A cohort study on diet and the risk of Parkinson's disease: the role of food groups and diet quality.

Previous studies on individual foods and nutrients and Parkinson's disease (PD) risk have been inconsistent. Furthermore, only one study has examined the association between the quality of diet and PD. We investigated the prediction of food groups and diet quality on PD in the Finnish Mobile Clinic Survey (1966-72). The population comprised 4524 individuals, aged 40-79 years and free from PD at baseline. Data collection included health examinations, a questionnaire and a 1-year dietary history interview. A modified Alternate Healthy Eating Index was formed to assess diet quality. Statistical analyses were based on Cox's model. During a 41-year follow-up, eighty-five incident cases of PD occurred. No statistically significant associations were found between PD incidence and most of the food groups examined. A few exceptions were fruits and berries in men and milk in women, which showed positive associations. An inverse association between the intake of meat products and PD was found in women. The diet quality index did not predict PD, the adjusted relative risk between the highest and lowest quartiles being 1.83 (95 % CI 0.65, 5.18) in men and 0.97 (95 % CI 0.38, 2.48) in women. The present study suggests that since most of the single food groups or the quality of diet did not predict PD occurrence, the role of diet is apparently rather modest.

Prospective study of coffee consumption and risk of Parkinson's disease.

OBJECTIVE: To examine the prediction of coffee consumption on the incidence of Parkinson's disease. SUBJECTS AND METHODS: The study population comprised 6710 men and women, aged 50-79 years and free from Parkinson's disease at the baseline. At baseline, enquiries were made about coffee consumption in a self-administered questionnaire as the average number of cups per day. During a 22-year follow-up, 101 incident cases of Parkinson's disease occurred. Parkinson's disease cases were identified through a nationwide registry of patients receiving medication reimbursement, which is based on certificates from neurologist. RESULTS: After adjustments for age, sex, marital status, education, community density, alcohol consumption, leisure-time physical activity, smoking, body mass index, hypertension and serum cholesterol, the relative risk for subjects drinking 10 or more cups of coffee per day compared with non-drinkers was 0.26 (95% confidence interval 0.07-0.99, P-value for trend=0.18). The association was stronger among overweight persons and among persons with lower serum cholesterol level (P-value for interaction=0.04 and 0.03, respectively). CONCLUSIONS: The results support the hypothesis that coffee consumption reduces the risk of Parkinson's disease, but protective effect of coffee may vary by exposure to other factors.