New-onset anxiety in adults aged 50 years and older may double the risk of Parkinson’s disease, according to a UK primary care retrospective cohort study published in the British Journal of General Practice. Led by researchers from University College London and other UK institutions, the study analyzed data encompassing electronic health records from UK primary care practices gathered between 2008 and 2018.
Methods
The study utilized a retrospective cohort design, leveraging the comprehensive IQVIA Medical Research Database, which includes de-identified data from The Health Improvement Network. This dataset provides a robust representation of UK primary care patients, covering demographics, socioeconomic factors, and health conditions.
Researchers identified individuals aged 50 years and older who received a first-time diagnosis of anxiety between January 1, 2008, and December 31, 2018, and had at least one year of previous data without an anxiety diagnosis. For each participant with anxiety, four age- and sex-matched control individuals without anxiety were selected from the same database. This exposure density sampling method ensured comparability between groups.
Results
The study cohort included a total of 109,435 individuals with new-onset anxiety and 878,256 age- and sex-matched controls without anxiety. Over the follow-up period, 331 individuals from the anxiety group and 1,357 individuals from the control group developed Parkinson’s disease.
The incidence rate of Parkinson’s disease was significantly higher in the anxiety group, with a rate of 1.02 per 1,000 person-years (95% confidence interval [CI] = 0.92 to 1.13), compared to 0.49 per 1,000 person-years (95% CI = 0.47 to 0.52) in the control group.
After adjusting for age, sex, socioeconomic status (measured by the Townsend index), lifestyle factors (including smoking, alcohol use, and body mass index), and relevant health conditions (such as severe mental illness, head trauma, and dementia), individuals with anxiety had a 2.1-fold increased risk of developing Parkinson’s disease compared to those without anxiety (hazard ratio [HR] = 2.1, 95% CI = 1.9 to 2.4).
Clinical features associated with an elevated risk of Parkinson’s disease among individuals with anxiety included depression (HR = 1.7, 95% CI = 1.1 to 2.5), sleep disturbances (HR = 2.2, 95% CI = 1.5 to 3.2), fatigue (HR = 1.8, 95% CI = 1.3 to 2.6), cognitive impairment (HR = 1.8, 95% CI = 1.1 to 3.1), hypotension (HR = 4.0, 95% CI = 1.7 to 9.7), tremors (HR = 21.3, 95% CI = 14.4 to 31.5), rigidity (HR = 5.1, 95% CI = 1.2 to 21.2), balance impairment (HR = 4.2, 95% CI = 2.1 to 8.3), and constipation (HR = 2.6, 95% CI = 1.9 to 3.6).
Limitations
While the study benefited from a large and representative dataset, limitations included potential under-reporting or misclassification of anxiety diagnoses in electronic health records, which could affect the accuracy of exposure measurement. Additionally, despite adjustments for various confounding factors, residual confounding cannot be entirely ruled out.
Conclusions
The study provides evidence that new-onset anxiety in individuals aged 50 years and older is associated with a significantly increased risk of developing Parkinson’s disease. The findings underscore the importance of recognizing anxiety as a potential prodromal symptom of Parkinson’s disease in clinical practice, potentially facilitating earlier diagnosis and intervention.
Further research is warranted to elucidate the underlying mechanisms linking anxiety and Parkinson’s disease, as well as to explore the implications for targeted screening and preventive strategies in at-risk populations.
The authors have declared no competing interests.