title: Differences in calcium absorption and kinetics between black and white girls aged 5-16 years.
abstract: To assess racial differences in calcium (Ca) metabolism, we measured Ca absorption and kinetics in 89 girls (38 black and 51 white) aged 4.9-16.7 years using a dual-tracer stable isotope technique. We found significantly greater rates of fractional (0.44 +/- 0.13 vs. 0.25 +/- 0.08, p < 0.0001) and total calcium absorption (406 +/- 142 vs. 234 +/- 82 mg/day, p < 0.0003) in black than in white postmenarcheal girls. Fractional absorption of Ca was also greater in black than in white premenarcheal girls (0.39 +/- 0.14 vs. 0.30 +/- 0.10, p = 0.01). Fractional absorption of Ca was more closely correlated to Ca intake in white (r = -0.42, p = 0.002) than in black girls (r = -0.25, p = 0.14). Urinary Ca excretion was significantly lower in pre- but not postmenarcheal black girls than in white girls. Calcium kinetic values associated with bone calcium deposition were greater in black girls, indicating a greater rate of bone Ca deposition in both pre- and postmenarcheal black girls. These results suggest that the greater bone mass accumulated during childhood and adolescence in black than in white females is due, in part, to greater rates of Ca absorption in black girls.
authors.affiliation: USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Abrams
authors.forename: K O
authors.initials: KO
authors.lastname: O'brien
authors.forename: L K
authors.initials: LK
authors.lastname: Liang
authors.forename: J E
authors.initials: JE
authors.lastname: Stuff
mesh_terms: D000042:Absorption; D000293:Adolescent; D000704:Analysis of Variance; D044383:Black People; D001827:Body Height / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D015519:Bone Density / Q000502:physiology*; D002136:Calcium, Dietary / Q000008:administration & dosage / Q000493:pharmacokinetics*; D002648:Child; D002675:Child, Preschool; D003198:Computer Simulation; D004100:Dihydroxycholecalciferols / Q000097:blood; D005260:Female; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood; D007553:Isotope Labeling; D013058:Mass Spectrometry; D008572:Menarche / Q000378:metabolism; D011863:Radioimmunoassay; D011869:Radioligand Assay; D012044:Regression Analysis; D044465:White People
chemical_list: D002136:Calcium, Dietary; D004100:Dihydroxycholecalciferols; D006887:Hydroxycholecalciferols