Background This is a prospective study of bone mineral density in postmenopausical women treated with alendronate.

Objectives To evaluate the efficacy of alendronate in postmenopausical osteoporotic women for 1, 2 and 3 years.

Methods In a prospective study, we included 98 women diagnosed of postmenopausical osteoporosis attended from 1997 to 2000. The mean age was 59.07 (SD: 6.68). Patients received alendronate 10 mg daily, they were allowed to take calcium and vitamine D supplementation. The subjects were assessed at baseline, 12, 24 and 36 months for bone mineral density (BMD) measurements and X-ray and every 6 months blood and urinary biochemistries and markers of bone turnover were done.

Results Sixteen patients (16%) have dropped out because of adverse effects, the most common was gastrointestinal events. 34 (34.6%) patients had previous fractures (17 had spine fractures, 12 Colles´s fractures and one hip fracture). Three patients on treatment with alendronate had new fractures (1 spine, 1 scaphoid and one Colles´s fracture). 70, 24 and 7 subjects have completed one, two and three years of treatment, respectively. The results were analysed by Student´s t-test. Patients treated with alendronate for 1 year had significantly greater improvement in BMD at spine. The mean BMD at baseline was 0.373 vs 0.773 (p < 0.005) and at hip 0.665 vs 0.643 at baseline (p < 0.005). Patients who completed two years had similar values of BMD as the year before, the mean BMD was 0.745 at spine and 0.646 at hip.

Conclusion Patients treated with alendronate for one year had significantly greater improvement in BMD at both the spine and hip.