For my regular visitors, if you find that this blog hasn't been updating much lately, chances are pretty good I've been spending my writing energy on my companion blog. Feel free to pop over to Home is Where the Central Cardio-pulmonary Organ Is, and see what else has been going on.

Tuesday, September 13, 2011

How not to do (and publish) science; metabolic syndrome

I've got another post I've been working on in draft that is taking me forever to finish, but I just had to post about what I encountered in today's health news.

This was the first article I encountered.  One in 5 Canadian adults has 'metabolic syndrome": study

A very brief article, short on details, but at least clear that "Metabolic syndrome isn't a disease in and of itself."  Rather, it's a group of symptoms that increase the risks of increasing the risks of getting "real" diseases.

Seriously.  That's what it comes down to.

No link to the study.

Then I found this one.  Metabolic syndrome now affects 1 in 5 Canadians.  So what is it?

This one, at least, links to the study.  More on that later.  First to the article, which starts with...

If I were to ask you what my most important tool as a doctor was, I bet you would say it is my stethoscope! Wrong. It is a tape measure.

Seriously??  This doctor considers a tape measure her most important tool?  Over a stethoscope?  Over her blood pressure cuff?  Over any number of tools available to her, she chooses a tape measure?

I'm glad she's not my doctor!!

So what is metabolic syndrome?  Well, you have to have at least 3 of these 5 symptoms.

Abdominal obesity
high triglycerides
low HDL cholesterol ( the good cholesterol)
high blood pressure
impaired glucose tolerance
For full disclosure, I have only one of these symptoms - abdominal obesity (more on what that turns out to be later).    My husband has two.

So of these 5 symptoms, abdominal obesity is the most common at... wait for it... 35%.  In other words, while it was the most common of the five, 65% of people don't have it.   They have three of the other 4 symptoms.  Meanwhile, the most common combination of factors was abdominal obesity, high triglycerides and low HDL (note that high cholesterol, the long time scare, isn't even mentioned - they are specifically sticking with low "good" cholesterol).  The article doesn't say how many that group represents.

Now, what are the predictors of having metabolic syndrome?  Is it the usual stuff I hear of lazy fatties stuffing their faces with junk food and too stupid to know better?


These predictors that increased the risk were: education and income level. Higher levels of education and income predicted a lower likelihood of metabolic syndrome.
In other words, the more you know and the more money you have, the less likely you are to have metabolic syndrome.  Which could be considered good news, since 80% of Canadians do NOT have metabolic syndrome.  So solving this "problem" should just be a matter of helping people become more educated, and improving income.  Right?


The implications of these findings are truly important. Among younger adults particularly, it is critical to address poor lifestyle habits.

Wait.  What?  Where did that come from?  Didn't she just write that education and income were...


And in conclusion...

Cardiovascular disease increases with age and if we don't address abdominal obesity, and the other symptoms of metabolic syndrome the burden of chronic disease will continue to soar. What is more critical is that each if the components of metabolic syndrome can be addressed by lifestyle changes.

 So we have a study that, according to this article, shows that low income and education levels are the most common predictors of metabolic syndrome, and that 65% of the people with metabolic syndrome in this study did NOT have abdominal obesity as their  minimum 3 of 5 symptoms (note that some people in the study would have had 4 or 5 of 5 of these symptoms, too), and the cure for this is lifestyle changes.

Well, I suppose if lifestyle changes includes improving our education and increasing income, I could go with that. 

So what does the original report say?  The abstract is here

Notice something?

Yup.  This report is based on a survey.  In the pdf, you learn this survey was done in 2007-2009.

The abstract doesn't even end with a conclusion, but an interpretation (good to see that, for a change, but that doesn't seem to stop the media from reporting is as fact).

Interpretation: About one in five Canadian adults had metabolic syndrome. People at increased risk were those in households with lower education and income levels. The burden of abdominal obesity, low HDL (high-density lipoprotein) cholesterol and hypertriglyceridemia among young people was especially of concern, because the risk of cardiovascular disease increases with age.
 Which tells us... what?  Poor people with a lack of education are at higher risk for poor health than everyone else?  This is news?  Cardiovascular disease increases with age, also not news, but how does this address the problem of young people with metabolic syndrome?  Young people tend to have less education than older people, and less money than older people, anyhow.  It takes time to increase income and continue education.  What is the news here?

Also not addressed; the headlines reads that metabolic syndrome "now effects" 1 in 5 Canadians.  So what was the rate of metabolic syndrome before?  No idea.  As far as I can tell, this is the first time anyone has actually tried to measure it before.  We have data for 2007-2009.  That's it. 

Now then.  What does the report tell us?

Oh, dear.

First, they describe the methods.  Not only is this survey data by Statistics Canada (granted, data taken only from those that had actual blood test information available), but there is a whole bunch of number crunching for weight by

multiplying the weight for the collection site by the selection weights for household, and adjusted for non response. The weights for collection site and households were based on the 2006 census. The household weights were then converted to individual weights and further adjusted for nonresponse.

In other words, it's a data dredge.  They never actually studied anyone, weighed anyone, measured anyone, or took blood tests from anyone.  They used Statistics Canada information.

So let's look at the criteria.  First, let's look at what it means to be "abdominally obese."

waist circumference ≥ 102 cm for men and ≥ 88 cm for women
To translate into Imperial, that means men with waists equal to or greater than 40 inches, and women with waists equal to or greater than 34 1/2 inches, are "abdominal obese."

In other words, unless you are quite thin at the waist, regardless of anything else about your body, you are "abdominal obese." 

No wonder that most people in the survey were "abdominal obese."  It would be almost impossible not to be!

And on it goes.

You can go ahead and read the rest of the report yourself.

It's a whole bunch of data, but what does it actually say?  And what does it recommend?

Well, it takes a bunch of symptoms and, if people have enough of them, they are labelled as having "metabolic syndrome."  It doesn't mean anything more than having a combination of medical readings.

Having that combination of medical readings increases your risks of increasing your risk of actual diseases.  Nothing about causes, of course.  Just correlation.

It shows that there is an increased risk of having metabolic syndrome (the increased risk of increasing your risks) if you lack education an income.

Then we're told in various articles that we can reduce our risk of metabolic syndrome by reducing our abdominal obesity through lifestyle changes, even though 65% of the people described as having metabolic syndrome do not have abdominal obesity.

What questions aren't answered? 

Well, I would wonder what role lack of education and income plays.  Education (and I do not mean "schooling" necessarily, though I imagine formal schooling is how Stats Can defines it) and income are tightly connected.  There are plenty of studies this connection.  No surprise that people's health would be compromised if they don't have enough money to buy nutritionally adequate food.  No surprise, also, that young people are the hardest hit when it comes to low income and less education. 

Instead, writers leap to the idea that, if we just loose our abdominal fat, we'd solve all our problems.

Critical thinking?  What's that?

No comments:

Post a Comment

Drop me a line...