title: Continued sedentariness, change in sitting time, and mortality in older adults.
abstract: OBJECTIVE
  Prolonged sitting time (ST) is associated with higher mortality. However, previous studies used only a single measure of ST at baseline, so they could not directly assess the effect of continued exposure to high ST, or of changes in ST, on mortality. We prospectively assessed the association of continued sedentariness and of changes in ST for 2 yr with subsequent long-term all-cause mortality.
  
  
  METHODS
  This study was based on a prospective cohort of 2635 persons representative of the Spanish population 60 yr and older. ST was self-reported in 2001 and 2003. The median of ST was used as the cutoff to define excessive ST. Individuals were classified as consistently sedentary (> median in 2001 and 2003), newly sedentary (≤ median in 2001 and > median in 2003), formerly sedentary (> median in 2001 and ≤ median in 2003), and consistently nonsedentary (≤ median in 2001 and 2003). The association of ST in the period 2001-2003 with all-cause mortality from 2003 through 2011 was assessed with Cox regression and adjusted for the main confounders, including physical activity.
  
  
  RESULTS
  Among the study participants, 846 died between 2003 and 2011. Compared with persons who were consistently sedentary, the hazard ratios (95% confidence interval) for mortality were 0.91 (0.76-1.10) in those who were newly sedentary, 0.86 (0.70-1.05) in formerly sedentary individuals, and 0.75 (0.62-0.90) in those who remained consistently nonsedentary. The results were similar across strata defined according to obesity, morbidity, functional limitations, or meeting recommendations for physical activity.
  
  
  CONCLUSIONS
  Compared with older adults who were consistently sedentary during 2 yr, consistently nonsedentary individuals showed reduced all-cause mortality. Individuals who changed ST experienced an intermediate reduction in mortality.
authors: CIBER of Epidemiology and Public Health, Madrid, Spain.
authors: Luz M
authors: LM
authors: León-Muñoz
authors: David
authors: D
authors: Martínez-Gómez
authors: Teresa
authors: T
authors: Balboa-Castillo
authors: Esther
authors: E
authors: López-García
authors: Pilar
authors: P
authors: Guallar-Castillón
authors: Fernando
authors: F
authors: Rodríguez-Artalejo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality; D011446:Prospective Studies; D011788:Quality of Life; D018570:Risk Assessment; D012307:Risk Factors; D057185:Sedentary Behavior; D011795:Surveys and Questionnaires; D015996:Survival Rate; D013997:Time Factors