title: Calcium absorption, bone mass accumulation, and kinetics increase during early pubertal development in girls.
abstract: To evaluate the changes in calcium and bone mineral metabolism associated with early pubertal development, we performed longitudinal measurements of calcium absorption, calcium kinetics, bone mineral content, and hormonal markers related to puberty in a multiethnic group of girls beginning when they were 7 or 8 yr old. Girls were Tanner stage 1 (breast) at the start of the study. They were placed on a 1200 mg/day dietary calcium intake and studied at approximately 6-month intervals until they reached Tanner stage 2 (breast). Results at that time point (PUB) were compared to values obtained approximately 1 yr earlier (LatePRE) and those 1 yr before that (EarlyPRE). We found an increase in calcium absorption comparing PUB to LatePRE (n = 34; 36.6 +/- 8.7% vs. 30.7 +/- 9.9%; P = 0.002). Using whole body, dual energy, x-ray absorptiometry scanning, we found an increase in calcium gain during the LatePRE to PUB period compared with that during the EarlyPRE to LatePRE period (135 +/- 53 vs. 110 +/- 45 mg/day; P = 0.04). Calcium kinetic studies showed a significant increase in the bone calcium deposition rate (Vo+) during the PUB compared to the LatePRE period. Hormonal and biochemical markers of bone development were also significantly increased at PUB compared to LatePRE. Hormonal activity, as evidenced by the unstimulated LH level, was significantly correlated with calcium gain between the LatePRE and PUB studies and the bone calcium deposition rate in the PUB study. These data demonstrate, using multiple independent methods, an increase in calcium utilization associated with the earliest physical signs of puberty.
authors.affiliation: U.S. Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Houston, Texas 77030, USA. sabrams@bcm.tmc.edu
authors.forename: S A
authors.initials: SA
authors.lastname: Abrams
authors.forename: K C
authors.initials: KC
authors.lastname: Copeland
authors.forename: S K
authors.initials: SK
authors.lastname: Gunn
authors.forename: C M
authors.initials: CM
authors.lastname: Gundberg
authors.forename: K O
authors.initials: KO
authors.lastname: Klein
authors.forename: K J
authors.initials: KJ
authors.lastname: Ellis
mesh_terms: D044383:Black People; D015519:Bone Density; D002118:Calcium / Q000378:metabolism* / Q000652:urine; D002136:Calcium, Dietary; D002648:Child; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006630:Hispanic or Latino; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007408:Intestinal Absorption; D007700:Kinetics; D008137:Longitudinal Studies; D007986:Luteinizing Hormone / Q000097:blood; D015675:Osteocalcin / Q000097:blood; D011627:Puberty / Q000502:physiology*; D014481:United States; D044465:White People; D001741:Black or African American
chemical_list: D002136:Calcium, Dietary; D015675:Osteocalcin; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D002118:Calcium