LOW INCIDENCE OF ACUTE MYOCARDIAL-INFARCTION IN BETA-THALASSEMIA TRAIT CARRIERS

The frequency of beta-thalassaemia trait was estimated in 209 consecut ive patients hospitalized for acute myocardial infarction in order to answer the question of the possible protective effect of heterozygosit y for beta-thalassaemia on the incidence of the disease. 212 patients hospitalized during the same period for various accidental bone fractu res served as controls. Diagnosis of both, acute myocardial infarction and beta-thalassaemia trait, was based on the standard clinical and l aboratory criteria. We found that patients with acute myocardial infar ction had low frequency of beta-thalassaemia trait (4.31%), as compare d with the mean incidence of heterozygosity for beta-thalassaemia in t he whole Greek population (7.61%) (p < 0.02). This finding was more cl ear in the older age groups of the patients studied. No statistically significant differences were found in the frequency of beta-thalassaem ia trait between control subjects (8.49%) and the whole Greek populati on. We concluded that the heterozygosity for beta-thalassaemia may pro tect the carrier from acute myocardial infarction. This effect is prob ably related to low serum cholesterol levels, slight anaemia, and micr ocytosis lowering the blood viscosity. These changes are usually prese nt in the beta-thalassaemia trait carriers.