Association between umbilical cord vitamin D levels and adverse neonatal outcomes

Objective We investigated the associations between cord blood concentration of 25-hydroxyvitamin D [25(OH)D], neonatal outcomes, and the risk of hospitalization during the first year of life. Methods A total of 402 newborn infants and their mothers were prospectively enrolled and divided in four groups according to season of the year. We determined 25(OH)D serum concentrations from maternal–neonatal pairs at delivery by electrochemiluminescence immunoassay. Cut-offs at 25, 50, and 75 nmol/L defined vitamin D status, corresponding to deficiency, insufficiency, and sufficiency, respectively. Crude odds ratio (cOR) and 95% confidence intervals (CI) were estimated using logistic regression. Results Vitamin D severe deficiency (i.e.,