Table 3.
Association between body mass index (independent variable) and longitudinal change in total sitting time (dependent variable),a stratified by sex, employment status, total sitting time at baseline, and MVPAb
| BMI (kg/m2)c; aOR (95% CI)d | pe | pf | ||||
|---|---|---|---|---|---|---|
| <18.5 (n = 256) | 18.5–25 (n = 10,276) | 25–30 (n = 10,482) | ≥30 (n = 5,162) | |||
| All participants (n = 26,176) | 1.10 (0.83, 1.44) | 1.00 [ref] | 1.05 (0.99, 1.12) | 1.20 (1.11, 1.30)*** | <0.001 | <0.001 |
| Sex | ||||||
| Women (n = 14,707) | 1.04 (0.77, 1.41) | 1.00 [ref] | 1.06 (0.97, 1.15) | 1.24 (1.12, 1.38)*** | <0.001 | <0.001 |
| Men (n = 11,469) | 1.44 (0.76, 2.72) | 1.00 [ref] | 1.04 (0.94, 1.15) | 1.14 (1.00, 1.29)g | 0.160 | 0.053 |
| Employment status | ||||||
| Not working (n = 6,711) | 0.98 (0.58, 1.65) | 1.00 [ref] | 1.06 (0.93, 1.20) | 1.40 (1.21, 1.63)*** | <0.001 | <0.001 |
| Part time (n = 7,053) | 1.25 (0.81, 1.92) | 1.00 [ref] | 1.00 (0.88, 1.12) | 1.23 (1.06, 1.44)** | 0.029 | 0.020 |
| Full time (n = 12,412) | 1.06 (0.65, 1.73) | 1.00 [ref] | 1.08 (0.98, 1.18) | 1.07 (0.95, 1.20) | 0.424 | 0.167 |
| Total sittingg (hours/day) | ||||||
| <4 (n = 6,758) | 0.91 (0.57-1.45) | 1.00 [ref] | 1.05 (0.94-1.17) | 1.24 (1.07-1.44)** | 0.033 | 0.006 |
| 4–8 (n = 12,008) | 1.08 (0.74-1.58) | 1.00 [ref] | 1.05 (0.96-1.15) | 1.18 (1.06-1.32)** | 0.034 | 0.005 |
| 8–11 (n = 5,385) | 1.66 (0.82-3.36) | 1.00 [ref] | 1.03 (0.87-1.21) | 1.17 (0.96-1.43) | 0.215 | 0.145 |
| ≥11 (n = 2,025) | 2.35 (0.49-11.20) | 1.00 [ref] | 1.25 (0.86-1.83) | 1.35 (0.86-2.10) | 0.424 | 0.160 |
| MVPAb (minutes/week) | ||||||
| <150 (n = 4,159) | 1.08 (0.56, 2.09) | 1.00 [ref] | 1.05 (0.89, 1.25) | 1.21 (1.01, 1.46)* | 0.223 | 0.061 |
| 150–300 (n = 4,554) | 0.68 (0.30, 1.55) | 1.00 [ref] | 1.05 (0.90, 1.22) | 1.14 (0.95, 1.37) | 0.398 | 0.179 |
| ≥300 (n = 17,463) | 1.18 (0.85, 1.63) | 1.00 [ref] | 1.06 (0.98, 1.14) | 1.21 (1.10, 1.34)*** | 0.002 | <0.001 |
Difference in total sitting time between follow up and baseline categorized as: (0) ≤0 (decrease/no change); and 1 >0 (increase).
Time spent in moderate- to vigorous-intensity physical activity.
Baseline body mass index calculated from self-reported height and weight (normal BMI [18–25 kg/m2] was used as the reference category).
Odds ratio adjusted for age, sex, educational level, area level socio-economic status, employment status, baseline total sitting time, chronic illnesses, risk of psychological distress, self-reported general health, and time spent in moderate- to vigorous-intensity physical activity and its 95% confidence interval.
p-value based on the likelihood ratio chi-square test of heterogeneity (complete vs. reduced model).
p-value based on the chi-square test for linear trend (linear contrasts method).
Total time spent sitting at baseline.
P < 0.05; **P < 0.01; ***P < 0.001.