Clinical experience in Israel, supported by statistical surveys, showed a low incidence of atherosclerosis among immigrants from eastern countries as compared to immigrants from western countries. In particular, the incidence of atherosclerosis among immigrants from Yemen was found to be strikingly low.
An investigation of the socioeconomic condition, diet, and nutritional status of 2,200 immigrants from western and eastern countries belonging to different social groups was carried out. Determinations of serum total lipids, total cholesterol, alpha and beta cholesterol, phospholipids, lipoproteins, proteins, and protein fractions were performed.
Significantly the lowest serum cholesterol and beta cholesterol values were found among the "recent" Yemenites (after 5 years in Israel), the poorest economically, and with an imbalanced caloric intake of the lowest fat content. Higher cholesterol and beta cholesterol values were found among "early" (after 20 years in Israel) Yemenites, Iraqi, and European manual workers with no significant differences among them, whereas in Europeans of higher economic level these values were even higher.
Review of 5,000 hospitalized cases of myocardial infarction showed a very low incidence for Yemenites, higher for immigrants from other eastern countries, and considerably higher for European immigrants.
A statistical survey of the entire population for the years 1953 to 1957 showed that the mortality rate from atherosclerosis was extremely low for "recent" Yemenites, considerably higher for "early" Yemenites, and still higher for European immigrants.
These results suggest the influence of socioeconomic conditions, diet, and total caloric balance on serum cholesterol values and atherosclerosis morbidity and mortality. They support the assumption that atherosclerosis is a disease of lipid metabolism influenced by phenotypic factors and therefore can be prevented.