title: Perinatal vitamin D metabolism. III. Factors influencing late gestational human serum 25-hydroxyvitamin D.
abstract: Sera were obtained during the last trimester from both black and white women receiving prenatal care for determinations of calcium, magnesium, and 25-hydroxyvitamin D (25-OHD). The mean serum 25-OHD concentrations were 15.4 +/- 5.9 ng, per milliliter (S.D.) in February (n = 56) and 42.1 +/- 13.9 ng.per milliliter in August (n = 61). There was no significant racial difference in serum 25-OHD in February or August. No seasonal difference in calcium was noted but magnesium concentrations were lower in August. No correlation existed between serum 25-OHD and serum calcium or magnesium, parity, time from last pregnancy, maternal age, or social class. Concentrations of 25-OHD showed weak correlations with vitamin D intake (r = 0.32) and duration of gestation (r = 0.26) in the winter only. These data suggest that, regardless of race, ultraviolet exposure is the major determinant of maternal serum 25-OHD concentration in St. Louis. Dietary intake and and other factors may be important during periods of decreased ultraviolet exposure.
mesh_terms: D044383:Black People; D002118:Calcium / Q000097:blood; D004032:Diet; D005260:Female; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood*; D008274:Magnesium / Q000097:blood; D008923:Missouri; D009747:Nutritional Physiological Phenomena; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D011830:Radiation Effects; D012621:Seasons; D012867:Skin / Q000528:radiation effects; D012923:Social Class; D013472:Sunlight; D014466:Ultraviolet Rays; D006113:United Kingdom; D014807:Vitamin D / Q000627:therapeutic use; D044465:White People; D001741:Black or African American
chemical_list: D006887:Hydroxycholecalciferols; D014807:Vitamin D; D008274:Magnesium; D002118:Calcium