Longitudinal Epidemiology of Multiple Sclerosis over 60 Years in Newcastle, Australia: 1961 to 2021

INTRODUCTION:Newcastle, Australia, has been serially studied for MS epidemiology since 1961, showing consistently increasing prevalence estimates and incidence rates, including to our 2011 study. OBJECTIVES:To assess the 2011-2021 epidemiology of MS in Newcastle and to compare with previous measures. METHODS:Demographic and clinical data were extracted from medical records of MS cases residing in Newcastle, as identified by public and private clinicians. Prevalence (2011 and 2021) and incidence rates (2011-2021, from onset and from diagnosis) and mortality rate (2011-2021) were estimated and age-standardised to the 2021 Australian population. RESULTS:The 2021 prevalence was 173.1/100,000 (age-standardised = 178.7/100,000, F/M-sex-ratio = 3.3), a 42.2 % increase from 2011 (F/M-sex-ratio = 3.1), 175.0 % from 1996 (F/M-sex-ratio = 2.6), and 831.0 % from 1961 (F/M-sex-ratio = 1.2). The 2011-21 age-standardised onset incidence rate was 3.5/100,000 person-years (F/M-sex-ratio = 2.8), a 68.7 % increase from 1971 to 81 (F/M-sex-ratio = 1.1) and 44.5 % from 1986 to 96 (F/M-sex-ratio = 2.3). The age-standardised diagnosis incidence rate was 6.1/100,000 (F/M-sex-ratio = 2.2), statistically unchanged from that in 2001-2011 (6.8/100,000, F/M-sex-ratio = 3.2). The 2011-21 mortality rate was 2.1/100,000 person-years (2.2 age-standardised, F/M-sex-ratio = 1.4), with a standardised mortality ratio of 1.6. CONCLUSION:The Newcastle region continues to be a high frequency zone for MS. The incidence rate from onset is significantly increased from previous estimates, but incidence rate from diagnosis is stable. Prevalence and incidence sex ratios have stabilised at roughly 3.0, similar to other Australian sites.