13 Oct Dopamine Genotype Linked to Walking Speed in Older Adults
MedicalResearch.com Interview with:
Caterina Rosano, M.D., M.P.H.
Professor of Epidemiology
University of Pittsburgh Graduate School of Public Health
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Most people think about dopamine’s role in mobility in the context of Parkinson’s disease, but not in normal aging. We were curious to see if a genetic predisposition to produce more or less dopamine was related to mobility in individuals who had some level of frailty, yet did not have dementia, parkinsonism or any other neurological condition.
While several genetic elements control dopamine signaling, my team and I focused on a gene called COMT, which breaks down dopamine to control its levels within the brain. We also considered the frailty status of participants, which is a common consequence of aging marked by a decline in physiological function, poor adjustment to stressors and a susceptibility toward adverse health outcomes. We suspected that frail participants could be particularly vulnerable to COMT-driven differences in dopamine levels.
We examined this gene in more than 500 adults above the age of 65 in Pennsylvania, North Carolina, California and Maryland, excluding any participants taking dopamine-related medications or diagnosed with Parkinson’s disease. We then looked for potential links between genotype, frailty and speed.
We discovered that frail participants with a high-dopamine COMT genotype had a 10% faster walking speed compared with participants with the low-dopamine COMT genotype.
MedicalResearch.com: What should readers take away from your report?
Response: This 10% difference may seem small, but it could make a big difference for a person walking across a busy street while negotiating traffic. This difference is even more striking when you consider just how many complex genes influence walking.
While more research is needed before our finding can be translated into the clinic, there are actions that seniors can take today to keep moving. I love to see grandparents walking around holding hands with their grandchildren because they have to look where they are going, where the child is going, keep an eye on the surroundings and pay attention to what the grandchild is saying, all at the same time. They get an amazing multi-sensory rehab, and it’s fantastic.
MedicalResearch.com: What recommendations do you have for future research as a result of this work?
Response: My co-author, Dr. Nicolaas Bohnen, a professor of neurology and radiology at the University of Michigan School of Medicine, and I, are working with a team of scientists at Pitt to quantify what level of dopamine could give elders greater resilience to gait-slowing and mobility disablement. Our hope is that older adults with low dopamine levels could one day receive pharmacologic supplements of dopamine to help preserve their mobility. There are a lot of individuals living in the community who have dopamine levels toward the lower end of normal who don’t have Parkinson’s disease or psychiatric conditions. If we give dopamine to these people, could we make them more resilient? That’s what we don’t know yet.
Additional authors on this research include first author Shannon Mance, B.S.N., R.N., Andrea Rosso, M.P.H., Ph.D., and Stephanie Studenski, M.D., M.P.H., all of Pitt; and Joshua Bis, Ph.D., of the University of Washington.
This research was supported by the National Institutes of Health (NIH) contracts HHSN268201200036C, HHSN268200800007C, HHSN268201800001C, N01HC55222, N01HC85079, N01HC85080, N01HC85081, N01HC85082, N01HC85083, N01HC85086 and NIH grants U01HL080295, R01HL087652, R01HL105756, R01HL103612, R01HL120393, U01HL130114, R01AG023629, and DK063491. Additional support was provided by UCLA Clinical Translational Science Institute grant UL1TR00181.
- Shannon Mance MPH, BSN, RN Andrea Rosso MPH, PhD Joshua Bis PhD Stephanie Studenski MD, MPH Nico Bohnen MD, PhD Caterina Rosano MD, MPH
Journal of the American Geriatrics Society
First published: 12 October 2020
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