmetic Directive, at the concentration of no more than 0.2%. Shampoos manufactured by Unilever contain formaldehyde of 0.04%. There is no evidence that at that concentration, application of formaldehyde to the skin for short durations causes any of the harmful effects Mr Yee mentioned.

Formaldehyde is a toxin in the commonly used sense of the word, but to say that shampoos can cause cancers, eyesight degeneration and autism, and that the authorities are not doing anything about it is dishonest and irresponsible.

The fact is information about regulations on the amount of formaldehyde permitted in shampoos and the dangers of formaldehyde is available on the internet if one would just search for them. Mr Yee had apparently not done so before sending in his alarmist letter, and the ST Forum editor has in angry doc's opinion lapsed in his duty by publishing it. This lack of editorial rigour is the real and apparent danger.

No Labs Please, We're Homeopaths

By Angry Doc

While googling about homeopathy in Singapore, angry doc came across a site that advertised as one of homeopathy's benefits the fact that:

"the system does not require expensive tests and reports."

Of course. Why wouldn't that be a benefit? Everybody hates lab tests, X-rays, and biopsies, right?

Patients certainly hate them most of the time.

Practitioners of alternative medicine can often make a diagnosis just by looking at you or feeling your pulse. In fact, some can even feel your energy field without actually having to physically touch you. Who needs tests and reports to know what's wrong with you, or if you are getting better?

Western doctors, with their inability to make decisions without time-consuming and expensive tests which often puts the patient at much inconveniece, discomfort, and not to mention risks, seem by contrast primitive and unsophisticated.

As a medical student, angry doc certainly hated "lab".

Much of the first two years of medical school, the "pre-clinical" years, were spent in stuffy laboratories, where we had to conduct repetitive experiments.

The subject of the week's experiment would vary (this week it would be sugars, the next week proteins, and the week after bilirubin or something), but the physical tasks always consisted of measuring minute quantities of chemicals, diluting them with deionised water from a large plastic vat, then placing the resultant solutions into small glass or plastic containers, which would then be placed inside a spectrometer. The result of each reading would be plotted on a graph, which seemed to be the point of the whole afternoon's labour.

It seemed a sadistic way of wasting our time, making us do the same thing with the same spectrometer week after week just to show something which they already knew was true. Yes, the spectrometer works, the values change with different concentrations of the chemical, in a linear fashion which can be represented graphically. We get it! Can we do something else please?

(OK, we did do something else. Occasionally we were required to supply bodily fluids as raw material for the week's experiment. angry doc will not elaborate further.)

Unlike 'A' level chemistry, lab-work in medical school was not an examinable subject, so angry doc never paid attention and had already forgotten almost all of what happened before the second year ended.

To angry doc's disappointment, "lab" did not end with the end of second year, as Pathology involved hours of eye-straining, vertigo-inducing work in the purple-and-pink topsy-turvy world of light microscopy, where moving a slide left shifted the field of view right, and moving it down shifted the field of view up. angry doc had difficulty using a computer mouse afterwards.

angry doc resolved to not choose a specialty that required any vision-enhancing aid more sophisticated than a pair of spectacles.

angry doc is also vaguely aware of the Radiology module, which he had skipped completely, because they seemed more interested in teaching him about how an X-ray machine worked than how to read an X-ray.

The only bit of lab angry doc didn't mind, and indeed enjoyed, was anatomy. Ah, sweet, gross anatomy!

It was with little regret that angry doc left the sterile world of lab and entered the wards, where finally! he could get his hands on some patients. When he heard that a classmate was interested in pursuing a career in lab medicine, angry doc thought the fellow was mad.

For the next few years angry doc didn't think much about labs. Lab was that mysterious but boring place where he sent his patients, their bodily fluids or some bits of their bodies, in return for which he received reports which allowed him to get on with the business of treating their illness.

But now that he has taken on the task of fighting alternative medicine, angry doc appreciates the purpose of all those lab hours.

Unbeknowst to him, the boring work in those foundation years demonstrated to angry doc that our work is based on real, quantifiable things which can be objectively and independently measured, and not on the postulation of some wise men, or abstract speculation about invisible life energies that seem to be only palpable to those who believe they exist.

Going through the science behind the investigation modalities and performing all those experiments ourselves taught us that we did not have to take anyone's word as authority, but could verify and find out first-hand if something was true, if we understood the scientific principles and had the knowledge.

