What is Osteoporosis?
Osteoporosis is a condition that results in reduction of bone strength (density), leading to increased risk of fractures.
Bone strength is determined by the structure and the mineral components. Bones are formed of a mineral called calcium hydroxyapatite with collagen fibers. Bone structure consists of a hard outer shell, called cortical bone and spongy interior called trabecular bone. Bone is constantly being remodeled; older bone is being broken down by cells called osteoclasts, and then rebuilt by cells called osteoblasts.
As we grow up, more bone is built than destroyed, leading to peak bone density around the age of 25. After the age of 40, bone density naturally starts to fall due to increased bone break down. If this is accelerated then the bones can become more fragile and result in osteoporosis.
Causes of Osteoporosis?
Osteoporosis is more common with age. In particular females are 4 times more likely to develop osteoporosis. This is due to females having a lower bone density peak than males and following the menopause, the reduction in the hormone oestrogen results in more bone breakdown.
More common risk factors for developing osteoporosis:
- Early menopause (before 45 years)
- Hysterectomy with ovary removal
- Hormone imbalances
- The parathyroid glands usually regulate calcium in the body, over active glands leach calcium from the bones
- Low testosterone in males
- Steroid treatments
- If long courses of steroids are needed to treat inflammation, often calcium and vitamin D tablets are prescribed at the same time.
- Gut malabsorption
- Coeliac disease
- Inflammatory bowel diseases
- Inflammatory joint disease
- Lack of exercise that’s weightbearing
- Family history
Symptoms of Osteoporosis
Usually the first signs of osteoporosis are insufficiency fractures. These are fractures that occur with less force than suspected to break a bone. Most commonly they occur in the hips, spine or wrists. Often fractures in the spine can occur with no injury, these are known as crush fractures. If there are multiple crush fractures in the spine, the spine can become shorter and curved leading to loss of height.
How do we diagnose Osteoporosis?
Osteoporosis is usually suspected after an insufficiency
fracture; this is the most common reason to get investigations carried out. However if you have strong risk factors for developing osteoporosis, then investigations can be carried out before possible fractures occur.
Often a scoring system is used to calculate the risk of fractures to see if you should be investigated- the most common score is the FRAX.
- X-Rays are the best first images to look for fractures
- DEXA scans (duel energy X-Ray absorptiometry
- These measure the bone density at the lower (lumbar spine) and hips
- The results calculate a T-Score. This is a score that determines if the bone thickness is normal, osteopenia (pre osteoporosis) or in the region of osteoporosis
- DEXA scans are repeated following treatment to monitor bone density changes
Investigations to look for secondary causes:
- Full blood counts
- Calcium and Vitamin D levels
- Liver function tests- high ALP (alkaline phosphatase) can be found in increased bone turnover
- Kidney function
- Myeloma screens
- Male and female hormone profiles
- Coeliac disease screening
- Weight bearing exercise
- Helps keep the bone density high
- Helps strengthen muscles which should help reduce the risks of falls as you get older
- Ensure you are getting enough calcium in your diet- aim for 700mg a day
- Vitamin D
- This is needed to help the body absorb calcium.
- It can be produced by the skin in sunlight and is available in some foods
- Supplements are recommended
- Calcium and vitamin D supplements
- Bisphosphonates- these can be either tablets or intravenously through a drip
Versus Arthritis: http://www.versusarthritis.org
Royal Osteoporosis Society: https://theros.org.uk
Dietary Calcium Calculator: https://www.cgem.ed.ac.uk/research/rheumatological/calcium-calculator/