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What Are The Causes Of Osteoporosis And What Can You Do About It?

The causes of osteoporosis may be related to family history, diet, lifestyle, drugs or a combination of all these factors.

Osteoporosis is a silent, bone-depleting condition that may not be diagnosed until you experience a fracture – most often at the spine, wrist or hip – by which point the condition is already fairly advanced.

Osteopenia is a condition where bone mineral density is lower than normal and may be a precursor to osteoporosis.

According to the American and Canadian Medical Associations, between 20 and 30 percent of women in menopause have osteoporosis and another 3 percent have low bone density.

The Silent Killer

It is often called "the silent killer" because in its early stages it has no symptoms and the causes can be quite varied.

Osteoporosis is an infrequent disease in the so-called third world, where calcium supplementation, and milk consumption for that matter, is virtually non-existent and daily dietary calcium intake is typically below the average intake of North Americans.

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The US National Osteoporosis Foundation reports that osteoporosis and osteopenia (the condition prior to full osteoporosis) affect almost 44 million women and men in the U.S. aged 50 or older while Osteoporosis Canada has estimated that 1.4 million Canadians suffer from osteoporosis.

Fractures resulting from the condition often occur in the wrist, hip and spine – injuries that can be difficult to heal and very painful, leading to a loss of mobility and independence in older adults.

The cost in Canada attributable to osteoporosis is estimated at close to $1 billion annually.

In the United States treatment of hip fractures is estimated at $10-20 billion annually. These costs are expected to rise with an aging population.

Early death is an additional factor when considering the impact of osteoporosis. About 20% of women and 40% of men die within one year after a hip fracture.

It has been estimated that 50% of women who sustain a hip fracture become functionally dependent in their daily activities and 19% require long-term nursing.

One of the causes of osteoporosis is simply aging. Women lose approximately 50 percent of their trabecular bone (spongy tissue that fills the inner cavity of long bones) and 30 percent of their cortical bone (hard tissue that forms the surface of bones) over the course of their lifetime.

Bone loss can begin around age 35 but accelerates after menopause. Women are especially susceptible to osteoporosis during the first five to seven years after menopause because the loss of estrogen/progesterone accelerates bone loss.

Osteoporosis begins to affect men about ten years later than it affects women... unless they have a high-risk lifestyle or use medications that inhibit calcium absorption.

Fortunately, research shows that proper diet, supplements, exercise and sometimes medication can address the causes of osteoporosis and sometimes halt and reverse bone loss.

The challenge is to consume and absorb sufficient calcium to strengthen our bones. While the type of calcium we consume is critical to how much we absorb, equally important is the intake of sufficient Vitamin D (which can increase calcium absorption by 30 to 70 percent) vitamin K and magnesium.

The value of exercise also cannot be overstated as inactivity is one of the chief causes of osteoporosis.

Bone Remodelling

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Bones are living, growing tissue that is constantly being renewed during our lifetime. Bone remodeling – the removal of old bone and replacement with new bone – occurs in two phases:


Cells called osteoclasts dissolve some tissue on the bone's surface, creating a small cavity. This process usually takes place over a few days.


Cells called osteoblasts fill the cavities with new bone. This process takes place over a few months. Factors such as hormones, calcium and exercise can affect the cells on the surface of the bone and trigger the remodeling cycle. If the bone removed by resorption is completely replaced, then the amount of bone does not change, and bone strength is maintained.

In osteoporosis, too much resorption may take place, or not enough bone formation. Both of these lead to decreases in the amount and strength of bone and are important causes of osteoporosis.

Osteoporosis can be classed as either primary (post-menopausal and age related bone loss) or secondary (bone loss due to a medical condition).

Primary Osteoporosis

There are two different types of primary osteoporosis.

Type 1 – Post-menopausal osteoporosis

Type 1 osteoporosis usually occurs between the ages of 50 to 70, largely because of estrogen loss at menopause. It mainly affects trabecular bone – the spongy looking bone on the inside of the vertebrae which is very susceptible to estrogen deficiency. Eighty percent of bone turnover occurs in trabecular bone which is 20% of our bone mass.

Tpe 2 – Age-related osteoporosis

Type 2 osteoporosis usually occurs in people older than 70 years and affects both trabecular and cortical bone.

Secondary Osteoporosis

Secondary osteoporosis can have many causes, including:

  • diseases that affect the endocrine system, such as hyperparathyroidism or hyperthyroidism
  • gastrointestinal (digestive) tract diseases like Crohns disease (due to poor gut absorption of calcium and vitamin D)
  • alcoholism
  • liver disease
  • premature menopause
  • amenorrhea or loss of periods due to an eating disorder such as anorexia or bulemia (low estrogen levels)
  • a vitamin D deficiency
  • time spent in bed because of illness (non-weight bearing activity)
  • poor nutrition
  • Paget's Disease

Sometimes, the causes of osteoporosis are not the actual health problem but the drug used to treat a disease. For example:

  • phenytoin (e.g. Dilantin – used for treatment of epilepsy)
  • corticosteroids (e.g. Prednisone, inhaled steroids for asthma)
  • drugs given to transplant patients (e.g. Heparin, Cyclosporin, corticosteroids.)

If you have an illness that needs medication, ask your doctor or pharmacist if either the disease or medication has any effect on your bone mass. Sometimes, taking the lowest dose possible to treat a condition can lessen the effect on bones.

An osteoporosis prevention program is particularly important for women who have been treated for breast cancer.

Osteoporosis And Men

Men gain more bone mass than women during adolescence and adulthood and they lose less bone later in life. However, as in women, sex hormones can play a role in male bone loss.

Hypogonadism and the gradual decline of the sex hormone testosterone can be one of the causes of osteoporosis in men. While menopausal women lose bone due to increased bone resorption, in men, bone loss is generally due to reduced bone formation.

Most men who develop osteoporosis earlier in life do so due to secondary causes:

  • excessive alcohol intake
  • tobacco use
  • stress
  • lack of physical activity
  • low calcium intake
  • reduced strength and activity due to an illness
  • small build or leanness
  • drug therapy, for example, long-term use of corticosteroids such as prednisone-used to treat rheumatoid arthritis, asthma, and Crohn's disease

Puritan's Pride Bone Care provides the recommended levels of calcium, magnesium, vitamin D and vitamin K for approximately $30 a year.