Risk of Parkinson's disease following anxiety disorders: a nationwide population-based cohort study

Consistent with the results of previous observational studies and a dose dependent effect as well...

Eur J Neurol. 2015 May 29. doi: 10.1111/ene.12740. [Epub ahead of print]

Lin CH, Lin JW, Liu YC, Chang CH, Wu RM.

BACKGROUND AND PURPOSE:

Anxiety is potentially a pre-motor symptom of Parkinson's disease (PD). Our aim was to investigate the association between anxiety and subsequent PD risk in a population-based sample.

METHODS:

A total of 174 776 participants, who were free of prior PD, dementia and stroke, were enrolled from Taiwan National Health Insurance Research Database between 1 January 2005 and 31 December 2005. The association between anxiety at the beginning of the study and the incidence of PD was examined using a Cox regression model. Information regarding comorbidities, especially depression, and concomitant medication use was adjusted in the proportional hazards models.

RESULTS:

Over an average follow-up of 5.5 years, 2258 incident PD cases were diagnosed. After adjusting for age, sex, comorbidities and concomitant medication use, patients with anxiety were more likely to develop PD than subjects without anxiety [adjusted hazard ratio (HR) 1.38; 95% confidence interval (CI) 1.26-1.51]. Anxiety severity was dose-dependently associated with increased likelihood of PD: crude HR 1.27 (95% CI 1.11-1.44) for mild anxiety, 1.35 (95% CI 1.19-1.53) for moderate anxiety and 2.36 (95% CI 2.13-2.62) for severe anxiety (P < 0.0001). Results were similar after adjustment for age, sex, comorbid depression and other PD risk factors, and in the sensitivity analyses excluding participants with comorbid depression or with a PD diagnosis <3 years after anxiety diagnosis, and controlling for Charlson's scores.

CONCLUSIONS:

The likelihood of developing PD was greater amongst patients with anxiety than patients without anxiety, and the severity of anxiety correlated with risk of PD.