In contrast, lower TSH levels were linked to increased hip fracture risk in a second study conducted by Avi Leader, MD, of Meir Medical Center in Israel, and colleagues.
“TSH levels within the lower normal range are associated with an increased risk of hip fractures in euthyroid women, but not men, aged 65 years and more,” they wrote.
Of 14,325 participants, 514 experienced hip fractures during a mean follow-up of 102 months, according to the study data. A higher incidence of hip fractures was noted for women in the lowest TSH group (OR=1.28; 95% CI, 1.03-1.59), as compared with the intermediate group. The researchers adjusted for age, comorbidities and use of drugs affecting bone metabolism.
The same association between low TSH and hip fracture incidence was not observed in men.
TSH levels were not associated with other osteoporotic fractures, according to Leader and colleagues.
A Clinical Perspective
In light of the results from both studies, Dr. Wartofsky recommended focusing on the connection between subclinical thyroid dysfunction and elderly women, as the data in men may not yet be robust enough to draw firm conclusions. Narrowing the scope, however, does not reconcile the differences between the conflicting results.
“So what is the clinician to conclude about the risk of BMD loss and hip fracture in elderly women with low or suppressed TSH levels, and how does that risk influence decision to treat?” he wrote.
Tailoring treatment appears to be the best option, according to Dr. Wartofsky. Carefully considering aspects of each individual case is important.
In some patients, for instance, normalizing TSH is the ultimate goal of treatment, and adjunctive therapies designed to minimize risk for bone loss can be added if necessary. In others, such as those who are already on replacement T4, dosage may need to be lowered. Nevertheless, weighing the risks and benefits for each individual patient is essential.
Further, Dr. Wartofsky emphasized the need to inform patients about factors that increase risk for bone loss, such as tobacco use, excessive alcohol intake, inadequate calcium and vitamin D intake, and leading a sedentary lifestyle.