MS: Busting the Myths
May 29, 2025 | News
Multiple Sclerosis New Zealand, Multiple Sclerosis Auckland, the New Zealand Multiple Sclerosis Research Trust, and Rare Disorders NZ supported research conducted by COMPASS Research Centre that leveraged the Stats NZ Integrated Data Infrastructure (IDI) to research MS epidemiology. This research was led by Dr Natalia Boven, with the guidance of Associate Professor Vanessa Selak, Dr Deborah Mason, Professor Barry Milne, Dr Lisa Underwood, Mr Andrew Sporle, Professor Anna Ranta and Dr Julie Winter-Smith.
The IDI captures data about government services accessed (‘administrative data’), along with data from the Census and Stats NZ surveys. This data is linked at the individual level. The IDI operates under a framework to ensure that data confidentiality is maintained. Researchers are only able to access data that has been de-identified, meaning that potentially identifying information, such as names and NHI numbers, has been removed. More information about the IDI is available here: https://www.stats.govt.nz/integrated-data/integrated-data-infrastructure/
People likely to have been diagnosed with MS were identified using data on hospitalisations, disability support, pharmaceutical dispensing of disease-modifying therapies (DMTs), and interRAI needs assessments. In total, 4,860 people likely to have been diagnosed with MS and resident in Aotearoa New Zealand on 30 June 2022 were identified, yielding an estimated crude prevalence of 96.6 per 100,000 people. This is an increase from 72.4 per 100,000 from the national MS prevalence study conducted in 2006.
Characteristics of this cohort were broadly consistent with previous research in Aotearoa, suggesting that the cohort is not strongly biased. MS prevalence was much higher for women than men (145.1 per 100,000 vs 47.9 per 100,000), and there was a clear latitudinal gradient with higher rates of MS further South.
Estimated crude prevalence of MS was highest for the European ethnic group (132.4 per 100,000), followed by the Middle Eastern/Latin American/African (72.6), Māori (33.1), Asian (16.0) and Pacific Peoples (9.2) ethnic groups. Notably, the estimated crude prevalence of MS increased substantially for Māori, Pacific Peoples and Asian ethnic groups than from the 2006 national prevalence study (e.g. the crude prevalence of MS among Māori rose from 15.9 per 100,000 in 2006 to 33.1 per 100,000 in 2022).
There was evidence that people identifying with Māori and/or Pacific Peoples ethnic groups who were living in more deprived areas were less likely to have been diagnosed with MS, suggesting there may be barriers to accessing services to get a MS diagnosis for these groups. Further research is needed in this area to explore whether this is the case, and the nature of any barriers.
People with MS more commonly reported difficulties with mobility, self-care, cognition, vision, and communication than the general population, although this was not the case for hearing.
This research has been published by the New Zealand Medical Journal, and is available here (note that subscribing is free for individuals): https://nzmj.org.nz/journal/vol-138-no-1612/identifying-multiple-sclerosis-in-linked-administrative-health-data-in-aotearoa-new-zealand
The main strength of this approach is that the IDI contains data for the entire population of Aotearoa New Zealand, which allows researchers to study a relatively small population, such as people living with MS. The IDI also captures information across many domains of life (e.g. education, housing, benefits), allowing researchers to explore a wide range of research questions. The IDI is inherently longitudinal, with some data sets spanning many years.
There are important limitations of using the IDI to study MS, however. The IDI does not contain primary care or outpatient diagnostic data. This means that people with MS who only interacted with these services were excluded from this research (e.g. people who did not have any hospitalisations, did not receive disability support or interRAI needs assessments, and were not prescribed DMTs). Furthermore, people living with MS who have not been diagnosed could not be captured. Lastly, people who were misdiagnosed with MS at some point, and this was recorded in any of the aforementioned data sets, will have been included in the MS IDI cohort.
Multiple Sclerosis New Zealand has contracted COMPASS Research Centre to further this important IDI research, building on these findings. This research is possible thanks to funding from The New Zealand Multiple Sclerosis Research Trust.. This research is exploring the demographic and socioeconomic characteristics of those living with MS in Aotearoa, including geographic distribution, education, income, and employment history. This research is also examining access to disability support, allied healthcare, and income support. In addition to examining these characteristics at the national level, a key focus of this research is characterising local areas corresponding to the local MS societies. This will help inform both national and local support and advocacy activities.
Please feel free to contact Natalia Boven at Natalia.boven@auckland.ac.nz if you have any questions or comments about this research.
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