Menopause is the time in the life of a woman of her last menstrual period. Hormonal changes occurring at this time can cause an accelerated loss of bone mass.

Post-menopausal osteoporosis is characterised by low bone mass and micro architectural deterioration of the bone, leading to bone fragility and therefore an increased risk of fracturing. It affects the entire skeleton.

In the first 5 years of menopause there can be up to a 25% loss of bone mass. Each year this loss is between 1-5% with the average loss being 2%.

The bone loss is due to bone resorption occurring at a rate faster than bone formation, resulting in bone loss [see bone biology]. The rate of trabecular bone loss is greater than the loss of cortical bone [see types of bone]. Ten years after the onset of menopause, most Caucasian and Asian women have osteopenia or osteoporosis. However, bone mass can easily be measured, preserved and increased.