Thyroid Research Thyroid Research Archive Hypothyroidism

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.