Background
Methods
Study design
Outcome variable (zBMI)
Independent variables (sedentary behaviour)
Mediating variables (dietary intake)
Covariates
Statistical analyses
Results
Variables | TV and zBMI (n = 259) | Sedentary time and zBMI (n = 140) |
---|---|---|
Age, years | 12.9 (12.9, 13.0) | 12.9 (12.9, 13.0) |
Sex, % | ||
Male | 47.5 (41.4, 53.6) | 50.0 (41.7, 58.3) |
Female | 52.5 (46.4, 58.4) | 50.0 (41.7, 58.3) |
Maternal education, % | ||
Low | 6.9 (4.4, 10.8) | 5.0 (2.3, 10.2) |
Medium | 65.3 (59.2, 70.8) | 62.8 (54.4, 70.5) |
High | 27.8 (22.7, 33.6) | 32.1 (24.8, 40.4) |
Pubertal status, % | ||
Early puberty | 19.3 (8.0, 4.6) | 14.3 (35.1, 56.2) |
Mid-pubertal | 35.5 (30.0, 41.6) | 41.4 (33.5, 50.0) |
Late-pubertal | 35.5 (30.0, 41.6) | 35.0 (27.5, 43.4) |
Post-pubertal | 27.0 (21.9, 32.8) | 22.1 (16.0, 30.0) |
BMI | ||
kg/m2
| 20.7 (20.2, 21.3) | 20.3 (19.7, 21.0) |
z-score | 0.4 (0.3, 0.5) | 0.3 (0.1, 0.5) |
Overweight, % | 18.9 (14.6, 24.2) | 13.6 (8.8, 20.4) |
Obese, % | 9.2 (6.3, 13.5) | 9.2 (5.4, 15.4) |
Sedentary behaviour | ||
TV viewing (hours/day) | 3.2 (3.0, 3.4) | |
Total sedentary time (hours/day) | 6.1 (6.0, 6.2) | |
Average sedentary bout (minutes/day) | 6.6 (6.5, 6.6) | |
MVPA (minutes/day) | 48.2 (35.0, 61.4) | |
Dietary intake | ||
Discretionary foods (freq/day) | 2.4 (2.2, 2.6) | 2.4 (2.1, 2.7) |
Sugar-sweetened beverages (freq/day) | 2.1 (1.8, 2.3) | 1.9 (1.6, 2.2) |
Takeaway food (freq/week) | 3.4 (3.1, 3.6) | 3.2 (2.8, 3.6) |
Associations between TV viewing, dietary intake and zBMI
Cross-sectionally
Outcome: zBMI | c`-coefficient (direct) β (95% CI) | a-coefficient β (95% CI) | b-coefficient β (95% CI) | ab/indirect (mediated/indirect)c
| |
---|---|---|---|---|---|
Independent: TV viewing | Uncorrected β (95% CI) | Bias-corrected β (95% CI) | |||
Cross-sectional mediators | |||||
Discretionary food (freq/day) | 0.05 (−0.02, 0.13) | 0.01 (−0.03, 0.05) | −0.39 (−0.65, −0.13)** | −0.04 (−0.18, 0.10) | −0.04 (−0.23, 0.12) |
SSB (freq/day) | 0.05 (−0.03, 0.13) | 0.02 (−0.03, 0.07) | 0.03 (−0.15, 0.22) | 0.01 (−0.04, 0.05) | 0.01 (−0.07, 0.09) |
Takeaway food (freq/week) | 0.05 (−0.02, 0.13) | 0.06 (0.01, 0.12)* | −0.07 (−0.24, 0.09) | −0.05 (−0.16, 0.07) | −0.05 (−0.22, 0.06) |
Prospective mediators | |||||
At baseline | |||||
Discretionary foods (freq/day) | −0.01 (−0.04, 0.02) | 0.01 (−0.02, 0.05) | 0.02 (−0.09, 0.13) | 0.01 (−0.01, 0.02) | 0.01 (−0.02, 0.04) |
SSB (freq/day) | −0.01 (−0.04, 0.02) | 0.02 (−0.03, 0.07) | 0.03 (−0.04, 0.11) | 0.01 (−0.02, 0.03) | 0.01 (−0.02, 0.04) |
Takeaway food (freq/week) | −0.01 (−0.04, 0.02) | 0.07 (0.01, 0.12)* | −0.01 (−0.07, 0.06) | −0.01 (−0.04, 0.05) | −0.01 (−0.06, 0.05) |
At follow-up | |||||
Discretionary foods (freq/day) | −0.01 (−0.04, 0.02) | 0.02 (−0.02, 0.07) | −0.04 (−0.13, 0.06) | −0.01 (−0.04, 0.02) | −0.01 (−0.06, 0.02) |
SSB (freq/day) | −0.01 (−0.04, 0.02) | −0.01 (−0.05, 0.04) | 0.03 (−0.06, 0.11) | −0.001 (−0.01, 0.01) | −0.001 (−0.03, 0.02) |
Takeaway food (freq/week) | −0.01 (−0.04, 0.02) | 0.10 (0.04, 0.16)* | 0.02 (−0.05, 0.08) | 0.02 (−0.05, 0.08) | 0.02 (−0.04, 0.09) |
Prospectively
Associations between total sedentary time, dietary intake and zBMI
Cross-sectionally
