Osteoporosis. Light micrograph of a section through bone tissue in osteoporosis. Osteoporosis (brittle bone disease) causes a reduction in bone density and an increase in porosity, resulting in increased brittleness and a greater risk of fracture. Here, the bony network (trabeculae) is dark green, and greatly reduced from the normal density and thickness. Surrounding the trabeculae is non-mineralised bone tissue (orange). This conditon is most common in women after the menopause because they no longer produce the hormone oestrogen that helps in keeping bones healthy.