Iron deficiency during pregnancy is associated with a reduced risk of adverse birth outcomes in a malaria-endemic area in a longitudinal cohort study

Table 3 Mediation of association between iron deficiency and low birth weight

Mediating variables	Natural direct effect, risk ratio (95% CI)	Natural indirect effect, risk ratio (95% CI)	Proportion indirect
All women
Placental malaria only	0.47 (0.25, 0.83)	0.92 (0.63, 1.25)	7%
Anaemia and placental malaria	0.45 (0.25, 0.79)	0.88 (0.60, 1.18)	10%
Malaria, anaemia and placental malaria	0.44 (0.25, 0.79)	0.87 (0.69, 1.39)	12%
Sensitivity analyses*
Placental malaria only	0.34 (0.17, 0.79)	1.09 (0.67, 1.80)	4%
Anaemia and placental malaria	0.33 (0.17, 0.78)	1.07 (0.63, 1. 86)	4%
Malaria, anaemia and placental malaria	0.33 (0.17, 0.78)	1.06 (0. 65, 1.84)	3%

Numbers are risk ratios (95% confidence interval). Natural direct effect is the effect of iron deficiency on birth outcome, not mediated through the specified mediators. Natural indirect effect is the effect of iron deficiency on birth outcome, mediated through the specified mediator.
CI confidence interval
*Women potentially misclassified as iron deficient (ferritin > 15 and C-reactive protein > 10) are excluded from analysis (N = 46)

ISSN: 1741-7015