The mother and child's 25-hydroxyvitamin D (25(OH)D) level and lung function at age 6–7 years
| Plasma level 25(OH)D | Lung function at age 6–7 years | ||||||
| FEV1 z scores | FVC z scores | ||||||
| Mean (nmol/litre) | Range (nmol/litre) | No. of subjects | Crude B (95% CI) | Adj B* (95% CI) | Crude B (95% CI) | Adj B* (95% CI) | |
| Mother 36th week of pregnancy | |||||||
| Quintile 1 | 21.5 | 12.0–28.2 | 83 | 0.0 | 0.0 | 0.0 | 0.0 |
| Quintile 2 | 34.6 | 28.3–40.4 | 83 | 0.16 (−0.11 to 0.42) | 0.09 (−0.19 to 0.38) | 0.09 (−0.16 to 0.35) | 0.06 (−0.21 to 0.33) |
| Quintile 3 | 45.9 | 40.5–50.9 | 83 | 0.09 (−0.18 to 0.36) | 0.05 (−0.23 to 0.33) | 0.10 (−0.16 to 0.35) | 0.06 (−0.21 to 0.33) |
| Quintile 4 | 55.5 | 51.0–61.7 | 83 | 0.11 (−0.16 to 0.37) | 0.09 (−0.19 to 0.37) | 0.08 (−0.18 to 0.33) | 0.08 (−0.19 to 0.35) |
| Quintile 5 | 72.6 | 61.8–106.9 | 83 | 0.02 (−0.25 to 0.28) | 0.01 (−0.28 to 0.29) | 0.07 (−0.19 to 0.33) | 0.07 (−0.20 to 0.35) |
| p for trend | 0.96 | 0.99 | 0.68 | 0.59 | |||
| Child age 2 years | |||||||
| Quintile 1 | 45.2 | 18.3–56.3 | 57 | 0.0 | 0.0 | 0.0 | 0.0 |
| Quintile 2 | 61.3 | 56.4–66.2 | 57 | −0.02 (−0.33 to 0.31) | −0.02 (−0.35 to 0.32) | 0.02 (−0.28 to 0.32) | −0.01 (−0.32 to 0.31) |
| Quintile 3 | 70.9 | 66.3–76.0 | 57 | 0.04 (−0.28 to 0.36) | 0.07 (−0.27 to 0.41) | 0.09 (−0.21 to 0.39) | 0.12 (−0.20 to 0.44) |
| Quintile 4 | 81.6 | 76.1–90.2 | 58 | −0.02 (−0.34 to 0.30) | 0.07 (−0.27 to 0.41) | 0.01 (−0.29 to 0.31) | 0.08 (−0.24 to 0.39) |
| Quintile 5 | 106.0 | 90.3–161.1 | 58 | 0.09 (−0.23 to 0.41) | 0.09 (−0.25 to 0.43) | 0.10 (−0.20 to 0.40) | 0.12 (−0.21 to 0.44) |
| P for trend | 0.62 | 0.51 | 0.62 | 0.41 | |||
Numbers in the table do not always add up to the total because of missing data.
↵* Adjusted for recruitment group, maternal age at delivery, maternal education level, maternal smoking during pregnancy, maternal alcohol consumption during pregnancy, birth weight, use of multivitamins at age 2 years, environmental tobacco smoke in the first 6–7 years of life, physical activity at age 4–5 years and 6–7 years, body mass index (BMI) (maternal 25(OH)D level adjusted for maternal BMI before pregnancy, child's 25(OH)D level adjusted for child's BMI at age 2 years), season of blood sampling.
adjB, adjusted beta; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity.