Large study ties early depression symptoms to higher Parkinson’s risk
Researchers urge monitoring of mental health and metabolic factors
Written by |
- A large study links early depressive symptoms to an increased risk of developing Parkinson’s, particularly for those with high genetic susceptibility.
- Metabolic changes involving fats appear to partly explain the connection between preclinical depression and Parkinson's disease risk.
- Monitoring depressive symptoms and metabolic factors may help identify high-risk individuals for earlier detection, per the researchers.
People with depressive symptoms may have higher odds of developing Parkinson’s disease, a large study suggests, with the researchers noting a potentially greater risk among those with stronger genetic susceptibility to the neurological condition.
The findings also point to changes in fat metabolism — one of several “metabolic disturbances” that the team says has been “independently associated with both depressive symptoms and [the development of Parkinson’s]” — as a possible link between the disease and these signs of depression. The researchers noted that “genetic factors also play a well-established role in [Parkinson’s] susceptibility.”
Overall, the study “demonstrates that even subthreshold depressive symptoms … are associated with a higher risk” of Parkinson’s, the researchers wrote. Still, the team noted that they could not definitively determine whether depression is a true independent risk factor for Parkinson’s or an early manifestation of the disease.
“Our results extend previous evidence linking clinical depression with [Parkinson’s] risk by focusing on preclinical depressive symptoms, which are more prevalent in the general population yet have been less studied in relation to [Parkinson’s],” the researchers wrote.
The study, “Association of pre-clinical depressive symptoms and its plasma metabolomic signature with Parkinson’s disease: a community-based longitudinal study,” was published in the journal Translational Psychiatry.
A progressive disease, Parkinson’s is caused by the loss of dopaminergic neurons, which are the nerve cells that produce dopamine, a brain signaling molecule involved in movement. In addition to its hallmark motor symptom of tremor, people with Parkinson’s may experience nonmotor symptoms, including mental health problems such as depression.
36% higher risk of Parkinson’s found with depressive disorders
Previous studies have also suggested that people diagnosed with depression may have a higher risk of developing Parkinson’s. However, it is less clear whether milder depressive symptoms preceding a formal diagnosis of depression may also be an early sign or risk factor for Parkinson’s.
In this study, researchers in China and Sweden aimed to clarify the extent to which depressive symptoms increase the risk of Parkinson’s development and whether this association varies according to genetic predisposition for the disease.
For that, they analyzed data from 451,922 people without Parkinson’s taking part in the UK Biobank, a large-scale biomedical database. Among the participants, 5.9% had a possible depressive disorder. That was defined as a score of three or higher on the two-item Patient Health Questionnaire, used by healthcare workers to screen and track the severity of mental health conditions such as depression and anxiety.
Those with possible depression were more likely to be younger, female, and of non-white race, the data showed. The researchers noted these individuals more frequently had less education, more irregular physical activity, and less sleep duration. They also were more likely to have other conditions such as diabetes, cardiovascular diseases, and a previous history of depression.
During a median follow-up of 14.6 years, 3,108 participants (0.7%) developed Parkinson’s: 194 who had possible depression and 2,914 who did not.
After adjusting for multiple factors, analyses showed that individuals with a possible depressive disorder had a 36% higher risk of developing Parkinson’s than those without.
Metabolism changes may partly explain link
Participants with a high genetic risk score had odds of developing Parkinson’s that were more than double those seen in those with lower genetic susceptibility, the researchers found. Possible depressive disorder was associated with a higher Parkinson’s risk in both groups, but the highest risk — a 2.15 times increase — was seen among participants who had both possible depressive disorder and a high genetic risk.
The researchers also found evidence that metabolic changes may partly explain the link between depressive symptoms and Parkinson’s. Of 249 blood metabolites analyzed, 21 were associated with both depressive symptoms and Parkinson’s development.
These metabolites — small molecules that can reflect changes in the body’s metabolism — were mainly fatty molecules, such as cholesterol, fatty acids, triglycerides, and lipoproteins. A metabolic signature based on these 21 substances appeared to account for 15% of the association between depression and Parkinson’s, the researchers noted.
[Assessing depressive symptoms and metabolic factors] may help identify individuals at elevated [Parkinson’s] risk for closer monitoring.
The scientists cautioned that these findings do not show that depressive symptoms directly cause Parkinson’s. Depression may instead be an early, nonmotor manifestation of the disease, the team noted.
“Our findings indicate that pre-clinical depressive symptoms are associated with a higher risk of Parkinson’s disease, with this relationship being partially explained by metabolomic alterations and modified by genetic susceptibility,” the researchers wrote.
According to the team, assessing depressive symptoms alongside genetic and metabolic factors “may help identify individuals at elevated [Parkinson’s] risk for closer monitoring.”
Leave a comment
Fill in the required fields to post. Your email address will not be published.