The Epidemiology of Parkinson’s Disease in an Australian Population

Abstract

A prevalence study of Parkinson’s disease (PD) was conducted in the rural town of Nambour, Australia. There were 5 cases of PD in a study population of 1207, yielding a crude prevalence ratio of 414 per 100,000 (95% confidence interval; 53–775). We performed a separate case-control study involving 224 patients with PD and 310 controls from South East Queensland and Central West New South Wales, to determine which factors 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 significant risk factor for PD (odds ratio = 1.8, p < 0.001). Hypertension, stroke and well water ingestion were inversely correlated with the development of PD. There was no significant difference between patients and controls for exposure to herbicides and pesticides, head injury, smoking or depression. The high prevalence of PD in Nambour may be explained by rural residency. However, the most significant risk factor for PD was a positive family hisotry. This demonstrates the need for improved understanding of the genetic nature of the disease.

Epidemiology and etiology of Parkinson’s disease: a review of the evidence

“…A similar Danish study also reported a weak association (standardized hospitalization ratio, SHR, 1.30, 95% CI 1.03-1.63) [354]. Among 29 case-control studies that studied rural living as an exposure, 11 reported an increased risk of PD [136,141,142,147,153,289,293,303,305,309,314] with ORs ranging between 1.5 and 4.9. One study reported an inverse association [350], whereas the others found no association [131, 143-146, 154, 291, 307, 311, 312, 315, 316, 321, 325, 356-358].…”

“…Two reported statistically imprecise ORs at 10.9 (95% CI 1.8-67.5) [355] and 8.7 (95% CI 1.5-52.0) [312]. Of the remaining 25 studies that examined well water in relation to PD, three reported a decreased risk [131,141,146], whereas the others found no association [136, 143-145, 154, 289, 292, 293, 300, 302, 307, 310, 311, 314, 315, 321, 325, 350, 351, 356-358].…”

“…Three hospital-based case-control studies reported increased PD risk related to previous depression with ORs between 1.54 and 3.01 [131,143,291]. Another hospital-based study [141] and a populationbased study [409] found no association. Obvious limitations of these studies are potential recall bias and reverse causation.…”

“…One study reported an OR of 7.0 (p value <0.05) [289] and another an OR of 10.9 (95% CI 2.5-48.0) [301]. The remaining 19 case-control studies that analyzed results from pesticide exposure overall reported no association [131,136,137,141,142,144,145,[305][306][307][308][309][310][311][312][313][314][315][316][317].…”

“…Three case-control studies [137,141,434], one with prospective data nested within the Leisure World Cohort, California [434], reported lower risk of PD in relation to hypertension (OR 0.3, 95% CI 0.2-0.4 [141]; OR 0.48, 95% CI 0.26-0.88 [137]; OR 0.71, 95% CI 0.56-0.89 [434]). …”