TABLE 3.
Protective factors against infants being born with serum 25(OH)D <30 or <40 nmol/L1
| Serum 25(OH)D < 30 nmol/L | Serum 25(OH)D ≥ 40 nmol/L | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Factor | n | % | P value | Unadjusted OR (95% CI) | Adjusted OR (95% CI)2 | % | P value | Unadjusted OR (95% CI) | Adjusted OR (95% CI)2 |
| Multivitamin use3 | 0.0244 | 0.10 | |||||||
| Preconception + pregnancy | 352 | 13.1 | 0.63 (0.42, 0.94) | 0.55 (0.36, 0.86) | 68.8 | 1.30 (0.95, 1.78) | 1.47 (1.04, 2.07) | ||
| Pregnancy only | 352 | 19.3 | Reference | Reference | 62.8 | Reference | Reference | ||
| Prepregnancy BMI, kg/m2 | 0.0152 | 0.0070 | |||||||
| <25 | 437 | 13.5 | Reference | Reference | 69.6 | Reference | Reference | ||
| ≥25 | 267 | 20.6 | 1.66 (1.11, 2.49) | 1.82 (1.18, 2.81) | 59.6 | 0.64 (0.47, 0.89) | 0.59 (0.42, 0.83) | ||
| Exercise in pregnancy4 | 0.25 | 0.0007 | |||||||
| Yes | 356 | 14.6 | Reference | Reference | 71.6 | Reference | Reference | ||
| No | 348 | 17.8 | 1.27 (0.85, 1.90) | 1.08 (0.69, 1.68) | 59.8 | 0.59 (0.43, 0.81) | 0.69 (0.49, 0.97) | ||
| Season at birth5 | 0.0100 | 0.0002 | |||||||
| Winter | 163 | 22.1 | 2.80 (1.51, 5.21) | 3.58 (1.84, 6.94) | 60.7 | 0.43 (0.27, 0.68) | 0.34 (0.21, 0.57) | ||
| Spring | 188 | 18.1 | 2.18 (1.17, 4.06) | 2.61 (1.34, 5.09) | 58.0 | 0.38 (0.24, 0.60) | 0.31 (0.19, 0.51) | ||
| Summer | 185 | 9.2 | Reference | Reference | 78.4 | Reference | Reference | ||
| Fall | 168 | 16.1 | 1.89 (0.99, 3.61) | 2.40 (1.21, 4.79) | 65.5 | 0.52 (0.33, 0.84) | 0.39 (0.23, 0.65) | ||
| Parity | 0.61 | 0.0468 | |||||||
| Primiparous | 326 | 15.3 | Reference | Reference | 69.6 | Reference | Reference | ||
| Multiparous | 378 | 16.9 | 1.13 (0.75, 1.69) | 1.27 (0.79, 2.05) | 62.4 | 0.73 (0.53, 0.99) | 0.67 (0.46, 0.96) | ||
| Maternal population group6 | <0.0001 | <0.0001 | |||||||
| Black | 36 | 36.1 | 4.74 (2.26, 9.96) | 5.58 (2.50, 12.47) | 36.1 | 0.20 (0.10, 0.40) | 0.16 (0.07, 0.34) | ||
| East/Southeast Asian | 35 | 34.3 | 4.38 (2.05, 9.34) | 5.22 (2.25, 12.10) | 40.0 | 0.23 (0.11, 0.47) | 0.20 (0.09, 0.42) | ||
| Latino | 27 | 18.5 | 1.91 (0.69, 5.26) | 2.09 (0.72, 6.04) | 51.9 | 0.37 (0.17, 0.81) | 0.38 (0.17, 0.87) | ||
| Middle Eastern | 67 | 28.4 | 3.32 (1.81, 6.10) | 3.81 (1.94, 7.46) | 46.3 | 0.30 (0.18, 0.50) | 0.25 (0.14, 0.45) | ||
| South Asian | 42 | 19.1 | 1.97 (0.87, 4.50) | 2.64 (1.10, 6.35) | 59.5 | 0.51 (0.27, 0.97) | 0.36 (0.18, 0.72) | ||
| Mixed or unknown | 37 | 21.6 | 2.31 (1.00, 5.34) | 2.63 (1.08, 6.38) | 64.9 | 0.64 (0.31, 1.29) | 0.50 (0.24, 1.07) | ||
| White | 460 | 10.7 | Reference | Reference | 74.4 | Reference | Reference | ||
| Maternal age, y | 0.19 | 0.3071 | |||||||
| ≤30 | 168 | 19.6 | 1.37 (0.88, 2.15) | 1.75 (1.03, 2.97) | 26.1 | 1.21 (0.84, 1.73) | 0.60 (0.39, 0.91) | ||
| >30 | 536 | 15.1 | Reference | Reference | 33.2 | Reference | Reference | ||
| Maternal education | 0.41 | 0.90 | |||||||
| High school or less | 76 | 19.7 | 0.76 (0.42, 1.39) | 0.84 (0.43, 1.65) | 32.9 | 1.07 (0.65, 1.77) | 0.84 (0.47, 1.48) | ||
| Postsecondary | 628 | 15.8 | Reference | Reference | 34.4 | Reference | Reference | ||
| Family income, CAD | 0.0056 | 0.11 | |||||||
| <70,000 | 134 | 25.4 | 2.04 (1.27, 3.27) | 1.11 (0.65, 1.91) | 41.8 | 1.53 (1.03, 2.28) | 1.17 (0.74, 1.85) | ||
| ≥70,000 | 448 | 14.3 | Reference | Reference | 31.9 | Reference | Reference | ||
| Not reported | 122 | 13.1 | 0.91 (0.50, 1.63) | 0.53 (0.28, 1.02) | 34.4 | 1.12 (0.73, 1.71) | 1.53 (0.94, 2.50) | ||
1
Values are n and row percentages or ORs (95% CIs) unless otherwise indicated. CAD, Canadian dollars; 25(OH)D, 25-hydroxyvitamin D.
2
Adjusted for all other independent variables in the table.
3
Surveyed as multivitamin used in the 3 mo before conceiving; and used during pregnancy.
4
Any exercise during pregnancy included any indoor or outdoor activity.
5
Seasons according to equinox and solstice dates.
6
Maternal self-reported population group according to ancestral origin.