While there is no doubt about the role of genetic factors in the aetiology of vascular diseases, especially in the genesis of disorders of the venous system, a place should be reserved for climatic and social factors. By means of an investigation which we undertook in a tropical environment in senegal, we examined the morbidity due to atheromatous disease. This study extended over a period of 30 years, from 1945 to 1975. We found that arteriopathy of the lower limbs due to overload did not exist before 1960. Since 1966, a few cases of myocardial infarction have been noted, and since 1970, a few cases of arteriopathy. These cases are confined to an urban environment which, during the same period, has undergone profound social upheavals. It all seems to be as if there were competition between climatic factors protecting and social factors aggravating. In contrast to the rarity of vascular disorders in hot countries is their high incidence in cold countries. In Canada and Sweden a particular clinical aspect of the disorder has been found: arteriopaths in a subarctic environment suffer more than sensory disturbances than ischaemia. In conclusion, it seems that the environment, in the broad sense of the term, plays a role in the aetiology of atheromatous disease, which has been classified, not without reason, among the diseases of civilization.