Bell's palsy preceding Parkinson's disease: a case-control study.

We investigated the association of Bell's palsy (BP) with the subsequent risk of Parkinson's disease (PD) using a case-control study design. We matched 196 incident cases of PD in Olmsted County, MN, to 196 general population controls with same age (+/-1 year) and sex, and we reviewed the complete medical records of cases and controls in a medical records-linkage system to detect BP. Six of the 196 patients with PD and none of the 196 controls were diagnosed with BP before PD (exact binomial probability, P = 0.02). The median age at occurrence of BP was 49.5 years (range, 15-84 years) and the median time between BP and the onset of PD was 27.5 years (range, 2-54 years). The findings were similar using a standardized incidence ratio (SIR) approach, but were not statistically significant. This initial association between BP and PD awaits replication. Copyright 2009 Movement Disorder Society.