Table 4. Genetic and environmental influences on objectively measured habitual physical activity in 9-12 year old twins.
| Model | Estimates of variance components | Model fit | ||||||
| a2 | c2 | e2 | -2LL | df | ΔAIC | Δ x2 | p | |
| Total physical activity | ||||||||
| ACE | 0.14 (0.00, 0.45) | 0.63 (0.34, 0.80) | 0.23 (0.15, 0.35) | 497.837 | 227 | - | - | - |
| CE † | - | 0.73 (0.63, 0.81) | 0.27 (0.19, 0.37) | 498.901 | 228 | −0.936 | 1.064 | 0.302 |
| AE | 0.78 (0.69, 0.85) | - | 0.22 (0.15, 0.31) | 510.988 | 228 | 11.151 | 13.151 | <0.000 |
| Time spent in MVPA in minutes | ||||||||
| ACE | 0.28 (0.00, 0.73) | 0.39 (0.00, 0.68) | 0.33 (0.22, 0.48) | 590.487 | 227 | - | - | - |
| CE † | - | 0.61 (0.48, 0.71) | 0.39 (0.30, 0.52) | 592.531 | 228 | 0.044 | 2.044 | 0.153 |
| AE | 0.69 (0.56, 0.79) | - | 0.31 (0.21, 0.44) | 593.991 | 228 | 1.504 | 3.504 | 0.061 |
| Sedentary time in minutes | ||||||||
| ACE | 0.24 (0.00, 0.69) | 0.37 (0.00, 0.65) | 0.39 (0.27, 0.57) | 611.341 | 227 | - | - | - |
| CE † | - | 0.55 (0.41, 0.66) | 0.45 (0.34, 0.59) | 612.423 | 228 | −0.918 | 1.082 | 0.298 |
| AE | 0.63 (0.48, 0.74) | - | 0.37 (0.26, 0.52) | 614.132 | 228 | 0.791 | 2.791 | 0.095 |
Standard ACE model-fitting analyses were used to estimate additive genetic (a2), shared environment (c2), non-shared environment effects (e2).
†
indicates the most parsimonious model; Total physical activity (mean accelerometer counts per minute) MVPA moderate and vigorous physical activity mean accelerometer counts/min >2000; sedentary behaviour mean accelerometer counts/minute <100; LL log likelihood, AIC Akaike Information Criteria.