Osteoarthritis Linked With Higher Risk of Parkinson’s in 2 Studies
People with the most common form of arthritis, osteoarthritis, may be at increased risk of developing Parkinson’s disease, according to a study from the U.K.
This result is in line with an earlier study from Taiwan. Based on these findings, “measures aiming at the prevention of Parkinson’s disease should be implemented in patients with osteoarthritis,” its researchers wrote.
The study, “Association between osteoarthritis and the incidence of Parkinson’s disease in the United Kingdom,” was published in Clinical Parkinsonism & Related Disorders.
Arthritis is a disease characterized by pain and inflammation in the joints. Osteoarthritis is the most common form; it develops when the cartilage that protects and cushions bones at joints wears down. The hands, hip, and knees are most commonly affected.
Earlier this year, scientists in Taiwan published a study where they retrospectively reviewed data for 33,360 people with osteoarthritis and an equal number without it. Results showed that people with osteoarthritis were significantly more likely to develop Parkinson’s, by about 41%. The association was especially strong for people with osteoarthritis of the hips or knees.
Now, a team of researchers in Europe conducted a similar analysis using data from the U.K.
“Although the previous study conducted in Taiwan has advanced the field, its findings may not be generalizable to other countries,” the researchers wrote.
They noted that Taiwan has one of the lowest worldwide instances of osteoarthritis. Additionally, Taiwan is one of only two countries where rates of years lived with disability due to osteoarthritis have decreased over the last decade.
“Therefore, the goal of this retrospective cohort study … was to investigate the potential association between osteoarthritis and the incidence of Parkinson’s disease” among people in another country, the U.K., the researchers wrote.
The analysis included 130,112 people with osteoarthritis and an equal number without. Since both osteoarthritis and Parkinson’s are more common later in life, the analysis only included patients over age 40; the average age was 66.4 years. In both groups, 62% were female, and the most common health problems (apart from osteoarthritis) were high blood pressure, diabetes, and thyroid disease.
“This is one of the first studies on the potential association between osteoarthritis and Parkinson’s disease, [and] it is the study with the largest sample size to date,” the researchers wrote.
Over the course of a decade, 1.2% of patients with osteoarthritis and 0.6% of those without it were diagnosed with Parkinson’s. Statistical models suggested that the risk of Parkinson’s was significantly higher, by about 82%, in the people with osteoarthritis. Similar findings were obtained in analyses divided by age or sex.
“Osteoarthritis was positively and significantly associated with the incidence of Parkinson’s disease in the overall population and all sex and age subgroups,” the researchers concluded.
The team noted that the result is overall consistent with the study from Taiwan, although the association between Parkinson’s and osteoarthritis appeared stronger in the U.K. data. This is likely due to the countries’ differences in the frequency of osteoarthritis.
According to the scientists, several biological factors may link osteoarthritis and Parkinson’s. For example, people with osteoarthritis are often not very physically active to avoid pain, and physical activity is thought to help protect against Parkinson’s.
Increased inflammation is characteristic of both osteoarthritis and Parkinson’s, the researchers noted, while low levels of vitamin D are a risk factor for both conditions.
They recommended proactively taking measures to decrease Parkinson’s risk in people with osteoarthritis. For example, the study suggested that osteoarthritis patients stay active through activities like walking, running, and yoga. Researchers also stressed the importance of supportive mental healthcare for patients.
Several limitations were noted in this analysis: It relied mainly on insurance records, rather than clinical data, and the researchers did not have access to data about lifestyle factors like smoking or physical activity.
“More studies of longitudinal nature are needed to corroborate or invalidate these findings in other settings and countries, while further research should be conducted to better characterize the mechanisms underlying the osteoarthritis-Parkinson’s disease relationship,” the scientists concluded.
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