Osteoporosis is a condition that causes bones to become brittle. As bones lose their mineral content, or as their mineral content loses the collagen that "glues" bones together, they break more easily. When it strikes children, this rare condition is called juvenile osteoporosis.
Causes of secondary juvenile osteoporosis include:
- Lifestyle. When children don't get enough sun, their bodies don't make enough vitamin D to keep bones healthy. This was the cause of a dreaded condition called rickets, which plagued children forced to work long days in factories during the early Industrial Revolution. Rickets has not completely gone away, even in the United States. Children in the hot and humid southeast of the United States may spend so much time indoors in air conditioned environments that they develop similarly serious vitamin D deficiencies. Prolonged inactivity is a risk factor for osteoporosis, but so is excessive physical activity, especially in teenaged girls who are so physically active that they miss their periods. Smoking and alcohol abuse have a greater effect on growing bones than on adult bones, and may cause lifelong problems if enough bone is not built early in life.
- Medications. Three types of drugs are especially troublesome for bone health in children and teens. There is a well-established correlation between the use of the anticonvulsant medication valproic acid (Depakote, Depakene) and deficient bone mineralization in children and adults. The relationship between the medication and its effects on bone is poorly understood, and newer seizure medications have not been comprehensively studied. Immunosuppressive drugs for childhood cancer interfere with bone growth. And glucocorticoid medications for asthma and chronic obstructive pulmonary disease, especially those taken by mouth, are a major risk factor for fractures of the spine. Just a few months of treatment with these "steroid" drugs can have lasting effects on growing bones.
- Medical conditions. Loss of bone strength is a complication of numerous medical conditions, including anorexia, juvenile idiopathic arthritis, Cushing’s syndrome, cystic fibrosis, diabetes, inflammatory bowel disease, kidney disease, hyperthyroidism, and osteogenesis imperfecta.
Secondary osteoporosis tends to persist until its underlying cause is successfully treated. Idiopathic juvenile osteoporosis tends to follow a different course.
"Idiopathic" literally means "of an unknown cause." Until very recently, scientists had no idea what caused some cases of juvenile osteoporosis. Children would present baffling symptoms such as:
- Pain in the lower back, hips, and feet. Usually this pain causes trouble walking.
- "Fragility fractures" (fractures that occur after little or no trauma) in the toes, feet, and ankles.
- Kyphosis (curvature of the upper spine).
- Sunken chest.
- Losing height instead of gaining height.
Bone defects and poor mineral content spontaneously go into remission in most cases of idiopathic juvenile osteoporosis. It is important to guard against bone fractures until the disease goes into remission. The underlying osteoporosis corrects itself, but any breaks in bone have to heal through the usual processes. Catch up growth usually repairs skeletal deformities, although sometimes sunken chest and curvature of the upper spine (kyphoscoliosis) persist.
Osteogenesis imperfecta, a rare bone disease that also affects children, is a different diagnosis. Like osteoporosis, osteogenesis imperfecta causes bones that break easily, but they break for a different reason. In osteogenesis imperfecta, the bones accumulate enough minerals for normal strength but they don't make enough of the collagen that holds the minerals together. This keeps the bones from achieving normal shape or size as well as normal strength.
Common features of this childhood bone disorder include brittle bones that break easily and:
- Limited muscle strength.
- Hyperflexible joints.
- Reduced stature.
- Blue, gray, or purple tinting of the sclera ("whites") of the eyes (in about 50 percent of cases).
- Brittle teeth (dentinogenesis imperfecta).
- Hearing loss in late childhood or early adolescence.
If you are concerned that your child may suffer osteogenesis imperfecta, an important consideration is family history. If you do not have a family history of the condition, it is unlikely that your child suffers it. Also, if there are no blue, gray, or purple tints in the "whites" of the eyes, that is another indication that this relatively rare genetic condition is not the problem.
Bone diseases in childhood require resourceful parenting. Children who cannot safely play need to be provided with other outlets for their energy, curiosity, and socialization.. Good nutrition is a must, and sometimes it is necessary to persuade children to take their medications despite disagreeable side effects. If permanent damage to the bone can be avoided, however, most children who endure osteoporosis can achieve independent adulthood and enjoyment of life.