Our knowledge of orthopaedics. Your best health.

Bones are alive and dynamic. There are three basic components of bone — cells, protein fibers, and mineral.

• Calcium forms a mineral (hydroxyapatite) that is very hard and strong.
• Embedded within the mineral are strong protein fibers (collagen) that make the mineral much stronger and less brittle.
• The cells in a bone are constantly at work to maintain the bone structure.

When bone cells sense that we are doing physically demanding things, like running or lifting heavy objects, they build stronger bone to withstand that. On the other hand, if we are less active, these cells start to absorb bone mineral and our bones get weaker. In this way, bones are constantly adapting to our lifestyle.

However, as resilient as bones are, some chronic illnesses can have harmful effects on bone — leading to an increased risk of fractures (broken bones) and osteoporosis. People with these illnesses may experience:

• Direct effects, meaning the disease itself impacts bone health; and/or
• Indirect effects, such as issues caused by the medications used to treat an illness

Kidney Disease

Chronic kidney disease, or "chronic kidney failure," often results from high blood pressure, diabetes, and advanced age. It is a common cause of poor bone health in older adults.

When kidneys begin to fail, they lose the ability to help keep calcium and phosphate in balance, and the body starts pulling these minerals out of the bones. This makes the bones less dense and more brittle.

For people with chronic kidney disease, it is important to optimize kidney health by avoiding certain medications, staying well hydrated, and controlling blood pressure and diabetes.

Liver Disease

People with chronic liver disease (example: cirrhosis, chronic hepatitis C infection) often lose bone density. The reason for this is not well understood but is partly due to poor absorption of vitamin D and other fat-soluble vitamins.

Because of low vitamin D and other factors, the bone cells become less active and responsive. The bone mineral becomes more fragile and porous (osteoporosis) and lose their strong internal structure. This puts patients at higher risk of suffering a broken bone.

Bowel Disease

Intestinal problems such as celiac disease (inflammation of the bowels due to consuming gluten) and inflammatory bowel disease (examples: Crohn disease, ulcerative colitis) can also have harmful effects on bone. In fact, up to 42% of people with inflammatory bowel disease are found to have osteoporosis and, as a result, a high risk of broken bones. These are some of the possible reasons:

• Because the bowels can get very inflamed, they do not absorb nutrients (like calcium and vitamin D) as well.
• Sometimes, portions of the bowels must be surgically removed, so there is less area for these nutrients to be absorbed.
• Inflammatory molecules that flow throughout the body cause bone cells to lose function.
• Bone mineral loss may also be partly due to being treated with steroids (see Medications That Impact Bone Health below).

HIV/AIDS

Because drugs used to treat HIV infection are now quite effective, people with HIV are living longer than ever before. Though this is clearly a success story, it is becoming clear that people living with HIV for many years often have poor bone health. This may be caused by a combination of factors, including:

• Low testosterone levels
• Co-infection with hepatitis C (see Liver Disease above)
• Lifestyle (physical inactivity, poor diet, cigarette smoking)
• Some medications used to treat HIV, which can cause decreased bone density

Diabetes

Both type 1 and type 2 diabetes cause harmful effects on many organs and body parts. Bone is no exception. Although bone density tests (DXA scan) often show normal bone density in diabetics, research has shown that diabetics have more fragile bones.

The reason: Diabetics often have high blood sugar levels, which can cause damage to small nerves and blood vessels everywhere in the body. When these harmful effects reach bone, the bones become weaker and more likely to break. The best way to prevent this is to keep blood sugar levels well controlled through a low-carb diet, exercise, and taking diabetes medications as prescribed by your doctor.

Cancer

Cancer can affect bones in many ways:

• Malignant tumors can arise within bones and destroy the bone in that area.
• Cancer can develop in another organ (example: breast cancer, prostate cancer) and then spread, or "metastasize," to the bones. When this happens, the cancerous growths cause significant pain and may harm or destroy the bone tissue.
• Some cancer drugs (like chemotherapy drugs) and other treatments (radiation therapy or surgery) may cause harm to bones as well.

