Format

Send to

Choose Destination
CMAJ. 2017 Aug 21;189(33):E1056-E1064. doi: 10.1503/cmaj.161034.

Association between sedentary time and mortality across levels of frailty.

Author information

1
Division of Geriatric Medicine (Theou, Godin, Rockwood), Dalhousie University, Halifax, NS; MRC Unit for Lifelong Health and Ageing (Blodgett), University College London, London, UK olga.theou@dal.ca.
2
Division of Geriatric Medicine (Theou, Godin, Rockwood), Dalhousie University, Halifax, NS; MRC Unit for Lifelong Health and Ageing (Blodgett), University College London, London, UK.

Abstract

BACKGROUND:

Sedentary behaviours are associated with adverse health outcomes in middle-aged and older adults, even among those who exercise. We examined whether the degree of frailty affects the association between sedentary behaviours and higher risk of mortality.

METHODS:

In this prospective cohort study, we used data from 3141 community-dwelling adults 50 years of age or older from the 2003/04 and 2005/06 cohorts of the US National Health and Nutrition Examination Survey. Time engaged in sedentary behaviours was measured using uniaxial accelerometers, and frailty was based on a 46-item frailty index. Mortality data were linked up to 2011. We used Cox proportional hazard models to estimate the hazard ratio (HR) of sedentary behaviour.

RESULTS:

We found that for people with low levels of frailty (frailty index score ≤ 0.1), sedentary time was not predictive of mortality, regardless of physical activity level (adjusted HR 0.90, 95% confidence interval [CI] 0.70-1.15). Among people who were vulnerable (0.1 < frailty index score ≤ 0.2) or frail (frailty index score > 0.2), sedentary time was associated with higher mortality only among those who were physically inactive (not meeting the criterion for moderate physical activity) (HR 1.16, 95% CI 1.02-1.33 for the group defined by 0.1 < frailty index score ≤ 0.2; HR 1.27, 95% CI 1.11-1.46 for the group defined by 0.2 < frailty index score ≤ 0.3; HR 1.34, 95% CI 1.19-1.50 for frailty index score > 0.3).

INTERPRETATION:

The effect of sedentary behaviours on mortality varied by level of frailty. Adults with the highest frailty level experienced the greatest adverse impact. Low frailty levels (frailty index score ≤ 0.1) seemed to eliminate the increased risk of mortality associated with prolonged sitting, even among people who did not meet recommended physical activity guidelines.

PMID:
28827436
PMCID:
PMC5566605
DOI:
10.1503/cmaj.161034
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center