Vitamin D Status of Low Birth Weight Infants in Delhi: A Comparative Study

Abstract

To evaluate vitamin D status of preterm and term low birthweight (LBW) and term normal birth weight (NBW; weight ≥ 2500 g) infants at birth and in early infancy. We enrolled 220 LBW and 119 NBW infants along with their mothers. Blood samples of both infants and mothers were taken within 48 h of birth, and that of infants were repeated at 3 months. Serum levels of calcium, phosphate, alkaline phosphatase, 25 hydroxyvitamin D (25OHD) and parathormone (PTH) were estimated using standard tests. Our primary outcome was vitamin D deficiency (VDD; serum 25OHD <20 ng/ml in mothers and <15 ng/ml in infants). Other outcomes were raised PTH (>46 pg/ml), raised AlkP (>120 U/l in mothers and 420 U/l in infants), and clinical rickets. VDD was present in 186 (87.3%) of LBW and 103 (88.6%) of NBW infants at birth, and in 77 (60.6%) of LBW and 55 (71.6%) of NBW infants at a median corrected age of 12 and 15 weeks, respectively. VDD was almost universal (93-97%) among mothers of both groups. Raised PTH was present in 138 (63.6%) of LBW and 48 (41.4%) of NBW infants at birth, and in 58 (45.7%) of LBW and 38 (49.3%) of NBW infants at follow-up. Clinical rickets was present in 17 (13.4%) of LBW and 4 (4.9%) of NBW infants at 12-14 weeks of corrected age. High prevalence of VDD in LBW as well as NBW infants with clinical rickets at an early age underlines the need to study the effect of various vitamin D supplementation regimens in these infants to identify the optimal dose.