Last reviewed: January 2019

woman pointing her arm with medical professional

If you have Crohn’s or Colitis you may be more likely to develop weaker bones (osteoporosis) or low bone mass. This can mean bones break (fracture) more easily if you have a minor fall. Inflammation in the gut, taking steroids, low levels of calcium and vitamin D or removal of parts of the small bowel can all contribute to bone loss if you have Crohn’s or Colitis.

This information is for anyone with Crohn's or Colitis who may be worried about developing fragile bones. It looks at:

  • Why you might be at risk of bone loss.
  • What tests are available to measure your bone density.
  • How you can keep your bones healthy
  • Drugs that can help prevent bone loss.
Download this information (PDF)
  • Bones explained
    Bone is living, growing tissue. It is made mostly of collagen, a protein that provides a soft framework, and calcium phosphate, a mineral that adds strength and hardens the framework. Our bones are constantly remodelling themselves. Throughout our lives, specialist bone cells break down and remove old bone (bone resorption), and different cells lay down new bone (bone formation).

    During childhood and early adult life, bone density (also known as bone mass or bone mass density - BMD) increases, reaching a peak in the late 20s. After this, bone mass declines gradually as part of the natural ageing process.
    Normal peak bone mass may never be reached if a disease affects bones during early life. See IBD in Children:  A parent’s guide for more information. 

  • What type of bone loss are there?
    • Osteoporosis. Most of our bones have a hard outer shell with a strong honeycomb-like inner structure. In osteoporosis, (which means ‘porous bones’) the struts of bone that make up the inner structure become thin, so the bone becomes fragile and breaks more easily.

    • Osteopenia. This is a mild loss of bone density not severe enough to be labelled as osteoporosis. Research suggests that almost half of all people with Crohn’s or Colitis have osteopenia.

    • Osteomalacia. This is a softening (decalcification) of the bones usually caused by lack of vitamin D. Osteomalacia in growing children is known as rickets and can lead to bone deformity, in adults it can cause pain.

    • Osteonecrosis. This is caused by a reduction in blood supply to a bone, such as a hip, and can result in the death of bone and the surrounding cartilage. This sometimes causes pain and stiffness but may have no symptoms. Osteonecrosis (also known as avascular necrosis) is a rare but serious condition and can be a complication of steroid treatment.

  • How do I know if I have bone loss?

    There are usually no obvious symptoms of bone loss until a bone breaks. Thin bones are not painful, but broken bones (fractures) usually are. Some, such as fractures of the spine, can lead to a serious loss of mobility.

    I do worry that my bones will become more damaged over time as I’ve had several courses of steroids, but with density scans getting better and more treatments available, I hope to still be running well into old age!

    Living with Ulcerative Colitis

  • What are the risk factors?
    If you have Crohn’s or Colitis many of the factors associated with bone loss are the same as those for the general population. These include:

    • Age.  Some loss of bone density happens naturally with age. The process of bone formation slows down, and bone resorption happens faster, so our bones become less dense.

    • Gender.  A shortage of sex hormones (oestrogen and testosterone) can lead to a reduction in bone formation.

    • Women have smaller bones and tend to lose bone faster than men. This is because hormonal changes during the menopause increase the rate that bone breaks down. Younger women who have been through an early menopause may also be more at risk.

    • Men have lower levels of testosterone as they get older and this leads to weaker bones.

    • Family  history.  If members of your family have osteoporosis or   a history of broken bones you are also more likely to be at risk.
    • BMI  (Body Mass Index)  less than 18.5 kg/m2.  This is a measure of the relationship between your weight and height. A BMI of less than 18.5kg/m2 indicates that you have a low body weight for your height. The chances of breaking a bone are greater as people with low body weight have less bone tissue. Find out your BMI at

    • Smoking. Smoking reduces the mineralisation of bone, which means bones are not as strong. It also speeds up bone loss and can lead to calcium not being absorbed as well. See our information on Smoking and IBD

    • Drinking excessive amounts of alcohol.  Alcohol consumption of three or more units of alcohol a day can impact on bone health. Too much alcohol is thought to affect the rate of bone remodelling and can result in weaker bones.

    • Low levels of calcium or vitamin D. Calcium is important in bone mineralisation and vitamin D helps the body absorb calcium.

    • Little physical activity. Weight bearing exercise is particularly important because this stimulates the body to strengthen the bones. People with Crohn’s or Colitis often reduce their physical activity, perhaps because of weakness, fatigue, pain, diarrhoea or nausea.

  • What are the added risks if you have Crohn's or Colitis?
    Research has suggested that having Crohn’s or Colitis is another factor that may make bone loss more likely. Studies have found this is common in both men and women, with 5 out of 10 people with Crohn’s or Colitis experiencing low bone mass or osteoporosis.

    • Inflammation

    People with active Crohn’s or Colitis have a higher level of cytokines (hormone-like proteins), which are released as part of the inflammatory process in the gut. These chemicals can affect the rate at which new bone is formed.

