Can step count be used to identify older adults with high sedentary time and low moderate-to-vigorous physical activity?

ABSTRACT

INTRODUCTION: Combined high sedentary time (ST) and low moderate-to-vigorous physical activity (MVPA) has been associated with adverse cardiovascular events. However, accurately assessing ST and MVPA in older adults is challenging in clinical practice. PURPOSE: To investigate whether step count can identify older adults with unhealthier movement behavior (high ST/low MVPA) and poorer cardiometabolic profile. METHODS: Cross-sectional study (n = 258; 66 ± 5 years). Step count, ST, and MVPA were assessed by hip accelerometry during 7 days. The cardiometabolic profile was assessed using a continuous metabolic syndrome score (cMetS), including blood pressure, HDL-cholesterol, triglycerides, fasting glucose, and waist circumference. Receiving operating curve analysis was used to test the performance of step count in identifying older adults with unhealthier movement behavior (highest tertile of ST/lowest tertile of MVPA). Healthier movement behavior was defined as lowest tertile of ST/highest tertile of MVPA, with neutral representing the remaining combinations of ST/MVPA. RESULTS: A total of 40 participants (15.5%) were identified with unhealthier movement behavior (ST ≥ 11.4 h/day and MVPA ≤ 10 min/day). They spent ~73% and 0.4% of waking hours in ST and MVPA, respectively. Step count identified those with unhealthier movement behavior (area under the curve 0.892, 0.850-0.934; cutoff ≤5263 steps/day; sensitivity/specificity 83%/81%). This group showed a higher cMetS compared with neutral (ß = .25, p = .028) and healthier movement behavior groups (ß = .41, p = .008). CONCLUSION: Daily step count appears to be a practical, simple metric for identifying community-dwelling older adults with concomitant high ST and low MVPA, indicative of unhealthier movement behavior, who have a poorer cardiometabolic profile.