A Case for Promoting Movement Medicine: Preventing Disability in the LIFE Randomized Controlled Trial

Abstract

Background: The movement profile of older adults with compromised function is unknown, as is the relationship between these profiles and the development of major mobility disability (MMD)-a critical clinical outcome. We first describe the dimensions of movement in older adults with compromised function and then examine whether these dimensions predict the onset of MMD.

Methods: Older adults at risk for MMD (N = 1,022, mean age = 78.7 years) were randomized to receive a structured physical activity intervention or health education control. We assessed MMD in 6-month intervals (average follow-up of 2.2 years until incident MMD), with activity assessed at baseline, 6-, 12- and 24-month follow-up via accelerometry.

Results: A principal components analysis of 11 accelerometer-derived metrics yielded three components representing lifestyle movement (LM), extended bouts of moderate-to-vigorous physical activity (MVPA), and stationary body posture. LM accounted for the greatest proportion of variance in movement (53%). Within health education, both baseline LM (HR = 0.74; 95% CI 0.62 to 0.88) and moderate-to-vigorous physical activity (HR = 0.69; 95% CI 0.54 to 0.87) were associated with MMD, whereas only LM was associated with MMD within physical activity (HR = 0.74; 95% CI 0.61 to 0.89). There were similar nonlinear relationships present for LM in both physical activity and health education (p < .04), whereby risk for MMD was lower among individuals with higher levels of LM.

Conclusions: Both LM and moderate-to-vigorous physical activity should be central in treatment regimens for older adults at risk for MMD.

Trial registration: clinicaltrials.gov Identifier NCT01072500.

Keywords: Accelerometry; Disability; Exercise; Physical activity; Sedentary.

Figure 1.

Study flow

Figure 2.

Density plots of distribution of 6-month change by intervention group

Figure 3.

Nonlinear relationship between long-transformed hazard ratios and lifestyle movement scores. Log-transformed hazard ratios relative to a value of 1.6 within each group; there is a significant nonlinear component (p = .02 for PA, p = .04 for HE). Models are stratified the baseline hazard on sex and adjusted for baseline age, BMI, race/ethnicity, SPPB, history of high blood pressure and fracture, CVD, arthritis, lung disease, and diabetes. BMI = body mass index; CVD = cardiovascular disease; HE = health education; PA = physical activity; SPPB = short physical performance battery.