The effects of short-term hormone replacement therapy on long-term bone mineral density.

INTRODUCTION: Short-term hormone replacement therapy (HRT) relieves menopausal symptoms and increases bone mineral density (BMD), but bone loss reoccurs upon discontinuation. This study assesses whether short-term HRT provides long-term BMD benefits. METHOD: This was a prospective study of women aged 50-54 years followed up for 9 years. Women were categorized into three groups according to the treatment they received: No-HRT (n = 340), Short-term HRT (2-4 years, n = 60), and Long-term HRT (9 years, n = 187). RESULTS: BMD increased significantly at the hip (2.4%, p < 0.001) and spine (8.0%, p < 0.001) over 9 years in the Long-term HRT group. Women without treatment lost BMD at the hip (-4.2%, p < 0.001) and spine (-3.5%, p < 0.001). Women in the Short-term HRT group had no significant loss of BMD at the hip (-1.6%, p = 0.08) or spine (-1.4%, p = 0.18) over 9 years. BMD in the Short-term HRT group was significantly higher at 9 years than in the No-HRT group at both spine (difference 0.023 g/cm(2), p = 0.048) and hip (difference 0.016 g/cm(2), p = 0.042). CONCLUSION: After 9 years, women who had taken short-term HRT had no significant loss of BMD and were better off in terms of BMD than those left untreated. Short-term HRT in the early postmenopausal period provides long-term BMD benefits.