Lab work was an innoculation against the magical thinking and dogma that characterise some of the more absurd forms of alternative medicine.

angry doc wishes he had paid more attention in medical school.

(If you are a medical student, angry doc is interested in knowing how much lab work you are required to do these days, and also how much exposure to alternative medicine you have in your course. Do share with him in the comments section. Thank you.)

What's Wrong With The Placebo Effect?

By Angry Doc

Reader sprachen sie singlish, commenting on this previous post, wrote:

Never figured out why the Placebo had such bad rep.

Statistically significant improvement for the patient, no side effects. What more could your ask for when apply the Harm Principal?

What's wrong, indeed, with the placebo effect?

(Or more appropriately, with "placebo effects", since it is an umbrella term that covers a number of mechanisms which might affect a patient's physiology or how he perceives his symptoms.)

It is a commonly posed question and a common defence used by proponents of alternative medicine when evidence shows that their favoured modality of treatment is no better than placebo, and that any beneficial effect observed as a result of that therapy is therefore also likely due to the placebo effect.

Because it is a commonly posed question and a commonly used defence, it is a question that has been answered many times by science and medical writers and bloggers. angry doc does not claim to be able to answer the question comprehensively or in depth, but he will do the best he can, with regards to the study in question.

First of all, the improvement observed in the study is not large enough to be considered clinically significant.

That aside, it is also worth noting that while the parents and clinicians all reported improvement in their scores, scores given by the subjects themselves were a more mixed result - some subjects reported improvement in certain domains but felt they did worse in other domains. In other words, the observers thought that the subjects were functioning better, regardless or whether or not the subjects themselves were feeling better - the placebo effect affects the observers, and not the subjects! This of course has ethical implication when it comes to using a treatment on subjects who cannot communicate how they are feeling - patients such as infants, children, those who are mentally-impaired, and even pets; we can think that we are helping them, when in fact we may be doing nothing, or indeed harm to them.

Also, it is not true that there are no side effects with placebos or biologically non-active agents. Patients given non-active agents can in fact develop adverse effect to them, as was the case with one patient in this study, who had to drop out of the study. This is known as the nocebo effect. Placebos, because we do not always know the precise mechanism by which they work, are often unpredictable in their effect, and can in fact have the reverse effect from that which is desired.

Finally, even if we take the result of this study to mean that placebos are effective for ADHD in children and adolescent, the question of what to give the patients remain: do you give them "a mixture of rice protein powder and a small amount of activated charcoal" or "0.3% hypericin... free of heavy metals, pesticides, and adulterants"? Or something else which has already been proven to be more effective than placebo for ADHD?

If you choose to give a patient a placebo, do you tell him you are giving him a placebo, or do you lie to him and tell him you are giving him "something that works"? Do you want to lie to your patient? Would you want your doctor to lie to you?

The fact is there are practitioners out there who are prescribing treatment to patients which have been shown to be no superior to placebo. If indeed all that they are giving is the placebo effect, then does it justify the cost to the patients? Does it justify the practitioner's time learning all he learnt? Does it not make the whole practice dishonest?

Having said that, all 'healers' use the placebo effect to a degree in his or her practice. The simple ritual of a consultation is sometimes all it takes to make the patient feel better. It is probably impossible to quantify or eliminate such effects from our practice, but angry doc feels that where we know that a treatment is no better than placebo, it is detrimental to the patient-doctor relationship to prescribe it as "something which works", or to not resort to something which has indeed been proven to work.

Friday, June 20, 2008

A £10,000 Challenge

By Angry Doc

Via Orac, news about a professor of homeopathy who has offered a £10,000 prize to anyone who can "demonstrate that homeopathy is effective by showing that the Cochrane Collaboration has published a review that is strongly and conclusively positive about high dilution homeopathic remedies for any human condition".

As far as angry doc knows, no one has taken up the challenge, but Le Canard Noir at Quackometer tells us that "excuses for ignoring the challenge are already being discussed on homeopathic sites and message boards". angry doc believes that the Professor Ernst is familiar with most of them.

While not as well-known as acupuncture and TCM, two forms of alternative medicine which we discuss regularly on this blog, homeopathy nonetheless has its presence in Singapore, and from angry doc's personal observation it is growing. While herbal medicine and acupuncture have shown efficacy for certain conditions and have plausible or known mechanisms of action, the same cannot be said of homeopathy.

angry doc thinks all healthcare workers should be aware of this relatively new form of alternative medicine, so we can educate our patients about it. Homeopathy simply does not hold water*.

