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What causes bone loss?

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Osteoporosis - causes
Low bone density - causes

Osteoporosis, or weak bones, is a disease that causes bones to become brittle and more likely to fracture (break). With osteoporosis, the bones lose density. Bone density is the amount of calcified bone tissue that is in your bones.

A diagnosis of osteoporosis means you are at risk for bone fractures even with everyday activities or minor accidents or falls.

Video Transcript

Osteoporosis - Animation

If you've ever watched an apartment or office building under construction, you've seen the metal scaffolding that keeps the building standing upright. Inside your body, bones are the scaffolding that keep you standing upright. As you get older, these supports can weaken. And if they get too weak, you could wind up with a fracture. Let's talk about the bone-thinning condition called osteoporosis. Your internal scaffolding was built when you were young. Calcium and other minerals helped strengthen your bones, provided that you got enough of them from your diet. As you get older, those minerals can start to leech out of your bones, leaving them brittle, fragile, and easily breakable, a condition known as osteoporosis. Women over 50 are especially at risk for osteoporosis because during menopause they lose estrogen, which helps to keep bones strong. The tricky part about osteoporosis is that it's hard to tell you have it. You may not have any symptoms until you've already fractured a bone. Getting a bone density scan, which measures bone thickness, is one way to find out whether you have osteoporosis so you can start treatment right away if you need it. To keep your bones strong, try to get at least 1,200 milligrams of calcium daily, paired with 1,000 international units of vitamin D, which helps your body absorb calcium. You can eat foods that are high in these nutrients, like frozen yogurt, salmon, and low-fat milk, or, if you're not a big fan of fish or dairy, you can take supplements. Weight bearing exercise is also your ally when it comes to strengthening bones. A combination of weight bearing exercises like walking or playing tennis, plus strength training and balance exercises will reduce your risk of getting a fracture if you fall. You will want to get at least thirty minutes of exercise three times a week to see the benefits. And, stop smoking. Cigarette smoke both accelerates bone loss and blocks treatments from being as affective. If you've been diagnosed with osteoporosis, your doctor may recommend drugs called bisphosphonates to prevent further bone damage. Other medicines, including calcitonin, parathyroid hormone, and raloxifene are also treatment options. Don't let bone loss get so far along that you could have a disabling fracture from a minor fall. Start strengthening your bones with diet and exercise while you're still young. As you get older, talk to your doctor about bone density scans, and ask whether you need to take medicine if you're at risk for, or are starting to show signs of osteoporosis. And if your bones aren't as strong as they used to be, avoid falls by wearing shoes that fit well, and clearing clutter on the floor before it can trip you up, and bring you down.

Your Changing Bones

Your body needs the minerals calcium and phosphate to make and keep healthy bones.

  • During your life, your body continues to both reabsorb old bone and create new bone. Your entire skeleton is replaced about every 10 years, though this process slows as you get older.
  • As long as your body has a good balance of new and old bone, your bones stay healthy and strong.
  • Bone loss occurs when more old bone is reabsorbed than new bone is created.

Sometimes bone loss occurs without any known cause. Some bone loss with aging is normal for everyone. Other times, bone loss and thin bones run in families and the disease is inherited. In general, white, older women are the most likely to have bone loss. This increases their risk of breaking a bone.

Brittle, fragile bones can be caused by anything that makes your body destroy too much bone, or keeps your body from making enough bone.

Weak bones can break easily, even without an obvious injury.

Bone mineral density is not the only predictor of how fragile your bones are. There are other unknown factors related to bone quality that are as important as bone quantity. Most bone density tests only measure the bone quantity.

Aging and Bone Loss

As you age, your body may reabsorb calcium and phosphate from your bones instead of keeping these minerals in your bones. This makes your bones weaker. When this process reaches a certain stage, it is called osteoporosis.

Video Transcript

Osteoporosis - Animation

Osteoporosis is a condition that leads to loss of bone mass. From the outside, osteoporotic bone is shaped like normal bone. However, the inside of the bones becomes more porous during the aging process due to the loss of calcium and phosphate. The loss of these minerals makes the bones more prone to fracture even during routine activities, like walking, standing, or bathing. Often, a person will sustain a fracture before becoming aware of the presence of the disease. Prevention is the best measure for treating osteoporosis, by eating a recommended balanced diet including foods with sufficient amounts of calcium, phosphorous, and vitamin D. In addition, maintaining a regular exercise program as approved by your health care provider will help to keep the bones strong. Various medicines can be used as part of the treatment for osteoporosis and should be discussed thoroughly with your health care provider.

Many times, a person will fracture a bone before they even know they have bone loss. By the time a fracture occurs, the bone loss is serious.

Women over age 50 years and men over age 70 years have a higher risk for osteoporosis than younger women and men.

