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Resistance to bone resorbing effects of PTH in black women.
J Bone Miner Res 1997; 12(6):958-66JB

Abstract

Black women have a lower incidence of vertebral and hip fractures than white women, possibly due to differences in skeletal and mineral metabolism. One suggested mechanism is that blacks have decreased skeletal sensitivity to parathyroid hormone (PTH). To test this hypothesis, we infused h(1-34)PTH in healthy premenopausal black (n = 15) and white (n = 18) women over 24 h and measured serum and urine indices of bone turnover and calcium metabolism throughout the infusion. At baseline, the mean 25-hydroxyvitamin D (25(OH)D) concentration was significantly lower in black women (46%). There were also nearly significant trends toward higher PTH and lower urinary calcium and pyridinoline levels in black women. During infusion, there were no racial differences in the mean (1-34)PTH levels achieved or in resultant elevations of serum calcium or 1,25-dihydroxyvitamin D (1,25(OH)2D) levels. Endogenous parathyroid suppression (measured by (1-84)PTH levels) was also similar between blacks and whites. There was an initial decline in urinary calcium/creatinine in both groups with a greater reduction in black women early in the infusion period (p < 0.05 at 8 h). Furthermore, blacks had lower levels of urinary calcium/creatinine throughout the infusion (p < 0.05 group difference). Bone formation markers (carboxy-terminal propeptide of type I procollagen and osteocalcin) decreased within 8 h and continued to decline throughout the infusion with no distinguishable racial differences (p < 0.05 time trend for both). The most dramatic difference between black and white women in response to PTH infusion was represented by the bone resorption markers. Three separate metabolites of bone resorption (cross-linked N-telopeptide of type I collagen, cross-linked C-telopeptide of type I collagen, and free pyridinoline) all showed substantially greater elevations in white (mean peak increments 399, 725, and 43%) compared with black women (mean peak increments 317, 369, and 17%) during the infusion (p < 0.05 group differences for all three variables). These data strongly suggest that blacks have decreased skeletal sensitivity to the acute resorptive effects of increased PTH. This finding indicates that calcium homeostasis may be accomplished in blacks (during times of relative calcium deficiency) by greater conservation of calcium from nonskeletal sources (most likely renal) with relative preservation of skeletal tissue. These differences in calcium economy could account, at least in part, for the increased bone mass and lower incidence of osteoporotic fractures in black women.

Authors+Show Affiliations

Regional Bone/Clinical Research Centers, Helen Hayes Hospital, West Haverstraw, New York, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

9169356

Citation

Cosman, F, et al. "Resistance to Bone Resorbing Effects of PTH in Black Women." Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research, vol. 12, no. 6, 1997, pp. 958-66.
Cosman F, Morgan DC, Nieves JW, et al. Resistance to bone resorbing effects of PTH in black women. J Bone Miner Res. 1997;12(6):958-66.
Cosman, F., Morgan, D. C., Nieves, J. W., Shen, V., Luckey, M. M., Dempster, D. W., ... Parisien, M. (1997). Resistance to bone resorbing effects of PTH in black women. Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research, 12(6), pp. 958-66.
Cosman F, et al. Resistance to Bone Resorbing Effects of PTH in Black Women. J Bone Miner Res. 1997;12(6):958-66. PubMed PMID: 9169356.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Resistance to bone resorbing effects of PTH in black women. AU - Cosman,F, AU - Morgan,D C, AU - Nieves,J W, AU - Shen,V, AU - Luckey,M M, AU - Dempster,D W, AU - Lindsay,R, AU - Parisien,M, PY - 1997/6/1/pubmed PY - 1997/6/1/medline PY - 1997/6/1/entrez SP - 958 EP - 66 JF - Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research JO - J. Bone Miner. Res. VL - 12 IS - 6 N2 - Black women have a lower incidence of vertebral and hip fractures than white women, possibly due to differences in skeletal and mineral metabolism. One suggested mechanism is that blacks have decreased skeletal sensitivity to parathyroid hormone (PTH). To test this hypothesis, we infused h(1-34)PTH in healthy premenopausal black (n = 15) and white (n = 18) women over 24 h and measured serum and urine indices of bone turnover and calcium metabolism throughout the infusion. At baseline, the mean 25-hydroxyvitamin D (25(OH)D) concentration was significantly lower in black women (46%). There were also nearly significant trends toward higher PTH and lower urinary calcium and pyridinoline levels in black women. During infusion, there were no racial differences in the mean (1-34)PTH levels achieved or in resultant elevations of serum calcium or 1,25-dihydroxyvitamin D (1,25(OH)2D) levels. Endogenous parathyroid suppression (measured by (1-84)PTH levels) was also similar between blacks and whites. There was an initial decline in urinary calcium/creatinine in both groups with a greater reduction in black women early in the infusion period (p < 0.05 at 8 h). Furthermore, blacks had lower levels of urinary calcium/creatinine throughout the infusion (p < 0.05 group difference). Bone formation markers (carboxy-terminal propeptide of type I procollagen and osteocalcin) decreased within 8 h and continued to decline throughout the infusion with no distinguishable racial differences (p < 0.05 time trend for both). The most dramatic difference between black and white women in response to PTH infusion was represented by the bone resorption markers. Three separate metabolites of bone resorption (cross-linked N-telopeptide of type I collagen, cross-linked C-telopeptide of type I collagen, and free pyridinoline) all showed substantially greater elevations in white (mean peak increments 399, 725, and 43%) compared with black women (mean peak increments 317, 369, and 17%) during the infusion (p < 0.05 group differences for all three variables). These data strongly suggest that blacks have decreased skeletal sensitivity to the acute resorptive effects of increased PTH. This finding indicates that calcium homeostasis may be accomplished in blacks (during times of relative calcium deficiency) by greater conservation of calcium from nonskeletal sources (most likely renal) with relative preservation of skeletal tissue. These differences in calcium economy could account, at least in part, for the increased bone mass and lower incidence of osteoporotic fractures in black women. SN - 0884-0431 UR - https://www.unboundmedicine.com/medline/citation/9169356/Resistance_to_bone_resorbing_effects_of_PTH_in_black_women_ L2 - https://doi.org/10.1359/jbmr.1997.12.6.958 DB - PRIME DP - Unbound Medicine ER -