After adjusting for age and race/ethnicity, there were significant gender differences in all measures of sedentary time, with the direction and magnitude of the difference depending on the measure. For the domain-specific measures, prevalence was lower in women than men for high TV time (64.9% [95% CI=63.0%, 66.8%] vs 69.2% [67.6%, 70.7%], p<0.001), computer use (27.1% [25.1%, 29.1%] vs 31.3% [27.9%, 32.8%], p=0.034), and screen time (48.3% [46.2%, 50.3%] vs 52.0% [49.7%, 54.4%], p=0.012). However, more women than men reported sitting for most of the day (26.2% [24.4%, 28.0%] vs 21.5% [20.1%, 22.9%], p<0.001). This was consistent with the accelerometer findings (mean 8.50 [8.41, 8.59] hours/day in women vs 8.35 [8.25, 8.45] hours/day in men, p=0.006), although the magnitude of this difference was relatively small.
After adjusting for age and gender, Mexican Americans were significantly less sedentary (p<0.05) than non-Hispanic whites and non-Hispanic blacks according to all sedentary time measures, with the exception of high levels of TV time. Here, the prevalence was similar for Mexican Americans (69.0% [66.3%, 71.5%]) and non-Hispanic whites (67.6% [65.8%, 69.3%], p=0.383), but significantly higher for non-Hispanic blacks (79.1% [75.7%, 82.5%], p<0.01). Compared with non-Hispanic whites, non-Hispanic blacks also had a higher prevalence of high screen time (51.1% [48.6%, 53.7%] vs 65.8% [61.8%, 69.7%], p<0.001), but these two racial/ethnic groups did not differ significantly for any other measure.
shows the mean (a) and the prevalence estimates (b) of the sedentary time measures by age group (adjusted for gender and race/ethnicity). With the exception of computer use (where prevalence decreased with age), mean sedentary time and prevalence estimates tended to increase with age, but with a decrease between the 20–29 year and the 30–39 year age groups for all measures except sitting (which increased steadily with age).
Device-based (a) and self-reported (b) measures of sedentary time across age categories in U.S. adults aged ≥20 years (NHANES 2003–2006).
expands on by showing the mean (A and B) and the prevalence (C–H) estimates of the sedentary time measures by racial/ethnic group across age categories separately for men and for women. Among men, age trends in sedentary time differed significantly across racial/ethnic groups according to accelerometer-derived sedentary time (F(df: 10, 21)=3.24, p=0.01), but not according to the self-reported measures (p≥0.1). Among women, the age trends differed significantly by race/ethnicity according to the self-reported measures (sitting, screen time, TV time, and computer use; all p<0.05), but not the accelerometer-derived measure (p>0.1). Screen time results (omitted) were very similar to TV time. For a complete summary of results, see Appendixes A and B (www.ajpmonline.org
Prevalence (95% CI) of self-reported TV viewing ≥2 hours/day (a,b); computer use ≥1 hour/day (c,d); sitting (e,f) and mean (95% CI) accelerometer-measured sedentary time (g,h)