Thyroid drug may raise risk of fractures in elderly, study suggests
Hypothyroidism can be treated, sure. But it almost always requires a lifelong regimen of replacement thyroid hormone. Now a study stresses the importance of getting the dose right, finding that long-term use of a common replacement, levothyroxine, might be linked to a higher risk of fractures in elderly people.
The study, published Thursday in the British Medical Journal, analyzed data on more than 200,000 users of levothyroxine age 70 and older. Researchers were looking for fractures in the wrist, forearm, shoulder, upper arm, thoracic spine, lumbar spine, pelvis, hip or femur – common sites for fractures linked to bone-thinning.
The researchers noted how long patients had taken the drug – and at what dose -- and they adjusted for risk factors that might affect the rate of fractures.
Current users, they found, seemed to face a significantly higher risk than did users who had stopped taking the drug more than 180 days before the study started.
And dosage mattered – a lot.
The abstract concludes, fairly bluntly: “Among adults aged 70 or more, current levothyroxine treatment was associated with a significantly increased risk of fracture, with a strong dose-response relation. Ongoing monitoring of levothyroxine dose is important to avoid overtreatment in this population.”
“Overtreatment” is the key. Hypothyroidism is common, especially in women older than 50. And they’re the ones most susceptible to the effects of the bone loss that comes with age.
Prior research had suggested that levothyroxine might increase the risk of bone loss, and researchers were worried that levothyroxine users who started the replacement as adults were still taking the same dose into old age. The write in their study:
“Our findings provide evidence that levothyroxine treatment may increase the risk of fragility fractures in older people even at conventional dosages, suggesting that closer monitoring and modification of treatment targets may be warranted in this vulnerable population.”
So treatment is necessary. But perhaps not with a one-dose-fits-all-ages approach.
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