Multiple sclerosis epidemiology in Sardinia: evidence for a true increasing risk

Objectives - To update prevalence and incidence rates of MS among Sardinian s. Materials and methods - The present work is a "spider" kind of populatio n based survey, conducted over the interval 1968-97, on patients with MS (P oser criteria) living in the province of Sassari, Northern Sardinia (454,90 4 population). Results - A crude total prevalence rate of 144.4 per 100,000 , an onset-adjusted prevalence rate of 149.7 per 100,000 and an average ann ual incidence rate of 8.2 for the period 1993-7 were found. Conclusion - Re peated epidemiological assessments of MS in Sardinia over decades have show n that the island is at high risk for MS. The present work highlights that MS incidence in Sardinia has been increasing over time. Although a substant ial and widely spread improvement in MS case ascertainment can be postulate d as the reason for such observations, a comparison between our data and th ose recently reported from a more industrialized province in Northern Italy seems to prove an at least partially real increase in MS risk among Sardin ians and favours the hypothesis of a MS "Sardinian focus" as related to its latitude.