Parkinson Disease and Cigarette Smoking: Conditional Logistic Regression Analysis on Data of Patients and Hospital Controls.

Abbreviations: OR = odds ratio, CI = confidence interval.
aThe adjusted model includes coffee consumption (in quartiles).
bThe first P value for trend was based on analyses with the exposure as a continuous variable including the persons from the reference category. The second p value for trend was based on analysis whereby the persons from the reference category are excluded.