Poor zinc status in early infancy among both low and normal birth weight infants and their mothers in Delhi

Abstract

Background: Low birth weight (LBW) infants are at high risk of zinc deficiency, but there is a paucity of data on their zinc status. Objective: To evaluate zinc status of LBW (BW < 2,500 g) and normal birth weight (NBW; BW ≥2,500 g) infants at birth and in early infancy. Methods: A total of 339 infants (LBW, n = 220; NBW, n = 119) were enrolled, and venous blood samples of mother-infant dyad were taken within 48 h of birth. Infants’ levels were repeated between 2 and 10 months of age. Serum zinc levels were estimated using an inductively coupled plasma mass spectrometer. Primary outcome was zinc deficiency, defined as serum zinc < 65 µg/dl. Results: Zinc results were available for 182 LBW and 103 NBW infants at birth and for 100 LBW and 66 NBW infants at follow-up with a median postnatal age of 14 and 15.5 weeks, respectively. Median zinc levels were low and comparable at birth as well as at follow-up, with zinc deficiency being present in 51.0% of LBW and 42.4% of NBW infants at birth and in 79.0% of LBW and 66.7% of NBW infants at follow-up. Zinc levels decreased significantly in both groups from birth to follow-up, irrespective of zinc multivitamin supplementation. Zinc levels of infants with BW < 2,000 g at follow-up were significantly lower compared to infants with higher BW. Conclusion: Zinc status was poor in many infants at birth irrespective of BW. Zinc status worsened significantly during early infancy, with infants with BW < 2,000 g having the lowest zinc levels.