Mammograms

Several studies have disputed the efficacy of mammograms. I, being a man, of course ignored these when they hit the news last year. Some friends were discussing it, which got me thinking, "How could getting mammograms not help?"

Here are two articles which discuss the changing science on mamography:

• http://www.hsph.harvard.edu/news/features/vatten-mammography-screening/ (link) 
• http://well.blogs.nytimes.com/2012/11/28/ignoring-the-science-on-mammograms/ (link)

The first indicates that screening does not correlate with reductions in breast cancer mortality rates. Also, screening tends to find cancers that "would not have harmed them". The second reinforces that "that screening mammography doesn’t save lives" and "the number of cancers diagnosed at the advanced stage was essentially unchanged".

I thought about this for a while. How could screening mammograms, which find early stage cancer, not reduce advanced stage cancers or cancer deaths? I came up with five reasons:

1. The early cancers detected would not have become malignant, so finding and treating them doesn't affect mortality rates.
2. The early cancers that may have become malignant would have been caught at a later time. Treatments are now so advanced that the delay doesn't appreciably affect the mortality rate.
3. Other screening methods are finding cancers so mammogram screening is less effective at finding cancer. Maybe women who do self exams find more cancers compared to women who wait for their yearly mammograms. This would strangely lead to a correlation between mammograms and increased mortality rates.
4. The treatments may negatively affect mortality. Getting surgery or radiation or chemotherapy on early cancers or benign cancers may damage health enough to outweigh any benefits. I couldn't find a clear answer whether the mortality rates were just due to cancer, or due to anything (I'm guessing the latter).
5. The advanced cancers appear very quickly and are very deadly. This makes some sense because cancer is uncontrolled growth of previously normal cells. Fast growing cancers would seem to be the most deadly. In this case, the mammography screening rate might have to be monthly to have a hope of finding these advanced cancers in time to make a large difference in mortality.

I decided to actually read the original New England Journal of Medicine article, so see if I could understand what was going on.

• http://www.nejm.org/doi/full/10.1056/NEJMoa1206809

It enlightened the situation, and also showed the difference between scientists and science journalists. Here are some quotes for the NEJM study Discussion section:

• "Over the same period, the rate of death from breast cancer decreased considerably. Among women 40 years of age or older, deaths from breast cancer decreased from 71 to 51 deaths per 100,000 women — a 28% decrease. This reduction in mortality is probably due to some combination of the effects of screening mammography and better treatment. Seven separate modeling exercises by the Cancer Intervention and Surveillance Modeling Network investigators provided a wide range of estimates for the relative contribution of each effect: screening mammography might be responsible for as little as 28% or as much as 65% of the observed reduction in mortality (the remainder being the effect of better treatment). Our data show that the true contribution of mammography to decreasing mortality must be at the low end of this range."
• "As treatment of clinically detected disease (detected by means other than screening) improves, the benefit of screening diminishes"
• "Women now widely recognize the significance of a new breast lump and the need for diagnostic mammography. Ironically, increased awareness confers less opportunity for screening mammography to reduce the incidence of advanced cancer. ... We agree that women should understand that screening raises their risk of becoming a patient with breast cancer and that there is uncertainty about the benefit of screening. The assessment of how to cope with that uncertainty, however, remains a value judgment that we believe should be left to women and their doctors." - Authors response in Letters section

It should also be noted that the study did not follow women to see what they were doing, but looked at general statistics. It did not look at a woman's family risk of breast cancer, or whether they did self exams. Also, some fairly large adjustments had to be made to account for hormone-replacement therapy's effect on cancer rates.

What I take away from this is screening, in all forms, is useful, but results should be reflected on before health-affecting treatments are begun to make sure they are necessary. But this is a complicated subject, and my heart goes out to anyone who has to deal this these issues.

What catchy title for a post uses the word thermodynamics?

