Ongoing increase in incidence and prevalence of multiple sclerosis in Newcastle, Australia: A 50-year study

Abstract

Background: Since 1959, multiple sclerosis (MS) prevalence has been estimated for the east coast Australian city of Newcastle. Previous surveys, conducted in 1988 and 2003, have described an increase in the prevalence and incidence of MS.

Objectives: In this study, we evaluated whether these trends continue and provide 50 years of MS epidemiological follow-up for this southern hemisphere city.

Methods: Expressed per 100,000 people, prevalence of MS in Newcastle was calculated for those with a confirmed diagnosis of MS on 9 August 2011 and incidence based on the number of cases with MS diagnosis made during the preceding decade. Data were age-standardised to the total Australian population. Statistical comparisons were undertaken using Poisson regression analysis.

Results: In 2011, the estimate of MS prevalence was 124.2, with female-to-male ratio reaching 3.1, a 53% increase in female predominance since 1996. MS incidence increased to 6.7, with a significantly higher proportion of new female cases since the previous survey.

Conclusion: Prevalence of MS in Newcastle has risen linearly and is contributed to by a substantial increase in new cases over the preceding decade. Female predominance of MS cases continues to increase with a new diagnosis three times more likely in women.

Keywords: Incidence; epidemiology; prevalence; sex ratio.