Prevalence risk of sarcopenia in older Brazilian adults during the pandemic: A cross-sectional analysis of the Remobilize Study

ABSTRACT BACKGROUND: Social distancing has led to lifestyle changes among older adults during the coronavirus disease 2019 (COVID-19) pandemic. OBJECTIVES: This study aimed to estimate the prevalence risk of sarcopenia (RS) and investigate its associated factors during the COVID-19 pandemic in older Brazilian adults. DESIGN AND SETTING: Cross-sectional observational analysis of baseline data as part of the Remobilize Study. METHODS: Participants in the study were older adults (≥ 60 years), excluding those who were bedridden or institutionalized. The data collected consisted of answers about the RS (SARC-F), functional status, walking, sedentary behavior (SB), pain, comorbidity, and life space mobility. RESULTS: A total of 1,482 older adults (70 ± 8.14 years, 74% women) participated in the study, and an RS prevalence of 17.1% was found. (95% confidence interval [CI] 15.25–19.15%). The adjusted multivariate model showed a significant association between RS and functional limitation (odds ratio [OR]: 19.05; CI 13.00–28.32), comorbidity (OR: 5.11; CI 3.44–7.81), pain (OR: 4.56; CI 3.33–6.28), total walking (OR: 0.99; CI 0.99–1.00), SB of 8–10 hours (OR: 1.85; CI 1.15–2.93), and SB of > 10 hours (OR: 3.93; CI 2.48–6.22). RS was associated with mobility during the pandemic (OR: 0.97; CI 0.96–0.98). P < 0.05. CONCLUSIONS: During the pandemic, the prevalence of RS in older Brazilians was estimated at 17.1%. Moderate to severe functional limitation, comorbidities, presence of pain, walking, longer SB period, and reduced life space mobility significantly contributed to RS in older adults during the pandemic.


INTRODUCTION
Social restriction policies and lifestyle changes favor a reduction in mobility and the level of physical activity (PA), leading to a higher proportion of inactive people and an increase in sedentary behaviors (SB) during the pandemic. [1][2][3][4] A decline in life space mobility contributes to a reduction in intrinsic capacity, higher risk of sarcopenia (RS), and other adverse health consequences. 5,6 After 7 days of total bed rest, there is already a significant deterioration in muscle function in community-dwelling older adults, and 2,000 steps per day are not enough to prevent these deleterious effects on the musculature. 7 Coker et al. reported that a 15-day bed rest induces a significant reduction in fat-free muscle mass, poor performance, and increased fat in older individuals, which negatively impacts their mobility. 8 A longer SB time observed during the pandemic is related to a worse prognosis in health conditions and a higher RS. [1][2][3]7,9 These factors can alter the homeostasis between the pro-and anti-inflammatory systemic components and muscle anabolism and catabolism, leading to the reduction of physiological reserves in older adults. Consequences such as increased plasma pro-inflammatory cytokines, greater muscle catabolism drive, and anabolic and insulin resistance lead to a deleterious cycle of muscle function, explaining the higher incidence of RS in this population. [1][2][3] Sarcopenia is a generalized and progressive musculoskeletal disorder that is defined as a reduction in muscle mass and strength. It is a multifactorial disease with dynamic interrelationships and is commonly associated with a cascade of negative repercussions on health, functional limitation, and mortality. [10][11][12] Consequently, due to its considerable clinical impact on older individuals, it increases health-related expenses and imposes a burden on the public health system, being more costly in socially unequal and/or developing countries, such as Brazil. 10,12,13 Updates from the European Working Group on Sarcopenia in Older People (EWGSOP2) and the Asian Working Group for Sarcopenia proposed the practice of population screening for RS in older people through strength, assistance with walking, rising from a chair, climbing stairs, and falls (SARC-F) questionnaire, a self-reported screening questionnaire. 10,14 Identifying sarcopenia in its early stages enables the control of its progression and/or reversal of the individual's clinical condition, thereby reducing the negative impacts caused by the disease. 3

Design and sample
This study presents a cross-sectional analysis of baseline data collected from May to July 2020 through an online questionnaire as part of the Remobilize Study (www.remobilize.com. br). 4 Using convenience snowball sampling, the online questionnaire (SurveyMonkey platform) was distributed throughout the Brazilian territory via social media (Facebook and Instagram), WhatsApp groups, social groups for older adults, and/or their friends and acquaintances. A pilot project for calibration and adjustments was conducted in advance. This study was approved by the University City of São Paulo Research Ethics Committee (May 18, 2020; CAAE 31592220.6.0000.0064) and is currently under progress.
The sample population consisted of community-dwelling older Brazilians (≥ 60 years) without distinction of sex, race, and/or social class. Following the exclusion criteria, those residing in long-term care facilities and/or bedridden were not eligible to participate in the study. 4 Participants who presented with disabilities were allowed to have the questions be answered by a family member or caregiver. 16 Participants without familiarity with the Internet were able to answer the survey via telephone. 4