* - Sorry, I just couldn't resist.

Thursday, June 19, 2008

Science And How We Know We Are Wrong 3

By Angry Doc

This study made it into several newspapers when it was published last week. Science-blogger Orac gives a detailed look at the study, and points out the flaws in the arguments in the accompanying editorial, which tried to defend alternative medicine in the face of evidence of absence of efficacy.

In the meantime, angry doc finds the study interesting for a different reason.

The study looked at the subjects' performance on the ADHD Rating Scale-IV and Clinical Global Impression Improvement Scale (which are assessed and scored by clinicians) as primary end points, and also analysed the Parent-Reported Child Behavior Checklist or Youth Self Report Form (for subjects 11 years and older), Conners Parent Rating Scale, and parent-report and child-report forms of the Pediatric Quality of Life Inventory (which are scored by the subjects or their parents), and found that there were no statistically-significant differences in the scores before and after treatment between the group receiving St. John's Wort and the group receiving placebo.

But that's not all.

If you look at the scores (you'll need to register to read the full paper on JAMA), you will find that except for the Youth Self Report Form, scores for both groups improved at follow-up.

In other words, the clinicians involved in the trial and the parents of the subjects all *thought* that the children were improving.

What's more, children in the placebo group 'improved' more than children in the treatment group, even if the differences in the scores were not statistically-significant.

To angry doc, this trial demonstrates the power of the placebo effect, where just the fact that the children are being given a pill three times a day, regardless of whether it contains "a mixture of rice protein powder and a small amount of activated charcoal" or "0.3% hypericin... free of heavy metals, pesticides, and adulterants" can affect a clinician or parent's assessement of their behaviour.

So the next time you are tempted to say "I know it works because he got better after taking it", stop and think of this study, won't you?

Wednesday, June 11, 2008

Does A Vegetarian Diet Prevent Cancer?

A few days ago, Clearthought blogger Blacktag (When docs turn gods) engaged in a discussion about the health benefits of a vegetarian diet at Mr. Wang's blog article entitled "Vegetables Will Save The World".

The relevant exchange in the comments section is reproduced here for your reading pleasure.

Mr Wang Says So said:

The problem with red meat is that it has some strong links with quite a variety of cancers including breast cancer, colorectal cancer, stomach cancer, lymphoma cancer, bladder cancer and prostate cancer. And of course, since red meat has a high content of saturated fat, it is associated with cardiovascular diseases.

So you see quite quickly that red meat is a risk factor for just about all the top killer diseases in your average modern society (except lung cancer & COPD).

The other problem with meat in general is that it has synthetic growth hormones in it. Basically all the cows are jabbed with chemicals to make them grow faster.

The EU has banned the use of such hormones by the agricultural industry, but I think it goes on elsewhere.


Three cheers for this post. I am certainly encouraged to see regular "socio-political" bloggers like Mr Wang venture into the topic of health and highlight the harm of meat and milk.

But ah! Did you read the Doc Talk column by Singapore's "leading" oncologist Dr Ang Peng Tiam in Mind Your Body June 4?

According to him, all these beliefs about meat, milk and sugar contributing to cancer are "old wives tales".

So that makes you, Mr Wang, an "old wife" as well, along with all the scientists whose research you cited.

Such is the sad state of affairs in Singapore that even lawyers and bloggers like Mr Wang are more enlightened on health issues that top cancer doctors.

Blacktag said:

From a previous commenter: "Such is the sad state of affairs in Singapore that even lawyers and bloggers like Mr Wang are more enlightened on health issues that top cancer doctors."

My take: now I'd probably go look for Mr Wang for good advice on blogging, or perhaps the law, but advice on cancer? Sure, Mr. Wang could be right, but chances are, he is probably wrong, and none of us have time for this.

No one ever talks about the link between natural carcinogens found in our daily foods (including organic vegetables) and cancers, since it's inconvenient and unprofitable to the organic food industry. Though few of its carefully crafted evangelists would listen anyway.

Just to add, there are very good reasons for adding preservatives to food for example. I think it began with rotten food in transit.

