Loss of muscle mass and strength common in Parkinson’s, study finds
Japanese researchers say measuring calf is most useful screening tool
Nearly 1 in 3 people in Japan with Parkinson’s disease also had sarcopenia, a progressive loss of muscle mass and strength, according to a new study.
The researchers found that measuring the circumference of the calf, or the distance around the thickest part of the lower leg, was the most useful tool for screening for sarcopenia in Parkinson’s patients.
However, characteristics related to Parkinon’s — including motor problems, disease severity and duration, and medication use — did not correlate with the occurrence of sarcopenia, the team also found.
“In this study, we demonstrated that 31.2% of patients with [Parkinson’s disease] had sarcopenia,” the researchers wrote, while also noting that this work may underestimate the condition’s prevalence because of its limited patient population.
The study, “Prevalence, Impact, and Screening Methods of Sarcopenia in Japanese Patients With Parkinson’s Disease: A Prospective Cross-Sectional Study,” was published in the journal Cureus.
Investigating the prevalence of muscle mass loss in Parkinson’s
Sarcopenia is a progressive loss of muscle mass and strength that occurs with aging and/or immobility, or in some cases due to medical conditions. It leads to muscle weakness and an increased risk of falls, fractures, and disability, as well as a potentially poorer quality of life for those affected.
Emerging evidence suggests that the prevalence of sarcopenia is three times higher in people with Parkinson’s compared with those of the same age without Parkinson’s.
However, “few studies have investigated the prevalence, impact, and screening methods of sarcopenia in Japanese patients with [Parkinson’s],” the researchers wrote.
To know more, a team at Wakayama Medical University, examined sarcopenia in a group of 47 adults with Parkinson’s. Most patients were women (63.8%), who also had higher rates of high blood pressure and osteoporosis, a condition marked by increased bone fragility.
Among the participants, 15 or about 32% — three men and 12 women — were diagnosed with sarcopenia or severe sarcopenia. When compared with patients without such loss of muscle mass, those with sarcopenia were significantly older and had a lower body mass index (BMI), a ratio of weight to height.
Despite more women being affected, sarcopenia did not correlate with sex. Other Parkinson’s-related factors that did not correlate with sarcopenia were co-existing medical conditions, disease duration or stage, motor impairment or fluctuations, involuntary movements called dyskinesia, or the levodopa equivalent daily dose, which is the sum of all Parkinson’s medications taken by an individual. Quality of life, fatigue, and impulsive and compulsive behaviors also did not correlate with sarcopenia, the researchers found.
Significantly more Parkinson’s patients with sarcopenia had a reduced calf circumference, as measured on the widest part of the left calf (86.6% vs. 34.3%). Moreover, all sarcopenia patients had a significantly lower skeletal muscle mass index (100% vs. 6.25%), defined by the mass of skeletal muscle — those attached to bones — adjusted for height. More sarcopenia patients also had weaker handgrip strength, but the difference was insignificant.
Physical performance was assessed by the 4-meter gait test, which measures the time a patient takes to walk 4 meters, the five-time sit-to-stand test (FTSST), and the short physical performance battery (SPPB). Although all three tests showed worse performance in the sarcopenia group, only the FTSST showed a statistically significant difference between those with and without sarcopenia.
Measuring calf circumference more accurate in men than women
The researchers then assessed the ability of various tests to screen for sarcopenia in Parkinson’s patients. These measures comprised calf circumference, handgrip strength, FTSST, and the SARC-F questionnaire, a patient-reported tool to assess sarcopenia.
In men, the sensitivity of calf circumference, handgrip strength, and FTSST was 100%, meaning all three tests were useful in correctly identifying sarcopenia. Calf circumference was the most accurate test to indicate sarcopenia in men, with a specificity of 100%. Sensitivity is the ability of a test to correctly identify people with a disease, while specificity is the ability to correctly identify those without the disease.
Among the three tests conducted in women, calf circumference measurement demonstrated the highest sensitivity and specificity, achieving 83% sensitivity and 55% specificity, according to the study.
Further studies are required to develop more straightforward and comprehensive methods for assessing sarcopenia [or loss of muscle mass and strength] in patients with Parkinson’s.
The ability of the SARC-F questionnaire to detect sarcopenia ranked the lowest among all tests.
Worse scores on the SARC-F questionnaire did correlate with worse motor function, as indicated by the MDS-UPDRS part 3, as well as worse PDQ-39 scores, a questionnaire to assess the health and well-being of individuals with Parkinson’s.
Overall, these findings show that loss of muscle mass and strength is common in Parkinson’s patients, which supports the results of other research, the scientists noted.
“The prevalence of sarcopenia in this cohort was approximately 30%, which is consistent with previous studies,” the team concluded, noting, however, that “further studies are required to develop more straightforward and comprehensive methods for assessing sarcopenia in patients with Parkinson’s.”
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