Risk, research, and red meat

Most people really don't understand the concept of risk.

Let me give you an example.  Let's say that there is a woman who has been identified as being at risk of having a stroke.  She goes to a doctor, who offers her one of three medications to reduce her risk of stroke over the next five years.

Medication A would increase her likelihood of remaining stroke-free from 91% to 94%.

Medication B reduces her risk of a stroke by 1/3.

Medication C reduces her risk of a stroke by 3%.

Which one should she take?

Most folks seeing this problem pick B, largely because it sounds better -- a reduction by 1/3 is a lot, right?  3% is a pretty paltry change, and 91% and 94% chances of remaining healthy are pretty close.

It comes as a big surprise to find out that all three of them are the same.

If she has a 91% chance of remaining healthy without the medication and 94% with it, her risk of stroke drops from 9% to 6%.  That's a drop of 3%.

It's also an overall 1/3 reduction in her risk.

Such mathematical monkey-business is why there's been such confusion over the WHO's recent declaration that red meat causes cancer (and processed meat, such as hot dogs and pepperoni, are even worse).   In fact, processed meat is now in "Group 1" -- "substances that cause cancer" -- along with tobacco, human papilloma virus, and asbestos.

[image courtesy of photographer Jon Sullivan and the Wikimedia Commons]

It's even accompanied by statistics that seem, frankly, pretty terrifying:

[M]eta analysis found that colorectal cancer risk jumps by 17 percent for every 100 grams (3.5 ounces) of red meat consumed each day.  Meanwhile with processed meat, colorectal cancer risk increases by 18 percent for every 50 grams (1.7 ounces) eaten each day.

Holy crap, right?  1.7 ounces a day (not much) translates to an 18% increase (a lot) in your chance of colorectal cancer (a disease that is high on most people's "Least Favorite Things to Think About" list).

Add that to another study that found that "2% of hot dogs contain human DNA," and it looks like we might see a lot of people finding other things for their summer barbecues.

The problem is that all of this stuff is misleading.  First, what does an 18% increase look like?  According to the National Cancer Institute's Surveillance, Epidemiology and End Results Fact Sheet on colorectal cancer, current rates of diagnosis estimate the number of new cases at 42.4 per 100,000 each year.  An 18% increase brings that number up to a little over 50.

In other words, if 100,000 people ate 1.7 ounces of salami a day for a year, you'd expect there to be eight more cases of colorectal cancer in that group as compared to a comparable non-salami group of 100,000.

Here's another problem with the WHO information.  "Group 1" substances are said to be "known to cause cancer."  But all that means is "known to increase your risk."  It doesn't say by how much, nor what the risk was to begin with.  For example, cycling to work and swimming naked in a crocodile-infested river are both outdoor activities that are "known to increase your risk of dying in an accident."  So on the "Outdoor Activities Risk" list, these would both be classified as "Group 1."

Which one would you prefer doing?

At the risk of beating the point unto death, Casey Dunlop of Cancer Research UK cited statistics illustrating how silly it is to put tobacco and bacon in the same category.  Tobacco is a product that is toxic in any amount, confers no benefits whatsoever upon the people consuming it, and is directly responsible for 86% of lung cancers and 19% of all cancers combined.  Even assuming the worst-case scenario, daily consumption of processed meat is responsible for 21% of colorectal cancers and 3% of all cancers combined.

Puts things in perspective, doesn't it?

Oh, and about the human DNA in hot dogs thing; this doesn't mean that the hot dog manufacturers are incorporating Soylent Green into their meat.  Given the sensitivity of DNA tests, this probably means the presence of a few cells from a bit of dry skin or something.  And if you think that it's only hot dogs that have this kind of contamination, I have news for you.  The amount of extraneous cellular material (to put it euphemistically) that we consume by accident on a daily basis has not been tested, but is undoubtedly high.  If you are a pet owner, and don't think you consume dog and/or cat DNA every single day, well... either you clean your house far more frequently and thoroughly than I do, or you're living in a fool's paradise.

And amazingly enough, most of us are pretty healthy.  Funny thing, that.

Now, I'm not saying we should eat hot dogs and bacon and pepperoni with wild abandon.  Reducing your consumption of red and processed meat is definitely a good thing.  But everything has dangers; there are risks associated with every food out there.  The trick is to figure out which calculated risks are worth taking, and what the tradeoff is.

After all, as Chuck Palahniuk put it in Fight Club, "On a long enough timeline, the survival rate for everyone drops to zero."

Tetanus, hCG, and the danger of rumors

There's harmless woo-woo, and then there's woo-woo where people die.

It's all too easy to write off a lot of weird, counterfactual beliefs as harmless.  Certainly, some of them are; astrology, for example, is dangerous only to your pocketbook, at least overtly.  I've made the point, though, that engaging in such nonsense dulls you to the necessity that claims be established on the basis of evidence and some kind of scientific rigor.