Haven't we all heard enough stories about the person who was vegetarian, avoided smoking and other bad habits, but still wound up with cancer or heart disease or whatever? What does that suggest to one that is statistically inclined?

Here's some advice others might find truthful (but perhaps mildly depressing, given that it reminds us how helpless we really are).

1. Colorectal cancer: best quality evidence indicates that a high fruit and vegetable diet does not prevent polyps or colorectal cancer.

2. Breast cancer: All major intervention studies to date in ordinary people and breast cancer survivors suggest a diet high in fruits, vegetables and low in fat make no difference as to breast cancer incidence.

3. Lymphoma, Stomach, Bladder, Prostate: no need to even Google the answer.

Here's the only health advice that will be useful on a broad basis for most people, well supported by good data, but so highly unprofitable for industry that you'll hardly hear much about the message:

(a) Stop smoking.
(b) Exercise regularly.
(c) Eat less.

Meat is fine. Food with preservatives is as healthy as organic food really, save your money for a balanced diet. It's the total number of calories that matter.

Celestial said:

dear blacktag, there are more than just preservatives found in processed or even the so-called natural food.

Vegetables can be bad as well because of GMO, pesticides..etc

At the end of the day, we are eating our own "Karma".

Nevertheless, i support veg diet.

Mr Wang Says So said:

I found an interesting link:

The site is by a highly reputable institution (Harvard School of Public Health); it accepts no advertising or commercial sponsorship; nor does it endorse any particular products.

I think it is therefore a good source of independent, unbiased and expert info on healthy nutrition.

Interested readers are invited to check out the site and see for themselves.

Consider my post and comments again, then go there and see what it says about red meat, fruits, vegetables etc.

Blacktag said:

Thank you Mr. Wang for that link to the Harvard School of Public Health, which in fact, eerily echoes my sad looking three point plan exactly. Since we all like orang putih quotes, I shall draw some quotes (within context, I assure you) from the site:

"Aside from not smoking, the most important determinants of good health are what we eat and how active we are."

Sounds familiar ?

Some Singaporean dispensed free advice yesterday:
(a) Stop Smoking.
(b) Exercise more.
(c) Eat less.

"Most important of all is keeping calories in check, so you can avoid weight gain, which makes exercise a key partner to a healthy diet."

Thank goodness for medical school, it allows me to echo the Americans, with half the respect.

Now let's have some perspective.

No one likes being told to stop smoking, exercise and eat less (even though these are the only three solidly demonstrated interventions). And that would lead to a very sad looking website, instead of a colourful one, full of pretty fruits and vegetables.

The reality is that the three recommendations I have made are supported by Level I evidence. (a randomized controlled trial).

The fruit / vegetable hypothesis is no more than Level III (case control/ cohort studies), and all attempts to elevate this to Level I by formal large trials have failed, suggesting that the whole truth is not there, and that the cohort studies are not telling the whole truth. Does a lack of level I evidence mean it is untrue? Certainly not, but since formal trials have not shown protective effects, we can say that there is good evidence that there is no direct protective effect. Alternative hypotheses (no more than hypotheses) may include

(a) that the ang-mohs are not eating the sorts of vegetables that wise Chinese nutritionists want them to eat, resulting in the wrong sort of outcome.
(b) there is a confounder. It may be possible that consumption of fruits and vegetables is linked to increasing disposable income. Given that lifestyle factors are very different between those with/without disposable income, one of these (rather than fruit/vegetables) may underpin the difference in cancer incidence.

Anonymous said:

Blacktag, it seems that your biggest point is that it's important to exercise regularly, not smoke and not overeat. However, these are rather obvious and well-known facts, hardly the sort of thing that one needs to go to medical school to learn. And I would add , hardly the sort of thing that Mr Wang would bother to mention on his blog.

If you really want to contribute usefully, you could perhaps comment on the relationship between meat; saturated fat; harmful cholesterol and high blood pressure, stroke and heart disease.

Or you could tell us more about your Levels I, II and III and explain, for example, whether it is your view that the public should disregard all health studies that only hold true at Levels 2 and 3.

Also, I haven't bothered to visit that Harvard website, but I would have imagined that if you had wanted to copy some excerpts, the excerpts relevant to the present discussion would be those specifically relating to red meat, fruits and veggies. Rather than some general statement about not smoking or not exercising enough etc. Why don't you choose some more-salient excerpts to explain whatever point (whether positive or negative) that you want to make about vegetarian diets (if you do have any such point).

