Associations between active mobility index and objectively measured physical activity among older adults

Background Active mobility index (AMI) is a questionnaire to assess going-out behavior with physical and social activity. The association between AMI scores and objectively measured physical activity (PA) in older adults is unknown. Methods Community-dwelling older adults aged >= 70 years participated in an examination and wore a triaxial accelerometer for seven or more days. The accelerometer measured the time of moderate-to-vigorous intensity PA (MVPA) and light intensity PA (LPA), and step counts. The AMI assessed life space (distance from the respondent's home: < 1, 1-10, or > 10 km) and related activities during the previous month. The AMI total, physical, and social scores were calculated. Results The analyzed data were 2499 participants (mean age: 75.5 +/- 4.0 years; 54.4% female). Comparing PA among quartile groups of each AMI score, higher AMI total and physical score groups were associated with higher MVPA, LPA, and step counts (all P < 0.01). The Q4 group of AMI social scores showed significantly higher LPA and step counts than the Q1 and Q2 groups (P < 0.01). The logistic regression model showed higher score groups of AMI total and physical scores associated with increased adjusted odds ratio (aOR) of meeting recommended PA, >= 150 min/week of MVPA. Conclusions Older adults with higher AMI total and physical scores, engaged in more PA. Future studies can use the present findings when estimating PA in older adults from AMI scores and examining the association between AMI scores and health outcomes.