Prediction of rise in alkaline phosphatase at different vitamin D levels

Background: Vitamin D deficiency with a resurgence of rickets and tetany is increasingly being reported in young infants from temperate regions, African Americans, and also from India. The data on Vitamin D status of healthy term breastfed Indian infants and mothers are scant. In fact, the correlation between Vitamin D deficiency and alkaline phosphatase (ALP) is inaccurate in many studies. Aim and Objective: The aim and objective of this study are to determine whether serum Vitamin D levels are correlated with serum levels of ALP or not and to study the point, at which ALP surge occurs in Vitamin D deficiency. Materials and Methods: Ninety-six participants at birth were enrolled and followed up till 9 months of age. Serum 25 (OH) D along with ALP was estimated in cord blood at birth and 14 ± 1 weeks of life. Seventy-seven participants were followed up at 9 months for estimation of serum 25 (OH) D, parathyroid hormone, ALP, calcium, and phosphorus. Vitamin D deficiency was defined as serum 25 (OH) D <15 ng/mL as per the United States Institute of Medicine guidelines. Results: At 9 months out of 96 samples, 16 had mild insufficient (≥15–20 ng/mL) (20.8%), 42 had moderate deficient (<15 ng/mL) (54.5%), and 0 had severe deficient (<5 ng/mL) Vitamin D deficiencies. Serum alkaline phosphate were found to be normal in all the three groups of patients and the receiver operating characteristic curve demonstrated that low Vitamin D level is predicted by a high ALP cutoff of ALP is 190.90 IU/L with reasonable sensitivity and specificity. The correlation coefficient of ALP and serum Vitamin D3 levels was r = 0.501 (P = 0.001). Conclusion: Serum Vitamin D3 levels correlated well with increased serum ALP levels but the level, at which the ALP surge occurs was on the lower side.