Table 4.
Association of maternal vitamin D status at ≤26 weeks gestation and infant WAZ and BMIZ over the first year of life based on multivariate-adjusted* mixed effects linear regression models, with infant age centred at different points corresponding with ages at measurements.
| Weight-for-age z-score1 (n = 2473) | BMI-for-age z-score1 (n = 2466) | |||||
|---|---|---|---|---|---|---|
| β | 95% CI | p Value | β | 95% CI | p Value | |
| Maternal vitamin D status coefficients | ||||||
| Birth | ||||||
| <30 nmol/L | Ref | Ref | ||||
| ≥30 nmol/L | 0.144 | (0.050, 0.239) | 0.003 | 0.107 | (0.011, 0.202) | 0.028 |
| 4 months | ||||||
| <30 nmol/L | Ref | Ref | ||||
| ≥30 nmol/L | 0.100 | (0.015, 0.186) | 0.022 | 0.050 | (−0.030, 0.129) | 0.218 |
| 8 months | ||||||
| <30 nmol/L | Ref | Ref | ||||
| ≥30 nmol/L | 0.056 | (−0.032, 0.145) | 0.212 | −0.007 | (−0.091, 0.077) | 0.867 |
| 12 months | ||||||
| <30 nmol/L | Ref | Ref | ||||
| ≥30 nmol/L | 0.012 | (−0.089, 0.114) | 0.812 | −0.064 | (−0.171, 0.043) | 0.239 |
| Age coefficients, per month | ||||||
| Age for <30 nmol/L | 0.080 | (0.073, 0.087) | <0.001 | 0.130 | (0.121, 0.139) | <0.001 |
| Age for ≥30 nmol/L | 0.069 | (0.065, 0.073) | <0.001 | 0.116 | (0.110, 0.121) | <0.001 |
*
Adjusted for study site, mother and child specified as random effects and infant age, infant sex, maternal BMI, maternal socioeconomic status, maternal race, season of maternal blood draw and breastfeeding specified as fixed effects with interaction term for age (continuous) and 25(OH)D (dichotomous at 30 nmol/L). Interaction p<0.01 for weight-for-age and BMI models.