Role of calcium intake in modulating age-related increases in parathyroid function and bone resorption

J Clin Endocrinol Metab. 1996 May;81(5):1699-703. doi: 10.1210/jcem.81.5.8626819.


Serum parathyroid hormone (PTH) and bone resorption increase in elderly women and contribute to age-related bone loss. Whether these abnormalities are caused by calcium deficiency resulting from age-related decreases in absorption and renal conservation is unclear. We studied 28 normal elderly women (mean +/- SD, age 69.3 +/- 2.7 yr) who were maintained for 3 yr on usual calcium intake levels (20.4 +/- 7.2 mmol/day [815 +/- 289 mg/day]; n = 15) (known as the usual calcium group) or high calcium intake levels (60.4 +/- 6.5 mmol/day [2414+/260 mg/day]; n = 13) (known as the high calcium group) and a reference group of 12 normal young adult women (age 30.1 +/- 4.4 yr), whose calcium intake was 23.0 +/- 4.8 mmol/day (918 +/- 193 mg/day) (known as the young group). Serum PTH was measured every 2 h, and urinary excretion of deoxypyridinoline (Dpd), a new marker for bone resorption, was measured in 4 h collections. Parathyroid gland secretory capacity was assessed during induced hypocalcemia. The mean 24 h serum PTH was 40% lower (P < 0.001), and the mean 24 h urinary Dpd was 35% lower (P < 0.005) in the high than in the usual calcium group. Mean parathyroid gland secretory capacity also was 47% lower (P < 0.005) in the high calcium group than in the usual calcium group. However, the usual calcium group had a mean 24 h serum PTH level that was 70% higher (P < 0.001) and a mean 24 h urinary Dpd level that was 30% higher (P < 0.005) than the young group, whereas the high calcium group was indistinguishable from the young group. Thus, failure of elderly women to increase their calcium intake to offset age-related increases in calcium requirement contributes substantially to their development of increased parathyroid activity and increased bone resorption, whereas a high calcium intake can reverse both abnormalities.

Publication types

  • Clinical Trial
  • Comparative Study
  • Controlled Clinical Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Aged
  • Aging / physiology*
  • Amino Acids / urine
  • Bone Resorption*
  • Calcium / administration & dosage*
  • Calcium / blood
  • Circadian Rhythm
  • Diet
  • Female
  • Humans
  • Parathyroid Glands / physiology*
  • Parathyroid Hormone / blood


  • Amino Acids
  • Parathyroid Hormone
  • deoxypyridinoline
  • Calcium