Risk of Cognitive Problems Tied to Weight, Depression, Sleep

People with early Parkinson’s disease are at a higher risk of developing later cognitive problems if they are overweight, have symptoms of depression or anxiety, or have sleep issues or often feel sleepy during the day, a study has found.

Recognizing these signs early on, and identifying those at risk, could improve individual counseling and allow for early interventions, according to researchers.

Moreover, the scientists said, all of this may have implications for the rate of cognitive impairment over the course of the disease.

The study, “Modifiable comorbidities associated with cognitive decline in Parkinson’s Disease,” was published in the journal Movement Disorders.

Cognitive impairment is one of the most serious and debilitating complications of Parkinson’s, as it often leads to patient institutionalization. Such problems also place a large personal and financial burden on caregivers.

Statistics have estimated that up to 80% of all people with Parkinson’s will develop dementia by the time they have been living with the disease for 20 years, and that as many as 50% will start showing signs of cognitive problems within a decade of being diagnosed.

“Despite its common and devastating occurrence, treatment of CI [cognitive impairments] in PD is limited and no medications slow its onset or progression,” the researchers wrote.

“However, identification of treatable or modifiable comorbidities that affect the rate of progression of CI in PD [Parkinson’s disease] could provide opportunities for early intervention and improved prognosis,” they wrote.

Now, investigators at the University of Pennsylvania and their colleagues aimed to identify other concurrent health conditions (comorbidities), such as mental and sleep disorders, that could increase the likelihood of Parkinson’s patients developing cognitive problems.

The team analyzed data from the Parkinson’s Progression Markers Initiative (PPMI), an observational study that aims to document Parkinson’s progression and to identify relevant disease biomarkers in early, untreated patients.

The data came from 405 patients who participated in the PPMI study, and whose clinical information had been gathered at the time of enrollment (baseline) and in at least one subsequent follow-up visit. At baseline, information on several co-existing conditions, including sleep problems, mood and mental illnesses, and cardiovascular risk factors, were gathered.

Statistical analyses then were used to identify possible relationships between baseline co-existing conditions and changes in the patients’ cognition, which were evaluated over time by the Montreal Cognitive Assessment (MoCA).

The analyses found a series of starting comorbidities that were associated with a faster rate of cognitive decline over time. These included being overweight — specifically, having a high BMI — experiencing symptoms of depression or anxiety, showing signs of possible REM sleep behavior disorder (pRBD), and feeling excessively sleepy during the day. Yet, no relationships were found between any of these co-existing conditions and patients’ cognitive abilities at the study’s start.

Patients who were both overweight and showed signs of depression at the study’s start were more likely to lose their cognitive abilities at a faster rate than those who only had one of the two co-existing conditions, subsequent analyses revealed. This additive effect was not found for any other combination of baseline co-existing conditions.

“This study suggests that in patients with early PD, assessment of BMI, depression, anxiety, EDS [excessive day time sleepiness], and pRBD at the initial visit might identify individuals at higher risk of future cognitive decline,” the researchers wrote.

Such determinations, especially involving weight and depression, could enable clinicians to address such risk factors early on.

“Identifying at-risk patients may provide an opportunity for early interventions, such as treatment of mood or sleep disorders and maintenance of a healthy BMI, which may have implications for rate of cognitive impairment over the course of PD,” the scientists wrote.

“However, the potential effect of each of these treatments on cognitive decline needs to be studied in future prospective clinical trials,” they concluded.