ASSOCIATION BETWEEN PHYSICAL ACTIVITY AND SARCOPENIA AMONG MIDDLE-AGED AND OLDER ADULTS IN CHINA: A CROSS-SECTIONAL STUDY

Abstract

Physical activity has been reported to be an effective method to reduce the risk of sarcopenia.  In this cross-sectional study, we aimed to determine if there is a significant association between physical activity levels and the prevalence of sarcopenia among middle-aged and older adults in China in order to inform efforts to prevent and manage sarcopenia in the study population.  The data used in our study were obtained retrospectively from the China Health and Retirement Longitudinal Study (CHARLS) conducted in 2015.  The CHARLS assessed physical activity levels among study subjects using the International Physical Activity Questionnaire (IPAQ) asking about activity during the previous week, expressed as metabolic equivalents of task in minutes (MET-minutes) per week.  Sarcopenia in our study was defined using the 2019 Asian Working Group for Sarcopenia (AWGS) criteria and classified as possible sarcopenia, sarcopenia and severe sarcopenia.  Study subjects were divided into 3 groups based on their physical activity levels following IPAQ criteria as: low (<600 MET-min/week, reference group), moderate (600-3,000 MET-min/week) and high (>3,000 MET-min/week).  We used multivariable logistic regression analysis and restricted cubic splines to identify significant associations between physical activity levels and sarcopenia.  A total of 8,449 subjects were included in the study: 52.4% (n = 4,426) females.  The mean (±standard deviation (SD)) age of study subjects was 66.1 (±8.6) years (range: 45–90 years).  The mean (±SD) body mass index (BMI) of subjects was 23.56 (±3.70) kg/m².   1,855 subjects (22.0%) met the 2019 AWGS criteria for having possible sarcopenia and 1,346 (15.9%) met the criteria for sarcopenia and 605 (7.2%) met the criteria for severe sarcopenia.  The median (interquartile range (IQR)) physical activity levels among subjects without sarcopenia, those having possible sarcopenia, sarcopenia and severe sarcopenia were: 2,562.00 (933.00-7,337.00), 1,782.00 (462.00-6,716.25), 2,032.50 (309.50-6,318.00)  and 1,732.50 (462.00-5,544.00) MET-min/week, respectively.  The median IQR among subjects without sarcopenia was statistically higher than among subjects in the other 3 groups (p-value <0.001).  After adjusting for age, gender, marital status, location of residence, education level, body mass index, smoking status, alcohol consumption status and retirement status, subjects in the moderate and high physical activity level groups had significantly lower odds of having possible sarcopenia than subjects in the low physical activity group (moderate activity level versus (vs) low activity level: adjusted odds ratio (aOR): 0.791; 95% confidence interval (CI): 0.683-0.915, p-value = 0.002 and high activity level vs low activity level: aOR: 0.679; 95% CI: 0.594-0.776, p-value <0.001).  Subjects in the high physical activity level had significantly lower odds of having sarcopenia than subjects in the low activity level group (aOR: 0.745; 95% CI: 0.584-0.950, p-value = 0.017).  Subjects in the high physical activity level group had significantly lower odds of having severe sarcopenia than subjects in the low activity level group (aOR: 0.679; 95% CI: 0.499-0.923, p-value = 0.013).  Restricted cubic spline analysis showed subjects in the high activity group had significantly lower odds of having possible sarcopenia by overall association than subjects in the low activity group (p-value <0.001) and subjects in the high activity group had significantly lower odds of having possible sarcopenia by nonlinear association than subjects in the low physical activity group (p-value = 0.001).  However, subjects in the high activity group did not have significantly lower odds of sarcopenia than subjects in the low physical activity group by overall association or nonlinear association (p-value = 0.560).  For severe sarcopenia, the overall association approached significance but was not significant (p-value = 0.054).  When all sarcopenia categories were combined, on restricted cubic spline analysis, subjects with high activity levels had significantly lower odds of having any kind of sarcopenia than subjects in the low physical activity group for overall association (p-value <0.001) and nonlinear association (p-value = 0.002).  Subgroup analysis revealed subjects who did not smoke and had a high activity level had lower odds of having possible sarcopenia than subjects with a high activity level who did smoke (aOR: 0.644; 95% CI: 0.553-0.750, p-value <0.001).  Subgroup analysis also showed subjects who were not retired and who had a high physical activity level had lower odds of having possible sarcopenia than retired subjects who had a high physical activity level (aOR: 0.654; 95% CI: 0.566-0.756, p-value <0.001).   No significant differences were found by sarcopenia category (p-value for interaction >0.05).  In summary, subjects with higher physical activity levels had significantly lower odds of having possible sarcopenia, sarcopenia and severe sarcopenia than subjects with low physical activity levels.  We conclude, moderate to high physical activity levels are recommended for subjects in the study group in order to prevent or manage sarcopenia.  Further studies are needed to determine if interventions to increase physical activity are able to prevent or reduce sarcopenia in this population.