The study included 140 patients with Parkinson's disease (PD) and 280 non-Parkinson age-matched controls to evaluate environmental risk factors associated with PD. The effect of exposure to environmental and dietary factors was determined using conditional logistic regression. This multivariate analysis showed that PD in first-degree relatives and tea drinking were the main risk factors for PD. Smoking appeared to be a protective factor. Exposure to toxic compounds was not a significant risk factor. Further research is needed to validate that tea consumption increases the risk of PD.
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