Conclusion

In women, oestrogen deficiency due to the menopause is the major cause of both the early rapid and late slow phases of age-related bone loss. In ageing men, oestrogen deficiency also appears to be the dominant cause and is due to age-related increases in serum SHBG and to impaired gonadal production of sex steroids. The role played by decreases in bioavailable testosterone in bone loss in men is presently unclear. Thus, although other factors contribute, age-related osteoporosis appears to be primarily an endocrine deficiency disease in both genders.

This work was supported by National Institutes of Health grants AR27065 and AG04875. References

Ashcroft GS, Dodsworth J, van Boxtel E et al 1997 Estrogen accelerates cutaneous wound healing associated with an increase in TGF-b1 levels. Nat Med 3:1209—1215 Bennett A, Wahner HW, Riggs BL, Hintz RL 1984 Insulin-like growth factors I and II: aging and bone density in women. J Clin Endocrinol Metab 59:701—704 Bernecker PM, Willvonseder R, Resch H 1995 Decreased estrogen levels in male patients with primary osteoporosis. J Bone Miner Res 10:S445 Carani C, Qin K, Simoni M et al 1997 Effect of testosterone and estradiol in a man with aromatase deficiency. N Engl J Med 337:91—95 Center JR, Nguyen TV, White CP, Eisman JA 1997 Male osteoporosis predictors: sex hormones and calcitropic hormones. J Bone Miner Res 12:S368 Chapuy MC, Arlot ME, Duboeuf F et al 1992 Vitamin D3 and calcium to prevent hip fractures in elderly women. N Engl J Med 327:1637—1642 Eastell R, Yergey AL, Vieira N, Cedel SL, Kumar R, Riggs BL 1991 Interrelationship among vitamin D metabolism, true calcium absorption, parathyroid function and age in women: evidence of an age-related intestinal resistance to 1,25-dihydroxyvitamin D action. J Bone Miner Res 6:125—132

Ernst M, Heath JK, Rodan GA 1989 Estradiol effects on proliferation, messenger ribonucleic acid for collagen and insulin-like growth factor-I, and parathyroid hormone-stimulated adenylate cyclase activity in osteoblastic cells from calvariae and long bones. Endocrinology 125:825—833

Ettinger B, Genant HK, Cann CE 1985 Long-term estrogen replacement therapy prevents bone loss and fractures. Ann Intern Med 102:319—324 Falahati-Nini A, Riggs BL, Atkinson EJ, O'Fallon WM, Eastell R, Khosla S 2000 Relative contributions of testosterone versus estrogen in regulating bone resorption and formation in normal elderly men. J Clin Invest 106:1553-1560 Gennari C, Agnusdei D, Nardi P, Civitelli R 1990 Estrogen preserves a normal intestinal responsiveness to 1,25-dihydroxyvitamin D3 in oophorectomized women. J Clin Endocrinol Metab 71:1288—1293 Greendale GA, Edelstein S, Barrett-Connor E 1997 Endogenous sex steroids and bone mineral density in older women and men: the Rancho Bernardo Study. J Bone Miner Res 12:1833—

Khosla S, Melton LJ III, Atkinson EJ, O'Fallon WM, Klee GG, Riggs BL 1998 Relationship of serum sex steroid levels and bone turnover markers with bone mineral density in men and women: a key role for bioavailable estrogen. J Clin Endocrinol Metab 83:2266—2274 Khosla S, Atkinson EJ, Melton LJ III, Riggs BL 1997 Effects of age and estrogen status on serum parathyroid hormone levels and biochemical markers of bone turnover in women: a population-based study. J Clin Endocrinol Metab 82:1522—1527 Khosla S, Melton LJ III, Atkinson, EJ, O'Fallon WM, Riggs BL 2000 Relationship of sex steroids to longitudinal changes in bone mineral density and bone resorption in young

1843

versus elderly men: effects of estrogen on peak bone mass and on age-related bone loss. J Bone Miner Res 15:S159

