“linked levothyroxine use to a greater loss of bone mass and bone density over six years — even in older adults with normal thyroid function.”
A. why would older adults with normal thyroid function be taking levothyroxine?
B. did the study do a double-blinded, placebo-controlled study comparing bone-loss between those taking levothyroxine with folks with hypothyroidism who were NOT taking levothyroxine (t4) or triiodothyronine (T3) but taking the placebo instead? ... if not, then the study is completely useless ...
“Data indicates that a significant proportion of thyroid hormone prescriptions may be given to older adults without hypothyroidism, raising concerns about subsequent relative excess of thyroid hormone even when treatment is targeted to reference range goals,” said the study’s lead author Elena Ghotbi, M.D., postdoctoral research fellow at Johns Hopkins University School of Medicine in Baltimore, Maryland.
The researchers used the Baltimore Longitudinal Study of Aging (BLSA), a prospective observational cohort study of community-dwelling older adults. Participants aged 65 and older who had at least two visits and thyroid function tests consistently within the reference ranges were included in Dr. Ghotbi’s study.
This research is a collaboration between Johns Hopkins and the BLSA, the longest-running study on aging conducted by the Intramural Research Program of the National Institute on Aging,” said co-author Eleanor Simonsick, Ph.D., epidemiologist and BLSA co-director. “The BLSA’s extensive data include repeated DEXA measurements at each study visit, which provides valuable insight into the progression of bone density and bone mass changes over time, offering a more comprehensive understanding of aging-related osteoporosis.”
The study group included 81 euthyroid levothyroxine users (32 men, 49 women) and 364 non-users (148 men, 216 women), with a median age of 73 and TSH levels of 2.35 at the initial visit. Other risk factors like age, gender, height, weight, race, medications, smoking history and alcohol use were considered in propensity score matching of levothyroxine users versus non-users.
The results showed that levothyroxine use was associated with greater loss of total body bone mass and bone density—even in participants whose TSH levels were within the normal range—over a median follow-up of 6.3 years. This remained true when taking into account baseline TSH and other risk factors.
“Our study suggests that even when following current guidelines, levothyroxine use appears to be associated with greater bone loss in older adults,” said Shadpour Demehri, M.D., co-senior author and professor of radiology at Johns Hopkins.