Archive for the ‘soapbox’ Category

When I was in graduate school, I spent a semester as a teaching assistant in an introductory public health course. My duties consisted primarily of proctoring exams and leading discussion groups, but I also attended the class, mostly sitting in the back and working on my dissertation during lectures. One day, I heard the instructor, who was then heavily pregnant with her first child, begin her lecture by asking for a show of hands – who here was planning on vaccinating their children? My ears perked up immediately, as this has always been a pet subject of mine. She went on to say that she wasn’t sure, herself; shed been hearing a lot about their link to autism. Then, hand to god, she showed a YouTube video of Andrew Wakefield, proselytizing about the dangers of vaccinations. To a public health class of college freshman.

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Vaccinations are the hill that I will die on, the line in the concrete, the one thing I refuse to even debate. The subject my familiars know not to bring up, not least because there is a sign that says as much in my kitchen. The thing I cannot listen to differing opinions about, because I don’t think it’s in the realm of opinion. I think it is black and white, right and wrong.

I probably shouldn’t write a word about it, but it’s a central tenant of my existence. There is a very VERY limited set of scenarios in which it is acceptable not to vaccinate. It includes people who have had serious reactions to specific vaccinations, and people who are immunodeficient in specific ways.

The efficacy of vaccinations is based on the principle of herd immunity – that, if a certain proportion of the population is immune to a communicable disease, the remainder of that population is extended some measure of immunity simply because the pathogen cannot find enough vulnerable bodies to infect.

So when someone chooses not to vaccinate their child for personal reasons, that choice can affect entire communities and populations. Herd immunity is compromised. The most vulnerable people – infants and children too young to be vaccinated, or those who are medically unable – suffer the greatest consequences, as these (preventable!) illnesses are much more serious, even deadly, for them. So – when someone chooses not to vaccinate, not only are they relying on herd immunity to cover their child’s ass, they are endangering everyone else’s kids too.

I cannot believe that this is still a topic of discussion. The autism bullshit has been so thoroughly debunked, even the media slowly (so goddamn slowly) seems to have cottoned on. And yet, there is a pertussis EPIDEMIC in my state. People (BABIES) have died. Totally preventable. Makes me sick.

And one of reasons it makes me so viscerally upset is that I know that, at least to some degree, the blame lies with the scientific community. Not just the quacks (Wakefield et al.), but the rest of us too. For failing to communicate effectively, failing to make bold statements. Scientists hate to make definitive statements – it’s not scientifically accurate to claim something is wholly true or false. Rather, we say that “evidence suggests” or “no significant elevation was observed” or something that sounds similarly evasive or inconclusive to the layman’s ear.

That basic misunderstanding between scientists and laypeople, mixed with a sensationalist media and a litigious society is a recipe for disaster. Or a pertussis epidemic, I guess.

Here are some infographics that help communicate some of the issues surrounding vaccinations:

And here is a fantastic book recommendation:
Autism’s False Prophets: Bad Science, Risky Medicine, and the Search for a Cure, by Paul Offit (amazon).
Offit has another book out that I’m psyched to read, but I gotta finish Broken Harbour first. You know how it is.


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This is the next installment of Snoozical Rambles about Toxicology, which may or may not becomes a weekly theme.  If you are new here, you should go read my disclaimer.  

Today, I’m all jazzed about artificial sweeteners, specifically aspartame.  This is a subject near and dear to my heart, which is to say: don’t fuck with my diet coke, man.  More often than not, when people find out I’m a toxicologist, they give me the side eye and ask me why I’m drinking that diet soda because don’t I know that aspartame will make holes in my brain or give me cancer etc.??

Nope!  No it won’t!  Aspartame is so, so, SO non-toxic.  “But wait! Susie, you said before that the dose makes the poison! And I’ve seen you down a two liter in one evening!”  Yes, you are correct – the dose DOES make the poison – and aspartame doesn’t become a poison unless you are drinking ridiculous volumes.  Here are some numbers: the FDA acceptable daily intake (ADI) for aspartame is 50 mg per kg of body weight.  That equates to over 3 grams of pure aspartame per day for a 135 pound human, on up to 4.5 g for a 200 lb person.  There are about 125 mg of aspartame in a 12 oz can of diet coke, my drink of choice – so that’s about 10.4 mg per ounce.  In order to reach my daily limit of aspartame, I’d need to drink nearly 300 ounces of diet coke.  In a day. I’ve tried, I’ve done some serious focused work, and the most I’ve ever had in a day is two 2 liters.  That’s ~135 ounces. I had to use a bendy straw, and I had several people cheering me on.

Ok, so maybe you’re thinking, wait, that’s not that far from the limit! 135/300, that’s almost halfway there! Right, so that 300? That is equivalent to the 50 mg/kg/day FDA ADI.  That number is health protective, i.e., well below an exposure that could be expected to cause any toxicity in humans – you could ingest that much, every day, for your whole life and experience no health effects.

