A recent study found that people over the age of 50 who suffer from anxiety are more than twice as likely to be diagnosed with Parkinson’s disease than those without anxiety. British Journal of General Practicehighlights that anxiety may be an early indicator of Parkinson’s disease and encourages further research into its implications for early diagnosis and treatment.
Parkinson’s disease is the second most common neurodegenerative disease in the world, and is predicted to affect more than 14 million people by 2040 due to increasing life expectancy. Early detection is essential for disease management, but early non-motor symptoms of Parkinson’s disease remain difficult to recognize. Anxiety, which is common in older adults, has been observed to precede Parkinson’s disease, but the exact relationship was unclear.
Previous studies have shown that people with anxiety are at higher risk of Parkinson’s disease, but factors such as lifestyle and socioeconomic status have not been fully taken into account. This study aimed to fill these gaps by investigating the association between new-onset anxiety and a subsequent diagnosis of Parkinson’s disease, while taking into account various confounding factors.
The researchers used data from the IQVIA Medical Research Database, which contains anonymized electronic health records from the Health Improvement Network (THIN), which contains information from over 700 general practices in the UK, representing a diverse patient population.
The study focused on individuals aged 50 to 99 years who were enrolled in participating medical centers between January 2008 and December 2018. Participants were divided into two groups: those newly diagnosed with anxiety disorders and those without anxiety disorders. Each person with an anxiety disorder was matched with four controls based on age and sex, creating a dynamic cohort that could switch from the control group to the anxiety group if they later developed an anxiety disorder.
To analyze the data, the researchers used survival regression models to estimate the risk of developing Parkinson’s disease over time, adjusting for factors such as age, sex, socioeconomic status, lifestyle choices (smoking, alcohol intake, BMI) and relevant health conditions (severe mental illness, head trauma, dementia). The models were built in a stepwise manner to explore associations while taking these variables into account.
The study included 38,510 men and 70,925 women who had a first-time experience of anxiety, and 324,670 men and 553,586 women without anxiety. During follow-up, 331 people in the anxiety group were diagnosed with Parkinson’s disease, with the average time to diagnosis being 4.9 years.
The incidence rate of Parkinson’s disease in the anxious group was 1.02 per 1,000 person-years compared with 0.49 per 1,000 person-years in the non-anxious group. After adjusting for confounding factors, anxious people were found to have more than twice the risk of developing Parkinson’s disease (hazard ratio 2.1). The study also identified several prodromal symptoms associated with Parkinson’s disease in anxious people, including sleep disorders, depression, fatigue, constipation, cognitive impairment, and certain motor symptoms such as tremor and rigidity.
Co-first author Juan Bazo Avares from University College London said: “Anxiety is known to be a hallmark of the early stages of Parkinson’s disease, but prior to our study, the future risk of Parkinson’s disease in people over 50 with new-onset anxiety was unknown. By understanding that anxiety and the aforementioned characteristics are associated with an increased risk of developing Parkinson’s disease over 50, we hope that we can detect the disease earlier and help patients get the treatment they need.”
Although the study offers valuable insights, it also has limitations. The data relied on electronic health records that are collected primarily for clinical purposes, which may lead to underreporting of mental illnesses due to bias or incomplete recording. This underreporting may mean that the actual association between anxiety and Parkinson’s disease is even stronger than observed.
Furthermore, the study participants were restricted to those aged 50 years or older, excluding younger people who may have a different risk profile. The findings may not be generalizable to other populations, particularly outside the UK or with different healthcare systems.
Future studies should aim to investigate the severity of anxiety and its impact on the risk of Parkinson’s disease. Understanding the specific mechanisms linking anxiety and Parkinson’s disease may lead to earlier detection and management strategies. Furthermore, investigating anxiety in conjunction with other prodromal symptoms may provide a more comprehensive understanding of the early stages of the disease.
“Anxiety has been less studied than other early symptoms of Parkinson’s disease,” says co-author Annette Schrag, “Further research should explore how the early onset of anxiety relates to other early symptoms and the underlying progression of early-stage Parkinson’s disease. This may lead to better treatment of the condition at its earliest stages.”
the study, “Risk of Parkinson’s disease in people aged 50 years or older with new-onset anxiety disorders: a retrospective cohort study in UK primary care.” was written by Juan Carlos Bazo Alvarez, Daniel Nimmons, Kate Walters, Eileen Petersen and Annette Schrag.
