# BONE AND MINERAL METABOLISM IN BLACKS AND WHITES

> **NIH NIH R01** · MEDICAL UNIVERSITY OF SOUTH CAROLINA · 1989 · $137,183

## Abstract

There is evidence that bone mass is increased in black as compared to
white individuals so that there is less risk of osteoporosis and
associated fractures.  The increased skeletal mass is attributed to
increased muscle mass.  Further, urinary calcium is lower in blacks than
in whites.  It is proposed that the increase in bone mass in blacks
results from skeletal resistance to parathyroid hormone (PTH) and possibly
to 1,25-dihydroxyvitamin D [1-25(OH)2D] and that diminished urinary
calcium caused by consequent increases in circulating PTH.  Preliminary
results support this hypothesis:  young adult blacks (age 20-35 years)
show significant increases in mean serum immunoreactive PTH, serum
1,25(OH)2D and urinary cyclic AMP and significant decreases in mean
urinary calcium as compared to age-matched whites.  Mean serum calcium,
serum ionized calcium, serum phosphorus and creatinine clearance are the
same in the two groups.  In view of these observations, additional studies
are proposed a) to establish that the skeleton of blacks is resistant to
PTH by determining the response to human synthetic PTH (1-34) and whether
intestinal absorption of calcium is increased in blacks because of
increased circulating 1,25(OH)2D, b) to determine whether the skeleton of
blacks is resistant to 1,25(OH)2D3 and whether binding and uptake of
3H-1,25(OH)2D3 by cultured skin fibroblasts are diminished in blacks, c)
to determine the age at which increases in bone mass and skeletal
resistance to PTH become evident in blacks, d) to determine the effects of
aging on bone mass at 3 sites in blacks, forearm, lumbar spine and hip,
and whether there is an age-related loss of renal production of 1,25(OH)2D
and impairment in ability to adapt to a low calcium intake in blacks as
occur in whites, e) to determine the influence of the menopause on vitamin
D and mineral metabolism in black women, and f) to determine the effects
of increased body weight in obese subjects and of increased muscle mass in
body builders and weight lifters on bone mass and vitamin D and mineral
metabolism.  The proposed work should provide new information about why
the skeleton is resistant to the development of osteoporosis and urinary
calcium is reduced in blacks and whether increased strain produced by
gravitational forces can influence bone mass and produce alterations in
the vitamin D-endocrine system similar to those observed in blacks.  The
results could also lead to new approaches for investigating the
pathogenesis and treatment of osteoporosis.

## Key facts

- **NIH application ID:** 3157467
- **Project number:** 5R01AR036066-05
- **Recipient organization:** MEDICAL UNIVERSITY OF SOUTH CAROLINA
- **SAM.gov UEI:** NHV3GTWSALA7
- **Principal Investigator:** NORMAN H BELL
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1989
- **Award amount:** $137,183
- **Award type:** 5
- **Project period:** 1985-08-01 → 1991-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3157467

## Citation

> US National Institutes of Health, RePORTER application 3157467, BONE AND MINERAL METABOLISM IN BLACKS AND WHITES (5R01AR036066-05). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3157467. Licensed CC0.

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