[Ibanez]

continued from previous post....

With only 14% of the Framingham dead chosen for autopsy, the risk of bias must have been great because there is one exception from the above rule: patients with the rare disease familial hypercholesterolemia have much atherosclerosis, and very high cholesterol levels in their blood. If many such patients are included in a study of cholesterol and atherosclerosis, a correlation will be found.

The question about blood cholesterol and atherosclerosis has been studied by coronary angiography also. It seems as if every specialist in coronary angiography in America has performed his own study, funded with federal tax money awarded by the National Heart, Lung and Blood Institute. In paper after paper published in various medical journals, using almost identical words, these medical specialists emphasize the importance of the blood cholesterol level for the development of atherosclerosis (33).

But the reports offer no individual figures, only correlation coefficients, and these are never above a minimal 0.36, usually even smaller. And they never mention any of the previous studies that found no association between degree of atherosclerosis and level of blood cholesterol.

Studies based on coronary angiography are fundamentally flawed if their findings are meant to be applied to the general population. Coronary angiographies are performed, mainly, on young and middle-aged patients with symptoms of heart disease, which means that a relatively large number of patients with familial hypercholesterolemia must have been included. Again, there is an obvious risk for the kind of bias that I described above. The fact that this objection is justified was demonstrated in a Swedish study performed by Dr. Kim Cramér and his group in Gothenburg, Sweden (34). As in most other angiographic studies the patients with the highest cholesterol values had on average the most arteriosclerotic coronary vessels.

But if those who were treated with cholesterol-lowering drugs were excluded, and almost certainly this group must have included all patients with familial hypercholesterolemia, the correlation between blood cholesterol and degree of atherosclerosis disappeared.

In Japan the food is meager, blood cholesterol is low and the risk of getting a heart attack is much smaller than in any other country. Given these facts you will most probably say that in Japan atherosclerosis must be rare.

The condition of the arteries of American and Japanese people was studied in the fifties by Professors Ira Gore and A. E. Hirst at Harvard Medical School (35) and Professor Yahei Koseki from Sapporo, Japan. At that time US people on average had a blood cholesterol of 220 whereas Japanese had about 170.

The aorta, the main artery of the body, from 659 American and 260 Japanese people were studied after death. Meticulously all signs of atherosclerosis were recorded and graded. As expected, atherosclerosis increased from age 40 and upwards, both in Americans and in Japanese. Now to the surprising fact.

When degree of atherosclerosis was compared in each age group there was hardly any difference between American and Japanese people. Between age forty and sixty Americans were a little more arteriosclerotic than Japanese; between sixty and eighty there was practically no difference, and above eighty Japanese were a little more arteriosclerotic than Americans.

A similar study was conducted by Dr J.A. Resch from Minneapolis and Dr.s N. Okabe and K. Kimoto from Kyushu, Japan (36). They studied the arteries of the brain in 1408 Japanese and in more than 5000 American people and found that in all age groups Japanese people were more arteriosclerotic than were Americans.

The conclusion from these studies is of course that the level of cholesterol in the blood has little importance for the development of atherosclerosis, if any at all.