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. This is a close-up of one strut (trabecula, dark blue) of the bony network that gives bone its strength. The trabecula is greatly reduced from its normal thickness. Surrounding the trabecula is non-mineralised bone tissue (pink and white), including empty spaces (white) and cells with nuclei (dark spots). This condition is most common in women after the menopause because they no longer produce the hormone oestrogen that helps in keeping bones healthy.