Maternal and Infant Determinants of Zinc Status and Zinc’s Association with Anthropometry in 3-Month-Old Bangladeshi Infants

TL;DR

This study explores factors affecting zinc levels in 3-month-old Bangladeshi infants and finds that maternal age, early pregnancy zinc, and feeding practices influence infant zinc status and growth.

Contribution

The study provides new insights into the determinants of infant zinc status from maternal and infant factors in a South Asian context.

Findings

Infant zinc levels were positively associated with maternal age and early pregnancy zinc.

Exclusive breastfeeding and lower maternal parity were linked to higher infant zinc levels.

Infant length, but not weight, was associated with plasma zinc at 3 months.

Abstract

Background/Objectives: Zinc deficiency remains a public health concern in South Asia but is rarely studied through gestation to infancy. Methods: We identified maternal and infant factors related to plasma zinc of 3 mo old Bangladeshi infants (n = 317) in the context of a trial of a daily antenatal to 3 mo postpartum multiple micronutrient supplementation (MMS) with 15 vitamins and minerals, including 12 mg zinc, versus iron–folic acid (IFA). Factors explored included maternal age, parity, and plasma zinc in early (pre-supplementation) and late pregnancy, at 3 months postpartum, and in milk; cord blood zinc (n = 83); birth outcomes; and infant feeding and biomarkers. Consequently, infant zinc was explored with 3 mo anthropometry and growth rates. Results: Mean ± SD infant plasma zinc was 15.63 ± 6.65 µmol/L, with 10.1% deficiency (<9.9 µmol/L). In adjusted analyses, infant zinc was positively associated with maternal age [20–30 years +0.11 µmol/L (p = 0.018) and ≥30 years +0.28 µmol/L (p = 0.003) relative to <20 years], maternal early pregnancy zinc (+0.01 µmol/L per 1 µmol/L maternal zinc, p = 0.011), and infant ferritin (+0.001 µmol/L per 1 µg/L, p = 0.007); conversely, infant zinc was −0.13 µmol/L lower (p = 0.013) with maternal parity ≥2 versus 0–1 and with partial versus exclusive breastfeeding (−0.15 µmol/L, p = 0.038). Relationships with MMS, maternal later pregnancy, postpartum, milk, and cord blood zinc were absent. Length-for-age (+0.02 per µmol/L, p = 0.047) but not weight-for-length Z-scores at 3 months were associated with infant zinc. Conclusions: Thus, infant zinc was associated with pre- but not post-MMS maternal zinc, age and parity, feeding style, and infant iron status. Infant length but not weight was associated with plasma zinc.

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