The ADI is based on a LOT of science: a host of epidemiological studies of humans, as well as long term exposure studies in animal models.  Taking the animal studies first: the National Toxicology Program, an actual reputable research organization, conducted life time exposure studies in rodents  with daily intakes spanning

In acute studies in rodents, no effects were observed at doses exceeding 10,000 mg/kg.  That’s the equivalent of a rat pounding 20 cans (240 oz) of diet coke at once.  Or a human drinking 5600 cans of diet coke. THAT IS A LOT OF DIET COKE, even for me. In chronic, lifetime cancer bioassays in rodents, they fed doses up to 12,000 mg/kg/day for periods up to two years (the lifetime of most rodents), and were unable to detect effects.  NO EFFECTS.  You have to believe me when I say that this INSANE – laboratory rodents LOVE getting tumors, and they just WOULDN’T DO IT.

Epidemiological studies in humans have been similarly boring – no effects, no significance, nothing, nothing.  There was one by Olney et al. (1996) that tried to correlate aspartame with brain tumors, but that study has been roundly dismissed due to wonderful, ethical things like fudging and misrepresenting data. Every other study, and there have been MANY, has found no effects. NO EFFECTS.

Aspartame: the least toxic substance ever, except maybe water.

All the cold hard facts (numbers) in here came from the 2007 Safety Evaluation by B.A. Magnuson et al.  Here is the evaluation summary, and here is the evaluation itself (though you’d have to pay or have journal access to read it).

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There is a well written article on NYT regarding mammogram screening that I want everyone in the world to read.  The author describes the underlying motivation of that poor panel, much excoriated at this point: that statistically, financially, and for the women in question – physically, emotionally – it just doesn’t make sense to screen before age 50.

I’ve tried explaining this to a number of my friends, often to no avail – it’s a tough subject.  The author points out the fact that understanding very large and very small numbers, and even more so, very large and very small probabilities, is not intuitive for many people. Because it is intuitive to me, and also because I have spent the last several years learning to understand those ideas, I have a hard time explaining it to them.

Without even considering the negative effects of frequent and unnecessary exposure to radiation from mammograms (which is a very interesting part of this problem to me), it’s simply not worth it.  There are too many false positives, false negatives – reading the article for the discussion of these concepts alone is worth clicking over.  Can you imagine the emotional and physical toll of being diagnosed and treated for breast cancer, only to find out you don’t have it?

The problem is more easily explained with colon cancer screening, I’ve found.  Colonoscopies are uncomfortable, embarrassing, and risky.  Perforation of the colon occurs at a rate of about 1 in 1400 to 1 in 1000 – that is, for every 1400  (or less!) people who get a colonoscopy, a hole gets ripped in one of their colons (source below).  This requires surgery, with its inherent risks – you know how you sign a piece of paper that says you could die every time a scalpel or anesthesia is involved?  Yeah.

So the fact that colonoscopies are recommended for everyone over the age of 50?  A little scary.  I would wager that I know at least 500 people in that age group, professionally or personally.  That number will obviously go up as I get older.  And as you are to get one per year?  God, I’m getting scared just thinking about it.  But, 1 in 1000 is considered a low risk – that’s only 0.1%.  It all depends on how it is presented – I interpret the latter as less risky, intuitively, than the former.

Back to mammograms.  It’s tough to say whether I will follow the new screening advice (you know, if it hasn’t changed in 15 – 25 years when it becomes more relevant to me).  It’s hard to weigh the more nebulous risks of exposure to an invisible mutagen, and the possibility of unnecessary treatment against the more tangible (and publicized) demon – breast cancer.  It’s hard for me – for us – to consider “invisible” risks (things that will happen so far in the future that they seem disconnected from their stimuli) in a rational way.

What do you think?  Will you get mammograms before age 50 if you are asymptomatic?


Panteris, et al. 2009.  Colonoscopy perforation rate, mechanisms and outcome: from diagnostic to therapeutic colonoscopy.  Endoscopy 41, 941 – 951.

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State of the union

Earlier I was perusing the NYT and ran across an article (will link later) on Godwin’s Rule: the longer a Usenet thread, the closer the probability of one being compared to Hitler gets to 1. There was a video in the article of a woman explaining how Obama and Hitler are, to her, terrifyingly similar, and trying to kill certain portions of their respective citizenry. . .

I absolutely CANNOT wrap my head around what some people believe in this country. In the world. I cannot fathom who begins the absurd rumors about this shit, and to what end. I can’t understand the things Bush et al. foisted upon thus country, evoking little more than cries of “idiot!” Now an intelligent man tries to change an obviously and severely broken system, and he is called an elitist, a facist, a NAZI. I am terrified that some nutjob is going to assassinate our president, honestly thinking they are saving the world from evil.

What is there to gain from all this bullshit??

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vennthat is all.

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