Okay, I was dishonest in the title of this post. Not all Norwegians have heart disease. But almost all Norwegian men are (if we believe the prevailing guidelines) at high risk for heart disease.
Like most Americans, I spend very little time thinking about Norwegians. The great Chicago columnist Mike Royko once pointed out that in the ethnic melting pot of Chicago, you can hear jokes about the Irish, Jews, Italians, Poles, African-Americans, Mexicans, Puerto Ricans, French, British, Russians and Germans. He even remembered some jokes about Swedes. But when he asked around, nobody could remember ever hearing a joke about Norwegians. Royko even tracked down a Norwegian-American acquaintance who confirmed, “Naw, nobody tells jokes about us. We’re too nice.”
I got thinking about the Norwegians this weekend while answering comments on my post about the Spanish Paradox. I remembered logging a study about Norwegians and their risk of heart disease into my database and pulled it up. Here are some quotes from the study:
Since the first US Framingham model for predicting heart disease risk was published in 1991, it has become ever more widely recommended that doctors in primary care carry out risk assessment by combining several risk factors for cardiovascular disease using algorithms. Until recently most risk equations have been derived from the Framingham study, but these calculations tended to overestimate risk in the European context.
Actually, the Framingham model is lousy at predicting heart disease in the American context as well. But let’s move on.
A new European risk scoring system for cardiovascular disease, based on the first phase of the systematic coronary risk evaluation (SCORE) project, was presented in 2003. The system is based on a pooled dataset of cohort studies from 12 European countries, among these Norway, and offers a format for estimating fatal cardiovascular disease risk that is suitable for clinical practice.
After explaining those guidelines, the researchers report on the results of applying them to data collected from several thousand Norwegians. Here’s what they found:
At age 40, 22.5% of women and 85.9% of men were at high risk of cardiovascular disease. Corresponding numbers at age 50 were 39.5% and 88.7%, and at age 65 were 84.0% and 91.6%. At age 40, one out of 10 women and no men would be classified at low risk for cardiovascular disease.
Hmmm … people in Norway must be dropping like flies from heart disease, at least according to the prevailing guidelines for estimating heart-disease risk … you know, cholesterol levels and all that stuff.
Here again is the American Heart Association’s chart showing rates of cardiovascular disease around the world:
You’ll notice Norway is down toward the lower end of the scale – not as low as France or Spain, but lower than the U.S., U.K. or Germany.
For once, the researchers recognize that the current guidelines are poppycock. They don’t put it quite that way, of course. Their language is more academic and polite:
Implementation of European guidelines to prevent cardiovascular disease would label most people in an unselected Norwegian population at high risk of fatal disease from age 40
The validity of the evidence base of the guidelines is questionable and predicts practical and ethical dilemmas related to resource allocation and clinical counselling.
Any overestimation of a person’s risk for cardiovascular disease can have important implications. Apart from causing unnecessary concern, it undermines the patient’s informed choice for intervention. It is also likely to increase prescribing costs and affect life insurance premiums.
Yup. First thing you know, your doctor is scaring the bejeezus out of you and talking you into taking statins.
Over the weekend, I also had a mini-debate on Twitter with someone who insisted the French paradox is probably a matter of genetics. I pointed out that waves of French moved to England to become landowners after the Norman Conquest and that the French and English have been intermarrying for hundreds of years. I doubt that there’s a big difference between French DNA and British DNA. He didn’t buy it and tweeted a link to a document detailing the marked genetic differences among Europeans. He apparently didn’t notice that the document he linked described differences among Europeans separated by the Alps for most of history.
Look at the AHA chart one more time. Scotland and Ireland are near the top. England and Wales are near the middle. Now go find Australia. I’ll give you minute …
… Find it? Yup, Australia is near the bottom. My Australian readers can correct me if I’m wrong, but I’m pretty sure we can’t explain away the “Australian Paradox” by suggesting Australians are genetically distinct from the Irish, Scots and Brits.
So we have the Spanish, who are in “poor cardiovascular health” according to current guidelines, but have a low rate of heart disease. We have the Norwegians, nearly all of whom are at a high risk of heart disease according to current guidelines, but have a relatively low rate of heart disease.
I’m thinking the problem is with the current guidelines. Nice to see some researchers say as much.
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