The genetic characteristics of the diabetic types have been assessed by following up their frequency in first degree relatives of some non-selected diabetic patients, registered at eight different centers of the country. Out of 1,003 non-diabetic controls only 46 (4.6%) had 52 diabetic relatives, 65.4% of type 2 (non-insulin-dependent). Comparatively, out of the 704 patients, 172 (24.4%) had 229 diabetic first degree relatives, 72.5 of type 2. Out of 231 type 1 (insulin-dependent) diabetic patients, 29 (12.6%) had 34 diabetic relatives, 55.9% of type 1. Out of 300 type 2 patients, 99 (33.0%) had 121 diabetic relatives, 84.0% of type 2. The other 173 diabetic patients presented an "intermediary" type of the disease (needing insulin many years after onset). Forty-four (25.4%) of them had 64 diabetic relatives, 67.2% of type 2, 20.3% of type 1 and 12.5% with "intermediary" diabetes. The five times higher frequency of diabetes in patients' relatives versus controls is pointed out. Type 2 diabetic relatives predominated. The proportion of probands with diabetic relatives increased from 4.6% in non-diabetics to 12.6% in type 1, to 25.4% in "intermediary" diabetes and to 33.0% in type 2. The heredity of type 1 prevailed in type 1 and that of type 2 in type 2 and in "intermediary" diabetes. The fact that "intermediary" diabetes tends towards type 1 (insulin-dependent) as therapy and towards type 2 (non-insulin-dependent) as heredity might be an argument supporting the controversy on the diabetic syndrome classification.
Transversal epidemiologic investigations carried out in different populations from several regions of Romania : Gurghiu Valley (lumberjacks from a mountain region), Danube Delta and Razelm lagoon complex (fishermen), and Bucharest have shown that, in spite of the high caloric value of food and even of a high intake of saturated fats, mean serum cholesterol is lower in the rural areas than in Bucharest, probably owing to the strenuous physical work. However, except myocardial infarction, more frequent in the urban than in the rural regions, the other forms of coronary heart disease have a relatively higher frequency in villages, particularly atrial fibrillation and ECG signs of ischemia. These findings might be explained by a greater prevalence of hypertension in these populations. It is concluded that the risk factors, which act synergically, depend on the complex structure of the "ecologic niche".
