Risk of hip fracture is not increased in
women treated with thyroxine
(July 2002)
The background of
the study. Hyperthyroidism is a risk factor for osteoporosis
and hip fracture. Whether thyroid hormone therapy is a risk factor
for these problems is less clear. This study evaluated the frequency
of hip fracture in patients treated with thyroid hormone and control
patients.
How the study was done. The study
subjects were 23,183 patients treated with thyroxine (T4) for at
least one year and 92,732 age- and sex-matched patients attending
general practices in the United Kingdom. The mean age in both groups
was 65 years (66 percent were 60 years or older), and 88 percent
were women. Information was obtained about hip fracture and the
dose and duration of T4 therapy. The mean dose of T4 was 0.107 mg
daily, and the mean duration of therapy was 3 years (range, 1 to
22).
The results of the study. Among
the 23,183 T4-treated patients, 373 (1.6 percent) had sustained
a hip fracture, as compared with 1340 of the 92,732 control patients
(1.4 percent, P = 0.06). Among the patients aged 60 years or older,
2.3 percent of the T4-treated patients and 2.1 percent of the control
patients had sustained a hip fracture. The fracture rate was similar
in the T4-treated and the control women (1.7 vs. 1.6 percent), but
it was higher in the T4-treated than in the control men (1.2 vs.
0.7 percent. The mean T4 dose was lower in the women than in the
men (0.106 vs. 0.120 mg daily), but the doses were similar in the
fracture and no-fracture groups in both women and men.
Overall, after adjustments for other disorders and drugs that affect
bone, T4 therapy was not associated with hip fracture in women.
T4 therapy was weakly associated with hip fracture in men, but there
was no relationship between T4 dose and hip fracture.
The conclusions of the study. Hip
fracture is not associated with T4 therapy in women, but it may
be in men.
The original article. Sheppard MC,
Holder R, Franklyn JA. Levothyroxine treatment and occurrence of
fracture of the hip. Arch Intern Med 2002;162:338-43.
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