Association of Hypocalcaemia and Vitamin D Deficiency in Newborns Admitted in NICU: A Cross-sectional Study from a Tertiary Care Centre, Prayagraj, Northern India

Introduction: Hypocalcaemia is very common in sick newborns and is frequently associated with severe Vitamin D Deficiency (VDD). VDD can lead to both acute and long-term complications in newborns. Estimating vitamin D levels in hypocalcaemic newborns may therefore be cost-effective. Aim: To determine the association between hypocalcaemia and VDD in newborns admitted to the Neonatal Intensive Care Unit (NICU) of a tertiary care centre. Materials and Methods: The present cross-sectional study was conducted in the NICU of the Department of Paediatrics, MLN Medical College, Prayagraj, Uttar Pradesh, India, from 1st August 2021 to 31st July 2022. A total of 100 newborns (up to 28 days old) were enrolled and divided into two groups of 50 each. Group 1 included hypocalcaemic newborns (serum ionic calcium <1.2 mmol/L in term and <1.0 mmol/L in preterm infants), and Group 2 included newborns with normocalcaemia. Vitamin D levels were estimated in both groups. Maternal history regarding the intake of calcium (1000 mg/day) and vitamin D (500 IU/day) from 14 weeks of pregnancy until delivery was also recorded. The Chi-square test was used to assess the association of hypocalcaemia with vitamin D levels. Results: The mean age of the newborns was 4.93±4.61 days, with a male-to-female ratio of 2.03:1. VDD was observed in 74% (74/100) of the newborns. Among hypocalcaemic newborns, 46 (92%) were vitamin D deficient. Hypocalcaemia was significantly associated with VDD (p<0.001). Sixty-five mothers had a history of either no or inadequate calcium and vitamin D intake. Among these, 32 mothers of hypocalcaemic newborns had inadequate or no intake, which was not significantly associated with neonatal hypocalcaemia (p=0.580). Breastfeeding was significantly associated with normocalcaemia (p=0.037). Conclusion: There was a very high prevalence of VDD in the study population, with 74% of NICU-admitted newborns being vitamin D deficient. VDD was significantly associated with hypocalcaemia in the present cross-sectional study.