Table 2. Intraclass Correlations of BMI SD Score at 4 Years by Zygosity and Home Environment Risk.
| Home Environment Risk Group | No. (%) of Twin Pairs | Intraclass Correlation Coefficient (95% CI) | ||
|---|---|---|---|---|
| MZ (n = 314) | DZ (n = 611) | MZ | DZ | |
| Overall home environment | ||||
| Lower risk | 166 (52.9) | 351 (57.4) | 0.78 (0.71-0.83) | 0.51 (0.43-0.58) |
| Higher risk | 148 (47.1) | 260 (42.6) | 0.87 (0.83-0.91) | 0.41 (0.31-0.51) |
| Home food environment | ||||
| Lower risk | 146 (46.5) | 333 (54.5) | 0.80 (0.73-0.85) | 0.52 (0.44-0.59) |
| Higher risk | 168 (53.5) | 278 (45.5) | 0.84 (0.79-0.88) | 0.41 (0.31-0.50) |
| Home activity environment | ||||
| Lower risk | 179 (57.0) | 350 (57.3) | 0.81 (0.76-0.86) | 0.54 (0.46-0.61) |
| Higher risk | 135 (53.0) | 261 (42.7) | 0.83 (0.77-0.88) | 0.37 (0.26-0.47) |
| Home media environment | ||||
| Lower risk | 174 (55.4) | 375 (61.4) | 0.80 (0.74-0.85) | 0.48 (0.40-0.55) |
| Higher risk | 140 (44.6) | 236 (38.6) | 0.84 (0.78-0.88) | 0.45 (0.35-0.55) |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); DZ, dizygotic; MZ, monozygotic.