Table 3.
Association between maternal 25-hydroxyvitamin D (25(OH)D) and preeclampsia by maternal characteristics, Collaborative Perinatal Project (1959–66)
| Maternal serum 25(OH)D, nmol/L |
Cases (n) |
Unadjusted incidence |
Adjusted risk difference (95% CI) |
Adjustedb risk ratio (95% CI) |
|---|---|---|---|---|
| <18 weeks at blood sampling | ||||
| <30 | 53 | .023 | 0 (ref) | 1.0 (ref) |
| 30–<50 | 61 | .019 | −.001 (−.009, .007) | .96 (.62, 1.5) |
| 50–<75 | 41 | .014 | −.004 (−.013, .006) | .81 (.49, 1.3) |
| ≥75 | 24 | .018 | .002 (−.010, .014) | 1.1 (.60, 1.9) |
| 18–22 weeks at blood sampling | ||||
| <30 | 53 | .029 | 0 (ref) | 1.0 (ref) |
| 30–<50 | 70 | .031 | .0002 (−.008, .009) | 1.0 (.64, 1.6) |
| 50–<75 | 44 | .026 | −.002 (−.011, .008) | .91 (.55, 1.5) |
| ≥75 | 33 | .031 | .004 (−.009, .017) | 1.2 (.64, 2.2) |
| 22–26 weeks at blood sampling | ||||
| <30 | 79 | .031 | 0 (ref) | 1.0 (ref) |
| 30–<50 | 116 | .032 | .002 (−.004, .009) | 1.1 (.80, 1.6) |
| 50–<75 | 86 | .028 | −.001 (−.007, .005) | .93 (.62, 1.4) |
| ≥75 | 57 | .029 | .002 (−.006, .010) | 1.1 (.69, 1.8) |
| Pregravid BMI<25 kg/m2 | ||||
| <30 | 130 | .025 | 0 (ref) | 1.0 (ref) |
| 30–<50 | 180 | .024 | .001 (−.004, .005) | 1.1 (.79, 1.4) |
| 50–<75 | 134 | .021 | −.002 (−.006, .003) | .91 (.67, 1.2) |
| ≥75 | 81 | .021 | 0 (−.006, .006) | .99 (.69, 1.4) |
| Pregravid BMI≥25 kg/m2 | ||||
| <30 | 55 | .037 | .0 (ref) | 1.0 (ref) |
| 30–<50 | 67 | .040 | .003 (−.010, .016) | 1.1 (.69, 1.7) |
| 50–<75 | 37 | .030 | −.005 (−.019, .009) | .80 (.46, 1.4) |
| ≥75 | 33 | .056 | .015 (−.006, .037) | 1.6 (.87, 2.8) |
| White race | ||||
| <30 | 36 | .020 | 0 (ref) | 1.0 (ref) |
| 30–<50 | 83 | .021 | −.002 (−.010, .007) | .92 (.58, 1.5) |
| 50–<75 | 86 | .018 | −.004 (−.013, .004) | .79 (.50, 1.3) |
| ≥75 | 65 | .020 | −.003 (−.012, .006) | .87 (.54, 1.4) |
| Nonwhite race | ||||
| <30 | 149 | .031 | 0 (ref) | 1.0 (ref) |
| 30–<50 | 164 | .032 | .002 (−.003, .007) | 1.1 (.83, 1.4) |
| 50–<75 | 85 | .028 | −.002 (−.008, .004) | .91 (.66, 1.3) |
| ≥75 | 49 | .040 | .007 (−.001, .014) | 1.4 (.91, 2.1) |
| Nulliparous | ||||
| <30 | 94 | .046 | 0 (ref) | 1.0 (ref) |
| 30–<50 | 130 | .046 | .007 (−.009, .024) | 1.2 (.82, 1.6) |
| 50–<75 | 92 | .033 | −.006 (−.022, .011) | .87 (.60, 1.3) |
| ≥75 | 56 | .037 | .002 (−.018, .023) | 1.0 (.67, 1.6) |
| Parous | ||||
| <30 | 91 | .020 | 0 (ref) | 1.0 (ref) |
| 30–<50 | 117 | .019 | 0 (−.006, .006) | .98 (.72, 1.3) |
| 50–<75 | 79 | .016 | −.001 (−.008, .006) | .94 (.66, 1.3) |
| ≥75 | 58 | .020 | .004 (−.004, .013) | 1.2 (.82, 1.8) |
b
Adjusted for maternal race, prepregnancy body mass index, parity, socioeconomic status, smoking status, and season of blood sampling. A statistical interaction term was included in models to generate linear combinations of interest.