LIFE (trial)

LIFE (trial)
Name	LIFE
Full name	Lifestyle Interventions and Independence for Elders
Acronym	LIFE
Phase	Randomized controlled trial
Status	Completed
Start date	2009
Completion date	2014
Locations	United States
Sponsor	National Institute on Aging
Principal investigator	Roger A. Fielding
Participants	1,635
Primary outcome	Major mobility disability
Registry id	ClinicalTrials.gov NCT01072500

LIFE (trial) was a multicenter randomized controlled trial that evaluated whether a structured physical activity program could prevent major mobility disability among older adults at risk of functional decline. Conducted in the United States and led by investigators supported by the National Institute on Aging, the study tested a long-term, supervised exercise intervention against a health-education control to assess outcomes relevant to independence and public health. Results influenced guidelines on physical activity for older populations and stimulated follow-up studies in gerontology, rehabilitation, and chronic disease prevention.

Background

The trial was motivated by demographic shifts documented by United States Census Bureau projections showing an aging population and by epidemiologic findings from cohorts such as the Framingham Heart Study that linked physical inactivity to frailty, disability, and mortality. Prior interventional work, including randomized trials like the Lifestyle Heart Trial and observational studies from the Nurses' Health Study, suggested benefits of activity on cardiovascular risk and function but left uncertainty about prevention of mobility disability in sedentary older adults. The design drew on concepts from the Women's Health Initiative and the Cardiovascular Health Study to operationalize a feasible, scalable behavioral intervention targeting lower-extremity function and endurance.

Trial Design

LIFE was a parallel-group, single-blind randomized controlled trial conducted at multiple clinical sites coordinated by the University of Florida coordinating center and overseen by stakeholders including the National Institutes of Health and the Wake Forest School of Medicine. The primary endpoint was onset of major mobility disability, operationalized as inability to complete a 400-meter walk within 15 minutes, mirroring endpoints used in studies like the Health, Aging, and Body Composition Study. Secondary endpoints included persistent mobility disability, short physical performance battery scores, and hospitalization rates, with adjudication by committees patterned after procedures used in the Systolic Blood Pressure Intervention Trial.

Randomization and blinding

Participants were randomized centrally with stratification by site and sex, employing allocation methods similar to those in the ALLHAT trial to balance baseline characteristics. Outcome assessors were masked to group assignment, following precedent from trials such as the Dunedin Multidisciplinary Health and Development Study for preserving assessment objectivity.

Participants and Enrollment

The trial enrolled 1,635 sedentary men and women aged 70–89 years at eight field centers including sites affiliated with Harvard Medical School, Stanford University School of Medicine, and University of Pittsburgh. Inclusion criteria required a Short Physical Performance Battery score ≤9 and the ability to walk 400 meters at baseline; exclusion criteria included severe cognitive impairment screened with instruments used in studies like the Alzheimer's Disease Neuroimaging Initiative and contraindications identified via standards from the American College of Sports Medicine. Recruitment strategies leveraged partnerships with community organizations such as Area Agencies on Aging and clinical networks like the Veterans Health Administration to reach diverse older adults.

Interventions and Protocols

The active intervention was a structured, moderate-intensity physical activity program combining aerobic walking, strength training, balance, and flexibility, supervised at sites and with home-based components. Sessions referenced exercise prescriptions informed by guidelines from the World Health Organization and the American Heart Association. The comparator was a health-education program delivering monthly workshops on topics such as preventive care, nutrition, and community resources, modeled on educational controls used in trials like the Look AHEAD study. Adherence monitoring used activity logs, accelerometry methods developed in the National Health and Nutrition Examination Survey, and behavioral strategies rooted in frameworks from the Social Cognitive Theory to enhance retention.

Outcomes and Results

Over a median follow-up of approximately 2.6 years, the trial reported a statistically significant reduction in the incidence of major mobility disability in the physical activity arm compared with health education, with effect sizes reported across subgroups defined by baseline function, sex, and comorbidity burden. Secondary analyses documented improvements in 400-meter walk times, Short Physical Performance Battery scores, and measures of cardiorespiratory fitness, echoing functional benefits observed in trials like the Lifestyle Interventions and Independence for Elders Pilot Study. Prespecified subgroup and mediation analyses explored interactions with baseline gait speed, presence of diabetes mellitus, and depressive symptoms measured with instruments used in the Cardiovascular Health Study.

Safety and Adverse Events

Safety monitoring followed protocols similar to those used by the Data and Safety Monitoring Board in federally funded trials, with systematic collection of adverse events, serious adverse events, and hospitalizations. The intervention group experienced higher rates of musculoskeletal complaints and transient injuries such as strains and falls during supervised sessions, comparable to rates reported in exercise trials like the Otago Exercise Programme studies, but no excess in cardiovascular events was detected. Event adjudication involved clinicians with expertise akin to investigators in the Geriatrics Research, Education, and Clinical Centers network.

Impact and Subsequent Research

Findings from the trial informed clinical guidelines from professional bodies such as the American Geriatrics Society and influenced recommendations by the United States Preventive Services Task Force and the American College of Sports Medicine regarding exercise prescription for older adults. The dataset spawned ancillary studies on cost-effectiveness, biomarkers of aging, and implementation science, prompting pragmatic trials in health systems including those affiliated with Kaiser Permanente and pilot programs in long-term care settings like those overseen by the Centers for Medicare & Medicaid Services. Subsequent investigations examined adaptation of the intervention for populations with stroke, Parkinson's disease, and chronic obstructive pulmonary disease, and informed technology-assisted delivery via telehealth platforms exemplified by initiatives at Massachusetts General Hospital.

Category:Randomized controlled trials Category:Geriatric medicine Category:Physical activity