The word osteoporosis means spongy (porous) bone. Bone is made up of minerals, mainly calcium salts, bound together by strong collagen fibres.Our bones have a thick, hard outer shell (called cortical or compact bone) which is easily seen on x-rays. Inside this, there’s a softer mesh of bone (trabecular bone) which has a honeycomb-like structure.
Bone is a living, active tissue that’s constantly renewing itself. Old bone tissue is broken down by cells called osteoclasts and is replaced by new bone material produced by cells called osteoblasts.
Everybody will have some degree of bone loss as they get older, but the term osteoporosis is used only when the bones become quite fragile. When bone is affected by osteoporosis, the holes in the honeycomb structure become larger and the overall density is lower – which is why the bone is more likely to break (fracture).
Quite often the first sign of osteoporosis is breaking a bone in a minor fall or accident. Fractures are most likely to happen at the hip, spine or wrist. Spinal problems occur if the bones in your spine (vertebrae) become weak and lose height (described as a vertebral crushfracture). This usually happens around the middle/lower back. If several vertebrae are affected, your spine will start to curve and you may become shorter. This can sometimes cause back pain and some people may have difficulty breathing simply because there’s less space under their ribs.
People who have spinal fractures will also have a greater risk of hip and wrist fractures. Spinal fractures can even occur without any injury.
Anyone can get osteoporosis but women are about four times more likely than men to develop it. There are two main reasons for this:
A number of other risk factors can increase your chances of developing osteoporosis.
Steroids (corticosteroids) are drugs which are used for a range of inflammatory conditions, for example rheumatoid arthritis. They can affect bone production by reducing the amount of calcium absorbed from the gut and increasing calcium loss through the kidneys. If you’re likely to need steroids, such as prednisolone, for more than three months, your doctor will probably recommend calcium and vitamin D tablets and possibly other treatments to help protect against osteoporosis.
If you have an early menopause (before the age of 45) or a hysterectomy where one or both ovaries are removed, this increases your risk of developing osteoporosis. This is because they cause your body’s oestrogen production to reduce dramatically, so the process of bone loss will speed up. Removal of the ovaries only (ovariectomy or oophorectomy) is quite rare but is also linked with an increased risk of osteoporosis.
Exercise encourages bone development, and lack of exercise means you’ll be more at risk of losing calcium from your bones and so more likely to be diagnosed with osteoporosis. The only exception to this is that women who exercise so much that their periods stop will have a higher risk of developing osteoporosis because of a lack of oestrogen. Muscle and bone health have been shown to be linked so keeping up your muscle strength with exercise is important. This will also reduce the risk of falling
– If your diet doesn’t include enough calcium or vitamin D, you’re at greater risk of osteoporosis (see section ‘Diet and nutrition’)
Tobacco is directly toxic to bones, and smoking reduces the cells’ ability to make bone. It also lowers the oestrogen level in women and may cause early menopause. In men, smoking lowers testosterone activity, which can also weaken the bones
Drinking a lot of alcohol reduces your body’s ability to make bone. It also increases your risk of breaking a bone as a result of a fall
Osteoporosis does run in families, probably because there are inherited factors that affect bone development. If a close relative has suffered a fracture linked to osteoporosis then your own risk of a fracture is likely to be greater than normal. It’s not yet known if there’s a particular genetic defect that causes osteoporosis, although we do know that people with a very rare genetic disorder calledosteogenesis imperfecta are more likely to suffer fractures
Other factors that affect your risk include:
There are no clear physical signs of osteoporosis, and it may not cause any problems straight away. If your doctor thinks you may have osteoporosis, they may suggest you have a DEXA (dual-energy x- ray absorptiometry) scan to measure the density of your bones. The scan is readily available and involves lying on a couch, fully clothed, for about 15 minutes while your bones are x-rayed. The dose of x-rays is very small – about the same as spending a day out in the sun. The possible results are:
Your risk of a low-impact fracture is likely to be low.
Your bone is weaker but your risk of a low-impact fracture is relatively small. You may or may not need treatment depending on what other risk factors you have. You should discuss with your doctor how you can reduce your risk (see ‘Self-help and daily living’).
You have a greater risk of low-impact fractures and you may need treatment – discuss this with your doctor.
There’s no good evidence that screening everybody for osteoporosis would be helpful. However, you should speak with your doctor about having a scan if:
If you’re diagnosed with osteoporosis following a low-impact fracture, the fracture will need to be treated first. The next step is to begin treatment to reduce the risk of further fractures.
Most fractures are first treated in A&E, and you’ll usually have a follow-up appointment at a fracture clinic to see how things are going.
Unless you have a vertebral compression fracture, the fractured area will usually be put in a cast for several weeks so you can’t move it to allow the fracture to heal. In some cases the fracture may need manipulation by a specialist before this is done. This may be carried out in A&E, but you may need to be admitted to hospital. You’re also likely to be admitted if the fracture needs surgical fixing.
It’s likely that you’ll also need pain relief medications, for example:
Self-help measures such as diet and weight-bearing exercise can help to reduce the risk of fractures, but a number of specific treatments are also available.
You’re likely to have a bone density scan before you start treatment, although this may not be needed, for example, if you’re 75 or over. Once you’ve started treatment your bone density may be monitored in one of the following ways:
If you’re taking hormone replacement therapy (HRT), you’ll also have regular blood pressure checks and breast scans (mammograms). Your bone density should start to improve after 6–12 months, although you may need longer-term treatment to further reduce your fracture risk.
Because longer-term treatment can sometimes have side- effects your doctor may suggest a break from your treatment after 3–5 years. The benefits of osteoporosis treatment last a long time so these won’t be lost if your doctor does suggest a ‘treatment holiday’.
It’s recommended that you try to get enough calcium from your diet without using supplements. However, combined calcium and vitamin D supplements are often given alongside other osteoporosis treatments, especially if you struggle to get enough from other sources. Vitamin D is needed for the body to absorb and process calcium.
If you’re a woman over 70 and take a calcium-only supplement, don’t have more than the recommended daily intake, as there have been concerns that this may affect heart health. This seems to apply only to supplements and not calcium from food.
Bisphosphonates are a group of drugs that work by slowing bone loss; in many people, an increase in bone density can be measured over five years of treatment. They reduce the risk of hip and spine fractures. Bisphosphonates can be taken by mouth (orally) or through a drip (intravenous infusion) or injection.
Oral bisphosphonates tend to be poorly absorbed by the body and can cause irritation of the gullet (heartburn), so it’s very important that you carefully follow the instructions for taking your medication:
If you can’t tolerate bisphosphonates by mouth, it’s possible to have them through a drip into a vein (intravenous infusion) or as an injection: