24 Rosler M, Anand R, Cicin-Sain A, Gauthier S, Agid Y, Dal-Bianco P, et al. Efficacy and safety of rivastigmine in patients with Alzheimer's disease: international randomised controlled trial. BMJ 1999;318:633-40. 25 Dawson-Hughs B, Harris SS, Krall EA, Dallal GE. Effect of calcium and vitamin D supplementation on bone density in men and women 65 years of age or older. N Engl J Med 1997;337:670-6. 26 Black DM, Cummings SR, Karpf DB et al. Randomised trial of effective alendronate on risk of fracture in women with existing vertebral fractures. Fracture intervention trial research group. Lancet 1996;348:1535-41. 27 Ensrud KE, Black DM, Polermo L, Bauer DC, Barrett-Connor E, Quandt SD, et al. Treatment with alendronate prevents fractures in women at highest risks. Results from the fracture intervention trial. Arch Intern Med 1997;157:2617-24. 28 Ettinger B, Black DM, Mitlak BH, Knickerbocker RK, Nickelson T, Genant HK, et al for the Multiple Outcomes of Raloxifene Evaluation (MORE) Investigators. Reduction of vertebral fracture risk in postmenopausal women with osteoporosis treated with raloxifene. Results from a three-year randomised clinical trial. JAMA 1999;282:637-45. 29 Cummings SR, Eckert S, Krueger KA et al. The effect of raloxifene on risk of breast cancer in postmenopausal women. Results from the MORE randomised trial. JAMA 1999;