Our bones can be normal and strong, osteoporotic and fragile or somewhere in between. Skeletal bones are made up of a thick outer shell surrounding a strong inner mesh consisting of collagen, calcium salts and minerals. In the spaces between the inner supporting struts of bone are blood vessels and bone marrow. Bone is alive and constantly changing. Old, worn out bone is broken down by cells called osteoclasts and is then built up again by bone building cells called osteoblasts. This process is known as bone turnover. Up until the age of 35 there is a balance between bone break-down and new bone formation which means that bone density remains stable. After this age bone loss increases as part of the normal ageing process. However this can lead to osteoporosis and an increased risk of fracture.
Osteoporosis means that some of the struts of bone become thin or break and the bone becomes too porous. Osteoporosis may make a person more prone to a bone fracture which can follow from a fall or more rarely can occur spontaneously. Any bone may be affected, but the most common fractures involve the hip, wrist or the spine. Fractures resulting from bone fragility in the elderly have a major impact on quality of life and frequently cause serious disability.
One in two women and one in five men over the age of 50 in the U.K. will break
a bone because of underlying osteoporosis.
Peak bone mass is achieved by age 30. Genetics or lifestyle factors (Poor diet or excessive dieiting, lack of exercise, illness) may mean that a good bone density is not achieved. Low peak bone mass becomes a disadvantage in old age. After skeletal maturity, bone is lost in both women and men at about 1% a year. Women experience a phase of accelerated bone loss for three years after the menopause.
- These contribute to fracture risk independently of bone densityAge(50+ females, 65+males)
- Poor diet, including excessive, long-term dieting
- Previous fragility fracture especially after age 40
- Premature menopause or hysterectomy(Under 45 years)
- Family history of osteoporosis or hip fracture
- Prolonged use of oral corticosteroids.eg prednisolone
- Chronic disorders associated with osteoporosis, for example hyperparathyroidism, malabsorption syndromes, eating disorders.
- Low body mass index (BMI - less than 19 kg / m2) or weight less than 49kg (7stone 10lb)
- History of smoking
- High alcohol consumption
- Too little physical activity.