The human skeleton is strong enough to hold up your whole body.Like other parts of the body, bone can be affected by diseases. Bone disorders may make bones prone to fractures, and they may cause deformities or pain.
Here is what you need to know about bone structure and diseases that may affect bones, their causes, and understanding your risk.
The Human Skeleton
An adult human skeleton is made up of 206 bones. Those 206 bones can produce blood cells, store important nutrients, and release the hormones your body needs to function. They have their own blood cells, nerves, and lymphatic vessels.
Your bones are living tissues that go through a constant cycle of renewal. The older bone is replaced with newly formed bone tissue through a process called bone remodeling.
Bone density peaks when you are a young adult in your mid-20s to early 30s. As you age, your bones will slowly lose density. Bone density can be tested with a bone mineral density (BMD) scan. The test measures minerals in your bones and reflects your bone health.
Fortunately, there are things you can do to reduce natural bone density loss, including exercise, getting enough calcium and vitamin D in your diet, taking vitamins and minerals, or taking certain medications as prescribed. Some of these steps can also help you to manage your bone health and reduce your risk for bone diseases. Unfortunately, not all bone diseases are preventable.
Bone Disease Types
Bone diseases can be genetic, a consequence of aging, or due to controllable risk factors. Some bone conditions begin during adulthood, others mainly affect children, and many can affect anyone, regardless of age.
Osteoporosis causes low bone density and deterioration of bone tissue. The bones become brittle, with an increased risk of fractures. The most common fractures due to osteoporosis affect the hips, ribs, spine, and wrists.
More than 53 million Americans either have osteoporosis or have low bone mass and are at risk of developing it. While osteoporosis mostly affects older adults—mainly women—it can affect anyone regardless of age, including children.
People with osteoporosis are at high risk of fractures (bone breaks) that can occur very easily, including while doing routine activities like standing or walking.
Treatment for osteoporosis can slow down the breakdown of bone and even promote bone growth.
People with osteopenia have lower bone density than normal. Osteopenia increases your risk of osteoporosis. It doesn't cause symptoms because the loss of bone mass isn’t painful.If your healthcare provider thinks you have osteopenia, you might be given a bone density screening to measure your bone mass and strength.
Osteopenia affects about half of Americans over age 50.
Risk factors include:
- Being female
- A family history of low bone density
- Menopause before age 40
- Removal of ovaries before menopause
- Not getting enough exercise
- A poor diet
- Drinking too much alcohol or caffeine
- Long-term corticosteroid use
The goal of treatment is to keep it from progressing to osteoporosis. Treatment usually includes diet and exercise, and bone-strengthening medications if bone density is close to osteoporosis levels. Your healthcare provider may also recommend calcium and/or vitamin D supplements.
Rickets and Osteomalacia
Rickets and osteomalacia are caused by vitamin D deficiency. They can also be caused by a digestive or kidney disorder where the body is not able to absorb vitamin D adequately.
Rickets affects childhood bone development. It causes bone pain, poor growth, and soft, weak bones. The condition can lead to bone deformities.
Most children with rickets are treated with calcium and vitamin D through their diets or vitamin supplements. Children who have problems absorbing vitamins and minerals may need higher supplement doses or vitamin D injections.
Osteomalacia, which affects adults, weakens bones and makes them more susceptible to fractures. It causes bone mineral loss, so bones break down faster than they can rebuild.
The most common symptoms of osteomalacia are bone pain, fractures, and muscle weakness. Osteomalacia may affect your ability to walk.
Osteomalacia vs. Osteoporosis: What Are the Differences?
Bone cancer can start in any bone in the body, but it most often affects the pelvis and the long bones of the arms and legs. Bone cancers are rare, accounting for less than 0.2% of all cancers, according to the American Cancer Society.
Causes for most bone cancers are unknown but some types are related to genetics, previous radiation or chemotherapy, benign tumors, or other bone conditions.
Chondrosarcomas are the most common bone cancers affecting adults. In children and teenagers, the most common bone cancers are osteosarcoma and Ewing tumors.
In addition to primary bone cancer that starts in the bone, many different types of cancer can metastasize (spread) to the bone.
Chemotherapy and radiation are used to treat bone cancer, and some can be treated surgically.
What Is Bone Cancer?
