Familial and environmental risk factors in Parkinson's disease: a case-control study in north-east Italy

Background and objective– The aetiology of Parkinson's disease remains unknown, although both genetic susceptibility and environmental factors are considered putative contributors to its origin. We performed a case–control study to investigate the association of familial and environmental risk factors with Parkinson's disease (PD). Methods– We studied 136 patients with neurologist confirmed PD and 272 age- and sex-matched controls, affected by neurological diseases not related to PD. The risk of developing idiopathic PD associated with the following familial and environmental factors: positive family history of PD, positive family history of essential tremor (ET), age of mother at subject's birth, rural birth, rural living, well water use, farming as an occupation, exposure to pesticides, head tremor, exposure to general anaesthesia and to ionizing radiations, food restriction, concentration camp imprisonment and smoking has been assessed by using univariate and multivariate statistical techniques. Results– In the conditional multiple logistic regression analysis, positive family history of PD (OR 41.7, 95% CI 12.2–142.5, P < 0.0001), positive family history of ET (OR 10.8, 95% CI 2.6–43.7, P < 0.0001), age of mother at subject's birth (OR 2.6, 95% CI 1.4–3.7, P=0.0013), exposure to general anaesthesia (OR 2.2, 95% CI 1.3–3.8, P=0.0024), farming as an occupation (OR 7.7, 95% CI 1.4–44.1, P=0.0212) and well water use (OR 2.0, 95% CI 1.1–3.6, P=0.0308) exhibited a significant positive association with PD, whereas smoking showed a trend toward an inverse relationship with PD (OR 0.7, 95% CI 0.4–1.1, P < 0.06). Conclusions– We conclude that both familial and environmental factors may contribute to PD aetiology.