Prevalence survey of multiple sclerosis in the Australian Capital Territory.

AIM: This study sought to obtain an estimate of the prevalence of multiple sclerosis (MS) in the Australian Capital Territory (ACT), a largely urban region that differs climatically and socioeconomically from other Australian cities examined in previous MS surveys. METHODS: Prevalence day was chosen to coincide with the 1996 National Census. All ACT neurologists' records for the previous 5 years were examined and cases of MS were classified according to the published diagnostic criteria of Rose et al. and Poser et al. RESULTS: By the criteria of Rose et al., as used in previous Australian surveys of MS, prevalence was 79.9/100,000 (95% confidence interval (CI) = 63.4-99.2) for females, 32.8 (22.7-46.2) for males and 56.7 (43.1-74.1) for all people, standardized to the 1996 population. Standardized to the 1981 population for direct comparison with 1981 surveys in New South Wales, the prevalence of MS in the ACT was still unexpectedly high, particularly for females. Using the criteria of Poser et al., the prevalence of MS standardized to the 1996 population was 70.6/ 100,000 (95% CI = 58.4-85.3) for females, 28.0 (20.3-37.8) for males and 49.5 (42.2-58.2) for all people. There was evidence from a relatively short duration of disease in the ACT sample that some persons with long-standing MS had been missed in the survey and therefore that the prevalence of MS observed in the ACT was an underestimate. CONCLUSIONS: The survey found an unexpectedly high prevalence of MS in the ACT. Possible reasons for this are discussed. There was no evidence that the advent of magnetic resonance imaging had increased the numbers of persons diagnosed with MS in the present survey.

Prevalence of Huntington disease in New South Wales in 1996.

OBJECTIVE: To estimate the prevalence of Huntington disease (HD) in New South Wales on Australian Census Day (6 August) 1996. DESIGN: Survey of records of the Huntington Disease Service and major hospitals, and of neurologists, psychiatrists, clinical geneticists and genetic counsellors. SUBJECTS AND SETTING: All patients in NSW who, on Census Day 1996, either had a definite diagnosis of HD (motor signs of chorea or ataxia and family history of HD or positive DNA test result) or would have had signs and later received a definite diagnosis (assessed 1 April 1997 to 1 July 1999). MAIN OUTCOME MEASURES: Prevalence (HD patients per 100,000 population); patient characteristics; year and basis of diagnosis. RESULTS: 380 patients with definite HD were identified, giving a prevalence of HD in NSW in 1996 of 6.29 per 100,000 population (95% CI, 5.68-6.96). A third of HD patients were aged 60 years or older. Diagnosis was confirmed by DNA testing for 171 patients (45%), including 30 (8%) with no recorded family history. Average numbers of new diagnoses per year were 11.8 (1984-1988), 21.8 (1989-1993) and 28.6 (1994-1998). Estimated number of people with a 50% risk of inheriting the HD mutation was 25.2 per 100,000 population. Estimated incidence of HD in 1996 was 0.65 per 100,000 population. CONCLUSIONS: Prevalence of HD in NSW is similar to estimated prevalence in other Australian and Western populations. Increasing numbers of cases are being diagnosed, and the 18 chronic care beds currently designated for HD patients in NSW are unlikely to be sufficient.