Abstract P234: Associations Between Sedentary Time With Physical Activity and Sarcopenia in the Oldest-Old Adults: The Health, Aging and Body Composition (Health ABC) Study

Abstract

The oldest-old adults (aged 80+ years) are most impacted by sarcopenia, a progressive loss of muscle mass, muscle strength, and physical performance. Physical activity (PA) can slow progression of sarcopenia. However, this population is highly sedentary due to physical limitations and comorbidities. Replacing sedentary time (ST) with light-intensity physical activity (LPA) or small amounts of moderate to vigorous activity (MVPA) may be beneficial and feasible. We hypothesized that replacing ST with LPA or MVPA would be associated with a lower likelihood of developing sarcopenia. Methods: We used cross-sectional data (n=155, age 88.3±2.6 years) collected at the year 16 visit (2012-2014). Participants wore a hip-worn ActiGraph GT3X+ during waking hours for 7 days. Physical behaviors were quantified as minutes per day (min/d) in ST (0-99 counts per minute, cpm), low LPA (100-759 cpm), High LPA (760-1040 cpm), and MVPA (1041+ cpm). We defined probable sarcopenia using hand-grip strength cut points (males <27 kg; females <16 kg). Logistic regression and isotemporal substitution models were used to calculate odds ratios (OR) and 95% confidence intervals (95% CIs). Isotemporal substitution estimated the hypothetical effect of substituting ST with one standard deviation (SD) of respective PA categories. Results: MVPA was associated with lower odds of probable sarcopenia in the single model (OR=0.50, 95% CI: 0.27-0.83) and partition model (OR=0.35, 95% CI:0.15-0.83). In the substitution model, replacing ST with 13 min/d (1 SD) of MVPA was significantly associated with lower odds of probable sarcopenia (OR = 0.35; 95% CI: 0.15 - 0.83). There were no significant associations with LPA (Table 1). Conclusion: Findings suggest that even a modest increment of time spent in MVPA could reduce the likelihood of developing sarcopenia. Alternatively, findings could reflect the impact of sarcopenia on capacity to engage in MVPA. Confirmation of the direction of the association will require examination of these relationships over time.