Osteoporosis

STUDIES

Osteoporosis describes the condition where bones become porous and fragile so that they are more likely to break. This happens when the natural process of breakdown and formation of bone (remodelling) is unbalanced, particularly with ageing. Bone fractures as a result of osteoporosis are a major cause of poor health. The spine (vertebrae) is most vulnerable; other vulnerable areas are the top of the thigh bone (neck of the femur), resulting in a broken hip, and the wrist or forearm that can break as a person puts out their hand to break a fall.

Both oestrogen and testosterone help maintain bone, making post-menopausal women and elderly people more prone to osteoporosis. A petite body frame, insufficient exercise, a poor diet, smoking (reduces oestrogen levels), hormone related conditions such as diabetes mellitus and hyperthyroidism and medications such as corticosteroids all contribute to bone loss. Weight-bearing exercise is important for maintaining bone strength.

Bone mineral density is used as an indicator of osteoporosis. It does not, however, give an accurate prediction of the likelihood of bone fracture.

A healthy diet rich in proteins, vitamins (C, D, A) and minerals (calcium, phosphorus, magnesium and manganese) with weight-bearing exercise are important to maintain strong bones and prevent bone fractures.

We present some of the evidence from Cochrane systematic reviews about complementary and alternative treatments related to porous, fragile bones. This evidence comes from carefully researched reviews of information about clinical trials done to evaluate medical treatments. Studies are only included in these reviews if they meet pre-defined criteria.

CALCIUM SUPPLEMENTS FOR REDUCING BONE LOSS IN POSTMENOPAUSAL WOMEN

The hormonal changes with menopause result in rapid bone loss. Bone fractures as a result of osteoporosis are a major cause of poor health and death. Collapse of the vertebrae of the spine is the most common fracture in postmenopausal women and people on steroids.

What is known

Calcium is found in many foods and is also available as a dietary supplement (as a tablet) for people who would like to add more calcium to their diet. It is thought that taking calcium supplements may help prevent bone loss and osteoporotic fractures with minimal trauma.

What the synthesised research says

The bone mineral density test, which measures how dense bones are, showed that the amount of bone lost in women taking calcium supplements for two or more years was less than that in women who took a non-active supplement (placebo).

The results from small studies show a trend towards a decrease in spine (vertebral) fractures with calcium supplements and a smaller trend for non-spinal fractures, such as of the hip and wrist.

How it was tested

Researchers made a thorough search of the medical literature and found 15 well conducted trials that met inclusion criteria. A total of 1806 postmenopausal women were randomly assigned to receive 500 to 2000 mg of calcium supplements daily (including calcium gluconate, calcium carbonate, calcium citrate with or without vitamin D) or a non-active supplement (placebo). These studies provide the best evidence we have today.

Calcium was more effective than placebo in reducing rates of bone loss, by about 2%, for total body bone density, the lumbar spine, the hip, and the wrist and lower forearm (distal radius).

Five studies with 576 women measured the number of fractures as an outcome of treatment with calcium supplement. All 5 trials investigated the influence of calcium supplementation on vertebral fractures, without a clear benefit. Only 2 trials reported on non-vertebral fractures. Very few fractures occurred, making it difficult to determine any benefit of taking calcium compared with placebo.

Side effects and general cautions

Side effects were not reported in this review but stomach upsets and constipation can be experienced with calcium supplements.  

There are few studies that measure whether calcium supplements prevent fractures yet calcium supplements provide a simple and inexpensive way to prevent bone loss after menopause, as measured by bone mineral density.

Source

Shea BJ, Adachi JD, Cranney A, Griffith L, Guyatt G, Hamel C, Ortiz Z, Peterson J, Robinson VA, Tugwell P, Wells G, Zytaruk N. Calcium supplementation on bone loss in postmenopausal women. The Cochrane Database of Systematic Reviews 2004, Issue 1. Art. No.: CD004526.pub2. DOI: 10.1002/14651858.CD004526.pub2.

This review was withdrawn from The Cochrane Library in 2006, on a recommendation by the Cochrane Funding Arbitration panel. The review is being updated.

VITAMIN D FOR PREVENTING FRACTURES IN OLDER PEOPLE WITH OSTEOPOROSIS

What is known

Older people often have low vitamin D levels. Vitamin D acts on the intestine to increase absorption of calcium and also reduces the loss of calcium in the kidneys. Maintaining calcium levels protects the bones. The biggest source of vitamin D is from exposure of the skin to sunlight. Although there are a few dietary sources, such as oily fish, these contribute relatively little vitamin D (except in people who are not exposed to the sun).

In elderly people not exposed to the sun, vitamin D can be given not on a daily basis (intermittently) in high doses and by injection. If calcium is to be given at the same time, then daily tablets are required. This may change whether or not the person takes the supplement (compliance) as calcium can cause gastrointestinal upsets. Giving vitamin D, and particularly its derivatives (analogues), may carry a risk of high levels of blood calcium (hypercalcaemia) with calcium present in the urine (hypercalciuria).

Vitamin D is inexpensive. The vitamin D analogues calcitriol (1,25 dihydroxy vitamin D3) and alfacalcidol (1-alpha-hydroxy vitamin D3) are more expensive.

What the synthesised research says

Frail elderly people resident in nursing homes or residential care homes may suffer fewer hip and other non-vertebral fractures if they are given vitamin D with calcium supplements. The effectiveness of vitamin D alone in preventing fractures is unclear. There is no evidence that derivatives of vitamin D have an advantage compared with vitamin D.

