Changes in soluble transferrin receptor and hemoglobin concentrations in Malawian mothers are associated with those values in their exclusively breastfed, HIV-exposed infants

Abstract

Infant iron status at birth is influenced by maternal iron status during pregnancy; however, there are limited data on the extent to which maternal iron status is associated with infant iron status during exclusive breastfeeding. We evaluated how maternal and infant hemoglobin and iron status [soluble transferrin receptors (TfR) and ferritin] were related during exclusive breastfeeding in HIV-infected women and their infants. The Breastfeeding, Antiretrovirals, and Nutrition Study was a randomized controlled trial in Lilongwe, Malawi, in which HIV-infected women were assigned with a 2 × 3 factorial design to a lipid-based nutrient supplement (LNS), or no LNS, and maternal, infant, or no antiretroviral drug, and followed for 24 wk. Longitudinal models were used to relate postpartum maternal hemoglobin (n = 1926) to concurrently measured infant hemoglobin, adjusting for initial infant hemoglobin values. In a subsample, change in infant iron status (hemoglobin, log ferritin, log TfR) between 2 (n = 352) or 6 wk (n = 167) and 24 wk (n = 519) was regressed on corresponding change in the maternal indicator, adjusting for 2 or 6 wk values. A 1 g/L higher maternal hemoglobin at 12, 18, and 24 wk was associated with a 0.06 g/L (P = 0.01), 0.10 g/L (P < 0.001), and 0.06 g/L (P = 0.01), respectively, higher infant hemoglobin. In the subsample, a reduction in maternal log TfR and an increase in hemoglobin from initial measurement to 24 wk were associated with the same pattern in infant values (log TfR β = -0.18 mg/L, P < 0.001; hemoglobin β = 0.13 g/L, P = 0.01). Given the observed influence of maternal and initial infant values, optimizing maternal iron status in pregnancy and postpartum is important to protect infant iron status. This trial was registered at clinicaltrials.gov as NCT00164736.

Conflict of interest statement

Author disclosures: E. M. Widen, M. E. Bentley, D. Kayira, C. S. Chasela, E. J. Daza, Z. K. Kacheche, G. Tegha, D. J. Jamieson, A. P. Kourtis, L. H. Allen, S. Shahab-Ferdows, and L. S. Adair, no conflicts of interest. C. M. van der Horst received grant support from Abbott Laboratories and GlaxoSmithKline.

Figures

FIGURE 1

Mean maternal Hb from birth to 24 wk (A) in the mLNS (n = 624), mLNS-mARV (n = 341), mARV (n = 338), and control (n = 623) arms of the longitudinal sample of BAN Study mother–infant dyads with at least 1 concurrent mother and infant Hb measurement. Mean infant Hb from birth to 24 wk (B) in the mLNS (n = 255), mLNS-mARV (n = 341), mARV (n = 338), iARV (n = 356), mLNS-iARV (n = 369), and control (n = 267) arms of the longitudinal sample with at least 1 concurrent mother and infant Hb measurement. BAN, Breastfeeding, Antiretrovirals, and Nutrition; C, control; Hb, hemoglobin; iARV, infant antiretroviral drug; LNS, lipid-based nutrient supplement; mARV, maternal antiretroviral drug; mLNS, maternal lipid-based nutrient supplement; mLNS-iARV, maternal lipid-based nutrient supplement and infant antiretroviral drug; mLNS-mARV, maternal lipid-based nutrient supplement and maternal antiretroviral drug.

FIGURE 2

Estimated infant Hb coefficients (β ± 95% CI, g/L) for each age in the longitudinal sample of BAN Study mother–infant dyads at 6 (n = 1644), 12 (n = 1635), 18 (n = 1575), and 24 (n = 1329) wk. Predicted Hb values from a longitudinal random-effects model relating maternal Hb to infant Hb. Predicted values represent at each age the linear combination of the maternal Hb coefficient and the maternal Hb interactions with study visit. The model also contained infant birth weight, rate of weight gain since previous visit, infant Hb at birth, infant sex, and the mARV and iARV arms, which were compared with the control arm. Interactions between study visits included infant birth weight, rate of weight gain since previous visit, infant Hb at birth, infant sex, and iARV arm. Data from HIV-negative infants and their mothers with at least 1 concurrent mother and infant Hb measurement and birth Hb were included until 24 wk or cessation of exclusive breastfeeding: n = 341 in the mLNS-mARV arm; n = 338 in the mARV arm; n = 369 in the mLNS-iARV arm; n = 356 in the iARV arm; n = 255 in the mLNS arm; and n = 267 in the control arm. BAN, Breastfeeding, Antiretrovirals, and Nutrition; Hb, hemoglobin; iARV, infant antiretroviral drug; mARV, maternal antiretroviral drug; mLNS, maternal lipid-based nutrient supplement; mLNS-iARV, maternal lipid-based nutrient supplement and infant antiretroviral drug; mLNS-mARV, maternal lipid-based nutrient supplement and maternal antiretroviral drug.