TABLE 2.
Mean serum 25-hydroxyvitamin D levels
| Variable | Pregnant (n = 928) nmol/L (95% CI) |
Nonpregnant (n = 5173) nmol/L (95% CI) |
|---|---|---|
| Total (n =6101) | 65(61–68) | 59(57–61) |
| Age, y | ||
| 13–19 (n = 2710) | 57 (50–64) | 59(56–61) |
| 20–34 (n = 2203) | 64(61–68) | 60 (57–63) |
| 35–44 (n = 1188) | 71 (64–79) | 57 (54–60) |
| Race | ||
| NH white (n = 2296) | 77 (73–80) | 67 (65–70) |
| NH black (n = 1572) | 39 (35–42) | 33 (32–35) |
| Hispanic (n = 1969) | 56(51–62) | 48 (46–49) |
| Other (n = 264) | 54 (46–62) | 46 (42–50) |
| Poverty-income ratio | ||
| ≤1 (n = 1650) | 56 (50–63) | 53 (49–56) |
| >1 (n = 4182) | 68 (64–72) | 60 (58–62) |
| Unknown (n = 269) | 53 (48–59) | 60 (53–66) |
| Gestational age | ||
| First trimester (n = 198) | 55 (50–60) | – |
| Second trimester (n = 331) | 62 (62–57) | – |
| Third trimester (n = 312) | 80 (73–87) | – |
| Unknown (n = 87) | 53(45–61) | – |
| Vitamin D supplement dose (IU) | ||
| 0 (n = 4268) | 46(41–50) | 55 (53–57) |
| 1–399 (n = 157) | 68 (59–77) | 65 (59–71) |
| ≥400(n = 1676) | 72 (69–76) | 67 (65–69) |
| Duration of vitamin D supplement use, da | ||
| 0 (n = 4269) | 46(41–50) | 55 (53–57) |
| 1–30 (n = 251) | 62 (55–68) | 62 (55–68) |
| 31–180 (n =423) | 68 (62–73) | 62 (57–66) |
| ≥181 (n = 1152) | 77 (72–82) | 68 (66–70) |
| Physical activity in past 30 d | ||
| None(n = 1784) | 56(51–61) | 50 (47–52) |
| Outdoor (n = 3516) | 72 (67–76) | 63 (61–65) |
| Indoor/indeterminate only (n = 801) | 62 (54–71) | 56 (53–59) |
CI, confidence interval; NH, non-Hispanic.
a
Based on longest duration of use for any current vitamin D-containing supplement; 6 missing/unknown.