Understanding thermodynamics can help you in the world (seriously). There are four laws of thermodynamics, but one and two are most interesting. They are paraphrased below:

Law 1 - Energy cannot be created or destroyed, it can only change form.
Law 2 - When changing form, some energy is always lost as waste heat.

Put another way: "Not only can you not win, you can't break even."

Practical application #1
I read a story about a plan to put wind turbines near a highway to try and recapture the wind created by the fast passing cars. Sounds like a great idea, right? Use Law 1 above and tell me what is wrong with it.

Where does the energy come from? When the highway is empty, the wind turbine won't turn, so the cars must be providing the energy. And that is exactly what they found when they tested it. The fuel efficiency of each car was found to be reduced slightly. The energy created by the cars was being changed from mechanical energy (motion of the car) into wind energy (motion of the air molecules) into mechanical energy (motion of the turbine) into electrical energy.

The worst part is, as Law 2 states, every time you change form, you waste some energy. So you are basically burning gasoline to create electricity, but in the most inefficient way possible. It is sort of a Rube Goldberg contraption of idiocy.

So you may be asking yourself, "Where exactly is the practical application of thermodynamics you promised?" And here it is. You can yell at the monitor when you read these types of dumb ideas and your partner and/or dog and/or fish and/or D&D action figure can nod their head at how smart you are. Or maybe shake their head at how crazy you are. I'm not sure.

Practical Application #2
If the 1st practical application wasn't enough, here is a second one, which actually involves money and prison!

I had a co-worker pitch an idea for an invention to me. He said that his brother-in-law had a patent for a machine that could generate energy very cheaply. It was made from an outer hub with seven magnets, which was attached to an inner ring with .... (he paused and looked around, like he was about to blow my mind and didn't want any other minds around us to blow -- no collateral mind blowing) six magnets. "Because the magnets are spaced like that, the hub magnets are always pushing the ring magnets around, like a merry-go-round that never stops."

I'm sure you've all heard of perpetual motion machines. Now contrary to popular belief, the US Patent office will not reject the filing of a patent just because it is for a perpetual motion machine. However, it does stipulate that a working model must be provided before the patent will be granted. Needless to say, that has never happened.

Here's the thing. It is possible to build a "perpetual" motion machine with magnets. The reason is magnets do have energy in them, so as the machine moves it will slowly weaken the magnets. This obeys Law 1. However, taking the final step and trying to generate electricity from it can be a tricky step. Law 2 says that every time you try and change the form of energy, you piss some of that energy away. So the very act of hooking up a generator to your spinning 13 magnet science project will cause it to either spin slower or maybe weaken the magnets faster. In any case, you are just using the magnets like batteries and they will eventually die out, requiring you to get more magnets.

You may have been waiting for the money and prison part. Here it is. My co-worker told me about this incredible invention and asked me if I wanted to invest in it. His brother-in-law was selling stakes in the company, which could be "worth millions". I explained how perpetual motion machines were impossible without an energy source. My co-worker looked at me, and then tried to explain the 6 magnet / 7 magnet configuration again. He even produced a sketch on some graph paper which "proved" it. Did I mention this co-worker had a degree in Engineering? I politely looked at his sketch and explained that you couldn't violate the first or second law of thermodynamics, which this idea clearly did. I warned him that he should not invest, and should explain thermodynamics to his brother-in-law next time they meet. "Well, I won't be seeing him for a while. He's in prison on fraud charges." I got up and slowly backed out of his office, which was a surprisingly awkward way to leave an office.

Moral of the story: There is no thermodynamic law against being a moron.

PS. I swear to dog this story is true.

