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Posts tagged ‘statistics’

Caveat Emptor

You thought I fell off the face of the earth, didn’t you? Seriously, I haven’t been terribly motivated to write as much lately, and  it shows. However, I ran across an article today that made me just have to say something.

A journalist, John Bohannon, apparently wrote a bogus study, got it published, and it was subsequently picked up by the news media. I say “wrote a bogus study”, but he actually did a bogus study. He got volunteers, separated them into groups, a control and two study groups, had them follow certain protocols, took actual measurements, then ran the statistical analysis. What makes it bogus it that there were only 15 subjects. To use his own words:

Here’s a dirty little science secret: If you measure a large number of things about a small number of people, you are almost guaranteed to get a “statistically significant” result. Our study included 18 different measurements—weight, cholesterol, sodium, blood protein levels, sleep quality, well-being, etc.—from 15 people. (One subject was dropped.) That study design is a recipe for false positives.

Apparently, there are a number of  “peer-reviewed” journals out there that aren’t any such thing. Instead, they are money-making schemes.

Now, you may ask, how do I know this story is real? Maybe he’s faking the fake? I did do some homework on this. I followed the links, I read the original story. I couldn’t find his article in the International Archives of Medicine, but they may have pulled it after realizing what was going on, or maybe I just wasn’t successful. I think this does point out the pitfalls of getting any of your information from the internet. It’s only as good as the source. I do know that the problems he is pointing out are real. As Mark Twain once said, “There are three types of lies. Lies, D***ed lies, and statistics”.

I run into this every day. People ask me about this diet or that drug. This “cleanse” or that product. Very few people remember high school science, or even care.

Losing weight is simple, but not easy. There are no quick fixes. The basic principles still apply, whether you dress it up in new buzz words or fancy diets. I suggest you read his article and educate yourself on some of the pitfalls and take any “new study” that touts some amazing results or counter intuitive ideas.

Statistics and Lies

Mark Twain did not care much for statistics, he said:

Get your facts first, then you can distort them as you please.


There are lies, damned lies and statistics.

I have reason to agree, when simple curiosity drove me to do some quick research. Every time there is an article on health, I read it. The one that caught my eye today was one on Yahoo that another country beat out the United States as the fattest country. The main thrust of the article was that Mexico now has a greater proportion of obese people than the U.S. .This made me think about the link between obesity and heart disease, wondering where Mexico and the United States fall in the ratings of heart disease, so I went looking for statistics on heart disease to see what sort of correlation there was. That is where things got interesting. I googled it and clicked on the first two links. Both claimed to use the latest sources, both cited WHO, the World Health Organization, and yet they don’t have the same information. Part of this could be what filters they use, and that is part of the problem with statistics, they are endlessly maniple. The first site I went to worldlifeexpentancy.com, listed Turkmenistan as the number one country for coronary heart deaths, and Slovakia was way down on the list. The second site, nationmaster.com, listed Slovakia first, and Turkmenistan wasn’t even on their list. The initial article said that Japan was the slimmest country, and it was way down on both lists for heart disease, but not at the same point, and the number of deaths per million differed on the two lists.

I went to WHO’s website to try to find their original source, but either they don’t put it up there, or you can’t find it with a search engine. The closest I could get was a listing of CVD and diabetes. If anyone has a link to it, please put it in the comments, I would be interested.

Getting back to my original article, it raises some interesting points about the interpretation of facts:

According to a new report from the United Nations Food and Agricultural Organization, the United States is no longer the world’s fattest developed nation―Mexico is.

The key word here is developed. Take that out, and you go from Mexico’s 32 % to :

The world’s fattest nation overall is Nauru, a South Pacific island where a staggering 71.1 percent of its 10,000 inhabitants are obese.

The U.N. report does not include data for American Samoa, which has been tabbed in the past as the world’s fattest country. According to a 2010 World Health Organization report, nearly all of that Pacific island’s inhabitants (95 percent) are considered overweight.

So one world makes a word of difference in what we are talking about. To quote Mark Twain again, “it’s the difference between lightning and a lightning bug”. There are many points to be made from this little exercise.

  • People are doing their best to study health and fitness, the shifting recommendations come from a variety of factors. A lot of smart people are spending a lot of time gathering data, and trying to come up with study designs that compensate for the flaws of previous ones.
  • After we’ve collected the data, It has to be analyzed, and that is fraught with hazards. That is where bias can wreak havoc.
  • Every word can count. What factors are included/excluded from the study?
  • News reporters just read the summaries, they don’t sift through the data to see if the summary is justified. A study might show a weak correlation between two things, and the news article may read “A causes B!”
  • Heart disease is affected by a lot more than just weight. The top countries for heart disease have high rates of smoking, and less health care.
  • The furthur you get from primary sources, the more corrupted the data.

It is hard to when the information changes over time, and it will. I don’t want anyone to get discouraged, just don’t put all your faith in one study, or get cynical when a study gets discredited.  It takes a whole lot of research to get any kind of picture of what is really going on.

Many of you may have heard about the link between omega 3’s and prostate cancer. The whole fish oil craze started with studying people who ate high amounts of cold water fish, and their lower risk of heart disease. They then took the fish into the laboratory to see what aspect of it was causing this. Once the oil was isolated, we then started to put it in a pill, for those who don’t like fish. We can’t study every aspect at once, so the prostate link wasn’t found right away. We are starting to see that even if there is one active compound in a food, it doesn’t seem to have the same effect once isolated that it appeared to have in the food.

The last point I’d like to make on this is that we will all die of something, at some point. All we can do is try to improve the quality of life until the end. No food will extend your life to extreme levels, and there are a variety of factors that influence health and life expectancy. Pills are not magic, and they all have side effects. You are far better off eating the best you can and not worrying about the rest. By the way, if you read that  link to the 2010 WHO report inside the quote I put in this article, it will dispell any doubts you may have about the link between diet and life expectancy.

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