Pediatric Inactivity

A rapidly growing problem among children in the U.S. is lack of physical activity and exercise. Many factors are to blame here, but the big ones are too much screen time and not enough recess and physical education (PE) class time in schools.

Children who spend too much time sitting never allow their bodies to develop muscle strength and coordination. They never learn to enjoy being active. This may lead to lifelong habits of being inactive, which can result in many health problems.

Among these issues, children who are inactive suffer from low bone density even at the age (18 to 21 years old) when they are supposed to reach peak bone density. Even if they decide to become more physically active later in life, they may never recover the bone density that they would have had if they were physically active during childhood and their teenage years.

It is never too late to begin increasing physical activity. The key is to be consistent and choose activities you enjoy and will continue to do. Learn more: Osteoporosis Prevention Starts Early, Fitness for Kids

Other Health issues That Can Have Harmful Effects on Bone

• Sarcoidosis
• Eating disorders (anorexia nervosa, bulimia)
• Puberty suppression

Glucocorticoids (Example: Prednisone)

These medications are helpful for reducing inflammation, but they are harmful to bones if taken for longer than a few months. They cause bone cells to absorb more bone mineral than the cells produce. If the medication is taken continually, this eventually results in osteoporosis.

Proton Pump Inhibitors (PPIs)

The stomach cannot absorb calcium well without the normal acidity of the stomach. PPIs like omeprazole, used to treat gastroesophageal reflux disease (GERD), stomach ulcers, and heartburn, block stomach acid production, making it harder for the body to absorb calcium — especially if taken daily for months or years at a time.

Research has shown that long-term PPI use increases the risk of hip fracture by about 30%, and risk of any fracture by 16%.

Antidepressants

Antidepressants, which include tricyclics (example: amitriptyline) and selective serotonin reuptake inhibitors (SSRI) (examples: fluoxetine, sertraline) are excellent medications to help with depression, anxiety, and other problems. Unfortunately, research has shown that they also cause bones to be more fragile (more likely to break).

Antiseizure Medications

Medications used to treat seizures (examples: phenytoin, carbamazepine) may cause the body to break down vitamin D too fast. This results in low vitamin D levels, which causes the body to be unable to absorb calcium from food.

To compensate and ensure there is enough calcium in the blood, the body pulls calcium out of bones. The result is low bone density and increased risk of broken bones.

Depot Medroxyprogesterone Acetate

This is a common form of birth control. It is an injection, often called "the shot." Many studies have shown that it causes loss of bone density, especially if taken for more than 2 years. The U.S. Food and Drug Administration has issued a black box warning about this risk.

Other Medications That Can Have Harmful Effects on Bone

• Warfarin
• Methotrexate
• Loop diuretics (furosemide, torsemide)
• Cyclosporine
• Excess vitamin A
• Gonadotropin-releasing hormone (GnRH) agonists (used to delay puberty in transgender youth or lower testosterone in transgender women)

• Bones require regular exercise and good nutrition to stay as healthy as possible. Learn more: Bone Health Basics, Exercise and Bone Health, Calcium, Nutrition and Bone Health
• For people who smoke, quitting is one of the biggest steps for improving bone health. Learn more: Smoking and Musculoskeletal Health
• When your bone health is impacted by a chronic illness, work with your doctor to treat the illness in the most effective and safest ways.
• If you are taking a medication that causes harmful effects to bone, especially for an extended period of time, talk to your doctor about possible alternatives.
• If you have had a period of low physical activity (examples: being hospitalized or recovering from surgery), it is important to gradually resume being active when you are cleared to do so by your doctor. It can take months to safely return to the same physical activity level you were at prior to being immobilized. But by undertaking the journey of recovery, the strength of your bones will gradually improve.