Correlation Between Vitamin D Deficiency and Calcium, Phosphorus, Alkaline Phosphatase in Preterm Libyan Infants: Case-Control study

Vitamin D plays a vital role in regulating calcium and phosphorus levels and in bone mineralization. Vitamin D deficiency is a widespread issue contributing to metabolic bone disease in preterm infants. This study aimed to evaluate the biochemical parameters associated with varying levels of vitamin D deficiency. Serum samples were collected from preterm infants at the Neonatal Intensive Care Unit of Althawra Hospital Center, Al Beyda, Libya, from Feb-July 2019. The study included two groups: 62 preterm infants and a control group of 34 full-term infants. Serum levels of calcium, phosphorus, alkaline phosphatase, and 25OH-Vitamin D were measured using enzyme immunoassays and standard method. The study involved 62 preterm neonates, with a median gestational age of 32 weeks (range 28-36) and median birth weight of 1960 gm (range 900-2800 gm). The median levels recorded were calcium at 8.7 mg/dl (p=0.000), phosphorus at 4.1 mg/dl (p=0.584), ALP at 458 U/L (p=0.008), and vitamin D at 13.6 ng/ml. The prevalence of varying degrees of vitamin D deficiency was noted: very severe (9.7% < 5 ng/ml), severe (19.4% 5-10 ng/ml), and overall deficiency (45% 10-20 ng/ml), and suboptimal (25.8% 20-30 ng/ml). Comparing preterm infants to the control group revealed statistically significant differences across all parameters (Vitamin D p=0.000, Ca p=0.007, PO4 p=0.036, and ALP p=0.000). All preterm infants exhibited inadequate vitamin D levels, and there was an inverse relationship between the biochemical parameters and vitamin D deficiency. Notably, the elevated ALP level could serve as a crucial marker for diagnosing vitamin D deficiency in clinical settings.