Bone Density in Pediatrics

Broken bones or fractures in the pediatric population are generally thought of as caused by trauma or accident. Certainly, accidents do occur to anyone in the pediatric age range. However, there are some conditions in the pediatric population that can lead to broken bones from metabolic processes, including neurological issues.

Bone density concerns can arise from genetic issues, medical issues, or nutritional disorders. Some of the genetic issues that affect bone density are those issues that are passed through issues in the genetic code, including spina bifida, cerebral palsy, Rett syndrome, cystic fibrosis, and Duchenne muscular dystrophy, to name but a few. Medical issues can include epilepsy, cancer, anorexia, growth hormone deficiency, hyperthyroidism, head injury, and spinal cord injury. Nutritional issues include vitamin D deficiency, Type I diabetes, or other issues of metabolism, especially calcium and vitamin D absorption. (Osteogenesis imperfecta is a genetic issue where bones break from an unknown cause. This is a different issue and treatment than the discussion in this blog.)

All or some of these concerns can arise within the framework of neurological diagnosis. Some children may have neurological issues along with other conditions. Consequences of neurological issues affecting bone density include decreases in activity and weight bearing, being indoors more often, which decreases exposure to sunlight, and disadvantages in nutrition from being unable to consume enough calories, which may be due to feeling full from a slower bowel, to burning calories through tone (spasticity), or consuming too many calories. Treatments for some neurological conditions can lead to poor bone density, such as a side effect of antiepileptic drug treatment, ketogenic diet, and steroids.

In children, bone mineral issues or osteoporosis occurs from a lowering of bone accrual or building bones as opposed to adults who lose bone density through demineralization. Bone density builds through childhood, peaking at the end of adolescence. During childhood, children build their bone structure for adult life. If this process is interrupted by health issues, the bones do not completely develop into a solid foundation for the adult body. They still are developing bone but vary in the amounts built. Some children will develop a bone structure able to accommodate their adult body needs, others may not have the bone density needed for moving a larger, heavier adult body or for the challenges of everyday adult living.

Bone building is a complicated process of several body actions. The process of bone mineralization includes the metabolism of vitamin D through the skin being exposed to sunlight. Vitamin D can also be metabolized through diet. Supplements can be added but this is a very small part of the process. Sunlight exposure, even for a short period of time, is the most effective. The cellular process of bone building includes osteoblasts which make proteins and link collagen to enable bone reabsorption keeping bones healthy and strong. Osteocytes are bone cells created by osteoblasts for new bone formation. Osteoclasts break down the old bone for health maintenance. Vitamin D works to allow osteoblasts to build the bone. Bone formation occurs by pressures being placed on the bones from the impact of walking and from body movement.

Providing a healthy diet, including calcium through food, which is more integrative in the body than supplements, is essential. Generally, the amount of calcium needed per day is listed below. Your child may have different requirements based on body size and health issues. Check with your child’s healthcare professional for the correct amount for your child’s individual needs. Some calcium supplements may be needed due to swallowing issues, food intolerances, reflux, constipation, or even food-drug interactions.

Age Average Calcium Intake

0-6 months 200mg/day

7-12 months 260mg/day

1-3 years 700mg/day

4-8 years 1000mg/day

9-18 years 1300 mg/day

Physical activity of the body is needed to maintain bones. As the body moves, muscle contractions pull tendons which attach the muscle to the bone. The pulling of muscles and tendons makes bones stronger. Astonishingly, gravity also places pressure and pull on the body, which then makes bones stronger. Children with some tone (spasticity) can have normal bone density due to the tendons pulling on the bones during muscle spasms.

Lack or limited weight bearing, even temporarily, can affect childhood bone building and bone density as a child and for future adult bone needs. Combined with a lack of calcium in the diet, a lack of physical movement will affect short-term and long-term bone growth. Providing movement will create the pull needed for the tendons to help build bones. This can be through passive range of motion or activities that create movement. Toddlers enjoy stroller rides in strollers that have a bicycle attachment built in. Adaptions will be needed for foot placement. As the parent pushes the stroller, the bike pedals turn, which will provide an easy movement of the legs in an activity that both adult and child enjoy. Standing frames provide gravity input to the bones as the child or teen is safely putting their body weight through the bones while engaged in other activities. A standing frame is also a positive activity in the school setting for activities that require height. Both the benefits of being at the same height as the other children and gaining bone density are obtained.

Medications can affect bone formation in childhood. These may include anti-epileptic drugs, benzodiazepines, phenobarbital, phenytoin, carbamazepine, valproic acid, and steroids. These have been associated with effects on bone density and bone formation. Many of these drugs are used in neurological conditions and are necessary for the concerns being treated. Monitoring of bone density is needed to ensure proper bone growth.

Some children use the ketogenic diet for seizure control. This can interfere with vitamin D absorption, and parathyroid hormone (PTH) production which affects blood calcium levels, and increase in bone reabsorption. If your child is using any of these drugs or the keto diet, be sure to discuss bone density issues with their healthcare professional at every visit to ensure they are being assessed for bone density concerns.

Children and teens should be made aware of the effects of alcohol and smoking on their health. Both habits affect bone density. Secondhand smoking and alcohol use in pregnancy have long-term effects as well. Vaping and other inhalant use have effects that are under study.

Blood tests can indicate early bone density concerns so modifications can be made to the diet, supplements added, increases in physical activity, or additional medications used to improve bone health.

Bone density testing should be done as indicated by your child’s healthcare professional. This is a test that is easy for children as there are no needles or poking or prodding. The child lays on a table (be sure to monitor their skin) as a wand moves above their body. Nothing touches the child. Metal objects, like zippers, snaps, and jewelry, cannot be worn as they distort the imaging. The test takes little time. The inconvenience for your child is laying still and holding position. These measurements will indicate if your child has normal bone density, osteopenia (which is the beginning of bone density loss), or osteoporosis, which is the actual loss of bone density.

When bone density is affected by osteoporosis or even osteopenia, fractures or broken bones can occur. In children, most bone fractures are ‘greenstick’ or breaks that look like a twig broken from a tree. The bone looks splintered. Children with neurological conditions that include bone density issues can have fractures that are more severe and adult-like with clear edges. Fractures can occur more easily, even with simple movements, and often without any force. These are called fragility fractures. The bones can just ‘snap’ with a simple movement. Larger fractures can still occur from falls or feet that slip off a footrest.

Poor bone density makes the fracture more difficult to set, as the bone above and below the fracture will not be supportive of repair. More extensive surgical procedures will be needed to repair the bone. However, if bone density is followed so reductions can be caught in the early stages, with medication, diet, and physical activity, bones can remain healthy into adult life.

More information about pediatric bone density is available through the National Institutes for Health (NIH).