The human skeleton is strong enough that you can rely on it to hold you for your entire life. Much like other parts of the human body, bone can be affected by disease. Bone diseases can be a source of major abnormality and disability in the human skeleton. They can also make bones easy to break.
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.1 Those 206 bones can produce blood cells, store important nutrients, and release the hormones your body needs to function. They can do this because they have their own blood cells, nerves, and lymphatic vessels.2
Like other parts of your body, 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.2
The condition of one or all of your bones can be measured by bone density. Bone density is the measurement of bone mineral in bones. If your doctor were to perform a bone mineral density (BMD) scan, they would be able to tell you how strong your bones are.
Bone density peaks when you are a young adult in your mid-20s to early 30s.3 From that point forward, as you age, your bones will slowly lose density.
Fortunately, there are things you can do to reduce this natural bone density loss, including with vitamins and minerals, by taking certain medications, eating a calcium and vitamin D diet, and with exercise. Some of these actions 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 even due to controllable risk factors. Some bone conditions mostly affect adults, while others mainly affect children. And some others can develop in anyone regardless of their age.
Osteoporosis is a condition that causes low bone density and deterioration of bone tissue. It can lead to bone brittleness and increased risk of fractures, especially of the hips, ribs, spine, and wrists.
More than 53 million Americans either have osteoporosis or are at risk of developing it due to having low bone mass.4 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 is aimed at protecting and strengthening bones. Treatment, which includes bone-strengthening drugs, can slow down the breakdown of bone and even promote bone growth.
People with osteopenia have lower bone density than normal. Having osteopenia increases your risk of osteoporosis. Osteopenia will not cause symptoms because the loss of bone mass isn’t painful. If your doctor 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 50.5 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, smoking, drinking too much alcohol or caffeine, and long-term corticosteroid use.
The goal of treatment with osteopenia 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.5 Your doctor may also recommend calcium and/or vitamin D supplements.
Rickets and Osteomalacia
Rickets is a condition that affects childhood bone development. It causes bone pain, poor growth, and soft, weak bones. The condition can lead to bone deformities. Rickets is caused by inadequate vitamin D.6
Most children with rickets are treated by ensuring they get enough calcium and vitamin D through their diets or by taking vitamin supplements.6 Children who have problems absorbing vitamins and minerals may need higher supplement doses or vitamin D injections.
Adults experience a similar condition, known as osteomalacia. Osteomalacia weakens bones and makes them more susceptible to fractures. It causes bone mineral loss so bones break faster than they can rebuild.
Osteomalacia commonly develops because of vitamin D deficiency.7 It can also be caused by a digestive or kidney disorder where the body is not able to absorb vitamin D adequately. The most common symptoms of osteomalacia are bone pain, fractures, and muscle weakness. Osteomalacia may affect your ability to walk.
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.8
Causes for most bone cancers are unknown but some types are related to genetics, previous radiation or chemotherapy, benign tumors, or other bone conditions.
The term “bone cancer” doesn’t include cancers that start elsewhere in the body and metastasize (spread) to the bone. Those cancers are named by for where they start. Breast cancer that has metastasized to the bone is an example.
Chondrosarcomas are the most common bone cancers affecting adults. In children and teenagers, the most common bone cancers are osteosarcoma and Ewing tumors.
Most bone cancers are treated surgically. Chemotherapy and radiation are also used to treat bone cancers.
The Facts About Bone Cancer Everyone Should Know
Scoliosis is a bone condition that occurs 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%.9
Scoliosis can continue into adulthood or it can develop in adults as adult degenerative scoliosis.
Adult Scoliosis Has More Complications Due to Aging
Most cases of childhood scoliosis are mild, but sometimes, spine deformities will get more severe as children grow. Severe scoliosis can be painful and disabling. 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.9
If your child has mild scoliosis, they will be monitored with X-rays to see if the curve is getting worse. Mild cases usually require no 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.10 Arthritis is the leading cause of work disability in the United States.
Arthritis falls into two categories: osteoarthritis (OA) and inflammatory arthritis. OA and inflammatory arthritis have different causes and require different treatment approaches.
Inflammatory arthritis conditions affect multiple joints and are often the result of an overactive, malfunctioning immune system where inflammation is running rampant.
Common types of inflammatory arthritis include:
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.11 Typically, new bone tissue would gradually replace old bone tissue. But with Paget’s, there is excess breakdown and regrowth, which means bones are 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.
Your risk for Paget’s disease of bone increases with age and the condition is more common in older adults.11 People with European heritage have an increased risk, and the condition runs in families.
Complications of Paget’s disease of bone include:
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 cord11
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.
Osteonecrosis, also known as avascular necrosis, is a bone disease that results in the 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 50.12 Those affected tend to have a history of trauma, corticosteroid use, or significant alcohol use.
With osteonecrosis, bone death is the result of decreased blood flow. 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 lead to 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 caused by bacteria called Staphylococcus aureus. Having 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.13 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 inherited bone diseases called skeletal dysplasias—conditions known for causing fragile bones that can easily break. The cause of OI is defective genes—specifically, the genes responsible for making collagen, the bone-strengthening protein.
The estimated prevalence of OI in the United States is between 20,000 and 50,000.14 Because it affects less than 200,000 people, it is considered a rare disease.
OI can be a mild condition 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 more than 450 skeletal dysplasia bone disorders.15 They typically present in newborns, affecting the bones and joints. They can hinder a child’s growth and cause abnormally shaped bones in the head, spine, or the long bones of the arms and legs. Children with skeletal dysplasias will have limbs that are short in comparison to their bodies.
Skeletal dysplasias are caused by defective genes—either inherited or that mutate randomly during fetal development. The most common skeletal dysplasias are achondroplasia and other types of dwarfism, thanatophoric dysplasia, and hypochondroplasia.15
Left untreated, 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.16
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. But due to multiple potential risk factors, bones can become weak or fragile. These risk factors are either controllable or uncontrollable.
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 preserving your bone health. Being overweight puts too much pressure on bones and reduces their ability to support you. Being underweight can also increase your risk of bone loss and fractures as you get older. Your doctor will want you at 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.17 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 have similar effects as smoking.
Can Cigarettes Affect Your Bones?
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.18
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.3 This is because their bones are smaller and lose density more rapidly than men because of hormonal changes throughout their lives.
Thinner, weaker bones can be a consequence of getting older. This is because as you age, your bones will absorb calcium and phosphates rather than storing them. Hormonal changes like estrogen and testosterone drops as people age also contribute to bone loss in both men and women.19
Ethnicity and gender both play a part in bone health. For example, the highest risk for fractures is in White women.20 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.21 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. Ask your doctor to screen you early for the condition.
A Word From Verywell
If you are concerned about your bone health or genetic risk for bone conditions, consult your doctor. They can request bone density tests, genetic screenings, and other tests to help determine your risk and recommend ways to reduce risk factors or address plans for managing problems as they come up.
By evaluating your risk, you and your doctor can determine the best approaches to reducing bone loss and preventing and addressing problems before they arise.