Scoliosis, which is a curve of the spine, usually becomes apparent during the growth spurt before puberty. Scoliosis can be caused by diseases like cerebral palsy and muscular dystrophy, but most causes of scoliosis are idiopathic (no known origin). Adolescent idiopathic scoliosis has a prevalence of 0.47% to 5.2%.
Scoliosis can continue into adulthood or it can develop in adults as adult degenerative scoliosis.
Physical Therapy for Scoliosis
Most cases of childhood scoliosis are mild, but sometimes, spine deformities will get more severe as children grow. If a child has a severe spinal curve, it can reduce the amount of space within the chest cavity and lead to breathing problems and reduced lung function.
If your child has mild scoliosis, they will be monitored with X-rays to see if the curve is getting worse. Mild cases usually don't require treatment, although some children will need to wear a back brace to keep the condition from worsening. A child with severe scoliosis may need surgery to straighten their spine.
In the United States, over 54 million adults have some form of arthritis, according to the Centers for Disease Control and Prevention. Arthritis is the leading cause of work disability in the United States.
Arthritis falls into two categories: osteoarthritis (OA) and inflammatory arthritis, which have different causes and require different treatment approaches. OA is usually caused by injuries or joint overuse.
Inflammatory arthritis conditions affect multiple joints and are often the result of autoimmune inflammation when the body's immune system attacks its own joints.
Common types of inflammatory arthritis:
- Ankylosing spondylitis: Affecting the spine, sternum, and large joints of the body
- Gout: Inflammatory arthritis resulting from an excess of uric acid in the blood
- Lupus: Affecting many organs and systems in the body
- Psoriatic arthritis: Inflammatory arthritis that occurs with psoriasis, an autoimmune skin condition that shows up as red scaly, itchy patches
- Rheumatoid arthritis: A systemic, inflammatory disease where inflammation attacks many joints throughout the body
Paget’s Disease of Bone
Also called osteitis deformans, Paget’s disease of bone interferes with the body’s normal bone recycling process. With Paget’s, there is excess bone breakdown and regrowth, which makes the bones bigger and softer.
Bones might be misshaped, fragile, and prone to fractures.Paget’s mostly occurs in bones of the pelvis, skull, spine, and legs, but any bone could be affected.
The risk increases with age, and the condition is more common in older adults. The condition runs in families, with an increased risk among people of European heritage.
Complications of Paget’s disease of bone include:
- Broken bones
- Heart failure
- Hearing loss or vision loss if Paget’s affects the nerves of the skull
- Nervous system problems because bones can put pressure on the brain, nerves, and spinal cord and because of reduced blood flow to the brain and spinal cord
- Osteosarcoma—a type of bone cancer
- Kidney stones because of extra calcium in the body from the excessive bone breakdown
- Loose teeth if Paget’s affects your facial bones
Paget’s disease of bone is often treated with bisphosphonates—medicines often used to strengthen bones weakened by osteoporosis. Surgery can treat bone damage caused by Paget's.
How Osteoporosis Is Treated
Osteonecrosis, also known as avascular necrosis, is death of bone cells. According to the American College of Rheumatology, the condition affects up to 20,000 Americans each year between the ages of 20 and 50. Those affected tend to have a history of trauma, corticosteroid use, or significant alcohol use.
With osteonecrosis, decreased blood flow causes bone death.This happens because the condition causes tiny breaks in the bone that lead to the affected bone eventually collapsing. These tiny breaks will lead to interrupted blood flow to that section of the bone.
Osteonecrosis can cause pain, arthritis, and limited joint function. An exact cause of the condition is unknown. Some people with the condition may need joint replacement surgery to repair and replace damaged bone.
Osteomyelitis is an infection of the bone. It is frequently caused by bacteria called Staphylococcus aureus. Certain conditions—like diabetes, rheumatoid arthritis, or sickle cell disease—can increase your risk for osteomyelitis.
According to the Cleveland Clinic, osteomyelitis affects 2 out of every 10,000 people, both children and adults. Symptoms of osteomyelitis may include pain and swelling in the affected bone area, fever, swelling of ankles, feet, and legs, loss of joint motion, and changes to gait (the way a person walks).
Left untreated, osteomyelitis can affect blood supply and lead to bone tissue death. Fortunately, it can be treated with antibiotics. Severe bone infections may require surgery to remove the damaged bone or, in the case of spinal infection, to treat spinal cord or nerve root compression.
