What Is Bone Mineralization? 1

A. Michael Parfitt

University of Arkansas for Medical Sciences Division of Endocrinology and Metabolism Little Rock, Arkansas 72205

To the editor:

Roemmich et al. (1) report interesting data using inappropriate terminology. Bone is made in two stages; matrix is formed first, and about 2 wk later (in children) it begins to mineralize (2); the delay is longer in the adult skeleton (3). The process of adding mineral to matrix is referred to as "bone mineralization." It is important that this term not be used for the quite different process of adding bone to the growing skeleton, a confusion that arose because the measurement of bone mass in vivo is usually based on measuring the amount of mineral. This is possible because in the absence of rickets or osteomalacia the degree of mineralization of matrix varies between fairly narrow limits, so that for the most part mineral mass is a reasonable estimate of bone mass. An increase in mineral mass does represent bone mineralization in two circumstances: the treatment of osteomalacia (4) and the completion of secondary mineralization when bone turnover is reduced and bone age increased (5), but neither of these applies to the growing skeleton. Whatever its role in the control of bone mass, no effect of leptin on bone mineralization has been demonstrated.

Footnotes

1 Address correspondence to: A. Michael Parfitt, University of Arkansas for Medical Sciences, Division of Endocrinology and Metabolism, 4301 West Markham Street, Slot 587, Little Rock, Arkansas 72205. Back

A response to this letter was invited, but the authors of the original article chose not to provide one.

Received June 24, 2003.

References

  1. Roemmich JN, Clark PA, Mantzoros CS, Gurgol CM, Weltman A, Rogol AD 2003 Relationship of leptin to bone mineralization in children and adolescents. J Clin Endocrinol Metab 88:599–604[Abstract/Free Full Text]
  2. Glorieux FH, Travers R, Taylor A, Bowen JR, Rauch F, Norman M, Parfitt AM 2000 Normative data for iliac bone histomorphometry in growing children. Bone 26:103–109[CrossRef][Medline]
  3. Parfitt AM, Han Z-H, Palnitkar S, Rao DS, Shih M-S, Nelson D 1997 Effects of ethnicity and age or menopause on osteoblast function, bone mineralization and osteoid accumulation in iliac bone. J Bone Miner Res 12:1864–1872[Medline]
  4. Basha B, Rao DS, Han Z-H, Parfitt AM 2000 Osteomalacia due to vitamin D depletion in patients with gastrointestinal disorders. Am J Med 108:296–300[CrossRef][Medline]
  5. Boivin G, Meunier PJ 2002 The degree of mineralization of bone tissue measured by computerized quantitative contact microradiography. Calcif Tissue Int 70:503–511[CrossRef][Medline]