Abstract
INTRODUCTION: Oxidative stress is proposed to be one of the potential mechanisms leading to neurodegeneration in Parkinson's disease. However, previous epidemiologic studies investigating associations between antioxidant vitamins, such as vitamins E and C and carotenoids, and PD risk have produced inconsistent results. OBJECTIVE: The objective of this work was to prospectively examine associations between intakes of antioxidant vitamins, including vitamins E and C and carotenoids, and PD risk. METHODS: Cases were identified in two large cohorts: the Nurses' Health Study and the Health Professionals Follow-up Study. Cohort members completed semiquantitative food frequency questionnaires every 4 years. RESULTS: A total of 1036 PD cases were identified. Dietary intakes of vitamin E and carotenoids were not associated with PD risk; the multivariable-adjusted relative risk comparing extreme intake quintiles were 0.93 (95% confidence interval: 0.75-1.14) and 0.97 (95% confidence interval: 0.69-1.37), respectively. Dietary vitamin C intake was significantly associated with reduced PD risk (relative risk: 0.81; 95% confidence interval: 0.65-1.01; p(trend) , 0.01); however, this result was not significant in a 4-year lag analysis. For vitamins E and C, intake from foods and supplements combined were also unrelated to PD risk. CONCLUSIONS: Our results do not support the hypothesis that intake of antioxidant vitamins reduces the risk of PD. © 2016 International Parkinson and Movement Disorder Society.