# 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.

## Key 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.