THE EPIDEMIOLOGY OF PARKINSONS-DISEASE IN AN AUSTRALIAN POPULATION

A prevalence study of Parkinson's disease (PD) was conducted in the ru ral town of Nambour, Australia. There were 5 cases of PD in a study po pulation of 1207, yielding a crude prevalence ratio of 414 per 100,000 (95% confidence interval; 53-775). We performed a separate case-contr ol study involving 224 patients with FD and 310 controls from South Ea st Queensland and Central West New South Wales, to determine which fac tors increase the risk for PD in Australia. A positive family history of PD was the strongest risk factor for the development of the disease (odds ratio = 3.4; p < 0.001). In addition, rural residency was a sig nificant risk factor for PD (odds ratio = 1.8, p < 0.001). Hypertensio n, stroke and well water ingestion were inversely correlated with the development of PD. There was no significant difference between patient s and controls for exposure to herbicides and pesticides, head injury, smoking or depression. The high prevalence of PD in Nambour may be ex plained by rural residency. However, the most significant risk factor for PD was a positive family history. This demonstrates the need for i mproved understanding of the genetic nature of the disease.