  • For women, a drop in estrogen at the time of menopause is a major cause of bone loss.
  • For men, a drop in testosterone as they age can cause bone loss.

What's Your Osteoporosis Risk?

  • If you have good posture, you don't need to worry about osteoporosis.

    Correct Answer
    The correct answer is myth. People with osteoporosis have weak bones that are more likely to break. Bone loss from osteoporosis can lead to a stooped posture. Bad posture can cause stooping, but it doesn't cause bone loss or osteoporosis. Discuss your risk factors for osteoporosis with your doctor even if your posture is perfect!
  • Half of women over age 50 will fracture a hip, wrist or vertebra.

    Correct Answer
    The correct answer is true. Half of women over age 50 will fracture a hip, wrist, or vertebra during their lifetime. This is because many women lose a lot of bone as they get older. Finding osteoporosis early can help prevent bone breaks.
  • Going through menopause:

    Correct Answer
    The correct answer is raises your risk of osteoporosis. During menopause, estrogen levels fall, and the body may not be able to create new bone fast enough to replace the old bone used by the body. If you have gone through menopause, ask your doctor about being tested for osteoporosis.
  • Men don't get osteoporosis.

    Correct Answer
    The correct answer is myth. As men age, testosterone levels tend to fall. This can lead to bone loss starting at about age 70. Older men should talk with their doctor about being tested for osteoporosis.
  • Which group is most at risk for osteoporosis?

    Correct Answer
    The correct answer is Caucasians. White women are more likely to develop brittle bones than any other group. The risk is highest in women with a family history of osteoporosis. If the disease runs in your family, talk to your doctor about osteoporosis prevention and bone density testing.
  • Eating foods high in calcium can lower your osteoporosis risk.

    Correct Answer
    The correct answer is fact. Your body needs calcium to build strong bones. Women ages 51 to 70 should have 1,200 mg of calcium a day. Men ages 51 to 70 and adults age 50 or younger should have 1,000 mg of calcium a day. In addition, everyone needs 400 to 800 IU of vitamin D daily to help the body absorb calcium.
  • Which exercise can lower your osteoporosis risk?

    Correct Answer
    The correct answer is B and D. Weight-bearing exercises make your muscles pull on your bones. This makes bones stronger. Examples include tennis, walking, dancing, and weight-lifting. Protect your bones by doing weight-bearing exercises 3 or more days a week. Check with your doctor first if you haven't been active for awhile.
  • Drinking and smoking can increase your osteoporosis risk.

    Correct Answer
    The correct answer is fact. Men and women who smoke have weaker bones. Women who smoke after menopause have an even higher chance of bone breaks. Having three or more alcoholic drinks a day on most days can also damage the bones. Your doctor can help if you decide to quit smoking or cut back on alcohol.
  • Which health problem raises the risk of osteoporosis?

    Correct Answer
    The correct answer is all of the above. Any health problem that makes it hard to exercise or keeps the body from absorbing calcium or vitamin D can lead to weak bones. Some medicines, including steroids and anti-seizure drugs, can also cause osteoporosis.
  • You're more likely to get osteoporosis if you're overweight.

    Correct Answer
    The correct answer is myth. In fact, people who are underweight are more likely to get osteoporosis. Younger woman who do not have menstrual periods for a long time also have a higher risk of bone loss.
  • Bone density testing can spot osteoporosis before it causes symptoms.

    Correct Answer
    The correct answer is fact. Bone density testing is a painless scan that measures how much calcium and other minerals are in a section of bone. Women over 65 and men over 70 should consider having this test. Ask your doctor about starting earlier if you have any of the risk factors discussed in this quiz.

Your Lifestyle and Bone Loss

Your body needs calcium and vitamin D and enough exercise to build and keep strong bones.

Your body may not make enough new bone if:

  • You do not eat enough high-calcium foods
  • Your body does not absorb enough calcium from the foods you eat
  • Your body removes more calcium than normal in the urine

Certain habits can affect your bones.

  • Drinking alcohol. Too much alcohol can damage your bones. It can also put you at risk of falling and breaking a bone.
  • Smoking. Men and women who smoke have weaker bones. Women who smoke after menopause have an even higher chance of fractures.

Younger women who do not have menstrual periods for a long time also have a higher risk of bone loss and osteoporosis.

Low body weight is linked to less bone mass and weaker bones.

Exercise is linked to higher bone mass and stronger bones.

Medical Disorders and Bone Loss

Many long-term (chronic) medical conditions can keep people confined to a bed or chair.

  • This keeps the muscles and bones in their hips and spines from being used or bearing any weight.
  • Not being able to walk or exercise may lead to bone loss and fractures.