But the potentially deadly variants of this particular sort of worldview do exist.  And we've just seen an example, in the claim that Kenya's tetanus vaccination program is part of a secret mass-sterilization effort designed to reduce the human population in east Africa.

[image courtesy of the Wikimedia Commons]

Let's start out with some facts.  Tetanus is caused by a bacteria, and vaccination has a near 100% success rate of preventing the illness.  Unvaccinated, 50% or more victims die, and that's even if they seek medical treatment after symptoms start.  61,000 people died last year from it, which (to put it in perspective) is a little under ten times the number of documented deaths from Ebola ever.

So it's a serious health issue, and the last thing we need is someone putting the vaccination program on the skids.  Which is exactly what the Catholic Church in Kenya has done, by claiming that the vaccine is laced with hCG (human chorionic gonadotropin), which in sufficient quantities can cause lower fertility and/or miscarriages.

The fact is, the vaccines were not laced with hCG, and scientists even know how the claim started.  Back in the 1990s, there were allegations launched by the Catholic Church that there was something suspicious about the vaccination program, and some Kenyan labs tested the vaccine using an ordinary pregnancy test kit to see if it showed a positive result (and thus could contain the hormone).  They claim that there were some positive results, but the procedure was faulty, as was described in detail over at the science blog Respectful Insolence:

After these rumours were spread, attempts were made to analyse TT vaccines for the presence of hCG.  The vaccines were sent to hospital laboratories and tested using pregnancy test kits which are developed for use on serum and urine specimens and are not appropriate for use on a vaccine such as TT, which contains a special preservative (merthiolate) and an adjuvant (aluminum salt).  As a result of using these inappropriate tests, low levels of hCG-like activity were found in some samples of TT vaccine.  The laboratories themselves recognised the significance of these results, which were below the reliable detection capabilities of the adjuvant or other substances in the the vaccine and the test kit.  However, these results were misrepresented by ‘pro-life groups with the resulting disruption of immunisation programmes. 

When the vaccines were tested in laboratories which used properly validated test systems, the results showed that the vaccines clearly did not contain hCG.

In other words: the vaccines were safe, and not some part of a secret conspiracy to sterilize women in Kenya.  And, in fact, even if it were true, it's not working; the current birth rate in Kenya is 28.27 live births per 1,000 population -- or roughly twice the birth rate in the United States.

Oh, wait, we've all been vaccinated, too.  Q.e.d., I guess.

But the allegations became strident enough that responsible medical researchers launched their own investigation, and found (surprise!) no problems:

(T)he findings of the laboratory tests... all come out with normal values from the reference values assuming that the woman is not pregnant.  The highest level of the β-HCG hormone was found to be 1.12 mIU/ml (and 1.2 mIU/ml for S-Quantitative β-HCG).  There was no control used (or presented) and it would have been interesting to see what the result will be with tap water.  There is a situation where ant- β-HCG antibodies can be produced by the body and that can act as a contraceptive, however, this requires the administration of at-least 100 to 500 micrograms of HCG bound to tetanus vaccine (about 11,904,000 to 59,520,000 mIU/ml of the same hormone where currently less than 1 mIU-ml has been reported from the lab results.

The fact that there's absolutely no truth to this rumor has not stopped the Catholic Church from persisting with the allegations, nor people circulating this story around as if it has the slightest basis in reality.  Just last week, two Kenyan bishops and a prominent Catholic doctor made public their claim that the WHO vaccination program was, in reality, a forced sterilization program.  Dr. Muhame Ngare, of Mercy Medical Centre in Nairobi, said in a press release:

We sent six samples from around Kenya to laboratories in South Africa.  They tested positive for the HCG antigen.  They were all laced with HCG...  This proved right our worst fears; that this WHO campaign is not about eradicating neonatal tetanus but a well-coordinated forceful population control mass sterilization exercise using a proven fertility regulating vaccine.  This evidence was presented to the Ministry of Health before the third round of immunization but was ignored.

The problem is, they used the same test as the one performed back in the 1990s, which already has been shown to give false positives.  Which once again proves that if you don't know how to do science correctly, you shouldn't be making scientific press releases.

So this hasn't stopped the rumor mill, nor the anti-vaxx outrage here in the United States.  I've already seen the story (without, of course, the round debunking over at Respectful Insolence) at least six times on social media, usually with some sort of commentary like, "Isn't this horrible?" or "Think twice before you let them stick needles in your children!"

The whole thing is maddening, especially given the fact that this vaccine could prevent the deaths, in horrible agony, of 60,000 people this year.  If, of course, the anti-scientific rumor mill would get the fuck out of the way.  And if the Catholic Church would, for once, support science rather than impeding it.