Background: The reported prevalence and incidence rates of PD were signific
antly lower in China than those in Western countries. People in China and T
aiwan have a similar ethnic background. Objective: To investigate the preva
lence, incidence, and mortality rate of PD in Taiwan. Methods: The authors
conducted a population-based survey using a two-stage door-to-door approach
for patients aged 40 years or older in Ilan, Taiwan. Patients were diagnos
ed with PD by having at least two of the four cardinal signs of parkinsonis
m and exclusion of seconddary parkinsonism. To identify new cases of PD aft
er the survey, patients with negative results of parkinsonism in the first
stage were matched to the information on clinical diagnosis of PD from the
Bureau of National Health Insurance toward the end of December 31, 1997. Al
l cases of PD were linked to the Taiwan mortality registration to ascertain
causes of deaths until December 31, 1999. Results: The participation rate
was 88.1% among the 11,411 contacted individuals. Thirty-seven cases of PD
were identified. The age-adjusted prevalence rate of PD for all age groups
was 130.1 per 100,000 population after being adjusted to the 1970 US census
, assuming no cases of PD would be found among those younger than 40 years
of age. Of 9972 non-PD subjects in the first screen, 15 new cases of PD wer
e ascertained. The age-adjusted incidence rate was 10.4 per 100,000 populat
ion for all age groups. The case fatality rate of PD after a 7-year follow-
up was 40.4% (21 deaths in 52 patients with PD). The relative risk of death
for PD cases versus non-PD cases was 3.38 (95% CI: 2.05-4.34). The 5-year
cumulative survival rate in PD cases (78.85%) was statistically lower than
that in non-PD cases (92.84%). Conclusion: The prevalence and incidence rat
es of PD in Taiwan were much higher than those reported in China, but close
r to those in Western countries. These results suggest that environmental f
actors may be more important than racial factors in the pathogenesis of PD.