Table 2.
Factors associated with infant serum 25(OH)D <50 nmol/L at birth in multivariable analysis
| Characteristic | Variable | Crude OR (95% CI) | aOR (95% CI) |
|---|---|---|---|
| Maternal 25-hydroxyvitamin-D (nmol/L) | ≥50 | – | – |
| <50 | 5.8 (3.4 to 9.6) | 5.2 (2.9 to 9.6) | |
| Maternal race/ethnicity | Caucasian/other | – | – |
| African–American | 3.4 (1.6 to 8.2) | 3.2 (1.3 to 7.9) | |
| Gestational age | 28–32 weeks | – | – |
| <28 weeks | 2.4 (1.3 to 5.9) | 2.6 (1.1 to 6.2) | |
| Maternal prenatal vitamin use | No | – | – |
| Yes | 0.4 (0.2 to 0.7) | 0.24 (0.1 to 0.5) | |
| Season of birth | Summer | – | – |
| Fall | 1.8 (0.8 to 3.2) | 2.1 (1.1 to 4.2) | |
| Winter | 4.7 (2.4 to 9.6) | 4.3 (2.3 to 9.3) | |
| Spring | 2.3 (1.2 to 4.2) | 1.8 (0.9 to 2.8) |
All parameter estimates were adjusted for other covariates. Variables entered from univariate analysis that were not statistically significant in multivariable analysis were maternal age, maternal education, insurance and body mass index.