title: Socioeconomic differences in the benefits of structured physical activity compared with health education on the prevention of major mobility disability in older adults: the LIFE study.
abstract: Evidence is lacking on whether health-benefiting community-based interventions differ in their effectiveness according to socioeconomic characteristics. We evaluated whether the benefit of a structured physical activity intervention on reducing mobility disability in older adults differs by education or income.
  
  
  
  The Lifestyle Interventions and Independence for Elders (LIFE) study was a multicentre, randomised trial that compared a structured physical activity programme with a health education programme on the incidence of mobility disability among at-risk community-living older adults (aged 70-89 years; average follow-up of 2.6 years). Education (≤ high school (0-12 years), college (13-17 years) or postgraduate) and annual household income were self-reported (<$24 999, $25 000 to $49 999 and ≥$50 000). The risk of disability (objectively defined as loss of ability to walk 400 m) was compared between the 2 treatment groups using Cox regression, separately by socioeconomic group. Socioeconomic group×intervention interaction terms were tested.
  
  
  
  The effect of reducing the incidence of mobility disability was larger for those with postgraduate education (0.72, 0.51 to 1.03; N=411) compared with lower education (high school or less (0.93, 0.70 to 1.24; N=536). However, the education group×intervention interaction term was not statistically significant (p=0.54). Findings were in the same direction yet less pronounced when household income was used as the socioeconomic indicator.
  
  
  
  In the largest and longest running trial of physical activity amongst at-risk older adults, intervention effect sizes were largest among those with higher education or income, yet tests of statistical interactions were non-significant, likely due to inadequate power.
  
  
  
  NCT01072500.
authors.affiliation: Centre for Longitudinal Studies, UCL Institute of Education, London, UK.
authors.forename: David
authors.identifier: 0000-0002-6454-626X
authors.initials: D
authors.lastname: Bann
authors.affiliation: Division of Public Health Sciences, Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
authors.forename: Haiying
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Social and Environmental Health, London School of Hygiene and Tropical, Medicine, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Bonell
authors.affiliation: Center for Aging and Population Health, Department of Epidemiology, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Nancy W
authors.initials: NW
authors.lastname: Glynn
authors.affiliation: Nutrition, Exercise Physiology, and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, USA.
authors.forename: Roger A
authors.initials: RA
authors.lastname: Fielding
authors.affiliation: Department of Aging & Geriatric Research, University of Florida, Gainesville, Florida, USA.
authors.forename: Todd
authors.initials: T
authors.lastname: Manini
authors.affiliation: Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Abby C
authors.initials: AC
authors.lastname: King
authors.affiliation: Department of Aging & Geriatric Research, University of Florida, Gainesville, Florida, USA.
authors.forename: Marco
authors.initials: M
authors.lastname: Pahor
authors.affiliation: Department of Health and Exercise Science, Wake Forest University, Winston-Salem, North Carolina, USA.
authors.forename: Shannon L
authors.initials: SL
authors.lastname: Mihalko
authors.affiliation: Yale School of Medicine, New Haven, Connecticut, USA.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Gill
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006233:Persons with Disabilities; D015444:Exercise; D005260:Female; D006266:Health Education; D006293:Health Promotion; D006801:Humans; D008019:Life Style; D008297:Male; D019957:Motor Skills Disorders / Q000517:prevention & control*; D016138:Walking
keywords: AGEING; DISABILITY; PHYSICAL ACTIVITY; SOCIAL INEQUALITIES