Osteoporosis (bone loss) is a disease of the skeleton in which bone strength is reduced. The structural and functional changes make the skeleton unstable, with a risk of fractures. In older age, osteoporosis is the most common bone disease. Women after the menopause are particularly affected. One in four women over 50 has osteoporosis. However, it also becomes much more common in men over 70.
Bone mass increases during roughly the first 30 years of life (bone is built up in youth), then reaches a peak and slowly declines in later years. In general, bone density decreases with age. Osteoporosis usually results from insufficient bone formation in young years and/or accelerated bone loss later in life.
Osteoporosis without fractures often causes no symptoms. In advanced stages, the bones become so unstable that they can become deformed. Relatively minor stresses can also cause fractures, especially of the spine, the neck of the femur, the upper arm and forearm. Spontaneous fractures, i.e. without any external force, are also possible. The consequences are above all pain and restricted mobility, up to being bedridden and needing care. Patients with osteoporotic fractures have higher mortality and a higher risk of further fractures. 41% of patients with vertebral fractures permanently depend on help from others.
Osteoporotic changes in the vertebrae can lead to a rounded back, a hunchback and loss of height. Osteoporosis usually affects the whole skeleton. Only rarely is it limited to a particular region, for example osteoporosis near the joints in rheumatoid arthritis.