Sitting Time and Mortality in Older Adults With Disability: A National Cohort Study.

BACKGROUND: The progressive aging of the population has increased the number of older adults with disabilities. Regular physical activity has shown to improve health among these individuals, but the effects of sedentary behavior are mostly unknown. Thus, this study examined the association between sitting time and mortality in older adults with disability.

METHODS: Prospective cohort of 2470 people aged ≥60 years. In 2000-2011, the study participants reported their sitting time and physical activity levels and were subsequently followed up through 2011 to ascertain mortality.

RESULTS: During an average follow-up of 8.7 years, 982 deaths occurred. Compared with people who spent seated <4 hours/d, the hazard ratio (95% confidence interval) of mortality was 1.27 (1.07-1.51) in those seated during 4-6 hours/d and 1.55 (1.29-1.87) in those seated for >6 hours/d. Each increment of 1 hour/day in sitting time was linked to a 7% increase in mortality. Compared with active individuals who spent seated <4 hours/day, those who were inactive and spent seated >6 hours/d showed the highest mortality (hazard ratio 1.82, 95% confidence interval 1.37-2.42).

CONCLUSIONS: Sitting time is associated with higher mortality in older people with disability. Interventions combining the reduction of sedentary behavior with increased physical activity should be developed and evaluated in this group of population.