ABSTRACT
OBJECTIVE : To evaluate the vitamin D nutritional status and its influencing factors in Korean mothers and their newborn infants. METHODS : Maternal (n=181) and cord blood (n=180) serum concentrations of vitamin D (25OHD3), calcium, inorganic phosphorus, alkaline phosphatase, intact parathyroid hormone were measured at the time of delivery. We defined vitamin D deficient, insufficient, and sufficient as 25OHD3 30 ng/mL, respectively. Using questionnaires, average duration of sun-light exposure (minutes/day) and dietary intake of vitamin D (microngram/day) were obtained. RESULTS : 1) The mean 25OHD3 level in mothers was 23.4+/-9.9 (range 4~71.6) ng/mL, and in newborns, 16.9+/-7.5 (range 0.9~53.6) ng/mL. 2) 8.3% of mothers and 22.2 % of newborns were vitamin D deficient, and 70% of both mothers and newborns were insufficient. 3) Maternal 25OHD3 showed a strong positive correlation with cord blood 25OHD3 (r=0.727, p<0.001). 4) The most significant risk factor for low 25OHD3 levels was the season of birth (June through November) in both mothers and newborns. 5) In multiple logistic regression analysis, the season of birth and the mode of delivery remained significant for maternal vitamin D status, whereas maternal 25OHD3 and the mode of delivery remained significant for neonatal vitamin D status. CONCLUSION : In conclusion, vitamin D deficiency or insufficiency was relatively common in Korean mothers and their newborn infants, and the most significant risk factor for low vitamin D status was the season of birth.