Alendronate for Prevention of AntiRetroviral Therapy-associated Bone Loss

Multi-centre, prospective, randomised, double-blind, placebo-controlled trial over 50 weeks. The aims of this study include: 1. To determine if short-course treatment with alendronate versus placebo combined with calcium and vitamin D, initiated 2 weeks prior to start of ART and can prevent loss of BMD over 48 weeks of follow-up post ART initiation. 2. To explore the effect of alendronate on bone turnover in the setting of ART initiation. 3. To determine which factors, such as choice of ART, impacts the protective effect of alendronate in preventing BMD loss. 4. To determine the relationship between changes in bone turnover markers, vitamin D, parathyroid hormone and calcium levels. 5. To explore the pathogenesis of BMD loss with initiation of ART by investigating relationships between changes in immune function (T-cells and B-cells subsets), bone turnover and BMD.