Table 2.
Association Between Average Sedentary Bout Duration and Body Fat Distribution Among US Children and Adolescents, NHANES 2003-2006
| n | β coefficient (95% CI) |
||||
|---|---|---|---|---|---|
| Total fat percentage |
Trunk fat percentage |
||||
| Model 1* | Model 2† | Model 1* | Model 2† | ||
| Children | |||||
| Female 8-11 y | |||||
| Average sedentary bout duration‡ | |||||
| Q1 | 103 | 0 [Reference] | 0 [Reference] | 0 [Reference] | 0 [Reference] |
| Q2 | 115 | −0.35 (−2.80 – 2.10) | −0.37 (−2.64 – 1.90) | 0.17 (−2.76 – 3.09) | 0.14 (−2.62 – 2.91) |
| Q3 | 106 | 2.90 (0.50 – 5.31) | 1.66 (−0.86 – 4.19) | 4.08 (1.11 – 7.04) | 2.64 (−0.51 – 5.79) |
| Q4 | 102 | 2.68 (−0.14 – 5.50) | 0.90 (−1.83 – 3.63) | 3.39 (0.01 – 6.77) | 1.33 (−2.02 – 4.69) |
| P for trend§ | 0.010 | 0.253 | 0.009 | 0.218 | |
| MVPA (per 30 min) ¶ | −3.05 (−4.13 – −1.97) | −3.54 (−4.91 – −2.16) | |||
| Male 8-11 y | |||||
| Average sedentary bout duration‡ | |||||
| Q1 | 104 | 0 [Reference] | 0 [Reference] | 0 [Reference] | 0 [Reference] |
| Q2 | 93 | 1.91 (−1.34 – 5.17) | 0.99 (−1.99 – 3.96) | 2.27 (−1.19 – 5.74) | 1.28 (−1.98 – 4.54) |
| Q3 | 98 | 4.03 (1.51 – 6.54) | 2.53 (0.08 – 4.98) | 4.36 (1.53 – 7.19) | 2.75 (−0.14 – 5.64) |
| Q4 | 89 | 4.88 (2.11 – 7.64) | 3.13 (0.77 – 5.48) | 5.37 (2.41 – 8.34) | 3.49 (0.84 – 6.15) |
| P for trend § | <0001 | 0.004 | <0001 | 0.006 | |
| MVPA (per 30 min) ¶ | −2.07 (−2.82 – −1.32) | −2.22 (−3.05 – −1.39) | |||
| Adolescents | |||||
| Female 12-19 y | |||||
| Average sedentary bout duration‡ | |||||
| Q1 | 191 | 0 [Reference] | 0 [Reference] | 0 [Reference] | 0 [Reference] |
| Q2 | 255 | 0.42 (−1.38 – 2.22) | 0.26 (−1.46 – 1.98) | 0.88 (−1.45 – 3.21) | 0.72 (−1.57 – 3.01) |
| Q3 | 262 | 2.26 (0.56 – 3.96) | 1.65 (−0.06 – 3.36) | 2.57 (0.51 – 4.63) | 1.96 (−0.17 – 4.10) |
| Q4 | 272 | 2.08 (0.34 – 3.81) | 1.63 (−0.02 – 3.29) | 2.41 (0.41 – 4.42) | 1.97 (−0.01 – 3.95) |
| P for trend § | 0.006 | 0.020 | 0.009 | 0.029 | |
| MVPA (per 30 min) ¶ | −1.58 (−2.39 – −0.76) | −1.58 (−2.62 – −0.55) | |||
| Male 12-19 y | |||||
| Average sedentary bout duration‡ | |||||
| Q1 | 322 | 0 [Reference] | 0 [Reference] | 0 [Reference] | 0 [Reference] |
| Q2 | 270 | −0.18 (−1.66 – 1.29) | −0.35 (−1.92 – 1.21) | −0.35 (−1.98 – 1.28) | −0.54 (−2.28 – 1.20) |
| Q3 | 268 | 0.78 (−0.83 – 2.39) | 0.36 (−1.29 – 2.02) | 0.73 (−0.97 – 2.42) | 0.27 (−1.51 – 2.06) |
| Q4 | 222 | 1.10 (−0.51 – 2.71) | 0.30 (−1.35 – 1.95) | 1.10 (−0.70 – 2.90) | 0.22 (−1.68 – 2.12) |
| P for trend § | 0.135 | 0.578 | 0.166 | 0.671 | |
| MVPA (per 30 min) ¶ | −1.07 (−1.61 – −0.53) | −1.17 (−1.79 – −0.56) | |||
Abbreviation: AC, activity count; DXA, dual energy X-ray absorptiometry; HEI, Healthy Eating Index; MVPA, moderate-to-vigorous physical activity; NHANES, National Health and Nutrition Examination Survey.
Model 1 was adjusted for age, total accelerometer wear time (continuous), sex, race/ethnicity (Non-Hispanic White, Non-Hispanic Black, Hispanic, or others), family income poverty ratio (<1.30, 1.30-3.49, ≥3.50), total energy intake (continuous), and HEI-2010 (continuous).
Model 2 was additionally adjusted for MVPA (continuous).
Average sedentary bout duration was calculated as total sedentary time divided by sedentary bout frequency within valid wear time using accelerometer data; a sedentary bout was a period of consecutive duration in which AC <100. Average sedentary bout duration was further categorized according to quartiles (Qs) within each year age: Q1 indicates the lowest quartile of bout duration, and Q4 indicates the highest quartile of bout duration.
P for trend was calculated using the quartile of average sedentary bout duration within each age group as a continuous variable
Age-specific cutoffs for MVPA were used (AC ≥1638, ≥1770, ≥1910, ≥2059, ≥2220, ≥2393, ≥2580, ≥2781, ≥3000, ≥3239, and ≥2020 for age 8-, 9-, 10-, 11-, 12-, 13-, 14-, 15-, 16-, 17-, and ≥18 y, respectively) according to the thresholds used by the National Cancer Institute.