Table 23. The effect of maternal vitamin D status in gestation on risk of low birth weight (LBW)* in the offspring – Observational studies.
| First Author and year |
Bias score |
Study details |
Study type |
Confounders/ adjustments |
Number of weeks gestation when 25(OH)D was measured | Maternal mean (SD) 25(OH)D concentration (nmol/l) in cases of LBW infants | Maternal mean (SD) 25(OH)D concentration (nmol/l) in infants without LBW | Odds ratio (95% CI) of offspring having LBW from univariate analysis | Odds ratio (95% CI) of offspring having LBW from multivariate analysis | Conclusion |
|---|---|---|---|---|---|---|---|---|---|---|
| Sabour, 2006 88 | -2 (high) | Tehran, Iran n=449 women Cases of LBW*- not given |
Cross- sectional |
Nil | Not measured directly Estimated from validated dietary FFQ at delivery (unclear when assessed) |
Not given | Not given | Not given | Not given | Incidence of LBW significantly lower with adequate maternal calcium and vitamin D intake (1000mg ca, 200 IU vitamin D) p=0.007 |
| Maghbooli, 2007 89 | 1 (med) | Tehran, Iran n=552 women Cases of LBW*=5.4% (30) |
Cross- sectional |
None | Delivery** | Not given | Not given | Not given | Not given | No significant association seen between serum 25(OH)D3 and LBW p not given |
| Mehta, 2009 118 | 3 (med) | Tanzania Overall Cohort=1078. Women all HIV infected taking part in a clinical trial of vitamin use Cases of LBW*=80 Cohort for analysis=675 |
Prospective cohort |
Multivitamin supplementation, maternal age at baseline, CD4 count at baseline, HIV disease stage at baseline | 12-27 weeks (at enrolment to trial) | Mean not given 35% of LBW had 25(OH)D <80 nmol/l 65% had 25(OH) D>80 nmol/l |
Not given | 0.85 (0.55, 1.32) | 0.84 (0.55, 1.28) | No relationship between LBW risk and maternal 25(OH)D amongst women with HIV p=0.42 |
*
LBW defined as infants born <2500g
**
Measured 25(OH)D3