Parkinson's disease risks associated with dietary iron, manganese, and other nutrient intakes

Background: Dietary influences on oxidative stress have been thought to play important role in the etiology of PD. Objective: To examine associations of PD with dietary nutrients, including minerals, vitamins, and fats. Methods: A population-based case-control study was conducted among newly diagnosed case (n = 250) and control subjects ( n = 388) identified between 1992 and 2002 from enrollees of the Group Health Cooperative health maintenance organization in western Washington state. Controls were frequency matched to cases on sex and age. In-person interviews elicited data on food frequency habits during most of adult life. Nutrient intakes were calculated and analyzed by adjusting each person's nutrient intake by their total energy intake ( the nutrient density technique). Results: Subjects with an iron intake in the highest quartile compared with those in the lowest quartile had an increased risk of PD ( odds ratio = 1.7, 95% CI: 1.0, 2.7, trend p = 0.016). There was an apparent joint effect of iron and manganese; dietary intake above median levels of both together conferred a nearly doubled risk compared with lower intakes of each nutrient ( odds ratio = 1.9, 95% CI: 1.2, 2.9). No strong associations were found for either antioxidants or fats. Conclusion: A high intake of iron, especially in combination with high manganese intake, may be related to risk for PD.