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Original research
Increasing incidence and prevalence of multiple sclerosis in the Greater Hobart cohort of Tasmania, Australia
  1. Steve Simpson-Yap1,2,3,
  2. Roberts Atvars4,
  3. Leigh Blizzard3,
  4. Ingrid van der Mei3,
  5. Bruce V Taylor3
  1. 1 Neuroepidemiology Unit, Melbourne School of Population & Global Health, The University of Melbourne, Melbourne, Victoria, Australia
  2. 2 Clinical Outcomes Research Unit (CORe), Royal Melbourne Hospital, The University of Melbourne, Melbourne, Victoria, Australia
  3. 3 MS Flagship, Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
  4. 4 Royal Hobart Hospital, Hobart, Tasmania, Australia
  1. Correspondence to Dr Steve Simpson-Yap, The University of Melbourne School of Population and Global Health, Melbourne, Victoria, Australia; steve.simpsonyap{at}


Background The Greater Hobart region (42.5°S) of Tasmania has consistently had the highest recorded prevalence and incidence rates of multiple sclerosis (MS) in Australia. We reassessed MS epidemiology in 2009–2019 and assessed longitudinal changes over 68 years.

Methods Cases recruited from clinic-based datasets and multiple other data sources. 2019 prevalence and 2009–2019 annual incidence and mortality rates estimated, and differences assessed using Poisson regression.

Results 436 MS cases resident on prevalence day were identified, and 130 had symptom onset within 2009–2019. Prevalence 197.1/100 000 (95% CI 179.4 to 216.5; 147.2/100 000 age standardised, 95% CI 126.5 to 171.3), a 36% increase since 2001 and 3.1-fold increase since 1961. 2009–2019 incidence rate=5.9/100 000 person-years, 95% CI 5.0 to 7.0 (6.1/1000 000 age standardised, 95% CI 4.7 to 7.9), a 2.8-fold increase since 1951–1961 and 65% since 2001–2009. 2009–2019 mortality rate=1.5/100 000 person-years, 95% CI 1.1 to 2.2 (0.9/100 000 age standardised, 95% CI 0.4 to 1.7), comparable to 2001–2009 (1.0/100 000) but reduced by 61% from 1951 to 1959 (2.1/100 000). 2001–2009 standardised mortality ratio=1.0 in 2009–2019, decreased from 2.0 in 1971–1979. Female:male prevalence sex ratio was 2.8, comparable to the 2009 value (2.6); incidence sex ratio (2.9) increased from 2001 to 9 (2.1). Comparisons with Newcastle, Australia (latitude=32.5°S) demonstrate a near complete abrogation of the latitudinal gradients for prevalence (ratio=1.0) and incidence (ratio=1.1), largely attributable to changing Hobart demography.

Conclusions Prevalence and incidence of MS continue to increase significantly in Hobart, alongside marked reductions in mortality and increased case longevity. The marked increase in incidence is of particular note and may reflect longstanding changes in MS risk behaviours including changing sun exposure, obesity rates, and smoking behaviours, particularly in females. Falling mortality contributes to increase longevity and prevalence, likely reflecting improved overall MS healthcare and implementation of disease-modifying therapy.


Data availability statement

Data are available on reasonable request.

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Data availability statement

Data are available on reasonable request.

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  • Contributors SS-Y: data management, statistical analysis, manuscript drafting; RA: collected data, data management, critical review; LB: statistical guidance, critical review; IvdM: critical review; BVT: project conception, critical review; All authors have reviewed the article and approve it for submission. BVT accepts full responsibility for the work and/or the conduct of the study, had access to the data, and controlled the decision to publish.

  • Funding The Multiple Sclerosis Research Flagship is supported by a grant from the Australian Medical Research Future Fund: Emerging Priorities and Consumer Driven Research.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.