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.