Tue, Aug-06-13, 14:32
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Experimenter
Posts: 25,863
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Plan: DDF
Stats: 202/185.4/179
BF:
Progress: 72%
Location: San Diego, CA
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The Black Swan (LDL)
Excellent article! You are a very black swan indeed
Snippet:
Quote:
Given this problem of inherent bias, how could you tell if the FH is causing the CHD or not? Or, better, how could you falsify the hypothesis that FH causes CHD? Can you find a black swan?
Well the best way to find a black swan in this ara is to turn your study inside out. Instead of looking at people with FH and premature CHD, then looking at their relatives to find FH and CHD, you need look for premature CHD first (knowing nothing of FH status), then see if FH is more prevalent in first degree relatives.
How do you do this? Well, firstly you ask hundreds thousands of students if their father had a heart attack, or died of heart attack before the age of 55. Then you measure the LDL level of those students to see if they have FH. At the same time you find age and sex matched control students to see if they have FH.
Now, if FH really were a major cause of premature CHD you would expect to find that FH was far, far, more prevalent amongst those students whose fathers suffered CHD before the age of 55.
Such a study was done once, in the Netherlands. The results were as follows:
In the EARS (European Atherosclerosis Research Society) studies, University students whose fathers had proven CHD before the age of 55 years, were recruited …Age and sex-matched controls were recruited from the same populations for each case.
2 of 1089 students with family history of CHD had FH
4 of 1727 controls had FH
Thus, the prevalence of FH in both groups was not significantly different at approximately 1 in 500, which is the estimated prevalence of the condition in the general population. The evidence that heterozygote FH is, of itself, a cause of atherosclerosis is unsatisfactory.
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