However, Dr. Jacob Teitelbaum, a board-certified internist physician and nationally known expert in chronic fatigue syndrome, disagrees with the findings, telling The Epoch Times in an email that they are misinformation that may put people's lives at risk.
"The reporting I am seeing in the brief summary is, I suspect, dangerously misinforming doctors and the public," he said. His main concern is that the study may result in a lack of treatment for those who need it.
Researcher Dr. Shadpour Demehri, professor of radiology at Johns Hopkins, told The Epoch Times in an email that this could happen if someone misinterprets the findings.
"I completely agree with the possible risk of misinterpretation of our presentation among the general population, especially those patients who are in clear need of thyroid hormone replacement, such as in those with frank hypothyroidism or prior thyroid gland removal," Demehri said.
To illustrate what he regards as wrong reasoning, Teitelbaum provides the following analogy: People with high blood pressure are more likely to have heart attacks. If scientists conducting research on individuals taking blood pressure medications observed that they have more heart attacks than those who do not take them, it would be faulty reasoning to conclude that the medications were the cause of the heart attacks. Such a conclusion would ignore the effect of the high blood pressure itself. Likewise, he said, since the JHU study ignored the fact that the main cause of hypothyroidism also causes bone loss, the findings are pretty meaningless.
Demehri discussed Teitelbaum's comments on the connection between blood pressure and heart attacks, mentioning the potential confounders in interpreting observational data. Confounders in research are a factor separate from the outcomes being studied that could impact the results.
"His point, in general, is valid, and that is why we addressed those variables in our results," he said. "However, the observational nature of our work cannot preclude that unknown potential confounding variables could impact the results."
"The study shows something we have known and that I have discussed for decades," he continued. "Keeping what is called the free thyroxine level in the top 15 percent of the normal range, which is much too high for most people, does cause loss of bone density. Conversely, keeping the level in the normal range but below the top 15 percent does not. Consequently, the reporting and conclusion are grossly misleading."
Datis Kharrazian, a clinical research scientist and renowned functional medicine health care provider, agrees that dosage is a key factor in whether levothyroxine causes bone loss.
"When levothyroxine is dosed appropriately to maintain thyroid stimulating hormone (TSH) within the reference range, the risk of adverse effects, including bone loss, is minimized," he told The Epoch Times in an email.
Overtreatment with levothyroxine has been associated with bone density reduction, particularly in postmenopausal women who may also be deficient in sex hormones necessary to protect bone health, added Kharrazian.
Teitelbaum said that it is important for those who have had their thyroid gland removed or who have critically low thyroid levels for other reasons to take levothyroxine or another prescription-strength thyroid hormone.
"There are major disagreements about defining who needs thyroid," he said. "For standard physicians, the definition is having an elevated TSH level. The problem is that the TSH test is very unreliable, and designations of 'abnormal' levels may not be quite accurate."
Teitelbaum explained that due to these and other factors, some people with hypothyroidism may not receive a diagnosis or treatment, even if they have crippling hypothyroidism symptoms.
"To many endocrinologists, thyroid treatment in such cases is unnecessary regardless of whether it could take the person from bedridden and in pain to normally active," he said. "When treatment is necessary, doctors should use the lowest dose with the greatest benefit, while keeping thyroid levels in the mid-range for safety."
On the other hand, Teitelbaum discussed how some people, especially older adults, may take levothyroxine much longer than necessary due to a failure to discontinue the medication when it is no longer required.
Additionally, several natural measures may potentially improve thyroid function.
Teitelbaum does not want the JHU study to scare people away from getting treatment for hypothyroidism, saying that the benefits outweigh the serious consequences of no treatment.
Even though Kharrazian cautioned against the use of higher doses of levothyroxine, he did not refute the study findings, noting that they "raise valid concerns."
However, he said, "It is crucial to weigh the risks of bone density loss against the risks of untreated hypothyroidism, which include cardiovascular disease, neurocognitive issues, and overall poor health status."