To test the hypothesis that a long-term structured physical activity program is more effective than a health education program (also referred to as a successful aging program) in reducing the risk of major mobility disability.
The life expectancy of older Americans continues to increase, with persons aged 65 years or older representing the fastest growing segment of the U.S. population. While prolongation of life remains an important public health goal, of even greater significance is preservation of the capacity to live independently and to function well during late life. Identification of proven interventions to prevent disability is an important public health challenge.
Mobility - the ability to walk without assistance - is a critical characteristic for functioning independently.4;5 Those who lose mobility have higher rates of morbidity, disability, and mortality, and yet are often excluded from clinical trials. Preserving the ability to walk 400 m, an excellent proxy for community ambulation, is central to maintaining a high quality of life and independence in the community.
The Lifestyle Interventions and Independence for Elders (LIFE) Pilot study was conducted from 2004 to 2006 to plan for the Phase 3 randomized trial. As hypothesized, the LIFE Pilot study (N=424) showed significant improvements in walking speed and physical performance measures. The pilot was not powered for a disability endpoint, but showed a non-significant reduction in risk of major mobility disability in the physical activity group, compared with the health education group, also referred to as the successful aging group. In the LIFE study it was hypothesized that compared with a health education program, a long-term structured physical activity program would reduce the risk of major mobility disability.
The Lifestyle Interventions and Independence for Elders (LIFE) study was a multicenter, randomized trial that enrolled participants between February 2010 and December 2011, who participated for an average of 2.6 years. Follow-up ended in December 2013. Outcome assessors were blinded to the intervention assignment. Participants were recruited from urban, suburban, and rural communities at 8 centers throughout the United States. We randomized a volunteer sample of 1635 sedentary men and women aged 70 to 89 years who had physical limitations, defined as a score on the Short Physical Performance Battery of 9 or below, but were able to walk 400 m.
Participants were randomized to a structured, moderate-intensity physical activity program (n = 818) conducted in a center (twice/wk) and at home (3-4 times/wk) that included aerobic, resistance, and flexibility training activities or to a health education program (n = 817) consisting of workshops on topics relevant to older adults and upper extremity stretching exercises.
The primary outcome was major mobility disability objectively defined by loss of ability to walk 400 m. Incident major mobility disability occurred in 30.1% (246 participants) of the physical activity group and 35.5% (290 participants) of the health education group (hazard ratio [HR], 0.82 [95% CI, 0.69-0.98], P = .03).Persistent mobility disability was experienced by 120 participants (14.7%) in the physical activity group and 162 participants (19.8%) in the health education group (HR, 0.72 [95% CI, 0.57-0.91]; P = .006). Serious adverse events were reported by 404 participants (49.4%) in the physical activity group and 373 participants (45.7%) in the health education group (risk ratio, 1.08 [95% CI, 0.98-1.20]).
A structured, moderate-intensity physical activity program compared with a health education program reduced major mobility disability over 2.6 years among older adults at risk for disability. The findings suggest mobility benefit from such a program in vulnerable older adults.