Ledger GA, Burritt MF, Kao PC et al 1994 Abnormalities of parathyroid hormone secretion in elderly women that are reversible by short term therapy with 1,25-dihydroxyvitamin D3. J Clin Endocrinol Metab 79:211-216 Manolagas SC 2000 Birth and death of bone cells: basic regulatory mechanisms and implications for the pathogenesis and treatment of osteoporosis. Endocr Rev 21:115-137 Manolagas SC, Culler FL, Howard JE, Brickman AS, Deftos LJ 1983 The cytoreceptor assay for 1,25-dihydroxyvitamin D and its application to clinical studies. J Clin Endocrinol Metab 56:751-760

McKane WR, Khosla S, Burritt MF et al 1995 Mechanism of renal calcium conservation with estrogen replacement therapy in women in early postmenopause — a clinical research center study. J Clin Endocrinol Metab 80:3458-3464 McKane WR, Khosla S, Egan KS, Robins SP, Burritt MF, Riggs BL 1996 Role of calcium intake in modulating age-related increases in parathyroid function and bone resorption. J Clin Endocrinol Metab 81:1699-1703 McKane WR, Khosla S, Risteli J, Robins SP, Muhs JM, Riggs BL 1997 Role of estrogen deficiency in pathogenesis of secondary hyperparathyroidism and increased bone resorption in elderly women. Proc Assoc Am Physicians 109:174-180 Meikle AW, Daynes RA, Araneo BA 1991 Adrenal androgen secretion and biologic effects.

Endocrinol Metab Clin North Am 20:381-400 Melton LJ III, Kan SH, Wahner HW, Riggs BL 1988 Lifetime fracture risk: An approach to hip fracture risk assessment based on bone mineral density and age. J Clin Epidemiol 41:985-994 Morishima A, Grumbach MM, Bilezikian JP 1997 Estrogen markedly increases bone mass in an estrogen deficient young man with aromatase deficiency. J Bone Miner Res 12:S126 Riggs BL, Melton lJ 1986 Involutional osteoporosis. N Engl J Med 314:1676-1686 Riggs BL, Khosla S, Melton LJ III 1998 A unitary model for involutional osteoporosis: estrogen deficiency causes both type I and type II osteoporosis in postmenopausal women and contributes to bone loss in aging men. J Bone Miner Res 13:763-773 Riggs BL, Khosla S, Melton LJ III 2000 Primary osteoporosis in men: role of sex steroid deficiency. Mayo Clin Proc 75:S46-S50 Seeman E 1997 From density to structure: growing up and growing old on the surfaces of bone.

J Bone Miner Res 12:509-521 Slemenda CW, Longcope C, Zhou L, Hui SL, Peacock M, Johnston C 1997 Sex steroids and bone mass in older men. Positive associations with serum estrogens and negative associations with androgens. J Clin Invest 100:1755-1759 Smith EP, Boyd J, Frank GR et al 1994 Estrogen resistance caused by a mutation in the estrogen-receptor gene in a man. N Engl J Med 331:1056-1061 (erratum: 1995 N Engl J Med 332:131) Thorner MO, Vance ML 1988 Growth hormone, 1988. J Clin Invest 82:745-747 Tsai KS, Heath H III, Kumar R, Riggs BL 1984 Impaired vitamin D metabolism with aging in women. Possible role in pathogenesis of senile osteoporosis. J Clin Invest 73: 1668-1672

Tsai KS, Wahner HW, Offord KP, Melton LJ III, Kumar R, Riggs BL 1987 Effect of aging on vitamin D stores and bone density in women. Calcif Tissue Int 40:241-243 Van Cauter E, Leproult R, Kupfer DJ 1996 Effects of gender and age on the levels and circadian rhythmicity of plasma cortisol. J Clin Endocrinol Metab 81:2468-2473 Vanderschueren D, Van Herck E, Nijs J, Ederveen AGH, De Coster R, Bouillon R 1997 Aromatase inhibition impairs skeletal modelling and decreases bone mineral density in growing male rats. Endocrinology 138:2301-2307

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