GEOGRAPHIC-VARIATION IN THE PREVALENCE OF RAYNAUDS-PHENOMENON - A 5 REGION COMPARISON

Objective. To determine the population based prevalence of Raynaud's p henomenon (RP) in 5 geographic regions: one in South Carolina, USA, an d 4 in France; to explore the relationship of RP to the climate, to in vestigate possible risk factors; and to describe the characteristics o f RP+ subjects in the general population. Methods. The study consisted of 2 phases: a telephone survey of a randomly drawn sample of househo lds, with 10,149 completed interviews; these were followed by a face t o face interview and clinical evaluation (n = 1534), including diagnos is of RP. The same methodology was used in all 5 regions: for recruitm ent of subjects, criteria for RP, method of RP diagnosis, and for gath ering additional information. Results. The prevalence of RP was found to be related to the climate, The relationship between RP and climate was complicated, however, by the fact that many subjects had moved bet ween climate zones. The relationship of RP to a cold climate became mo re evident after taking the migration patterns into account: the major ity of RP+ subjects in the 2 coldest regions had lived all their lives in the same or a similar climate zone; the majority of RP+ subjects i n the 2 warmest regions had previously lived in a colder climate. Othe r factors associated with RP were Family history of RP, cardiovascular diseases, older age, a low body mass index, use of vibrating tools, a nd outings of a day or more. The classical triphasic RP was rarely enc ountered in the general population and the most frequently observed si gns and symptoms during an RP attack were blanching accompanied by num bness. Conclusion. In addition to being a triggering factor for RP att acks, cold also appears to be an etiologic factor in the pathogenesis of RP A subclinical cold injury, more likely to occur in colder climat es, may be responsible for the ''local fault'' that has been implicate d in the pathogenesis of RP and, in association with other risk factor s, may predispose subjects to develop clinical RP.