Sugar is poison

Those latest adds by the Corn Refiner's Association which are trying to "rebrand" high fructose corn syrup (HFCS) as the same as sugar scare me. Why would they spend so much telling me it is "safe" if it were actually safe? I know, I'm a skeptic.
Last night, I thought I'd try and educate myself about this. Here is what I found out.
Sucrose is normal granulated sugar, the stuff we put in coffee or on cereal. Sucrose is made up of two other sugars in equal proportions -- Glucose and Fructose -- which are bonded together. When you eat table sugar (Sucrose), your body breaks it down into Glucose and Fructose.
Glucose is the energy of life. It is in rice, pasta, grains, etc. It can be metabolized (used) by muscles, but is mostly broken down in the liver and stored until you burn it off (or, if you don't burn it off, it is turned into fat). Fructose, on the other hand, can only be metabolized by the liver. But there are a bunch of other nasty things that Fructose does.
Fructose is found mostly in fruit (but fruit contains fibre which mitigates some of its bad effects). Fructose does not create an insulin response, which is why it is used by diabetics as a sweetener. Fructose creates uric acid which causes gout and hypertension. Fructose is more readily turned into fat than Glucose. A good analogy for Fructose is another carbohydrate, Ethanol, or booze. Ethanol is fine in small quantities but in large quantities, it causes toxic effects on the liver and your body. Fructose acts in exactly the same way, but without the buzz. Fructose, like Ethanol, is a poison! With all poisons, it is dosage that determines toxicity.
Okay, so what is High Fructose Corn Syrup (HFCS) and why is it so bad? Well, HFCS is just Glucose (corn syrup) and Fructose, typically in exactly the same proportion as they are found in Sucrose (table sugar). They just aren't bonded together, which really doesn't mean anything because as soon as Sucrose hits your small intestine, it is broken apart. Look at the image above. The top (Glucose Fructose) is HFCS and the bottom (Sucrose) is table sugar. They are the same. Your body treats them the same. So what is the big deal? Here's the thing: it isn't that HFCS is worse than sugar, it is that sugar is really bad and HFCS is the same as it.
The real problem is HFCS is really cheap so it is put in everything to make it taste better. Here is a good analogy. Image table sugar is rat poison. In the past, it used to sit in a bowl on your table and you'd put it in coffee or on porridge or in baking. But if you didn't put it in stuff you wouldn't eat it. You could control your intake. But now, the rat poison is in everything: bread, juice, pop, cereal, anything processed. So if you don't put rat poison in your coffee, who cares, because you are getting it in everything else you eat. That is what makes HFCS so dangerous, is that there is no escaping it.
Sugar is poison, whatever the form.

Poor impulse control

I just recently bought a new high definition TV (HDTV). TV buying can be daunting and complicated, so I thought I'd go through the things I learned in my hunt.

Only a year ago, I bought a 46" LCD Toshiba TV for $1600 at Visions. One of the main reasons we got it was it had an "upscaler", which allegedly made standard definition (SD) inputs (like from a DVD player) look high definition (HD). It worked okay, but we started watching more movies on our Blu-ray player and HD cable, so it because less and less useful.

It was fine, but the feature that I really coveted was called Smoothing. Sony calls it "Motion Flow" and Samsung calls it "Auto Motion Plus". Before I explain what Smoothing is, I have to explain how TV signals work.

Motion pictures are filmed at a rate of 24 frames per second (fps). Every second, 24 unique frames flash before your eyes. Television is broadcast at 60 fps. Since 60 is not divisible by 24, when movies are shown on TV they have to do something called 3:2 pulldown. What it means is the first frame is shown twice, the second frame is shown three-times, the third frame is shown twice, etc. See below for an example:

[A] [A] [B] [B] [B] [C] [C] [D] [D] [D] ...

3:2 pulldown can result in a flickery and blurry effect which is typically called judder. TV manufacturers have tried to combat this by increasing the frame rate of HDTVs to 120 fps (more commonly called 120 Hz). 120 is dividable by 24, so each movie frame is shown 5 times.

This can only fix the picture so much. Just flashing the same picture 5 times may make it slightly clearer, but it doesn't change the fact that it is the same picture. This is where Smoothing comes in.

