Osteoporosis Causes

Osteoporosis is less common in men than in women because men have larger skeletons, their bone loss starts later and progresses more slowly, and they have no period of rapid hormonal change and bone loss.

As with other tissues in the body, bone tissue is alive and constantly changing, remodelling and rebuilding, and bone mass and strength can be affected by factors such as genetics, hormones, physical exercise and diet (especially intake of calcium, phosphate, vitamin D, and other nutrients).

Problems with any of these factors can result in more bone loss than bone rebuilding thereby causing osteoporosis which can occur at any age - broken wrists, hips and spinal bones are the most common fractures and while it is more widespread in older age, younger people can sometimes be affected.

Osteoporosis occurs when the struts which make up the mesh-like structure within bones become thin, causing bones to become fragile and break easily following a minor bump or fall and though fractures can occur in different parts of the body, the wrists, hips and spine are most commonly affected.

Bones contain collagen (protein), calcium salts and other minerals and each bone is made up of a thick outer shell known as cortical bone and a strong inner mesh of trabecular bone which looks like a honeycomb, old and worn out bone is broken down by cells called osteoclasts and replaced by bone building cells called osteoblasts.

This process of renewal is called bone turnover and in childhood, osteoblasts work faster, enabling the skeleton to increase in size, density and strength and during this period of rapid bone growth, it takes the skeleton just two years to completely renew itself whereas in adults this process takes seven to ten years.

Somewhere between the ages of 16 and 18, bones stop growing in length but bone density continues to increase slowly until a person reaches their late 20s, when the balance between bone demolition and bone construction becomes stable.

Around 35, bone loss increases very gradually as part of the natural ageing process and this can lead to osteoporosis and an increased risk of broken bones, especially in later life - women are particularly susceptible because bone loss becomes more rapid for several years following the menopause.

Osteoporosis is only painful if fractures occur and having thin, fragile bones in themselves are not painful but osteoporosis means it is more likely that you have a 'greater risk of fracture' which can result in pain and other problems.

Osteoporosis does not generally slow or stop the healing process and bones that break because of osteoporosis will still heal in the same way as they do in people who do not have osteoporosis, usually over a six to eight week period.

Broken wrists can be the first indication of osteoporosis and often occur in middle aged women who have put out their arm to break a fall - healthy bones should be able to withstand a fall from standing height.

Hips broken as a result of osteoporosis occur most commonly in the late 70s or 80s usually as a result of a fall and can affect all aspects of life.

While full recovery is always possible it will often depend on how well someone is before the broken hip occurs and often regaining fully mobility and independence can be difficult requiring the support of physiotherapists and social care services.

Falling is common in later life because of poor balance and co-ordination, leading to a higher risk of breaking a hip, something which could have a significant impact on quality of life.

Reducing risks of falling may be a way of reducing risks of fracture as breaking a hip when older can have a major impact on a person's independence and can create a fear of falling which makes older people nervous to engage in everyday activities.

Fractures due to osteoporosis of the bones in the spine (vertebrae) usually occur in the lumbar (lower) or thoracic (middle) area of the spine and while they do not interfere with the spinal cord or result in paralysis or loss of sensation except in very unusual cases they can cause height loss or spinal curvature.

A fracture of one or more of the vertebrae can occur as the result of an awkward movement, like reaching up to get something from a kitchen cupboard or lifting heavy shopping bags. Sometimes, they may occur spontaneously, with very little cause, such as following an episode of coughing or sneezing.

If fractures are numerous and severe they can lead to significant height loss and curvature causing shortness of breath, protruding stomach, indigestion problems and stress incontinence.

Other bones such as the humerus (upper arm), ribs or the pelvis may also break if they are fragile.

Less common types of osteoporosis such as idiopathic juvenile osteoporosis is an unusual condition in young people where broken bones occur spontaneously without an apparent underlying problem, sometimes due to other factors such as corticosteroid use, brittle bone disease (osteogenesis imperfecta) or because a child is immobile.

Osteoporosis associated with pregnancy is also a rare condition when bones, usually in the spine or hip, break easily during or after pregnancy.

Osteoarthritis differs from osteoporosis and is a disease that affects the joints in the body causing them to become damaged - hips, knees and knuckles can be affected and so can joints in the spine and both osteoarthritis and osteoporosis occurs more commonly as people age.

Another rare condition is transient migratory osteoporosis which can cause chronic pain and is also associated with sudden loss of bone density, usually in a hip and is unlike 'ordinary' osteoporosis which is only painful when broken bones have occurred.

The pain eventually dissipates but sometimes recurs in another part of the body and referral to a pain clinic may be necessary to help deal with the pain problems associated with this condition.

Complex regional pain syndrome CRPS affects a hand, foot, wrist, ankle or knee but can spread up a whole limb; although often triggered by a minor injury or previous broken bone, the reason for continuous pain is poorly understood - sometimes the pain is traced to a specific nerve injury but sometimes not and there is often a loss of bone density in the affected area. This is a localised problem and does not result in general osteoporosis.

Osteoporosis and fragility fractures can be prevented by maximising bone strength during childhood, adolescence and early adulthood, when the skeleton is growing.

By 'banking' plenty of bone in these years, the skeleton is in a better position to withstand the bone loss that occurs with advancing age and this can be achieved by undertaking plenty of weight bearing exercise and eating a well balanced, calcium-rich diet.

Whatever age or sex, a healthy diet is vitally important to ensure strong bones and a diet which includes a wide variety of foods from the four main groups - fruit and vegetables, carbohydrates such as bread, potatoes, pasta and cereals, milk and dairy products and proteins such as meat, fish, eggs, pulses, nuts and seeds, will all help provide all the vitamins, minerals and energy needed to reduce the risk of chronic diseases such as osteoporosis.

Experts also recommend people cut down on saturated fats, sugar and salt and they say exercise is very important for everyone at all stages of their lives, but is especially important for people with osteoporosis who are at risk of fracture.

Things that can increase your chances of developing osteoporosis include:

  • being female
  • small, thin body (under 127 pounds)
  • family history of osteoporosis
  • being postmenopausal or of an advanced age
  • Caucasian or Asian race, but African American and Hispanic women are also at significant risk for developing the disease
  • abnormal absence of menstrual periods or having an eating disorder, such as anorexia nervosa or bulimia that can cause menstrual periods to stop before menopause, and loss of bone tissue from too much exercise
  • low testosterone levels in men
  • a diet low in dairy products or other sources of calcium and vitamin D
  • inactive lifestyle
  • long-term use of glucocorticoids (medicines prescribed for many diseases, including arthritis, asthma, and lupus) anti-seizure medications; gonadotropin releasing hormone for treatment of endometriosis; aluminum-containing antacids; certain cancer treatments; and excessive thyroid hormone
  • cigarette smoking and drinking too much alcohol

Further Reading

Last Updated: Aug 27, 2013

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