Low normal TSH levels are associated with increased osteoporosis risk and decreased BMD in Chinese men

Previous studies have suggested that serum thyroid-stimulating hormone (TSH) plays an important role in bone metabolism. However, the results are controversial, and little is known about the Chinese. The aim of the study was to investigate the association of serum TSH levels with bone mineral density (BMD) and the prevalence of osteoporosis in the Chinese population with normal thyroid function. A total of 1,912 participants, including 1,366 men and 546 women, were enrolled in our study. BMD was measured by using quantitative computed tomography in the spine. Sex-specific multivariable logistic regression models were performed to estimate the odds ratios ( OR s) and 95% confidence intervals ( CI s), adjusted for age, systolic blood pressure, body mass index, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and fasting plasma glucose. In men, those in lower TSH quartiles had lower BMD than participants in the other quartile groups ( P < 0.05 for trend). Compared with the fourth quartile of TSH, men in the lowest TSH quartile had significantly higher odds of osteoporosis ( OR = 2.62, 95% CI : 1.16 to 5.88). After adjustment for covariates, a significant dose-response relationship between BMD and TSH was observed across quartiles ( P for trend = 0.02). No significant association was found between TSH level and BMD or osteoporosis in women. Our findings indicated that lower serum TSH concentrations within the normal range were associated with a higher prevalence of osteoporosis and poorer BMD levels in men. Low-normal TSH levels may serve as a potential indicator for osteoporosis risk assessment in men.