Blacktag said:

This will be my last comment, and I thought I should be constructive and provide useful health advice for readers here. Warning: this is a long comment.

[stopping smoking, exercising and eating less] are rather obvious and well-known facts, hardly the sort of thing that one needs to go to medical school to learn.

You'd be very surprised. Unfortunately, there are people less perceptive than yourself who don't realize that. These individuals find popping pills/supplements, taking herbs and drinking diet sodas a more proactive act of control than stopping smoking.

Generally, the impact of any of the three interventions prescribed far outweighs any other intervention out there in terms of actual health outcomes, which indeed distract from these core issues. There is really very little benefit to changing to a vegetarian diet, and maintaining the same caloric intake. Perspective is the issue. The best analogy is a person who orders a supersize meal with a diet coke.

The major problem in all these nutritional recommendations derived from epidemiological studies (that often conflict) is that the noise generated by industry and well meaning individuals detract from the actually useful three point recommendations. For example, the simple fact that a low fat diet makes no difference to weight loss versus a high fat one with the same caloric intake. is still little known today.

"If you really want to contribute usefully, you could perhaps comment on the relationship between meat; saturated fat; harmful cholesterol and high blood pressure, stroke and heart disease."

I define my own usefulness by the dispelling of myths, and the provision of truth, not hearsay. Mr. Wang began from "red meat is a risk factor for just about all the top killer diseases" and arrived at the conclusion that a vegetarian diet was the answer. Now I may agree that red meat is regarded as a probable risk factor for colorectal cancer (but not other cancers) based on best Level III evidence currently, but the conclusion that a vegetarian diet is better for you does not follow. There are lots of in betweens, including limiting of red meat, as well as white meat. In fact, the difference between red and white meat has not been highlighted in these comments to date.

Or you could tell us more about your Levels I, II and III and explain, for example, whether it is your view that the public should disregard all health studies that only hold true at Levels 2 and 3.

Absence of gold standard evidence does not mean a need to reject a supposition in public health. So where it is not formally examined, it may be possible to accept lower level evidence. However, in the presence of higher level (i.e. better) evidence, it is irrational to deny the findings of randomized trials. As mentioned, very large randomized trials demonstrate that diets rich in vegetables and fruits do not protect against breast cancer or colon cancer, despite suggestive Level III evidence.

The link between colorectal cancer and red meat is based on Level III evidence, which is quite extensive. There is no Level I evidence, because it is not possible to do a formal trial in randomizing people to eating more / less red meat, so we should accept this link. The link between red meat and other cancers is not established.

Also, I haven't bothered to visit that Harvard website

Then may I assure you that nowhere in the Harvard website does it say a vegetarian diet is good for you, and allow you to verify this?

These would be my answers today, to a patient's questions:

Is consumption of red meat linked to higher incidence of cancer overall?
Yes there is suggestive data for colorectal cancer, but not conclusive evidence for other sorts of cancer.

Is consumption of white meat linked to higher incidence of cancer?
No, there is no convincing data.

Is it therefore prudent to limit consumption of red meat then, to prevent colorectal cancer?
Yes, but don't get distracted from the bigger issues, which are (a) stop smoking (b) exercise and (c) lose weight, all three which are far more strongly linked to prevention of almost ALL cancers than mere red meat avoidance. Having said that, prudence and limitation of consumption should be applied to all food groups. There is relatively little benefit being vegetarian and maintaining the same caloric intake.

Can I still get cancer if I avoid red meat completely?
Certainly, the link between red meat and other sorts of cancers is not definitive based on current data. The incremental benefit in preventing colorectal cancer by avoiding red meat may be outweighed by other risks, some modifiable (smoking and obesity) and some not (e.g. age and family history).

One has to keep in mind that at the end of the day, these findings are derived from large population studies, which apply to the general group, rather than the individual. Hence the large proportion of people who develop cancers, despite not having specific risk factors.

Based on current knowledge, does that mean one has to be vegetarian for potential gains in life expectancy / cancer prevention from this?
There is no good data to support this. Options include limiting red meat intake, as well as taking white meat such as fish and chicken.

Dear Mr. Wang - I hope this is clear and sufficiently constructive health advice for the readers, and that some people will stop smoking and start exercising. :) The latter is truly the only miracle panacea currently known.