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Published on: December 9, 2015
[Epidemiology of multiple sclerosis in Japanese: with special reference to opticopsinal multiple sclerosis]
1Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University.
Abstract:
The fourth nationwide survey of multiple sclerosis (MS) disclosed that the estimated number of MS patients in Japan was 9,900, and the estimated prevalence rate of MS is 7.7 per 100,000, indicating that the number of MS patients has been rapidly increasing for the past 30 years. The demographic features of the present series were compared with those of the three past nationwide surveys. The ratio of female to male patients has increased from 1.3 to 2.9. As to distribution of age at onset, in 2004, the peak of the age at onset curve shifted from the 30s to 20s and the second peak at 50s seen in the 1989 survey disappeared this time. About 60% were conventional MS (CMS) while 20% were opticospinal MS (OSMS) plus optic-brainstem-spinal MS (OBSMS). The female to male ratio was significantly greater in OSMS than in CMS, and age at onset was also significantly higher in OSMS than in CMS in both male and female. By distribution of age at onset, CMS showed a single peak in the early 20s while OSMS showed the highest peak in the early 20s and a second peak in the 30s. Both visual impairment at onset and severe visual impairment during the course have decreased to about half of those found in the first survey, while frequencies of both quadriparesis and transverse myelitis considerably decreased in 2004 compared to 1989 in addition to a decrease of visual impairment. Disease progression was significantly faster with advancing age at onset. In respect to the McDonald criteria, dissemination in space was fulfilled in 45.5% in CMS while only in 8.2% in OSMS patients. Spinal cord lesions were found in more than 90% of OSMS and 70% of CMS patients. Longitudinally extensive spinal cord lesions extending over 3 vertebral segments were detected in 41.2% of OSMS and 16.7% of CMS patients. In conclusion, the fourth nationwide survey disclosed significant changes in the prevalence and demographic features of MS in the Japanese population.
Insights
Multiple sclerosis (MS) prevalence in Japan has risen significantly, with a notable increase in female patients and a shift in age of onset. Opticospinal MS (OSMS) shows distinct demographic and clinical features compared to conventional MS (CMS).
Area of Science:
- Neurology
- Epidemiology
- Public Health
Background:
- Multiple sclerosis (MS) is a chronic neurological disease with varying prevalence and demographic patterns globally.
- Understanding temporal trends in MS prevalence and patient characteristics is crucial for public health planning and resource allocation.
- Previous nationwide surveys in Japan have provided insights into MS epidemiology, but recent data is needed to assess current trends.
Purpose of the Study:
- To report the findings of the fourth nationwide survey on multiple sclerosis (MS) in Japan.
- To compare current demographic features of MS patients with data from previous surveys.
- To analyze changes in clinical presentation, disease progression, and lesion characteristics over time.
Main Methods:
- Conducted the fourth nationwide survey of MS patients in Japan.
- Collected demographic data, including age at onset, sex, and clinical subtypes (conventional MS [CMS], opticospinal MS [OSMS], optic-brainstem-spinal MS [OBSMS]).
- Compared findings with data from three previous nationwide surveys (1970s, 1980s, 1990s).
- Utilized McDonald criteria for diagnosis and analyzed lesion distribution (spinal cord, dissemination in space).
Main Results:
- Estimated MS prevalence in Japan is 7.7 per 100,000, with approximately 9,900 patients, indicating a rapid increase over 30 years.
- The female-to-male ratio increased from 1.3 to 2.9; the peak age of onset shifted from the 30s to the 20s.
- Opticospinal MS (OSMS) demonstrated a higher female-to-male ratio and later age of onset compared to conventional MS (CMS).
- Visual impairment at onset and during the course decreased significantly; quadriparesis and transverse myelitis frequencies also decreased.
- Disease progression was faster with advancing age at onset.
- Spinal cord lesions were prevalent (>90% in OSMS, >70% in CMS), with longitudinally extensive lesions more common in OSMS (41.2%).
Conclusions:
- The fourth nationwide survey reveals significant shifts in MS prevalence and demographic features in Japan.
- Changes include an increasing prevalence, a higher female predominance, and an earlier age of onset.
- Distinct clinical and radiological characteristics differentiate OSMS from CMS, highlighting the need for subtype-specific management strategies.
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