MS Prevalence Study

History

In the early 2000s the most recent figures at the time on MS prevalence were 20 years old—thus the true incidence of MS in this country was unknown. Estimates ranged from 25 to 70 cases per 100,000 New Zealanders, so providing an accurate measure of the incidence of the condition would have a significant impact on policies and services affecting people and families affected by MS.

Furthermore, as this study was the first of its type involving a whole country it aimed to provide data of interest worldwide, particularly with regards to possible relationships between MS and latitude, and whether exposure to ultraviolet radiation in childhood may influence the later onset of the condition.

In 2004 the MS Society signed a Memorandum of Understanding with the Health Research Council of New Zealand to share the cost of funding a national MS Prevalence Study. A contract was signed between the HRC and Otago University’s Christchurch School of Medicine and Health Sciences who undertook the study.

The full study got underway in early 2006 coinciding with the 2006 Census Study. Auckland and Christchurch were the first regions covered in the study, and investigators were to finish their travels throughout the country by the end of 2006. Interim results were released on 7 August 2006. Results of the study were published on 31 January 2008.

Key Findings

Results from the Prevalence Study have been used to support a number of research papers and advocacy campaigns.

Numbers of PwMS

The study identified 2,896* people with MS living in New Zealand on census day (7 March 2006). Of the 2,896 people with MS, 2,176 (75%) were women and 720 (25%) were men; giving a female to male ratio of 3:1.

• The overall prevalence of MS in NZ is 71.9 per 100,000.

*Note: This figure was later increased to 2,917 people living with MS in New Zealand when the results were later re-analysed.

Gender

For males the age-standardised prevalence is 37.0 per 100,000 (34.3 to 39.7). For females the age-standardised prevalence is 104.3 per 100,000 (99.9 to 109).

Ethnicity

Maori have a substantially lower prevalence rate than NZ Europeans as reported in previous studies. Of the 2896 people with MS we identified only 61 who classified themselves as Maori.\

• For Maori the age-standardised prevalence of MS was 17.5 (12.7 to 22.4)

Geographical Gradient

The results suggest a gradient in prevalence, with the age-standardised prevalence increasing from north to south.

One interesting and unexpected finding was that while the age standardised prevalence of relapsing remitting multiple sclerosis (RRMS) and secondary progressive multiple sclerosis (SPMS) showed a latitudinal gradient. This gradient was not as clearly seen in patients with primary progressive multiple sclerosis (PPMS).

Employment

Results of this study showed that MS directly influenced the work force status of New Zealander’s within the working age (25-64 years) population living with the diagnosis:

• 54.6% were not working despite 90% having a work history (NZ overall average 22%)
• At least 67% had changed their work status due to the effects of MS, most within the first 4 years of diagnosis.
• The effect is significantly greater for females.
• The median annual personal income was NZ$20,000, compared with NZ$34,750 for the general NZ population.
• Income sources showed that over 30% were receiving an Invalid’s Benefit compared with 3% of the NZ population.

Further Information

About the MS Prevalence Study
Prevalence of Multiple Sclerosis in New Zealand
Interim results announced August 2006
Innovative Work to Increase Knowledge and Understanding of Multiple Sclerosis – Speech from Hon. Ruth Dyson, Minister for Disability Issues, 7 August 2006
Press Release

Research Papers

Multiple Sclerosis in NZ – S. Alla and D. Mason – September 2013
The Increasing Prevelance of Multiple Sclerosis in New Zealand – S. Alla, J. Pearson, L. Debernard, D. Miller and D. Mason – 15 December 2013
Multiple Sclerosis in New Zealand Maori – J. Pearson, S. Alla, G. Clarke, B. Taylor, D. Miller, A. Richardson, D. Mason – 11 May 2014 – Sage Publications Online