For people with Parkinson's disease, quality of life linked to race, ethnicity

Among those living with Parkinson's disease, Black, Hispanic and Asian people were found to have a lower health-related quality of life than white people, according to a new study published in the April 5, 2023, online issue of Neurology.

Health-related quality of life is a measure of a person's level of comfort, health and happiness.

Parkinson's disease is a disorder of the central nervous system that causes uncontrolled movements, stiffness and loss of balance. It can be debilitating. Symptoms worsen over time, making it increasingly difficult to engage in daily activities.

"Racial and ethnic minorities have been underrepresented in Parkinson's disease research, which has limited our understanding of treatments and outcomes across these populations," said study author Daniel Di Luca, MD, of the University of Toronto in Canada.

"Previous research has shown that some populations may have limited access to neurologists, medications and other therapies. Our study found that Black, Hispanic and Asian people with Parkinson's do have a lower quality of life than white people, and that some health disparities and management differences persist even with ongoing expert neurologist care."

The study involved 8,514 people with Parkinson's disease; 90% were white, 6% were Hispanic, 2% were Asian and 2% were Black.

To evaluate quality of life, researchers asked participants to complete a questionnaire. It included 39 questions on how often during the past month participants had experienced difficulty with daily tasks such as housework, cooking and getting around in public. It also asked how often they felt anxious, depressed, ignored by others or unable to communicate properly. Participants answered each question using a five-point scale with zero representing never and four representing always. The higher the score, the worse the quality of life.

After adjusting for factors such as age, sex and disease duration as well as medical conditions such as diabetes and high blood pressure, the total average score was 29 for Black people, 27 for Hispanic people, 25 for Asian people and 23 for white people. When looking at responses to various questions, scores for mobility, emotional well-being, social support and pain were also worse for Black, Hispanic, and Asian people than for white people.

The researchers found that thinking and memory tests accounted for some of the differences in quality-of-life scores among Black, Hispanic, Asian and white people. Di Luca noted that previous studies have shown lower socioeconomic status, education and other psychological stressors may be associated with worse cognitive scores. In addition, cultural biases have also been shown to potentially influence the results of cognitive testing.

"Evaluating the underlying reasons behind differences in quality of life between racial and ethnic groups is crucial to improve care," Di Luca said. "Future studies are needed to gain a better understanding of the reasons for treatment and outcome differences in underrepresented populations, including differences in thinking and memory, clinical care and quality of life."

A limitation of the study was the small number of people in the non-white, non-Hispanic groups, which Marras said limited researchers' ability to detect small but potentially important differences.