Measures
The sociodemographic, clinical, and lifestyle data are presented in Table 1. The self-reported functional comorbidity index questionnaire was used to detect the presence of comorbidities (two or more chronic diseases). 17 All participants answered questions about the presence or absence of pain.
The SARC-F questionnaire is recommended by the EWGSOP2 and the Asian Working Group for Sarcopenia as a population screening tool for RS. 10,14 The final score ranges from zero to ten points, and a score of ≥ 4 points identifies individuals with sarcopenia. SARC-F has a high specificity, but low to moderate sensitivity. 10,14,15,18 Population screening for RS (SARC-F) allows the exclusion of older patients with preserved muscle function in primary health care and identification of changes in the early stages of muscle function, functionality, and RS in older adults. 10,14,15,19 Functional performance was assessed using the Older American Resources and Services questionnaire that has been translated and Walking, including PA, utilitarian walking, and walking time, was assessed using the Incidental and Planned Exercise Questionnaire. 23 Validated for older adults, this is a simple, self-report questionnaire probing on walking activities during the prior week, specifically on the frequency and duration of the activity. The final score for walking as physical exercise and utilitarian walking was given by the product of frequency and duration for each item (minutes/ week). The total walking time was calculated as the sum of walking as PA and utilitarian walking.
Life space mobility was measured using the Life-Space Assessment (LSA). 24 It estimates the individual perspective of mobility relative to the spatial area in five levels of life space in the prior week: mobility in the rooms at home, outside the bedroom (level 1), outside the home (level 2), a neighborhood close to home (level 3), circulation within the municipality where they reside (level 4), and inter-municipal areas (level 5). The answers were based on the frequency and need for mobility devices. The score was calculated as the product of frequency and performance skill, extracting a score based on level and the total by the sum of levels (0-120 points). Higher final scores indicated better mobility performance in the life space.

Statistical analysis
The prevalence of RS in participants was estimated using a 95% confidence interval (CI). Descriptive statistics were performed using absolute and relative frequencies for the total sample and RS, respectively. Continuous variables did not show a normal distribution in the Shapiro-Wilk test; therefore, the data are pre- Texas, United States), with a 5% statistical significance level.

RESULTS
A total of 1,482 participants were included in this study, and the study flowchart is shown in Figure 1. The prevalence of RS Crude logistic regression analysis showed a significant association for all analyzed variables. After adjusting for sociodemographic factors, the following variables remained statistically significant, as seen in Table 2: moderate to severe functional limitations, comorbidity, pain, walking (exercise and total), SB 8-10 hours, SB > 10 hours, and total LSA score during the pandemic.

DISCUSSION
The results showed a high prevalence of RS in older Brazilians at  The prevalence of total sarcopenia and per SARC-F item is reported as %. The prevalence of each SARC-F item refers to the sum of the two options (some difficulty or great difficulty). and support from the scientific community. 10,14,15,17 In addition, it is impossible to conduct anthropometric measurements due to pandemic-related restrictions.
Findings on sociodemographic differences between participants with and without RS were similar to those found in studies before the pandemic, whether in older patients with RS or with sarcopenia or on diagnostic parameters for sarcopenia. 18,[25][26][27][31][32][33][34][35] The difference in the presence of moderate to severe functional limitation between the groups was significant. After adjusted logis-  lower back pain, and the results showed an association between pain intensity and poor mobility and balance. 37 The authors pointed out that RS, if present in older women with lower back pain, can negatively influence functionality. 37 Pain is multifactorial and subjective. Moreover, psychosocial factors are known to interfere with pain and its pro-inflammatory process, and social isolation predisposes to the development of chronic pain. 38  Our results showed lower life space mobility during the pandemic in the RS group. A similar and significant difference was found in a study published before the pandemic. 45 In this study, the group without RS had lower average age, was more active, and presented with a lower percentage of comorbidity than the group with RS. Higher mobility rates are associated with better muscle function, functional and cognitive performance, and social support. 46 This finding serves as a warning for this target population, given the prolonged course of the pandemic and the deleterious relationship between restriction of outdoor mobility and skeletal musculature.
Some limitations of this study must be considered.
Snowball sampling was carried out on an online platform, differentiating our sample from the general community. The participants could have had access to the Internet and a higher level of education or social support as opposed to the older Brazilian population in general. Our findings were extrapolated to older adults with characteristics similar to those of our sample. In addition, the study had a cross-sectional design, making it impossible to identify causality in the analyzed relationships. However, this cross-sectional analy-