The role of hormone therapy and calcium plus vitamin D for reduction of bone loss and risk for fractures: lessons learned from the Women's Health Initiative.

Osteoporosis, a major public health problem, is characterized by increased risk for fracture. To reduce the morbidity and excess loss of life associated with this common disease, we need to understand the efficacy of treatment strategies for fracture reduction. The Women's Health Initiative Clinical Trials have extended our understanding of the effect of hormone therapy and calcium plus vitamin D supplements on risk for hip and total fractures. Although estrogen, with or without progestin, significantly decreases fracture risk at all skeletal sites-almost irrespective of underlying risk for osteoporosis-its risks outweigh its benefits, negating its general use for fracture reduction. For calcium-replete women, calcium plus vitamin D supplementation has a non-significant effect, hence the case for universal supplementation loses merit. But, that argument gains credibility for women over age 60-as a 21% reduction in hip fractures attests-showing that calcium plus vitamin D has a positive effect on bone health in older postmenopausal women.