Incidence of multiple sclerosis among European Economic Area populations, 1985-2009: the framework for monitoring

Abstract

Background: A debate surrounding multiple sclerosis epidemiology has centred on time-related incidence increases and the need of monitoring. The purpose of this study is to reassess multiple sclerosis incidence in the European Economic Area.

Methods: We conducted a systematic review of literature from 1965 onwards and integrated elements of original research, including requested or completed data by surveys authors and specific analyses.

Results: The review of 5323 documents yielded ten studies for age- and sex-specific analyses, and 21 studies for time-trend analysis of single data sets. After 1985, the incidence of multiple sclerosis ranged from 1.12 to 6.96 per 100,000 population, was higher in females, tripled with latitude, and doubled with study midpoint year. The north registered increasing trends from the 1960s and 1970s, with a historic drop in the Faroe Islands, and fairly stable data in the period 1980-2000; incidence rose in Italian and French populations in the period 1970-2000, in Evros (Greece) in the 1980s, and in the French West Indies in around 2000.

Conclusions: We conclude that the increase in multiple sclerosis incidence is only apparent, and that it is not specific to women. Monitoring of multiple sclerosis incidence might be appropriate for the European Economic Area.

Figure 1

Attrition flow towards study selection.

Figure 2

Geographical distribution of MS surveys included in age-specific incidence analysis (top) and time trends (bottom).

Figure 3

Age-and sex-specific incidences of selected EEA surveys.

Figure 4

Time trends of reported MSI in the following EEA populations: (left) Nordic; (centre) Italian, Greek, and French Caribbean; (right) French mainland and Spanish.

Figure 5

Data based on age at or year of MS diagnosis.

Figure 6

Outline of the framework for registry-based MS monitoring on different EEA populations, assuming stable annual MSI (N onsets per year) and MS diagnostic improvement secondary to synergistic effects of improved access to neurological expertise (NE), CSF oligoclonal bands, neurophysiological tests and visual evoked potentials (CSF-EP), and magnetic resonance imaging (MRI).