Relationship between vitamin D level and related indicators in breastfeeding infants in People's Hospital of Longhua New District in Shenzhen City

Abstract

Objective To investigate the changes of vitamin D level and its relationship with bone alkaline phosphatase (BAP) and parathyroid hormone (PTH) in infants fed with breast milk and vitamin D supplementation for 0-8 months in People's Hospital of Longhua New District in Shenzhen city. Methods Totally 67 newborns in the Department of Obstetrics and Gynecology of People's Hospital of Longhua New District were selected. These newborns were breastfed and began to supplement vitamin D 400 U/d in the 15th day after birth. The serum 25-(OH)D3 and BAP and PTH levels were measured in newborns and 4-/8-month-old infants, and the correlations of serum 25-(OH)D3 with BAP and PTH were analyzed by Pearson correlation analysis. Results Compared with the newborns, the serum 25-(OH)D3 [(78.47±36.41)nmol/L, (75.26±34.73)nmol/L], BAP[(231.43±78.81)μg/L, (205.97±71.64)μg/L], PTH[(31.76±11.54)pg/ml, and (32.94±13.82)pg/ml] levels of 4- and 8-month-old infants were significantly higher, and the difference were statistically significant (t4 months=7.823, 12.568, 11.852, t8 months=7.364, 9.473, 11.947; all P=0.000). There was a negative correlation between serum 25-(OH)D3 and BAP in newborns and 4-/8-monthold infants (r=-0.372, -0.463, -0.309; P=0.008, 0.016, 0.021), the serum BAP was positively correlated with PTH in infants aged 4 months and 8 months (r=0.487, 0.338; P=0.005, 0.032), and the serum 25-(OH)D3 was negatively correlated with PTH in infants aged 4 months (r=-0.297, P=0.041). Conclusions Infants at birth are prone to vitamin D deficiency in Shenzhen City. After 4 months of breastfeeding and vitamin D400U/d supplementation, the vitamin D levels in most infants become normal. 25-(OH)D3 is correlated with BAP and PTH in different months. Key words: Vitamin D; Breastfeeding; Serum 25-(OH)D3; Parathyroid hormone; Bone alkaline phosphatase