Table 2.
Principle characteristics of parents and infants between the patients who completed the study or were lost to follow up
| Variable | Completed the study (n = 202) | Lost to follow up (n = 186) | p value |
|---|---|---|---|
| Maternal childbearing age (year) | 30.3 (27.7, 33.6) | 30.5 (27.8, 34.0) | .9 |
| Paternal childbearing age (year) | 31.4 (28.8, 35.7) | 32.7 (29.4, 36.3) | .06 |
| Maternal college education (%) | 74.0 | 77.5 | .6 |
| Paternal college education (%) | 69.6 | 78.9 | .1 |
| Maternal use of vitamin D supplements during pregnancy (%) | 89.1 | 83.3 | .1 |
| Infant birth weight (kg) | 3.3 ± 0.3 | 3.2 ± 0.4 | .2 |
| Infant birth length (cm) | 50 (49, 51) | 50 (49, 51) | .3 |
| Infant age at clinical visit (days) | 50 (49, 51) | 50 (49, 51) | .6 |
| Infant weight at 6 months (kg) | 7.8 (7.3, 8.4) | 7.8 (7.3, 8.4) | .7 |
| Infant height at 6 months (cm) | 67.3 ± 2.3 | 67.3 ± 2.4 | .9 |
| Infant head circumference at 6 months (cm) | 42.4 ± 1.2 | 42.5 ± 1.2 | .8 |
| Exclusively breastfed (%) | 54.0 | 54.9 | .9 |
| Initiated weaning at 6 months (%) | 81.9 | 76.6 | .4 |
| Infants supplemented with vitamin D at 6 months (%) | 93.6 | 91.9 | .6 |
| Cord blood 25OHD (nmol/L) | 44.7 (34.6, 55.2) | 43.2 (29.4, 57.7) | .5 |
Note. M ± SD (all such values) and median; interquartile range in parentheses (all such values); used in the case of non‐normally distributed variables. Differences between two groups were tested using analysis of independent t test for normally distributed variables and independent U test for non‐normally distributed variables. The chi‐square test was used to compare the rates.
Abbreviation: 25OHD, 25‐hydroxyvitamin D.