Also called brittle bone disease, osteogenesis imperfecta (OI) is part of a group of bone diseases called skeletal dysplasias—conditions known for causing fragile bones that can easily break. A defect in the genes responsible for making collagen, a bone-strengthening protein, causes OI.
The estimated prevalence of OI in the United States is between 20,000 and 50,000. Because it affects less than 200,000 people, it is considered a rare disease.
The condition can be mild, causing only a few fractures throughout a person’s life. But it can also be severe and cause hundreds of fractures that have no known causes. It is treated with bone-strengthening medicines, physical therapy, and surgery.
Other Skeletal Dysplasias
There are more than 450 skeletal dysplasia bone disorders. They typically become apparent in newborns, affecting the bones and joints. They can hinder a child’s growth and cause abnormallyshaped bones in the head, spine, or the long bones of the arms and legs. Children with skeletal dysplasias have limbs that are short in comparison to their bodies.
Skeletal dysplasias are caused by defective genes—either inherited or acquired during fetal development.The most common skeletal dysplasias are achondroplasia and other types of dwarfism, thanatophoric dysplasia, and hypochondroplasia.
Skeletal dysplasias can cause breathing issues, spinal problems, including a curving, bowing, and narrowing of the spine, fluid buildup in the brain—called hydrocephalus, and vision and hearing loss.
Treatment for skeletal dysplasia will depend on the symptoms associated with the condition. This may include treating hydrocephalus, surgery to manage spinal stenosis or spine instability, joint replacement of knees and hips severely affected by arthritis, limb-lengthening surgery, and lower extremity surgeries to correct bone alignment.
Your bones need to be able to support your body, provide structure, protect vital organs, and act as attachment sites for muscle so that you can move. Certain risk factors can cause bones to become weak or fragile.
Controllable Risk Factors
Controllable bone health factors include diet, exercise, body weight, the use of alcohol and tobacco, and use of some kinds of medications.
Having a diet low in calcium and vitamin D increases your risk of getting osteopenia or osteoporosis.If you have a mostly sedentary lifestyle, that is another risk factor for osteopenia and osteoporosis.
Keeping a healthy body weight is important to preserve your bone health. Being overweight puts too much pressure on bones. Being malnourished can also increase your risk of bone loss and fractures as you get older. It's important to maintain a healthy weight for your age, bone structure, and height.
Smoking cigarettes and using other types of tobacco can restrict the flow of oxygen-rich blood responsible for nourishing bones, muscles, and joints, and helping them to heal. Smoking also affects the body’s ability to absorb calcium, which means lowered bone density and weaker bones.
In addition, nicotine will slow down the production of bone-forming cells that the human body needs to heal. Heavy consumption of alcohol can affect your nutritional status.
Smoking and Bone Health
Long-term use of corticosteroid medications—like prednisone, cortisone, or dexamethasone—can be damaging to your bones.
Other medications that can affect bone health include aromatase inhibitors to treat breast cancer, selective serotonin reuptake inhibitors—prescribed for mood disorders, methotrexate often taken for inflammatory arthritis, some anti-seizure medications, hormonal contraceptives, and proton pump inhibitors used to reduce stomach acid production.
Risk Factors You Can't Control
Some bone disease risk factors are out of your control, including gender, age, ethnicity, and family history.
Women are more likely to have conditions that cause bone loss, like osteopenia and osteoporosis. Women have smaller bones and lose density more rapidly than men because of hormonal influences.
With advancing age, bones will absorb calcium and phosphates rather than storing them. Hormonal changes in estrogen and testosterone levels as people age also contribute to bone loss in both men and women.
Ethnicity also plays a part in bone health. For example, the highest risk for fractures is in White women. And people of European and Asian backgrounds get osteoporosis more often than other ethnic groups.
Some genetic bone conditions are associated with family history. For example, Paget’s disease of bone can be inherited across generations in an affected family. Osteogenesis imperfecta and other types of skeletal dysplasia also run in families.
If you have an immediate family member with osteoporosis, there is a good possibility you might develop the condition later in life.
A Word From Verywell
If you are concerned about your bone health or genetic risk for bone conditions, consult your healthcare provider to see if you need screening. You might benefit from bone density tests, genetic screenings, and other tests to help determine your risk. Your healthcare provider may recommend ways to reduce risk factors or begin treatment if you are diagnosed with a bone disorder.