Vitamin D with calcium marginally reduced hip fractures (7 trials, 10,376 participants) (eight people had fractures in the group receiving supplement for every ten in the placebo or no treatment group), non-vertebral fractures (seven trials, 10,376 participants (nine compared to every 10). There was no evidence of effect of vitamin D with calcium on vertebral fractures.

How it was tested

The researchers searched the medical literature thoroughly and identified thirty-eight trials where participants were randomly assigned to receive vitamin D supplements, placebo or no treatment.

Vitamin D alone showed no clear effect on hip fracture in 7 trials with 18,668 participants), or spine (vertebral) fracture in 4 trials with 5698 participants or any new fracture in 8 trials with 18,903 participants.

Vitamin D with calcium reduced hip fractures slightly (7 trials, 10,376 participants, RR 0.8), non-vertebral fractures (seven trials, 10,376 participants, RR 0.9) compared with placebo or no treatment, but there was no evidence of effect of vitamin D with calcium on vertebral fractures. The effect appeared to be restricted to those living elderly people in institutional care.

Calcium alone and vitamin D with calcium had similar effects on hip fracture (3 trials, 6866 participants), any non-vertebral fracture (4 trials, 3061 participants, or vertebral fracture (2 trials, 2681 participants).

Side effects and general cautions

High blood levels of calcium (hypercalcaemia) were more common when vitamin D or its analogues was given compared with placebo or calcium alone (14 trials, 8035 participants, RR 2, range 1.5 to 4). The risk was particularly high with calcitriol (three trials, 742 participants, RR 15, 95% CI 3 to 76).

There was no evidence that vitamin D increased gastro-intestinal symptoms in seven trials (10,188 participants) or renal disease in nine trials (10,107 participants).

Participants of trials were men or post menopausal women over 65 years of age. The benefits seen appeared to be restricted to those living in institutional care. Participants were included still if they had neurologic disease impairing mobility (for example stroke or Parkinson's disease but could not be on corticosteroid therapy (an exclusion from the trial).

In the past there has been serious concern that vitamin D may be associated with hypercalcaemia when given in only moderate doses, which may have led to cautious use of low doses in the trials of vitamin D. There is increasing evidence that potential toxicity has been seriously overestimated, and that the doses required may also be more than previously recognized, hence the small benefits observed.

Source

Avenell A, Gillespie WJ, Gillespie LD, O'Connell DL. Vitamin D and vitamin D analogues for preventing fractures associated with involutional and post-menopausal osteoporosis. The Cochrane Database of Systematic Reviews 2005, Issue 3. Art. No.: CD000227.pub2. DOI: 10.1002/14651858.CD000227.pub2.

CALCIUM AND VITAMIN D FOR OSTEOPOROSIS IN PEOPLE WHO TAKE CORTICOSTEROIDS REGULARLY

Corticosteroid therapy is a risk factor for the development of osteoporosis. The hormonal changes with menopause also results in rapid bone loss. Vertebral collapse is the most common fracture in postmenopausal women and people on steroids.

It has been suggested that patients initiating steroids should receive preventative therapy (calcium, Vitamin D, estrogens or bisphosphonates).

What is known

People with inflammatory disorders are particularly at risk of osteoporosis both because of their underlying disease and the need to frequently take corticosteroids. Steroids are most commonly used to treat asthma and other inflammatory lung disorders, connective tissue disease, rheumatic diseases, inflammatory bowel disease, and in people who have had transplants. Steroids decrease absorption of calcium from the intestine, and increase urinary calcium loss. This leads to increased bone loss (resorption) to maintain the body’s calcium levels in ther blood. Men with rheumatoid arthritis who take corticosteroids may also lower testosterone levels, leading to bone loss.  

What the synthesised research says

The benefit of calcium and vitamin D appears to be modest. For people on corticosteroids, treatment with calcium and vitamin D is more effective at slowing lower spine (lumbar) and forearm bone loss than placebo or calcium alone.

These conclusions were based on pooled results of 3 trials for each part of the body.

Bone mineral density at the top of the thigh bone (femur) was not clearly protected. Nor was there any difference in the number of new non-traumatic fractures over two years when taking calcium and vitamin D. Each of these conclusions was based on 2 studies. There is no evidence to suggest that calcitriol (three trials) is any more effective than vitamin D (2 trials).

How it was tested

Researchers made a thorough search of the medical literature and found five trials. The 274 participants were randomly assigned to receive calcium and vitamin D supplement or a non-active treatment (placebo) over two years. The analysis was performed at two years after starting calcium and vitamin D.

Three of the trials enrolled younger people and 2 trials enrolled an older age group. The amount of corticosteroid they were taking varied a lot; a higher daily dose is generally felt to cause a higher rate of bone loss.

Side effects and general cautions

The side-effects reported were mainly constipation with calcium and hypercalcemia with calcitriol. Withdrawal from the trial because of side-effects was clearly reported in one trial and was similar with or without active supplement. Three other trials appeared to have no dropouts due to side-effects.

The studies varied widely in how well they were conducted and reported.

Adequate evaluation of fractures would require trials with large numbers of participants and longer term follow up.

Source

Homik JJEH, Cranney A, Shea BJ, Suarez-Almazor ME, Tugwell P, Wells G. Calcium and vitamin D for corticosteroid-induced osteoporosis. The Cochrane Database of Systematic Reviews 1998, Issue 2. Art. No.: CD000952. DOI: 10.1002/14651858.CD000952.