Table 4. Odds of suboptimal outcomes in offspring by maternal vitamin D status (< 50.0 vs ≥ 50.0 nmol/L) according to whether maternal vitamin D was measured in the first or second half of gestation (Adjusted Model 3).
| First half of gestation (≤ 22 weeks) | Second half of gestation (> 22 weeks) | P value for interaction* | |||||||
|---|---|---|---|---|---|---|---|---|---|
| OR (95% CI) | P value | n | OR (95% CI) | P value | n | ||||
| ALSPAC pre–school development assessments | Gross Motor Skills | 6 mo† | 0.92 (0. 70, 1.22) | 0.56 | 1500 | 0.98 (0.79, 1.21) | 0.84 | 2880 | 0.21 |
| 18 mo | 0.97 (0.76, 1.23) | 0.78 | 1522 | 1.31 (1.08, 1.58) | 0.005 | 2861 | 0.13 | ||
| 30 mo | 1.07 (0.84, 1.38) | 0.58 | 1435 | 1.28 (1.05, 1.57) | 0.02 | 2698 | 0.79 | ||
| 42 mo | 1.03 (0.79, 1.34) | 0.85 | 1422 | 1.10 (0.89, 1.36) | 0.37 | 2648 | 0.72 | ||
| Fine Motor Skills | 6 mo† | 1.09 (0.83, 1.44) | 0.52 | 1436 | 1.03 (0.83, 1.27) | 0.80 | 2703 | 0.25 | |
| 18 mo | 1.05 (0.82, 1.36) | 0.69 | 1522 | 1.10 (0.90, 1.33) | 0.35 | 2859 | 0.46 | ||
| 30 mo | 0.99 (0.76, 1.29) | 0.95 | 1436 | 1.37 (1.12, 1.67) | 0.002 | 2700 | 0.05 | ||
| 42 mo | 1.03 (0.78, 1.37) | 0.83 | 1420 | 1.24 (1.00, 1.53) | 0.05 | 2648 | 0.37 | ||
| Social Development | 6 mo† | 0.88 (0.66, 1.16) | 0.37 | 1453 | 1.11 (0.90, 1.38) | 0.32 | 2754 | 0.90 | |
| 18 mo | 1.23 (0.95, 1.60) | 0.12 | 1522 | 1.07 (0.87, 1.32) | 0.51 | 2859 | 0.11 | ||
| 30 mo | 0.96 (0.74, 1.26) | 0.79 | 1431 | 1.13 (0.91, 1.40) | 0.28 | 2696 | 0.36 | ||
| 42 mo | 1.07 (0.82, 1.41) | 0.62 | 1420 | 1.28 (1.03, 1.58) | 0.02 | 2646 | 0.26 | ||
| Communication | 6 mo† | 0.90 (0.65, 1.23) | 0.50 | 1468 | 1.04 (0.81, 1.34) | 0.75 | 2815 | 0.37 | |
| 18 mo | 1.27 (0.98, 1.65) | 0.07 | 1524 | 1.04 (0.85, 1.28) | 0.71 | 2864 | 0.17 | ||
| Behaviour | Prosocial‡ | 7 yr | 0.75 (0.48, 1.17) | 0.21 | 1216 | 1.15 (0.83, 1.61) | 0.40 | 2301 | 0.10 |
| Peer problems | 7 yr | 1.14 (0.78, 1.66) | 0.49 | 1210 | 0.97 (0.73, 1.30) | 0.86 | 2298 | 0.55 | |
| Hyperactivity | 7 yr | 0.95 (0.68, 1.33) | 0.75 | 1213 | 1.10 (0.86, 1.41) | 0.46 | 2298 | 0.31 | |
| Emotional‡ | 7 yr | 1.25 (0.87, 1.80) | 0.23 | 1214 | 1.17 (0.87, 1.58) | 0.29 | 2301 | 0.71 | |
| Conduct | 7 yr | 1.13 (0.84, 1.52) | 0.42 | 1212 | 1.04 (0.82, 1.31) | 0.74 | 2300 | 0.76 | |
| Total Score‡ | 7 yr | 1.20 (0.79, 1.82) | 0.40 | 1214 | 1.24 (0.90, 1.71) | 0.18 | 2300 | 0.79 | |
| Cognition | Verbal IQ | 8 yr | 1.09 (0.77, 1.55) | 0.64 | 1025 | 0.93 (0.72, 1.21) | 0.60 | 1925 | 0.20 |
| Performance IQ | 8 yr | 1.15 (0.83, 1.59) | 0.42 | 1017 | 0.89 (0.68, 1.16) | 0.38 | 1926 | 0.03 | |
| Total IQ | 8 yr | 1.18 (0.84, 1.66) | 0.33 | 1015 | 0.90 (0.69, 1.17) | 0.43 | 1921 | 0.13 | |
| Reading ability | Words per min | 9 yr | 1.41 (1.00, 1.97) | 0.05 | 936 | 1.00 (0.77, 1.31) | 0.98 | 1825 | 0.20 |
| Accuracy | 9 yr | 1.31 (0.92, 1.87) | 0.13 | 938 | 0.87 (0.66, 1.14) | 0.32 | 1827 | 0.06 | |
| Comprehension | 9 yr | 1.09 (0.77, 1.55) | 0.62 | 938 | 0.98 (0.75, 1.29) | 0.89 | 1827 | 0.31 | |
| Reading Score | 9 yr | 1.30 (0.94, 1.78) | 0.11 | 1060 | 0.91 (0.71, 1.16) | 0.44 | 1966 | 0.20 | |
mo, month; OR, odds ratio; n, number of subjects; yr, years. Suboptimal outcome defined as scores in the bottom quartile for ALSPAC pre–school development assessments, cognition, and reading ability. Published cut-offs(17) were used for behaviour: Prosocial (≤5; 9·8%), Peer problems (≥3; 13·5%), hyperactivity (≥6; 18·7%), emotional symptoms (≥4; 12·2%), conduct problems (≥3; 24·3%), and total score (≥14; 10·5%). Maternal vitamin D status ≥ 50.0 nmol/L was the reference group and Model 3 was used (without gestational week of vitamin D assessment as this was used to split analyses).
interaction between vitamin D (deficient/sufficient) and gestational week of sample (continuous variable)
age of child at development test included in all models
ethnicity removed as model would not converge.