This study aimed to identify the prevalence of sarcopenia among the elderly in the community during the COVID-19 pandemic and to identify relevant risk factors, including COVID-19-related factors and psychological and physical factors. First, based on the study results, the prevalence of sarcopenia was 7.8% in elderly men and 32.0% in elderly women based on the SARC-F diagnostic criteria. Compared to the 4.2% in men and 15.3% in women given in a cohort study of 1,222 Korean elderly people aged 70 years and older in 2016, before the COVID-19 period, this study showed a higher prevalence of sarcopenia However, the difference in prevalence according to gender was approximately four times higher in women than in men20, which was similar to the results of this study. According to the AWGS diagnostic criteria revised in 2018, among those with a SARC-F score of 4 or higher, if a person with a grip strength of less than 28 kg for men and less than 18 kg for women is diagnosed with sarcopenia8, the prevalence of sarcopenia that satisfies both conditions at the same time was 4.8% for the male elderly and 29.1% for the female elderly, and the risk of sarcopenia was about six times higher in the female elderly than in the male elderly. This was a high result compared to 1.7% for men and 4.6% for women when the prevalence of sarcopenia was diagnosed with SARC-F and grip strength in 2,123 elderly people 70 years of age or older in Korea in 201630, As a result of the prevalence of sarcopenia measured by walking speed and muscle strength, the result was lower than that of 38.0% for men and 62.0% for women29.
The reason for this difference was that the average age of this study was 75.8 years, in Kamo's study 29, which targeted older adults with an average age of 86.4 years old, the proportion of elderly women was also high (82.4%), indicating a high prevalence of sarcopenia. Kim et al30., it is thought that the prevalence of sarcopenia was low because only elderly individuals who were able to walk were investigated. Previous studies have shown that the decrease in the level of physical activity, such as a long time at home due to social policies such as social distancing due to low social interaction and social distancing due to COVID-19, is greatly affected by the elderly living alone5,6 In Kim's study 20, the average number of family members living with the elderly with a SARC-F score of 20 SARC-F 4 or higher was 2.9. In future studies, it will be necessary to confirm the degree of influence of the number of family members on sarcopenia. The prevalence of sarcopenia differs according to evaluation criteria. As a result of a study of the prevalence of sarcopenia among hospitalized elderly over 70 years of age in the Netherlands, the prevalence of sarcopenia was higher when men used muscle mass as a diagnostic criterion and women used muscle strength31. In this study, muscle strength was used as the standard, and previous studies in Korea showed that the muscle strength of elderly women was about 50% higher than that of men32. It is inferred that the prevalence of sarcopenia in women is higher than in men. Accordingly, additional research that applies certain diagnostic standards and methods should be conducted after the COVID-19 pandemic.
Sarcopenia is not an irreversible condition but changes according to external factors5,6,10 Logistic regression analysis was performed to identify factors related to sarcopenia prevention and management during the COVID-19 pandemic. As a result, age, sex, physical performance, and depression were identified as sarcopenia-related factors. The most relevant factor was age, and the risk of sarcopenia was high in those aged 85 years or older. Sarcopenia occurs during aging and occurs with advancing age13 According to a study of elderly aged 85 years16, a study of the elderly living alone in a Chinese community33, a study of elderly patients with osteoarthritis of the knee34, a study of the elderly over 70 years of age and a study of the elderly living in residence18, the prevalence of sarcopenia increased with age, supporting the results of this study. In terms of gender, the risk of sarcopenia was higher among elderly women than among men16. In particular, as a result of analyzing factors affecting muscle strength according to gender, older women were more stressed than men, perceived that they had a more obese body image, and had a lower quality of life32. In addition, this study found that obesity and physical activity had an effect on the sarcopenia in the elderly in China33. In order to prepare a plan for preventing sarcopenia in the elderly, nursing education and interventions should be devised to identify the exact physical condition of the elderly and to have a positive body image.
In this study, the risk of sarcopenia was 5.2 times higher in the group with depression than that in the group without depression. With prolonged COVID-19, the incidence of depression among the elderly also increased, and even among the elderly without a history of depression, the risk of developing depression increased by 2.4 times compared to before COVID-1935, and the mental health of the elderly was also very vulnerable. In a study of factors affecting sarcopenia in the elderly with knee arthritis, the lower the depression score, the lower the sarcopenia by 0.5 times34, supporting the findings of this study. In a previous study, social and religious activities decreased due to COVID-19 but did not affect the risk of developing depression35. In this study, 61% of the elderly living alone without family members had an average depression score of 4.25 ± 3.87, and about 60% of the elderly with mild depression corresponding to a score of 5 or higher. This is about twice as high as the average depression score of 2.76 ± 2.43 for the elderly aged 60 years or older with osteoarthritis, and the depression rate was also 14.4%34, which is the depression rate for the elderly with knee osteoarthritis and the elderly aged 65 years or older living in Turkey in 2015. The rate of depression is about 3 to 4 times higher than the target depression rate of 25.2%, hence an intervention plan through continuous psychological support for depression in the elderly after COVID-19 is needed. As an influencing factor on depression in the elderly, the lower the physical activity, the higher the sarcopenia; it was reported to be 7.63 times higher34. In a study on the American elderly over 70 years of age living in the geriatric residence, those with depressive symptoms and low social support had lower muscle strength18 and this may be a factor that can exacerbate sarcopenia5,8. Nursing education and interventions for the elderly in the community should be devised so that health behaviors and perceptions related to reduced physical activity can change during the COVID-19 period.
Sarcopenia has been known to predict a poor prognosis, such as falls and death, when muscle function is reduced, such as a decrease in walking speed13. In this study, the physical performance-restricted group with a cut-off score of 9 or less in the SPPB score measured for muscle function was 7.4 times more likely to have sarcopenia than the normal group. Among the independent variables input to the regression model of the Bathel ADL index, which evaluates the level of daily activities for the elderly in nursing homes in Japan, SPPB, grip strength, and age were significantly higher29 In order to prevent and maintain daily life, it is necessary to prepare an intervention plan to detect and prevent the degree of sarcopenia in advance.