Changes in Prevalence and Incidence of Parkinson’s Disease in Japan during a Quarter of a Century

Abstract

Background/Aim: To determine the prevalence and incidence of Parkinson’s disease (PD) and compare them with results from our previous studies. Methods: We examined epidemiological characteristics of PD patients using a service-based study in Yonago City, and a door-to-door study in Daisen Town. The prevalence days were April 1, 2004 in Yonago, and April 1, 2003 in Daisen. Results: In Yonago, we identified 254 PD patients. The crude prevalence was 180.3 (95% CI, 158.1–202.4) per 100,000 population. The adjusted prevalence was 145.8 (95% CI, 145.2–146.5) in 1980, 147.0 (95% CI, 146.3–147.6) in 1992, and 166.8 (95% CI, 166.1–167.5) in 2004, when calculated using the Japanese population in 2004. The crude incidence was 18.4 (95% CI, 11.3–25.5) per 100,000 population per year. The crude incidence in 1980 was 10.2 (95% CI, 4.6–15.8), and the adjusted incidence was 9.8 (95% CI, 4.3–15.3) in 1992, and 10.3 (95% CI, 4.7–15.9) in 2004, when calculated using the population in Yonago in 1980. In Daisen, there were 21 PD patients. The crude prevalence was 306.6 (95% CI, 175.7–437.6) and the adjusted prevalence was 192.6 (95% CI, 191.9–193.8). Conclusions: The prevalence of PD had increased, primarily because the population had aged. Differences in prevalence between these adjacent areas may have resulted from differences in the methods of investigation.