Effect of Hyperthyroidism on Bone Mineral Density in Premenopausal Women

Document Type : Research Paper



Introduction: Hyperthyroidism is a state of high bone turnover, but there is controversy about its effects on bone mineral density. It is more common in females (F: M ratio 10:1). Since post-menopausal women are potentially at risk for osteoporosis because of aging and estrogen deficiency and because hyperthyroidism is more common in females, this study was done to determine the effects of hyperthyroidism on bone mineral density (BMD) in premenopausal thyrotoxic women.
Material and Methodes: In this case- control study 50 women with untreated hyperthyroidism (age- range 20-50 yr) from outpatient endocrine clinics in the years 2004 – 2005 were selected. Patients who used drugs or had diseases that affect bone mineral density were excluded. After history taking and physical examination, thyroid function tests, PTH, phosphorus, calcium, alkalin phosphatase, fasting plasma glucose and creatinine were measured and then bone densitometry by LUNAR (DPX-IQ) device was performed. One hundred and ten age- and weight – matched healthy women from participants in Iranian Multicenter Osteoporosis Study (IMOS) were selected as controls. SPSS version 11.5 was used for data analysis and P value less than 0.05 cosidered as significant.
Results: Mean of age, height and weight was similar in patients and controls. Forty seven cases (94%) had Graves’ disease and 3 cases (6%) had toxic solitary adenoma. Mean duration of disease before diagnosis was 6.02±4.38 months. There was no significant difference in mean of bone mineral density in vertebral column (p=0.83) and also in femural neck (p=0.74) between patients and controls. There was no correlation between bone mineral density in vertebral column and also in femural neck with serum levels of T4, T3, TSH and FT4I. There was no correlation between bone mineral density and duration of disease before diagnosis and also between bone mineral density and age.
Conclusion: Hyperthyroidism is a known state of high bone turnover, but in hyperthyroid premenopausal women with disease of short duration and without other risk factors of low bone mass, bone densitometry could not be recommended as a required routine measurement.


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