Participants will be taking risedronate (oral bisphosphonate, once weekly), rounded to the nearest 5 mg) together with Vitamin D and calcium for 6 weeks. Vitamin D and Calcium will be given as Calcichew 500mg/200 IU tablets, 1 tablet for participants weighing less than 30 kg and 2 tablets for participants weighing 30 kg or more. Risedronate Sodium belongs to Bisphosphonates group of medicine. As per BNF, it is not licensed for use in children. The trade name is Actonel® Warner Chilcott). This study will use 5mg and 35mg film-coated tablets.