Low vitamin D status in mother-newborn pairs in Greece

Abstract

Adequate vitamin D status during pregnancy is crucial to assure normal fetal skeletal growth and to provide the vitamin D needed for infants' stores. To determine the actual situation in Greece, we evaluated serum 25-hydroxyvitamin D (25[OH]D), calcium (Ca), phosphorus (P), alkaline phosphatase (ALP), parathyroid hormone (PTH), osteocalcin (OC), and calcitonin (CT) concentrations in 123 healthy mother-newborn pairs recruited from a public hospital of the sunny Athenian region. Blood samples were obtained from pregnant women at term and their neonates (cord blood). The study was conducted between June 2003 and May 2004. None of the mothers has been prescribed vitamin D supplements. Maternal 25(OH)D levels (16.4 [11-21.1] ng/mL) were significantly lower than umbilical venous blood concentrations (20.4 [13.9-30.4] ng/mL) (P < 0.001). A strong correlation was observed between maternal and infant 25(OH)D concentrations (r = 0.626, P < 0.001). Twenty-four (19.5%) mothers and 10 (8.1%) neonates had 25(OH)D <10 ng/mL. Pregnant women who delivered in summer and autumn reported higher levels of 25(OH)D (18.9 [12.9-23.3] ng/mL) than those who delivered in winter and spring (14.6 [10.1-18.5] ng/mL) (P = 0.006). Mothers with a darker phototype had lower levels of serum 25(OH) D than those with a fair phototype (P = 0.023). Umbilical venous blood Ca, P, OC, and CT levels were significantly higher than maternal venous blood levels (P < 0.001). PTH umbilical levels were lower than maternal levels (P < 0.001). Apparently, the abundant sunlight exposure in Athens is not sufficient to prevent hypovitaminosis D. Pregnant women should be prescribed vitamin D supplementations, and the scientific community should consider vitamin D supplementation of foods.