Abstract P421: Self-reported Sedentary Behaviors and Steps/day in the United States, 2005-2006
Introduction: Self-reported sedentary behaviors have been associated with increased mortality. It is plausible that self-reported sedentary behavior is inversely related to daily ambulatory activity (i.e., steps/day). This analysis of the 2005-2006 National Health and Nutrition Examination Survey examines objectively monitored steps/day in adults ≥ 20 years of age across categories of self-reported daily sitting (usual occupational/domestic activity; UODA), leisure-time sedentary behavior (LTSB), and cross-classifications of UODA and LTSB.
Hypothesis: We hypothesized that 1) adults reporting their UODA as “mostly sitting” would accumulate fewer steps/day than individuals reporting “standing, walking, lifting, or carrying,” 2) adults reporting ≥ 3 hr/day LTSB would accumulate fewer steps/day than individuals reporting < 3 hr/day LTSB, and 3) accumulated steps/day would vary significantly among cross-classifications of UODA and LTSB.
Methods: UODA was assessed with a single query about usual daily occupational/domestic behavior (sitting, standing, walking, lifting, or carrying loads). LTSB was calculated from questions regarding leisure-time screen-time behaviors (i.e., television viewing and computer usage). Objectively monitored steps/day were measured using the ActiGraph accelerometer (model 7164) worn for 7 consecutive days. The analytic sample comprised 3737 individuals with complete UODA and LTSB data as well as valid accelerometer data (at least 1 day with at least 10 monitored hours). Planned comparisons of mean steps/day among groupings of UODA, LTSB, and their cross-classifications were assessed using two-directional t-tests (Bonferroni-corrected to maintain global alpha ≤ 0.05) using SAS survey procedures.
Results: Mean ambulatory activity was significantly lower (p < 0.01) for participants describing their daily UODA as “mostly sitting” (4902 ± 142 steps/day) than for those reporting “standing, walking, lifting, or carrying” (7031 ± 118 steps/day). Mean ambulatory activity was also significantly lower (p < 0.01) for participants reporting ≥ 3 hr/day LTSB (5496 ± 132 steps/day) than for those reporting < 3 hr/day (7174 ± 102 steps/day). Cross-classifications of UODA and LTSB were significantly different from each other (all p < 0.01). The most sedentary group (reporting “mostly sitting” UODA and ≥ 3 hr/day LTSB; 4315 ± 162 steps/day) accumulated 43% (3246 of 7561) fewer steps/day than the least sedentary group (reporting “standing, walking, lifting, or carrying” UODA and < 3 hr/day LTSB; 7561 ± 118 steps/day).
Conclusions: Among non-institutionalized American adults, there is an inverse association between self-reported sedentary behavior and objectively monitored ambulatory activity. Future research is needed to investigate whether objectively monitored ambulatory activity may be used as a proxy indicator of sedentary behavior.
- © 2013 by American Heart Association, Inc.