Other medical conditions that may also lead to bone loss are:

Sometimes, medicines that treat certain medical conditions can cause osteoporosis. Some of these are:

  • Hormone-blocking treatments for prostate cancer or breast cancer
  • Some medicines that are used to treat seizures or epilepsy
  • Glucocorticoid (steroid) medicines, if they are taken by mouth every day for more than 3 months, or are taken several times a year

Any treatment or condition that causes calcium or vitamin D to be poorly absorbed can also lead to weak bones. Some of these are:

  • Gastric bypass (weight-loss surgery)
  • Cystic fibrosis
  • Other conditions that prevent the small intestine from absorbing nutrients well

People with eating disorders, such as anorexia or bulimia, are also at higher risk for osteoporosis.

What's Next?

Talk to your health care provider about your risk for bone loss and osteoporosis. Find out how to get the right amount of calcium and vitamin D, what exercise or lifestyle changes are right for you, and what medicines you may need to take.

Text only

Review Date: 5/13/2020

Reviewed By

Brent Wisse, MD, board certified in Metabolism/Endocrinology, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

References

De Paula FJA, Black DM, Rosen CJ. Osteoporosis: basic and clinical aspects. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ , eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 30.

Eastell R, Rosen CJ, Black DM, Cheung AM, Murad MH, Shoback D. Pharmacological management of osteoporosis in postmenopausal women: an Endocrine Society* Clinical Practice Guideline. J Clin Endocrinol Metab. 2019;104(5):1595-1622. PMID: 30907953 pubmed.ncbi.nlm.nih.gov/30907953/.

Weber TJ. Osteoporosis. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 230.

Disclaimer

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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Osteoporosis

Osteoporosis

Animation

Vitamin D benefit - Illustration Thumbnail

Vitamin D benefit

Vitamin D promotes absorption of calcium from the gut. Too much vitamin D may cause increased levels of calcium in the blood.

Illustration

Calcium source - Illustration Thumbnail

Calcium source

Getting enough calcium to keep bones from thinning throughout a person's life may be made more difficult if that person has lactose intolerance or another reason, such as a tendency toward kidney stones, for avoiding calcium-rich food sources. Calcium deficiency also effects the heart and circulatory system, as well as the secretion of essential hormones. There are many ways to supplement calcium, including a growing number of fortified foods.

Illustration

Osteoporosis

Osteoporosis

Animation

Vitamin D benefit - Illustration Thumbnail

Vitamin D benefit

Vitamin D promotes absorption of calcium from the gut. Too much vitamin D may cause increased levels of calcium in the blood.

Illustration

Calcium source - Illustration Thumbnail

Calcium source

Getting enough calcium to keep bones from thinning throughout a person's life may be made more difficult if that person has lactose intolerance or another reason, such as a tendency toward kidney stones, for avoiding calcium-rich food sources. Calcium deficiency also effects the heart and circulatory system, as well as the secretion of essential hormones. There are many ways to supplement calcium, including a growing number of fortified foods.

Illustration

 

Osteoporosis - Animation

This elderly woman had to be taken to the hospital last night. While getting out of the tub, she had a fall and broke her hip. Because her bones are so fragile, the woman probably broke her hip first, which then caused her to fall.

Like millions of people, the woman suffers from osteoporosis, a condition that leads to loss of bone mass.

From the outside, osteoporotic bone is shaped like normal bone. But the inside appearance of the bone is quite different. As people age, the inside of the bones becomes more porous, due to the loss of calcium and phosphate. The loss of these minerals makes the bones more prone to fracture, even during routine activities, like walking, standing, or bathing. Many times, a person will sustain a fracture before becoming aware of the presence of the disease.

Prevention is the best measure for treating osteoporosis by eating a recommended balanced diet including foods with sufficient amounts of calcium, phosphorous, and vitamin D. In addition, maintaining a regular exercise program as approved by a qualified health care professional will help to keep the bones strong.

Various medications can be used as part of the treatment for osteoporosis and should be discussed with a qualified health care professional.

 

Osteoporosis - Animation

This elderly woman had to be taken to the hospital last night. While getting out of the tub, she had a fall and broke her hip. Because her bones are so fragile, the woman probably broke her hip first, which then caused her to fall.

Like millions of people, the woman suffers from osteoporosis, a condition that leads to loss of bone mass.

From the outside, osteoporotic bone is shaped like normal bone. But the inside appearance of the bone is quite different. As people age, the inside of the bones becomes more porous, due to the loss of calcium and phosphate. The loss of these minerals makes the bones more prone to fracture, even during routine activities, like walking, standing, or bathing. Many times, a person will sustain a fracture before becoming aware of the presence of the disease.

Prevention is the best measure for treating osteoporosis by eating a recommended balanced diet including foods with sufficient amounts of calcium, phosphorous, and vitamin D. In addition, maintaining a regular exercise program as approved by a qualified health care professional will help to keep the bones strong.

Various medications can be used as part of the treatment for osteoporosis and should be discussed with a qualified health care professional.

 
 
 
 

 

 
 

 
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