Decreasing incidence and severity of Behcet's disease: a changing trend in epidemiological spectrum possibly associated with oral health.

Behcet's disease (BD) is a systemic and inflammatory disorder that is mainly present along the ancient Silk Road, from the Mediterranean Sea to East Asia. A wide range of prevalence figures (0.1-420/100,000) have been reported for BD, also among Turkish populations of similar genetic background living in different countries. Recently, a decline in the incidence of BD and a change of the disease spectrum to less-severe manifestations have been reported from Japan and Korea, two genetically homogenous, affluent populations with limited immigration. It was hypothesized that a decline in infectious diseases, especially dental/periodontal infections, associated with the improvement in oral health, could be a part of these changes in the disease expression. Further epidemiological studies in other populations might demonstrate whether there is a worldwide similar trend and may provide a better understanding of the triggering factors for the onset and course of BD.