Baseline characteristics of children who participated in the study and nonparticipants
| Characteristic | Participants n = 2831* | Nonparticipants n = 1692 | |||
|---|---|---|---|---|---|
| Only cow’s milk n = 1950 | Only non–cow’s milk n = 146 | Both n = 157 | Neither n = 215 | ||
| Age, yr, mean ± SD | 3.0 ± 1.4 | 2.9 ± 1.5 | 3.3 ± 1.3 | 1.7 ± 1.2 | 2.7 ± 1.5 |
| Sex, male, no. (%) | 1025 (52.6) | 76 (52.1) | 88 (56.1) | 109 (50.7) | 850 (50.2) |
| BMI z score, median (IQR) | 0.23 (−0.44 to 0.88) | 0.10 (−0.70 to 0.58) | 0.32 (−0.34 to 0.84) | −0.11 (−0.90 to 0.51) | 0.19 (−0.48 to 0.88) |
| No. of cups† per day, mean ± SD | |||||
| Non–cow’s milk | – | 1.8 ± 1.1 | 1.1 ± 0.8 | – | 0.2 ± 0.6 |
| Cow’s milk | 2.0 ± 1.1 | – | 1.7 ± 1.1 | – | 1.7 ± 1.2 |
| Margarine consumption, no. (%) | 587 (30.1) | 22 (15.1) | 43 (27.4) | 35 (16.3) | 336 (19.9) |
| Vitamin D supplementation, no. (%) | 1020 (52.3) | 92 (63.0) | 93 (59.2) | 123 (57.2) | 600 (35.5) |
| Skin pigmentation,‡ no. (%) | |||||
| Light (type I or II) | 1003 (51.4) | 68 (46.6) | 83 (52.9) | 97 (45.1) | 592 (35.0) |
| Medium (type III or IV) | 766 (39.3) | 68 (46.6) | 63 (40.1) | 92 (42.8) | 855 (50.5) |
| Dark (type V or VI) | 107 (5.5) | 9 (6.2) | 6 (3.8) | 17 (7.9) | 66 (3.9) |
| Outdoor play, h/wk, mean ± SD | 5.0 ± 2.3 | 5.1 ± 2.1 | 5.2 ± 2.2 | 4.5 ± 2.5 | 4.6 ± 2.4 |
| Serum 25(OH)D level, nmol/L, median (IQR) | 81 (67 to 100) | 78 (62 to 96) | 76 (63 to 93) | 74 (61 to 98) | NA |
| Serum 25(OH)D level < 50 nmol/L, no. (%) | 92 (4.7) | 16 (11.0) | 11 (7.0) | 16 (7.4) | NA |