TY - JOUR
T1 - Relationships among vitamin D levels, parathyroid hormone, and calcium absorption in young adolescents
AU - Abrams, Steven A.
AU - Griffin, Ian J.
AU - Hawthorne, Keli M.
AU - Gunn, Sheila K.
AU - Gundberg, Caren M.
AU - Carpenter, Thomas O.
PY - 2005/10
Y1 - 2005/10
N2 - Background: Evidence suggests that vitamin D status in adults, as assessed by serum 25-hydroxyvitamin D (25-OHD), is positively associated with calcium absorption fraction and inversely associated with serum PTH. Few comparable pediatric data exist. Objectives: The objective of this study was to evaluate the relationships among vitamin D status, PTH, and calcium absorption in mid-pubertal boys and girls. Methods: Calcium absorption was measured as part of an evaluation of the effects of prebiotics (inulin-type fructans) using a stable isotope method in 93 young adolescents, 12.7 ± 1.0 yr of age, receiving diets averaging approximately 900 mg/d calcium. Results: A significant positive relation to calcium absorption was found for serum 1,25-dihydroxyvitamin D (P=0.048) and PTH (P=0.007), but not for 25-OHD (P = 0.77). PTH was significantly inversely related to 25-OHD and was positively related to serum 1,25-dihydroxyvitamin D and osteocalcin. PTH was marginally significantly inversely related to lumbar spinal, but not whole body, bone mineral density. Conclusions: These data suggest that in adolescents, especially in the presence of vitamin D insufficiency, PTH secretion increases to adapt to higher rates of bone formation associated with growth. This results in higher serum 1,25(OH)2D concentrations and increased calcium absorption results. Vitamin D status, as reflected by the serum 25-OHD level, is not closely related to calcium absorption. Whether adaptation to low serum 25-OHD is adequate under physiologically stressful situations, including those leading to very low serum 25-OHD levels, is unknown.
AB - Background: Evidence suggests that vitamin D status in adults, as assessed by serum 25-hydroxyvitamin D (25-OHD), is positively associated with calcium absorption fraction and inversely associated with serum PTH. Few comparable pediatric data exist. Objectives: The objective of this study was to evaluate the relationships among vitamin D status, PTH, and calcium absorption in mid-pubertal boys and girls. Methods: Calcium absorption was measured as part of an evaluation of the effects of prebiotics (inulin-type fructans) using a stable isotope method in 93 young adolescents, 12.7 ± 1.0 yr of age, receiving diets averaging approximately 900 mg/d calcium. Results: A significant positive relation to calcium absorption was found for serum 1,25-dihydroxyvitamin D (P=0.048) and PTH (P=0.007), but not for 25-OHD (P = 0.77). PTH was significantly inversely related to 25-OHD and was positively related to serum 1,25-dihydroxyvitamin D and osteocalcin. PTH was marginally significantly inversely related to lumbar spinal, but not whole body, bone mineral density. Conclusions: These data suggest that in adolescents, especially in the presence of vitamin D insufficiency, PTH secretion increases to adapt to higher rates of bone formation associated with growth. This results in higher serum 1,25(OH)2D concentrations and increased calcium absorption results. Vitamin D status, as reflected by the serum 25-OHD level, is not closely related to calcium absorption. Whether adaptation to low serum 25-OHD is adequate under physiologically stressful situations, including those leading to very low serum 25-OHD levels, is unknown.
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U2 - 10.1210/jc.2005-1021
DO - 10.1210/jc.2005-1021
M3 - Article
C2 - 16076940
AN - SCOPUS:26244462306
VL - 90
SP - 5576
EP - 5581
JO - Journal of Clinical Endocrinology and Metabolism
JF - Journal of Clinical Endocrinology and Metabolism
SN - 0021-972X
IS - 10
ER -