Neurology. 2002 May 14;58(9):1407-1409

Based on a preceding survey performed in 1985, the authors estimated the prevalence and incidence of cluster headache (CH) in the Republic of San Marino (26 628 inhabitants at 31 December 1999). All cases were diagnosed by direct interview according to International Headache Society criteria. The prevalence rate was 56/100 000 (95% CI 31.3 to 92.4), and the incidence rate was 2.5/100 000/year (95% CI 1.14 to 4.75). Most cases showed rare clusters. This is the first prospective study on the incidence of CH.

Comment: There continues to be debate on the prevalence of cluster in the general population. Since San Marino is small, the entire cluster population, with a smaller denominator for the general population, could be estimated, making this a very important study. SJT