    Inflammation in the gut can sometimes be associated with an inflammatory process affecting joints. If you have pain or swelling in your joints, talk to your doctor or IBD team and find out more in Joints.

    • Steroids (corticosteroids)

    Steroids are often used to help control flare-ups in Crohn’s and Colitis. But they do not maintain remission and are not used as long-term therapy.

    Steroid treatment can increase the risk of weak bones because:
    • the rate that bone-building cells work is slowed down. This means bone loss happens more quickly
    • the amount of calcium absorbed from food is reduced, and calcium lost from the body in urine increased. This loss of calcium means bones are weakened.

    How seriously the bones are affected usually depends on the dose and length of steroid treatment.

    Using steroids for a short time is unlikely to cause problems. But repeated courses with limited time between them or longer use may mean greater risks to bones. If you are worried about taking steroids and how this might affect your bones, speak to your doctor or IBD team.
    Steroids taken in enemas or suppositories (via the rectum) are less likely to cause bone weakness than taking them by mouth or injected into a vein (intravenously). This is because they are not so easily absorbed into the blood. Find out more about Steroids in our treatment information.

    Osteonecrosis of the hip is a rare but serious condition that often needs surgical treatment If you develop hip pain when you are taking steroids, tell your doctor or IBD team.

    • Reduced absorption of nutrients

    The nutrients important to bone formation, especially calcium and vitamin D, are absorbed in the small intestine. If you have extensive Crohn’s Disease that affects the small bowel, or have had parts of your small intestine removed, you may be at additional risk.

    • Avoiding dairy foods

    If you do not eat dairy products, perhaps because of lactose (milk sugar) intolerance or abdominal pain, you are more likely to have a shortage of calcium in your diet. Low levels of calcium can slow down bone formation.

    • Lower levels of sex hormones

    The combination of inflammatory cytokines and reduced absorption of nutrients can lower levels of sex hormones (oestrogen and testosterone). These hormones are important in maintaining bone health.

  • What tests are used to find out if you have weak bones?
    Osteoporosis is diagnosed by measuring bone density using a DXA (DEXA - dual energy x-ray absorptiometry) scanning machine. This uses low dose x-rays to take a scan of your hip or spine. It is a simple, painless test which takes about five minutes.

    Blood tests can be used to measure levels of vitamin D, calcium and phosphorus. This can be helpful in identifying people at risk of osteomalacia.

  • What do the results mean?
    The results from a DXA scan are used to work out a bone density score. Your bone density is compared to that of an average healthy person in their 20s and is known as a T score.
    T Score Bone density
    0 to -1 Healthy bone density 
    -1 to -2.5 Osteopenia – mild loss of bone density
    -2.5 and above  Osteoporosis  
  • Will I be offered these tests?
    You are most likely to be offered a DXA bone scan if you have Crohn’s or Colitis and other risk factors such as:
    • a woman after the menopause
    • a woman who has had an early menopause
    • a person who has been taking steroids

    Your doctor may also use a scoring system such as FRAX or QFracture. These consider several factors including your age and steroid use to calculate the chance of breaking a bone over the next 10 years. The results will help your doctor decide if you should have a DXA scan. See the FRAX tool here

    IBD teams may measure blood levels of vitamin D and calcium if you are thought to be at risk of bone disease. Around 1 in 3 people with Crohn’s or Colitis have been found to be deficient in vitamin D, which has also been associated with greater disease activity, poorer quality of life and increased risk of surgery.

    For the past five years, I have had to manage my Crohn's, on and off, with steroid medication. I have been diagnosed with osteopenia but I make sure I take calcium and vitamin D supplements to help maintain my bones. 

    Diagnosed with Crohn's in 2010

  • What can I do to reduce bone loss?
    Prevention and treatment of low bone density and osteoporosis aims to:

    • strengthen bones
    • prevent further bone loss
    • reduce the risk of bones breaking.

    Your health professionals can also help you to protect your bones, especially if you are taking steroid medicines. By being aware of the risk of bone loss, you might also be able to change your diet or lifestyle to help prevent it.

    Take regular exercise that is suitable for you

    If you can, take regular weight-bearing exercise, such as brisk walking, jogging, dancing, aerobics, or active team sports. Gardening and housework, even just using the stairs whenever possible, is also useful. Any weight-bearing activity stimulates bone formation. Outdoor exercise is especially valuable as this will increase your exposure to sunlight and boost your vitamin D production. If in doubt, ask your doctor or IBD team for guidance on exercise.

    Stop smoking

    Research shows smoking increases the severity of Crohn’s Disease. For people with Ulcerative Colitis, the relationship between smoking and active disease is a more complex issue. For more details see our information on smoking. Many GPs and hospitals run stop-smoking programmes.

    Limit alcohol intake to two units or less a day

    The National Osteoporosis Guideline Group recommend drinking two units or less of alcohol a day for good bone health. Find out more about alcohol units here.


    Current guidelines from Public Health England suggest you need 700 mg of calcium per day in your diet. If you are not getting enough calcium from your food, or are avoiding dairy products you may need calcium supplements.

