Epidemiology and Geographical Variation of Myasthenia Gravis in the Province of Pavia, Italy

Abstract

Background and Aims: Previous studies have reported a prevalence estimate of myasthenia gravis (MG) from 7.7 to 11.1 per 100,000 inhabitants in Europe. Moreover, the study of the geographical distribution of MG should be useful to generate specific hypotheses. The aims are to estimate MG prevalence and to investigate its geographical variation in a delimited area in Northern Italy. Methods: The primary source of data was the MG database of the Neurological Institute of Pavia and all other sources of case collection in and outside the province. We adopted a Bayesian approach to analyze MG geographical variation within the finest geographical grid. Results: We identified 119 live MG prevalent cases resident in the province of Pavia on December 31, 2008. The overall crude prevalence was 24 per 100,000 inhabitants. The Bayesian analysis identified a small cluster of higher MG prevalence in the northern area of the province. Conclusions: The estimated MG prevalence sets the province of Pavia among the high-risk areas. The identification of high/low MG risk areas deserves further investigation of genetic and environmental factors possibly related to a major risk of the disease in that area.

Geographical Distribution of Myasthenia Gravis in Northern Europe - Results from a Population-Based Study from Two Countries

“…Number of patients 1 6 -1 9 2 0 -2 9 3 0 -3 9 4 0 -4 9 5 0 -5 9 6 0 -6 9 7 0 -7 9 > 8 0 1 6 -1 9 2 0 -2 9 3 0 -3 9 4 0 -4 9 5 0 -5 9 6 0 -6 9 7 0 -7 9 > 8 0 1 6 -1 9 2 0 -2 9 3 0 -3 9 4 0 -4 9 5 0 -5 9 6 0 -6 9 7 0 -7 9 > 8 0 1 6 -1 9 2 0 -2 9 3 0 -3 9 4 0 -4 9 5 0 -5 9 6 0 -6 9 7 0 -7 9 > 8 0 1 6 -1 9 2 0 -2 9 3 0 -3 9 4 0 -4 9 5 0 -5 9 6 0 -6 9 7 0 -7 9 > 8 0 1 6 -1 9 2 0 -2 9 3 0 -3 9 4 0 -4 9 5 0 -5 9 6 0 -6 9 7 0 -7 9 > 8 0 1 6 -1 9 2 0 -2 9 3 0 -3 9 4 0 -4 9 5 0 -5 9 6 0 -6 9 7 0 - We did not find any prevalence or clinical differences in thymoma MG between the Norway and the Netherlands. Thymoma occurrence rates were similar to other population-based studies in northern as well as in southern Europe, estimated to be around 10% [2,3,33] . The prevalence rate found is exactly the same as it was in the Netherlands in 2000 [5] .…”

“…The studied area in the Netherlands is characterized by a high population density and urbanity, with large cities and an airport. Two recent studies examining the geographical variation have found more prevalent MG cases in the urban areas compared to the rural areas [2,45] . One could speculate whether the urban differences reflect individual behavior or exposure of exogenous environmental factors like, for example, air pollution influencing the disease development.…”

“…In Europe, the highest prevalence rate is reported from Serbia (317/million inhabitants) and Spain (328/million inhabitants) and the highest an- [2,11,28] . When reviewing population-based European MG prevalence studies from the latest decade, one could suspect lower prevalence rates in northern Europe [1] than southern Europe [3,28] , but the assessments are hampered by a lack of uniformity of inclusion criteria and small sample sizes.…”

“…Myasthenia gravis (MG) is an autoimmune neuromuscular disorder with a prevalence of 77-317/million inhabitants in Europe [1][2][3][4][5][6] . The disease occurs predominantly in adults and the typical clinical symptoms are ocular, bulbar, or generalized weakness and fatiguability.…”

Prevalencia de miastenia gravis en la comarca de Osona (Barcelona, Cataluña)

“…La prevalencia descrita de MG oscila entre 5 y 24 casos por 100.000, representando los mayores de 65 años menos del 50% del total 7,8 . Estos estudios están realizados en grandes poblaciones o bien sobre diagnósticos del sistema de salud, circunstancias que pueden dificultar la correcta identificación de los casos para el cálculo de la prevalencia.…”