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Low normal TSH levels are associated with low bone mineral density in healthy postmenopausal women
Author(s) -
Kim Duk Jae,
Khang Young Ho,
Koh JungMin,
Shong Young Kee,
Kim Ghi Su
Publication year - 2006
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.2005.02422.x
Subject(s) - medicine , femoral neck , bone mineral , osteoporosis , endocrinology , postmenopausal women , bone density , body mass index , confidence interval , menopause , lumbar spine , surgery
Summary Objective Hyperthyroidism is accompanied by low bone mass. Because the reference range of TSH levels is defined statistically, some individuals with low normal TSH levels may have mild hyperthyroidism and reduced bone mass. We therefore determined whether serum TSH levels correlate with bone mineral density (BMD). Design A cross‐sectional hospital‐based survey. Participants Nine hundred and fifty‐nine healthy postmenopausal women. Measurements We measured BMD at the lumbar spine and femoral neck using dual energy X‐ray absorptiometry, and serum TSH concentrations using immunoluminometry. Results BMD at the lumbar spine and femoral neck increased with TSH level ( P for trend < 0·001 at both sites). Even after adjustment for age, years since menopause and body mass index, subjects with low normal TSH levels (0·5–1·1 mU/l) had significantly lower BMDs at the lumbar spine (0·863 ± 0·009 g/cm 2 vs 0·900 ± 0·009 g/cm 2 , P = 0·004) and femoral neck (0·660 ± 0·006 g/cm 2 vs 0·683 ± 0·006 g/cm 2 , P = 0·006) than those with high normal TSH levels (2·8–5·0 mU/l), as well as a 2·2‐fold increased risk of osteoporosis (95% confidence interval: 1·2–4·0). Conclusion These results suggest that low normal TSH levels may not be physiological for postmenopausal women and, during treatment of hypothyroidism, may not be adequate for avoiding osteoporosis.