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

To update prevalence and incidence rates of MS among
Sardinians. Materials and methods ± The present work is a ``spider'' kind
of population based survey, conducted over the interval 1968±97, on
patients with MS (Poser criteria) living in the province of Sassari,
Northern Sardinia (454,904 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 annual incidence rate of 8.2 for the
period 1993±7 were found. Conclusion ± Repeated epidemiological
assessments of MS in Sardinia over decades have shown 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 substantial and
widely spread improvement in MS case ascertainment can be postulated
as the reason for such observations, a comparison between our data and
those recently reported from a more industrialized province in Northern
Italy seems to prove an at least partially real increase in MS risk among
Sardinians and favours the hypothesis of a MS ``Sardinian focus'' as
related to its latitude