Relationship between circulating tumor necrosis factor system and bone mass before and after estrogen plus progestogen therapy

OBJECTIVE: The aim of his study was to investigate the relationship between the circulating tumor necrosis factor (TNF) system and bone mineral density (BMD) before and after estrogen plus progestogen therapy (EPT). METHODS: Serum levels of TNF-α, TNF-β, soluble TNF receptor (sTNFR) 1, sTNFR2, and bone turnover markers and BMDs at the lumbar spine and proximal femur were measured in 192 postmenopausal Korean women. Among all women, 70 were treated with sequential EPT for 1 year. RESULTS: BMDs at all skeletal sites and bone turnover markers were not correlated with serum TNF and sTNFR. After adjustment for age, years since menopause, and body mass index, serum TNF-β levels were significantly lower in osteoporotic women than in normal women, whereas serum levels of TNF-α and sTNFR did not differ among normal, osteopenic, and osteoporotic postmenopausal women. After 6 months of EPT, serum TNF-β levels increased significantly (P < 0.05), whereas serum TNF-α, sTNFR1, and sTNFR2 levels were unchanged. The 1-year changes in BMD at the lumbar spine and proximal femur after EPT were not correlated with the basal levels of serum TNF-α and sTNFR and their changes 6 months after EPT. CONCLUSIONS: In the circulating TNF system, only serum TNF-β levels were lower in osteoporotic postmenopausal women compared with normal postmenopausal women and increased after EPT, but changes in circulating TNF and sTNFR after EPT had no association with changes in bone markers and BMD. The circulating TNF system may not be clinically useful for predicting BMD and bone response after EPT.