Outcome: zBMI | c`-coefficient (direct) β (95% CI) | a-coefficient β (95% CI) | b-coefficient β (95% CI) | ab/indirect (mediated/indirect)c
| |
---|---|---|---|---|---|
Independent: total sedentary time | Uncorrected β (95% CI) | Bias-corrected β (SE) | |||
Cross-sectional mediators | |||||
Discretionary food (freq/day) | 0.27 (−0.03, 0.58) | −0.01 (−0.15, 0.14) | −0.42 (−0.77, −0.07)* | 0.01 (−0.61, 0.62) | 0.01 (−0.62, 0.69) |
SSB (freq/day) | 0.27 (−0.05, 0.58) | −0.16 (−0.38, 0.06) | −0.04 (−0.29, 0.20) | 0.07 (−0.33, 0.46) | 0.07 (−0.31, 0.61) |
Takeaway food (freq/week) | 0.27 (−0.05, 0.58) | −0.06 (−0.30, 0.18) | −0.04 (−0.26, 0.18) | 0.02 (−0.13, 0.18) | 0.02 (−0.36, 0.35) |
Prospective mediators | |||||
At baseline | |||||
Discretionary food (freq/day) | 0.05 (−0.07, 0.17) | 0.03 (−0.12, 0.17) | 0.03 (−0.10, 0.17) | 0.01 (−0.05, 0.07) | 0.01 (−0.08, 0.15) |
SSB (freq/day) | 0.05 (−0.06, 0.17) | −0.15 (−0.37, 0.07) | 0.02 (−0.07, 0.11) | −0.03 (−0.17, 0.11) | −0.03 (−0.22, 0.13) |
Takeaway food (freq/week) | 0.05 (−0.07, 0.17) | −0.05 (−0.30, 0.19) | −0.03 (−0.12, 0.05) | 0.02 (−0.08, 0.11) | 0.02 (−0.12, 0.16) |
At follow-up | |||||
Discretionary food (freq/day) | 0.05 (−0.07, 0.17) | 0.08 (−0.09, 0.24) | 0.01 (−0.11, 0.13) | 0.01 (−0.05, 0.10) | 0.01 (−0.16, 0.17) |
SSB (freq/day) | 0.05 (−0.06, 0.17) | −0.04 (−0.23, 0.15) | 0.01 (−0.10, 0.12) | −0.01 (−0.05, 0.04) | −0.01 (−0.11, 0.09) |
Takeaway food (freq/week) | 0.05 (−0.06, 0.17) | 0.21 (−0.57, 0.47) | −0.01 (−0.08, 0.07) | −0.01 (−0.16, 0.15) | −0.01 (−0.19, 0.17) |
Prospectively
Associations between average sedentary bout duration, dietary intake and zBMI
Cross-sectionally
Outcome: zBMI | c`-coefficient (direct) β (95% CI) | a-coefficient β (95% CI) | b-coefficient β (95% CI) | ab/indirect (mediated/indirect)c
| |
---|---|---|---|---|---|
Independent: sedentary bouts | Uncorrected β (95% CI) | Bias-corrected β (SE) | |||
Cross-sectional mediators | |||||
Discretionary food (freq/day) | 0.12 (−0.36, 0.61) | −0.08 (−0.31, 0.15) | −0.42 (−0.77, −0.06)* | 0.32 (−0.67, 1.32) | 0.32 (−0.55, 1.37) |
SSB (freq/day) | 0.14 (−0.36, 0.64) | −0.36 (−0.69, −0.02)* | −0.06 (−0.30, 0.19) | 0.20 (−0.71, 1.11) | 0.20 (−0.68, 0.12) |
Takeaway food (freq/week) | 0.16 (−0.33, 0.65) | 0.03 (−0.34, 0.41) | −0.05 (−0.28, 0.18) | −0.02 (−0.21, 0.18) | −0.02 (−0.62, 0.34) |
Prospective mediators | |||||
At baseline | |||||
Discretionary food (freq/day) | 0.08 (−0.10, 0.26) | −0.06 (−0.29, 0.17) | 0.04 (−0.10, 0.17) | −0.02 (−0.14, 0.10) | −0.02 (−0.24, 0.14) |
SSB (freq/day) | 0.09 (−0.09, 0.27) | −0.36 (−0.70, −0.02)* | 0.02 (−0.07, 0.11) | −0.09 (−0.42, 0.24) | −0.09 (−0.52, 0.24) |
Takeaway food (freq/week) | 0.08 (−0.10, 0.26) | 0.04 (−0.34, 0.41) | −0.04 (−0.12, 0.04) | −0.01 (−0.15, 0.13) | −0.01 (−0.27, 0.16) |
At follow-up | |||||
Discretionary food (freq/day) | 0.08 (−0.10, 0.26) | −0.08 (−0.34, 0.17) | 0.02 (−0.10, 0.14) | −0.02 (−0.12, 0.09) | −0.02 (−0.28, 0.16) |
SSB (freq/day) | 0.08 (−0.10, 0.26) | 0.11 (−0.18, 0.40) | 0.01 (−0.010, 0.11) | 0.01 (−0.11, 0.12) | 0.01 (−0.19, 0.20) |
Takeaway food (freq/week) | 0.08 (−0.10, 0.26) | 0.06 (−0.35, 0.48) | −0.01 (−0.08, 0.07) | −0.01 (−0.05, 0.04) | −0.01 (0.18, 0.17) |