Bone mass decreases with ageing, leading to increased risk of fractures in the elderly. Bone material quality (e.g. the composition of bone, and its distribution in the skeleton) also changes with age, but whether this is caused by gradual deterioration over time, or by defective production of bone in older people is not known. This project will assess whether newly formed bon, made by older men and women has poor composition, using confocal microscopy, back-scattered electron microscopy, and computer based image analysis of the osteocyte network.