title: Social inequality in walking speed in early old age in the Whitehall II study.
abstract: BACKGROUND
  We investigated social inequalities in walking speed in early old age.
  
  
  METHODS
  Walking speed was measured by timed 8-ft (2.44 m) test in 6,345 individuals, with mean age of 61.1 (SD 6.0) years. Current or last known civil service employment grade defined socioeconomic position.
  
  
  RESULTS
  Mean walking speed was 1.36 (SD 0.29) m/s in men and 1.21 (SD 0.30) in women. Average age- and ethnicity-adjusted walking speed was approximately 13% higher in the highest employment grade compared with the lowest. Based on the relative index of inequality (RII), the difference in walking speed across the social hierarchy was 0.15 m/s (95% confidence interval [CI] 0.12-0.18) in men and 0.17 m/s (0.12-0.22) in women, corresponding to an age-related difference of 18.7 (13.6-23.8) years in men and 14.9 (9.9-19.9) years in women. The RII for slow walking speed (logistic model for lowest sex-specific quartile vs others) adjusted for age, sex, and ethnicity was 3.40 (2.64-4.36). Explanatory factors for the social gradient in walking speed included Short-Form 36 physical functioning, labor market status, financial insecurity, height, and body mass index. Demographic, psychosocial, behavioral, biologic, and health factors in combination accounted for 40% of social inequality in walking speed.
  
  
  CONCLUSIONS
  Social inequality in walking speed is substantial in early old age and reflects many factors beyond the direct effects of physical health.
authors.affiliation: Department of Epidemiology and Public Health, University College London, UK. e.brunner@ucl.ac.uk
authors.forename: Eric
authors.initials: E
authors.lastname: Brunner
authors.forename: Martin
authors.initials: M
authors.lastname: Shipley
authors.forename: Victoria
authors.initials: V
authors.lastname: Spencer
authors.forename: Mika
authors.initials: M
authors.lastname: Kivimaki
authors.forename: Tarani
authors.initials: T
authors.lastname: Chandola
authors.forename: David
authors.initials: D
authors.lastname: Gimeno
authors.forename: Archana
authors.initials: A
authors.lastname: Singh-Manoux
authors.forename: Jack
authors.initials: J
authors.lastname: Guralnik
authors.forename: Michael
authors.initials: M
authors.lastname: Marmot
mesh_terms: D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004651:Employment; D005260:Female; D005684:Gait; D015438:Health Behavior; D006304:Health Status; D006801:Humans; D008131:London; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D012923:Social Class