Geographic variation in the prevalence of Raynaud's phenomenon: Charleston, SC, USA, vs Tarentaise, Savoie, France.

We estimated the prevalence of Raynaud's phenomenon (RP) in the general population of 2 geographic areas, Charleston County, South Carolina, USA, and Tarentaise, Savoie, France, using the same methodology in both countries. The first phase of the study, consisting of the telephone survey of a randomly drawn sample of households, yielded 2086 completed interviews in Charleston and 2000 in Tarentaise. Cold sensitivity or unusual digital color changes were reported by 17.9% of the subjects in Charleston and by 31.3% in Tarentaise. In the second phase of the study the diagnosis of RP was made by a medical team. Based on these results, the estimated prevalence of RP is 5.0% (0.8% SE) in Charleston (women 5.7%, men 4.3%) and 16.8% (2.0% SE) in Tarentaise (women 20.1%, men 13.5%).