Purpose
The purpose of this study was to examine patterns of objectively-measured sedentary behavior in a national cohort of U.S. middle-aged and older adults and determine factors that influence prolonged sedentary behavior.
Methods
We studied 8,096 participants from the REasons for Geographic and Racial Differences in Stroke (REGARDS) Study, a population-based study of black and white adults ≥45 years. Seven-day accelerometry was conducted. Prolonged sedentary behavior was defined as accumulating ≥50% of total sedentary time in bouts ≥30 min.
Results
The number of sedentary bouts ≥20, ≥30, ≥60, and ≥90 min were 8.8 ± 2.3, 5.5 ± 1.9, 1.9 ± 1.1, and 0.8 ± 0.7 bouts/day, respectively. Sedentary bouts ≥20, ≥30, ≥60, and ≥90 min accounted for 60.0 ± 13.9%, 48.0 ± 15.5%, 26.0 ± 15.4%, and 14.2 ± 12.9% of total sedentary time, respectively. Several factors were associated with prolonged sedentary behavior in multivariate-adjusted models (Odds Ratio [95% CI]): older age (65-74 years: 1.99 [1.55-2.57]; ≥75 years: 4.68 [3.61-6.07] vs. 45-54 years), male sex (1.41 [1.28-1.56] vs. female), residence in non-stroke belt/buckle region of U.S. (stroke belt: 0.87 [0.77-0.98]; stroke buckle: 0.86 [0.77-0.95] vs. non-belt/buckle), body mass index (BMI) (overweight: 1.33 [1.18-1.51]; obese: 2.15 [1.89-2.44] vs. normal weight), winter (1.18 [1.03-1.35] vs. summer), and low amounts of moderate-vigorous physical activity (MVPA) [0 min/week: 2.00 [1.66-2.40] vs. ≥150 min/week).
Conclusions
In this sample of U.S. middle-aged and older adults, a large proportion of total sedentary time was accumulated in prolonged, uninterrupted bouts of sedentary behavior as almost one-half was accumulated in sedentary bouts ≥30 min. Several sociodemographic (age, sex, BMI), behavioral (MVPA), environmental (region), and seasonal factors are associated with patterns of prolonged sedentary behavior
