New-onset anxiety in adults aged 50+ doubles risk of developing Parkinson's disease

By Pooja Toshniwal PahariaReviewed by Danielle Ellis, B.Sc.Jun 27 2024

In a recent study published in The British Journal of General Practice, researchers investigated Parkinson's disease (PD) risk among individuals with new-onset anxiety and associated risk factors.

Background

Anxiety problems are common among older individuals, frequently beginning early in life and connected to cognitive impairment. PD has the second-highest prevalence rate among neurodegenerative disorders worldwide, causing symptoms of motor and non-motor type. Anxiety is more prevalent in PD patients, but the PD risk in individuals aged 50 years and above with incident anxiety is unclear.

Previous research indicating that anxiety or anxiolytic prescriptions increased the risk of developing Parkinson's disease failed to account for lifestyle characteristics, socioeconomic position, and prodromal aspects. The Health Professionals Follow-Up Study (HPFS) examined PD incidence over 12 years among male and predominantly White healthcare personnel.

About the study

In the present retrospective cohort study, researchers evaluated Parkinson's disease incidence among individuals aged 50 years and above presenting with and without anxiety. They also explored clinical signs and symptoms that may increase PD risk among anxious individuals.

The researchers examined primary care data from the United Kingdom from 2008 to 2018, focusing on individuals over the age of 50 who had experienced incident anxiety. They obtained IQVIA Medical Research Data (IMRD), comprising de-identified information of The Health Improvement Network (THIN), including routine electronic medical records collected using In Practice Systems (IPS) or Vision GP. The researchers also included general practice data meeting the acceptable mortality reporting (AMR) and acceptable computer usage (ACU) requirements.

Participants in THIN were 50 to 99 years old, enrolled in participating practices between January 1, 2008, and December 31, 2018, with records of one or more anxiety episodes in the general practitioner database following a year without previous anxiety episodes. During the first report of anxiety, the researchers paired each participant with four unexposed individuals, matching for gender and age. They used the incident and dynamic group approach or exposure density sampling, in which individuals could initially function as controls and may subsequently become exposed (if they acquire anxiety).

The researchers used Weibull survival regressions to predict the time to Parkinson's disease among individuals with anxiety and those without and determine PD risk in anxious individuals. They estimated the hazard ratios (HR), adjusting for sociodemographic variables and lifestyle behaviors [age, biological sex, body mass index (BMI), socioeconomic deprivation, smoking status, and alcohol use], and significant mental and physical health issues.

The researchers used survival estimations to plot the progression of patients with and without anxiety. They investigated the existence of PD risk and associated prodromal characteristics in the period between the diagnosis of anxiety and one year before PD diagnosis. They visually assessed proportional hazard assumptions for survival modeling. They accounted for missing covariate data by multiple imputations using chained equations.

Results

There were 70,925 women and 38,510 men diagnosed with their initial episode of anxiety, whereas the unexposed cohort comprised 553,586 women and 324,670 men. Sleep problems, constipation, exhaustion, and sadness were typical prodromal symptoms among anxious individuals. In total, 331 individuals with anxiety acquired Parkinson's disease during follow-up, with a median duration of five years between the initial anxiety episode and Parkinson's disease diagnosis. Parkinson's disease incidence rates among those with anxiety and without were 1.0 and 0.5 per 1,000 individual years, respectively.

After adjusting for age, gender, lifestyle characteristics, social deprivation, head trauma, severe mental disease, and dementia, the risk of Parkinson's disease doubled compared to the non-anxious group. In addition, non-anxious individuals lived longer without acquiring Parkinson's disease than anxious people did. Women (HR, 0.4) and individuals from the most impoverished socioeconomic backgrounds (HR, 0.6) had a lower PD risk.

Symptoms associated with Parkinson's disease development among anxious individuals were motor features such as tremors (HR, 21), rigidity (HR, 5.1), balance impairments (HR, 4.2), autonomic features such as low blood pressure (HR, 4.0), and constipation (HR, 2.6), sleep disturbances (HR, 2.2), cognitive impairment (HR, 1.8), fatigue (HR, 1.8), and depression (HR, 1.7).

Conclusion

The study findings showed that anxiety considerably elevates Parkinson's disease risk among individuals aged ≥50 years, with a two-fold increase in risk for those with anxiety as the initial presentation. Depression, sleep disruption, cognitive impairment, fatigue, hypotension, tremors, stiffness, constipation, and balance impairment increase Parkinson's disease risk.

Further research could determine the relationship between anxiety and other prodromal symptoms, which might lead to earlier diagnosis and better management of Parkinson's disease and an increased risk of PD in those over the age of 50.