Association between intestinal vitamin D receptor, calcium absorption, and serum 1,25 dihydroxyvitamin D in normal young and elderly women

H. Karimi Kinyamu, J. Christopher Gallagher, Jean M. Prahl, Hector F. Deluca, Kimberly M. Petranick, Stephen J. Lanspa

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The exact mechanism for the decrease in intestinal calcium absorption with age is not yet understood. A decrease with age in serum 1,25- dihydroxyvitamin D (1,25(OH)2D) or a decrease in the intestinal vitamin D receptor (VDR) protein concentration are possible causes. The objective of this study was to examine the effect of age on these factors. Fifty-nine young women age 25-35 years were compared with 41 elderly women age 65-83 years who underwent measurements of VDR, calcium absorption using a 20 mg and 100 mg calcium carrier, and calciotropic hormones. Calcium absorption by both tests was lower in the elderly women compared with the young women (p <0.05). Serum 1,25(OH)2D and duodenal VDR protein concentration were not significantly different between the two age groups. Serum 1,25(OH)2D correlated with the 20 mg calcium absorption test in both young (r = 0.35, p <0.007) and elderly women (r = 0.58, p <0.0001) and with the 100 mg calcium absorption in the elderly (r = 0.32; p <0.05). VDR did not correlate with calcium absorption in young women or elderly women, nor did VDR correlate with serum 1,25(OH)2D and serum 25-hydroxyvitamin D. In summary, the decrease in calcium absorption cannot be explained by a decrease in intestinal VDR. The correlation between serum 1,25(OH)2D and both calcium absorption tests only accounts for 12-30% of the variance in the age-related change in the calcium absorption tests. Other factors, not yet understood, are responsible for the decline in calcium absorption with age.

Original languageEnglish (US)
Pages (from-to)922-928
Number of pages7
JournalJournal of Bone and Mineral Research
Issue number6
StatePublished - Jun 9 1997


All Science Journal Classification (ASJC) codes

  • Endocrinology, Diabetes and Metabolism
  • Orthopedics and Sports Medicine

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