Smoothing software in the TV tries to predict what the image would look like between two frames. So if a golf ball is on one side of the screen in one frame, and then on the other in the next, the Smoothing software tries to create a new frame with the ball in the middle. Smoothing tends to make film look more like video. It is very visible when the camera pans slowly across a scene. It also makes computer-animated movies look hyper-real.

Smoothing tends to only be available on higher end TVs. Sony and Samsung (the top two LCD TV manufacturers) each had TVs with the feature that I was looking at but they were about $2400. If I had better impulse control, I'd wait until September or January, which are the best times to buy TVs. But I walked into a Walmart last week. Right in the middle of a bank of TVs I saw the beautiful glassy image of a TV with Smoothing enabled. They were showing Avatar and even though I don't really like that movie, I stood there for 20 minutes, totally ignoring the three phone calls Karen made to my cell phone. (I swear, honey, I did not hear my phone ringing.) I couldn't believe the incredible smooth image on a 47" TV that was only $1000. I did a little bit of research on the brand (no-name Vizio) to make sure it wasn't a total dog, and then picked it up on the weekend.

It was the wife and my 11th anniversary, so it is really a gift to us. Your welcome, Karen.

Gay Marriage and Abortion

These are very serious and controversial issues. I will not talk about them at all. Instead, I'll talk about some other issues which concern me.

Usury

In Canada, it is illegal to charge more than 60% yearly in interest. But every day, thousands of Canadians are charged much higher rates at payday loan companies like Money Mart and Cash Money. The maximum amount these companies can charge in interest and "fees" is 0.13% per day. For example, if you borrow $1000 you can only be charged $1.28 per day! These stores get around the law by adding fees to the transaction, in addition to the interest rate, which can drive the actual annual interest rate up into the thousands of percent.

Payday loan companies pray on the poor and those who may not understand how punishing compound interest is. They must be regulated nationally.

Statistics and Surveys

There is a subject I think requires more explanation in school. That is Statistics.

Almost every day, we are exposed to some survey in the media. But we should not treat them as all the same. Surveys are only valid if 1) they are random, 2) enough people participate, 3) the questions are good.

First, many surveys aren't truly random. Telephone surveys can be slightly biased because they only survey people who own phones, have their number in a phone book, and (more importantly) agree to participate in the survey. Internet surveys are terrible because only people who are truly passionate tend to respond.

Second, the more people who participate, the more accurate the survey. But keep in mind the actual population size. 100 people surveyed may be fine to know the opinion of Kia drivers but not to know the opinion of all Canadians.

Third, the questions need to be clear, not-loaded, and unbiased. For example, "Should it be illegal to beat your child?" will give different results than "Do you think the government should be able to tell you how to discipline your child?". This is why it is important to look at the source of the survey if the results look wonky.

Finally, what do those margin of error statements mean (e.g., plus or minus 5 percentage points, 19 out of 20 times)? The first number is accuracy and the second is repeatability. Accuracy is how close the survey is to the actual opinion of the population being surveyed. Repeatability means if they did the survey again, how likely are they to get that same accuracy. Luckily, the repeatability on most surveys is 95% (19 out of 20 times) so looking at the percentage accuracy is a good judge of the survey.

Surveys are just one part of statistics. Many people confuse correlation and causation (e.g., most prisoners are smokers, but that doesn't mean most smokers are criminals) and put far too much weight on anecdotal evidence (e.g., violent crime has steadily decreased since the 70's, but people still yearn for the "good ol' days").

Okay, there I'm done. Oh right, I hate ads before movies. Yeah. Okay, now I'm done.

Don't stop taking anti-stupid pills

A recent study found that placebos are nearly as effective as Prozac in dealing with mild depression.

http://www.breitbart.com/article.php?id=080227102745.p467o58k&show_article=1

Fine. But why would anyone think this means they should stop taking their anti-depressants? The study compared placebos (i.e., sugar pills) to anti-depressants, not nothing to anti-depressants. The doctors and researchers are still fairly sure that nothing still does nothing. This study reveals how powerful placebos are, not about how ineffective anti-depressants are.