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Young & Restless: ADHD Medications and the Link to Broken Bones

A new study shows that there’s a link between kids with ADHD and broken bones…but it may not be the link you think it is.

If you’ve seen a large number of your pediatric patients with casts on their arms or legs and they’re known to be…unruly, there could be a connection.

Obviously a child who never sits still is going to be prone to more accidents than the little boy or girl who spends all their time staring dead-eyed into a television screen, video controller in hand, or the quiet child who spends time writing stories and drawing pictures. However, just because these active youths are putting themselves in harm’s way more than the calmer kids may not be the only link to the cast on their arms; the medication they’re taking may be the real culprit, or at least a coconspirator.

A new study presented at ENDO 2016 in Boston in April showed that children who are taking drugs to treat attention-deficit hyperactivity disorder (ADHD) may actually have lower bone density than their peers who don’t take these medications. According to according to the study’s lead investigator Alexis Feuer, MD, assistant professor of pediatrics and a pediatric endocrinologist at Weill Cornell Medicine in New York, she was not entirely surprised by her study’s results since it was her original hypothesis that stimulant medications would adversely affect bone density.

“There is a very clear molecular mechanism by which this would occur,” she explains. “I was pleased with our results as they support animal data which reveal that activation of beta-adrenergic signaling pathways – the signaling pathway through which stimulants exert their effects – leads to decreased bone mass.”

The medications – methylphenidate (Ritalin, et al.) and amphetamine – are often used to treat ADHD, which, according to the Centers for Disease Control and Prevention (CDC), affects more than 6 million children in the U.S.

“Increased Lifetime Risk”

While past studies have shown that stimulants could slow a child’s growth rate in terms of height, the effect of the meds on bone health has remained unclear, according to Feuer, who says that adolescence and young adulthood are critically important times for accruing peak bone mass, i.e., the largest and densest bone. “Failure to accrue peak bone density by early adulthood puts an individual at an increased lifetime risk of osteoporosis and fractures,” she says.

“All healthcare providers caring for children on stimulants should start screening their patients for bone health as soon as possible.” – Alexis Feuer, MD, assistant professor of pediatrics; pediatric endocrinologist, Weill Cornell Medicine, New York, N.Y.

Feuer and her team studied the association between these stimulant medications and bone density using data from the National Health and Nutrition Examination Survey (NHANES), a series of surveys from the CDC that assesses American health. Among 6,489 subjects aged 8 to 20 years who participated in NHANES between 2005 and 2010 and had a bone density scan using dual-energy X-ray absorptiometry (DXA), only 159 used stimulants.

The DXA scans evaluated bone mineral density – a surrogate measurement of bone strength – as well as bone mineral content (bone weight) at both the hip and the lumbar spine. According to Feuer, interpreting bone density results in growing children can be challenging since the child’s height has to be taken into consideration.

She explains that the bone density results obtained from a DXA scan are areal measurements, so the DXA will measure height and width of the bone, but not thickness. Therefore, if two children have the exact same volumetric bone density (height, width and thickness), the shorter child will appear to have a lower measured BMD than the taller child. Additional factors must also be taken into consideration- for example commonly scanned anatomic sites such as the hip are not preferred for children because of difficulty with proper positioning due to lack of bony landmarks for orientation.

“Pubertal development also leads to increases in bone density, so if a child has delayed puberty they will also appear to have a lower bone density than peers their age who are already in puberty,” she says. “Pediatric DXA scans should therefore be interpreted by radiologists and/or endocrinologists with experience in pediatric DXA.”

Study Results

In the study, in the kids who were taking stimulants, the average bone mineral content at the lumbar spine was 5.1% lower than in nonusers, and 5.3% lower at the hip, according to the investigators. Bone density was 3.9% lower in stimulant users at the spine and 3.7% lower at the hip than nonusers.
So do the study’s findings mean that children on ADHD medication are more likely to develop osteopenia or osteoporosis?

“That’s the question we must answer,” Feuer says. “Right now, from this study, we have only an association between stimulant use and lower bone density. The study was cross-sectional in design, so we cannot infer any type of cause and effect from it. We need to perform prospective studies to decipher if stimulant use actually does lower bone density in children and what future effects this may have.”

Feuer says that children and adolescents who fail to obtain peak bone mass by young adulthood are at a greater risk for developing osteoporosis, “so it would be reasonable to conclude that if a prospective study reveals that stimulant use does in fact lead to low bone density in children and prevents them from obtaining peak bone mass that they would also likely be at increased risk for fractures and osteoporosis.”

Handle With Care

Feuer says that children taking stimulant medications should have regular screening for bone health, which would entail checking vitamin D levels and giving them supplements if the levels are insufficient. “They should have their height and weight assessed at regular intervals to ensure they are growing appropriately,” she explains, adding “they should have dietary calcium intake assessed and again supplemented if needed and they should be getting an hour of weight-bearing exercise daily.” However, bone density scans, or DXA scans, are not recommended for screening purposes at this time, she says.

She adds that having children participate in weight-bearing exercise will help with building strong bones so Feuer says that children should get about 60 minutes of this type of exercise daily. “It is also important to monitor for appropriate linear growth, weight gain and appropriate pubertal development,” she adds.

Moving forward, Feuer feels that since the number of children, adolescents, and young adults taking stimulant medications for the long term is high — and continues to increase annually — there must be more prospective studies to assess the medications’ effects on bone density. “Additionally,” she adds, “all healthcare providers caring for children on stimulants should start screening their patients for bone health as soon as possible.”

 

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