Osteoporosis

Updated 20 January 2016

Risk factors for osteoporosis

Some examples of risk factors for osteoporosis are alcohol abuse, malnutrition, age and eating disorders.

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Osteoporosis can be divided into two types: primary and secondary osteoporosis. Primary osteoporosis is the more common of the two. Secondary osteoporosis is usually the result of an identifiable agent or disease process that causes the bone loss.

Although the exact cause of primary osteoporosis is not always clear, a number of risk factors are known to increase the chances of developing this disease.

Remember - an individual may have these risk factors and not develop osteoporosis. Conversely, many people may have no apparent risk factors and develop osteoporotic fractures.

There are many secondary causes for osteoporosis. Your doctor will mostly be able to detect these on the history you provide, or on the initial examination you undergo.

The more common associated secondary causes of osteoporosis include:

(A) Decreased bone strength

(i) Genetic Factors

  • Elderly females
  • Family history of osteoporosis
  • White, Asian and Mixed-race origin
  • Excessive leanness

(ii) Lifestyle factors

  • Alcohol abuse
  • Heavy smoking
  • Malnutrition
  • Sedentary lifestyle
  • Chronic immobilisation
  • Excessive exercise plus low energy intake

(iii) Diseases/drugs

(iv) Aging Factors

  • Premature menopause (before age 45)
  • Osteoblast (bone building cell) incompetence
  • Negative calcium balance resulting in overproduction of parathyroid hormone

(B) Increased propensity to fall

  • Mental impairment*
  • Institutionalisation
  • Gait and balance disorders*
  • Weakness and immobility
  • Visual impairment
  • Environmental hazards/accidents
  • History of falls

* Increased by alcohol and drugs like sedatives, anti-depressants, antihypertensive drugs and anti-diabetes agents.

Gender, Age and Race

The peak bone mass of women, which is reached at 25-30 years, is usually about 10-25% less than that of men. After peak bone mass is reached, bone mass gradually declines in both women and men.

Because of the rapid bone loss during the menopause, osteoporosis occurs more frequently in women than in men, who have no well-defined “andropause.” Men also lose sex hormones (testosterone) at a much slower rate.

Although osteoporosis is not a normal part of aging, the likelihood of developing this disease and associated fractures become greater, the longer you live.

South African White, Asian and Coloured populations are at higher risk to develop osteoporosis than Blacks and researchers are currently studying the reasons for this occurrence.

Heredity

Genetic factors play an important role in achieving adult peak bone mass. This is apparent in females those mothers suffer from spinal osteoporosis and tend to have lower bone densities.

Calcium intake, exercise, hormonal factors and general health can however, influence peak bone mass.

Body Build

Short, small framed individuals with low body weight have less bone to lose than larger, big boned women. Fat tissue is an important source of oestrogen production – petite women often have lower blood levels of this bone-protective hormone.

Reproductive History

The female sex hormone oestrogen protects against bone loss. A premature menopause (before age 45), whether spontaneous or surgically induced, noticeably increases the risk of osteoporosis.

Not breastfeeding also appears to incur additional risk, whereas pregnancy – with its accompanying high levels of oestrogen– actually protects against bone loss. A rare form of pregnancy-induced osteoporosis is however, well documented.

A decrease in testosterone levels of men can also result in bone loss and osteoporotic fractures. Up to 30% of men with osteoporosis have low testosterone levels.

Diet

A variety of nutritional factors influence bone health. Therefore, a balanced diet containing adequate calories, minerals, vitamins and other nutrients is required to build and maintain strong bones. Sufficient calories, protein and vitamin C are required for normal collagen synthesis.

Excessive phosphorous, protein and salt intake may enhance the excretion of calcium in the urine.

Caffeine has still to be proven harmful to bone.

Calcium is probably the most important nutrient needed for a healthy skeleton – especially in the elderly, children and pregnant or lactating women.

Calcium is important for bone, muscle, heart, nerve and blood cells to function normally. Since we lose calcium in urine and stools every day, it is therefore important to balance this loss with an adequate intake of calcium. If the calcium loss exceeds the intake, calcium gets released from bones and a longstanding depletion can result in decreased bone mass.

Lack of exercise

Mechanical muscle-pull on bone is the only physiological way to stimulate bone formation. Immobilisation causes a dramatic decrease in bone tissue and 20-40% of bone mass can be lost within a two-year period. Weight-bearing exercises like walking, jogging, dancing etc. are important to prevent bone loss.

Over-training in both men and women can also lead to bone loss.

Alcohol

Studies have shown that exceeding the intake of one alcoholic drink per day in women and two per day in men can lead to osteoporosis. Chronic alcoholism is associated with significant bone-loss in nearly 50% of cases and alcohol has a direct toxic effect on bone.

Smoking

Women who smoke tend to have lower blood levels of oestrogen, a lower body mass and tend to go through an earlier menopause than non-smokers. Bone mass in smokers is generally 15-25% lower than non-smokers.

Medications

The long-term use (more than six months) of glucocorticoids (e.g. cortisone used for treating asthma, eczema, arthritis, etc.) is an important cause of osteoporosis.

Other medications known to influence bone formation negatively include anti-epileptic drugs, certain diuretics, anti-coagulants, immuno-suppressive drugs and aluminium-containing antacids.

Patients on thyroid hormone replacement therapy should have their hormone levels checked regularly, since excess thyroid hormone can also result in bone loss.

Read more:

Symptoms of osteoporosis

Treating osteoporosis

Preventing osteoporosis

Reviewed by Dr Gareth Lorge FCP (SA), Specialist Physician in private practice, Netcare Rosebank Hospital, February 2015.

Previously reviewed by Tereza Hough, CEO, National Osteoporosis Foundation of South Africa, 2010.  


 

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Healthy Bones

Tereza is the CEO of the National Osteoporosis Foundation and worked as a Nursing Sister in the field of Osteoporosis for 18 years prior to her appointment with the Foundation. She used to be the Educational Officer for the Foundation and co-wrote the patient brochure on Osteoporosis. Read more

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