    Dairy sources of calcium:
    • milk (skimmed milk contains slightly more calcium than whole milk)
    • hard and soft cheeses
    • yoghurt, fromage frais, dairy ice cream

    Non-dairy sources of calcium:
    • fortified soya milk,
    • tofu
    • green leafy vegetables such as broccoli, cabbage and okra (but not spinach)
    • fish with edible bones, such as pilchards and sardines
    • nuts

    Vitamin D

    The Scientific Advisory Group on Nutrition recommends a daily intake of 10 micrograms (400 International Units) of Vitamin D for adults in the general population. However, it is suggested that to maintain blood levels of vitamin D for people with Crohn’s or Colitis, 25 micrograms (1000 International Units) may be needed.

    Exposure to sunlight

    The vitamin is made by the body under the skin in reaction to sunlight. From late March to the end of September, most people should be able to get all the vitamin D they need from sunlight on their skin. However, during the winter months vitamin D deficiency is common and the recommendation is to eat foods high in vitamin D.

    People whose skin has little or no exposure to the sun, or who always cover their skin when outside, risk vitamin D deficiency and are recommended to take a supplement of 10 micrograms throughout the year.

    However, if you take azathioprine or mercaptopurine remember to take precautions in the sun including wearing a hat and using sun screen. These medicines increase the skin’s sensitivity to sunlight and the risk of developing some forms of skin cancer. Find out more in our information on azathioprine and mercaptopurine.

    Food sources of vitamin D:

    • oily fish such as salmon and sardines
    • eggs, cheese and red meat
    • fortified fat spreads and breakfast cereals.

    Continue to take prescribed Crohn's or Colitis medicines

    Continuing to take your Crohn's or Colitis medicines may reduce the risk of osteoporosis by minimising the amount of ongoing inflammation in the gut. It has been shown that bone density can return to normal when a person’s Crohn’s or Colitis has been in remission for three years or more.

    Talk about bone loss prevention with your IBD team if you are taking steroids. Calcium and vitamin D supplements are recommended if you are taking steroids. You may also be offered bisphosphonates.

    Some of the newer steroids, such as budesonide, may be less harmful to the bones as less of the steroid is absorbed into the body. Find out more in our information on steroids.

    If you have persistently active Crohn’s or Colitis, guidelines suggest you should be offered immunosuppressive therapy such as azathioprine or biological drugs such as infliximab or adalimumab. These drugs treat inflammation, can avoid the need for prolonged steroids and so reduce the chances of bone loss. Research suggests infliximab (one of the biological drugs) may also improve bone density in people with Crohn’s Disease.

    See our information on biologic medicines. We also have information on other medicines.

    Bisphosphonate drugs

    If you have a T score of -1.5 or less, you may be offered treatment with bisphosphonates. These include alendronate, ibandronate and risedronate sodium. These work by slowing down the cells that break down bone and allow the bone building cells to work more effectively. They can be used prevent and treat bone loss linked to taking steroids and research has shown that they are well tolerated in people with Crohn’s and Colitis.

    Regular use of these medicines may also be indicated to prevent further bone loss in postmenopausal women or in people who have experienced spontaneously broken bones.

    For more information to help you and your health professionals consider the options around taking bisphosphonates, visit the NICE Decision Support.

    If you are a woman who has reached the menopause, talk to your doctor or IBD team about bone loss, even if you are not on steroids. You can ask for a referral to a rheumatologist (who will have experience of osteoporosis) or a dietitian.

  • Help and support from Crohn's & Colitis UK
    We offer more than 50 publications on many aspects of Crohn’s DiseaseUlcerative Colitis and other forms of Inflammatory Bowel Disease. You may be interested in our comprehensive booklets on each disease, as well as the following publications:

    • Living With Crohn's or Colitis
    • Fatigue
    • Taking Medicines
    • Managing Bowel Incontinence
    • Living With a Stoma

    Health professionals can order some publications in bulk by using our online ordering system. If you would like a printed copy of a booklet or information sheet, please contact our helpline.

    Our helpline is a confidential service providing information and support to anyone affected by Crohn's or Colitis. Our team can:
    • help you understand more about Crohn's or Colitis, diagnosis and treatment options
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    Call us on 0300 222 5700 
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    Crohn’s & Colitis UK Forum

    This closed-group community on Facebook is for everyone affected by Crohn's or Colitis. You can share your experiences and receive support from others.

    Crohn’s & Colitis UK Patient Panels

    IBD Patient Panels, which are supported by Crohn’s & Colitis UK, are groups of people with Crohn's or Colitis who use their perspective as a patient to work with their IBD healthcare team to help improve their hospital services. For more information on patient panels, please contact our Patient Engagement Team.

    Crohn’s & Colitis UK Local Networks

    Our Local Networks of volunteers across the UK organise events and provide opportunities to get to know other people in an informal setting, as well as to get involved with educational, awareness-raising and fundraising activities. You may find just being with other people and realising that you are not alone can be reassuring. Families and relatives may also find it useful to meet other people with Crohn's or Colitis. All events are open to members of Crohn’s & Colitis UK


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