Child's vitamin D supplement use at age 1 and 2 years, vitamin D dosage at age 6–7 years and lung function at age 6–7 years
| Lung function at age 6–7 years | |||||
| No. of children | FEV1 z scores | FVC z scores | |||
| Crude B (95% CI) | Adj B* (95% CI) | Crude B (95% CI) | Adj B* (95% CI) | ||
| Vitamin D supplement use at age 1 year | |||||
| No (reference) | 214 (49.2%) | 0.0 | 0.0 | 0.0 | 0.0 |
| Yes | 221 (50.8%) | 0.17 (−0.03 to 0.37) | 0.17 (−0.03 to 0.37) | 0.07 (−0.09 to 0.24) | 0.07 (−0.10 to 0.23) |
| Vitamin D supplement use at age 2 years | |||||
| No (reference) | 102 (23.6%) | 0.0 | 0.0 | 0.0 | 0.0 |
| Yes | 331 (76.4%) | −0.12 (−0.32 to 0.07) | −0.15 (−0.35 to 0.06) | −0.12 (−0.32 to 0.07) | −0.13 (−0.33 to 0.07) |
| Vitamin D dosage/day at age 6–7 years | |||||
| 0 μg (reference) | 310 (71.6%) | 0.0 | 0.0 | 0.0 | 0.0 |
| >0 μg to ≤2.5 μg | 82 (18.9%) | −0.11 (−0.33 to 0.11) | −0.13 (−0.35 to 0.09) | −0.01 (−0.21 to 0.20) | −0.02 (−0.24 to 0.20) |
| >2.5 μg | 41 (9.5%) | −0.19 (−0.48 to 0.09) | −0.22 (−0.51 to 0.08) | −0.08 (−0.36 to 0.20) | −0.11 (−0.40 to 0.18) |
| p for trend | 0.12 | 0.09 | 0.64 | 0.50 | |
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, physical activity at age 4–5 years and 6–7 years.
adjB, adjusted beta; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity.