Regular exercise with depression can lower person’s risk of Parkinson’s
Study looked into activity habits of 1.34M people with depressive disorder onset
Engaging in regular physical activity before and after being diagnosed with depression can lower a person’s risk of developing Parkinson’s disease, while stopping to exercise increases that risk, a large study that followed patients in South Korea for about five years reports.
Becoming more active only after a depressive disorder diagnosis, however, had no effect on Parkinson’s risk.
“Promoting regular [physical activity] across lifetime would be the key to reduce future PD [Parkinson’s disease] in individuals with depression,” the researchers wrote. “Shifting the onset of PD by a few years could result in significant reducing incidence of PD in late life.”
The study, “Association of physical activity with the risk of Parkinson’s disease in depressive disorder: A nationwide longitudinal cohort study,” was published in the Journal of Psychiatric Research.
Exercise as a lifestyle factor in Parkinson’s development
As populations worldwide age, the prevalence of Parkinson’s disease has doubled and made the burden of patient care more costly, both in human and financial terms. Identifying modifiable factors, such as lifestyle changes, that reduce the disease’s risk or slow its progression are of increasing importance.
Among these factors, a large and growing body of evidence indicates that regular physical activity can delay Parkinson’s onset, ease symptoms, and slow its progression.
“Depression is frequently observed prior to the onset of PD, and it is associated with a 1.5 to 3.2-fold increased risk of PD development,” the researchers wrote.
The scientists set out to examine whether physical activity levels among people diagnosed with depression in South Korea would influence the risk of developing Parkinson’s disease.
A review of national health insurance records identified 1.34 million people — 60% women — diagnosed with new onset depression between 2010 and 2016. All were followed up to Dec. 31, 2019, with information on their physical activity levels before and after diagnosis collected using a patient-reported questionnaire.
Patients then were grouped based on changes in physical activity levels before and after their depression diagnosis. The “no PA” group were those who never engaged in physical activity, the “increased PA” group covered patients who started regular exercise only after their diagnosis, the “decreased PA” group marked those who stopped exercise after the diagnosis, and the “maintaining PA” group included those who consistently engaged in regular physical activity.
Patients who kept up with exercise least likely to develop Parkinson’s
Maintaining PA patients were more likely to be male and drink alcoholic beverages relative to the no activity group, the researchers found, while those in the decreased activity group had the highest prevalence of co-existing conditions, like high blood pressure or diabetes.
Over a mean follow-up of 5.3 years, 8,901 of these people (0.66%) were diagnosed with Parkinson’s.
Individuals who maintained being physical activity before and after their depression diagnosis were found to have the lowest risk of Parkinson’s — about a 10% lower risk compared with those in the no regular exercise group.
In contrast, patients in the decreased PA group — those who stopped regular exercise after being diagnosed with depressive disorder — had about a 10% higher risk of Parkinson’s compared with those who never exercised.
No other clinical factors associated with the relationship between physical activity and Parkinson’s, including sex, age, smoking, drinking alcohol, income, weight, and other health conditions.
“This study revealed not only the baseline PA [amount of regular exercise at the study’s start] but consistently maintaining PA even after developing depressive disorder was the important factor” in reducing a Parkinson’s “future risk,” the researchers wrote.
They speculated that patients who maintain physical activity may have a “motor reserve” that compensates for the motor declines that typically spark a Parkinson’s diagnosis, potentially allowing for a delay in disease onset.
Depression and activity levels as prodromal Parkinson’s symptoms
Depression and a decline in physical activity might themselves be prodromal symptoms of Parkinson’s disease, the researchers added, helping to explain why patients who stopped exercising were found to be at a higher risk. Subtle motor changes and fatigue before diagnosis also might be contributing factors.
“To comprehensively understand these prodromal symptoms and disease severity, a prospective investigation over time is warranted,” the researchers wrote.
Increasing physical activity levels after a depression diagnosis did not influence Parkinson’s risk in either direction, possibly because for this patient group an “irreversible” process was in play, the researchers speculated.
“It is possible that there is a biological ‘tipping point’ in the development of [Parkinson’s] that render the neurodegenerative process irreversible,” they wrote. “Once an individual reaches this critical point, delaying the onset of [Parkinson’s] through lifestyle changes alone may become challenging.”
The scientists noted that a longer follow-up will be needed to better understand how changes in physical activity influence the Parkinson’s risk. Such future research also should take into account the severity of a person’s depression.
Likewise, an investigation into how physical activity influences outcomes in people with risk factors for Parkinson’s and depression, such as genetic mutations, environment or family history, is warranted.