Exercise Staves Off Cognitive Decline in Some Parkinson’s Patients | #elderly | #seniors | #execrise
Greater physical activity was tied to less APOE4-related cognitive decline in early Parkinson’s disease, a longitudinal study showed.
Of 173 recently diagnosed Parkinson’s patients, those who carried an apolipoprotein E ε4 (APOE4) allele had a steeper rate of cognitive decline on the 30-point Montreal Cognitive Assessment (MoCA) scale than noncarriers (estimate -1.33, 95% CI -2.12 to -0.47, P=0.002).
But among that group of APOE4 carriers, higher physical activity was related to slower cognitive decline (estimate 0.007, 95% CI 0.003-0.011, P=0.001), reported Jin-Sun Jun, MD, of Hallym University in Seoul, and colleagues in Neurology.
A number of studies have demonstrated that Parkinson’s patients who exercise regularly show better clinical outcomes, including motor and cognitive function, Jun noted.
“These observations are supported by epidemiological data showing a link between physical activity and decreased risk for Parkinson’s disease,” Jun told MedPage Today. “Because previous data indicate that physical activity modifies the APOE4 effect on the development and progression of Alzheimer’s disease, we hypothesized that physical activity also plays a role in modulating the association between APOE4 and cognition in Parkinson’s disease.”
Genetic factors interact with physical activity on other health outcomes, noted Jacob Raber, PhD, of Oregon Health and Science University in Portland, and colleagues, in an accompanying editorial.
“If similar gene-by-physical activity interactions were identified in Parkinson’s disease, they could pave the way for personalized treatment,” Raber and colleagues wrote. “While the effects of APOE4 on promoting beta-amyloid and tau pathology are well-established, recent studies show that APOE4 is also associated with more profound pathology of alpha-synuclein and higher measures of cognitive burden, both in mouse models and in humans with Parkinson’s disease.”
In their study, Jun and colleagues followed recently diagnosed patients in the Parkinson’s Progression Markers Initiative cohort who were not treated for Parkinson’s and who had abnormal dopamine transporter (DAT) imaging.
Self-reported physical activity, measured by the Physical Activity Scale of the Elderly, was initiated 2 years after enrollment. Cognitive function was measured annually with the MoCA, which has been shown to be well-suited for Parkinson’s patients, and DAT imaging was performed at years 2 and 4. The researchers based their analysis on assessments performed at years 2, 3, and 4.
Mean age of the group at year 2 was 63. Mean age at Parkinson’s onset was 59; 68% of the cohort were men and 27% were APOE4 carriers. Carriers tended to be younger than noncarriers (61 vs 64 years); there were no significant differences between the two groups in other demographic and clinical variables.
No significant interaction was seen between physical activity and APOE4 regarding change in striatal DAT activities. This suggests striatal dopaminergic function may not be a major factor contributing to the protective effect of physical activity on APOE4-related cognitive decline, Jun and colleagues noted. “These negative results may be explained by the modest effect of APOE4 on the nigrostriatal dopaminergic system,” they wrote. “Furthermore, our follow-up duration may be too short to comprehend the impact of APOE4 on this system, considering the slow progressive nature of alpha-synucleinopathy.”
On the other hand, it’s possible physical activity confers benefits through mechanisms that are not disease-specific, the researchers pointed out. “Although we cannot conclude what types or amounts of exercise help to slow progression from this study design, even non-high-intensity physical activity positively modified the impact of APOE4 on cognitive function,” Jun said.
The study had several limitations: physical activity was self-reported, cognitive function was based only on MoCA scores, and follow-up time was short. Though the researchers adjusted for motor scores in the off-medication state, physical activity may have been less due to underlying disease severity.
Last Updated March 31, 2021
The study was supported by the Korean National Research Foundation.
Jun, Raber, and co-authors disclosed no relevant relationships with industry.
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