Low TSH Levels Within Euthyroid Range Could Play a Negative Role on Bone Mineral Density in Postmenopausal Women with Type 2 Diabetes

Abstract

Objective: We aimed to evaluate the relationship between thyroid-stimulating hormone (TSH) and bone mineral density (BMD) in euthyroid type 2 diabetes (T2D). Methods: This retrospective analysis enrolled 439 T2D patients with normal thyroid function, including 226 males and 213 females. All the female patients were postmenopausal. Serum glycosylated hemoglobin A1c (HbA1c), TSH, free triiodothyronine (FT 3 ), and free thyroxine (FT 4 ) concentrations were analyzed. BMD of the lumbar spine (L 1 -L 4 ), femoral neck, and hip joint was determined using dual-energy X-ray absorptiometry. Results: The patients were grouped based on tri-sectional quantiles of the TSH levels: 0.55~1.70mIU/L (Group 1), 1.71~2.58mIU/L (Group 2), and 2.59~4.74mIU/L (Group 3). Our data showed that, in male patients, no difference in BMD was identified among groups. In postmenopausal women, unlike at the lumbar spine (P = 0.459), the mean BMD at the femoral neck (P = 0.014) and hip joint (P = 0.014) had a statistical difference among groups and increased with TSH level. In addition, our analysis demonstrated that TSH levels shown no correlation with BMD at all sites in males. However, in females, BMD at the femoral neck (r = 0.156, P = 0.023) and hip joint (r = 0.172, P = 0.012) had a positive correlation with TSH levels. After adjusting for age and BMI, multiple regression analysis showed that TSH levels influenced BMD at the femoral neck (β = 0.188, P = 0.001) and hip joint (β = 0.204, P = 0.001) in female patients. Conclusion:In summary, our data demonstrates that low TSH levels are associated with decreased BMD at the femoral neck and hip joint in postmenopausal T2D women with euthyroidism.

The Comparative Study on the Status of Bone Metabolism and Thyroid Function in Diabetic Patients with or without Ketosis or Ketoacidosis

“…According to one of our published studies, thyroid hormones and TSH may influence bone transformation in postmenopausal women. 40 This concept was also supported by multilinear regression analyses in this recent study, which found that the level of FT3 could predict the status of N-MID.…”

High-normal free thyroxine level is related with decreased bone mineral density in nonobese male patients with type 2 diabetes over 50 years old

“…[22][23][24] A retrospective study from Shanghai also showed that low-normal TSH levels were associated with decreased BMD at the femoral neck and hip joint in postmenopausal T2DM women. 14 However, their subjects had a higher BMI of over 25 kg/m 2 and an older age of over 65 in average. On the other hand, Hwangbo's team from Korea reported the negative correlation of high-normal free T4 and trabecular bone scores in postmenopausal women, and TSH levels were not related to trabecular bone scores in either gender.…”

“…A recent retrospective study from Shanghai including 226 male and 213 female subjects aged over 65 years old showed that low TSH levels within euthyroid range are associated with decreased BMD at the femoral neck and hip joint in postmenopausal T2DM women. 14 However, the impact of obesity on BMD was neglected in the analysis. Another prospective cohort study conducted in Brazil claimed that the thyroid hormone profile was not associated with variations in BMD and body composition after 1 year follow-up in euthyroid healthy women who were both normal weight and overweight.…”

Effect of Thyroxine and Thyrotropin on Bone Mineral Density in Postmenopausal Women: A Systematic Review

“…However, this study was small enough to have this conclusion [ 21 ]. Also, a study demonstrated a significant difference in both FN and hip BMD between low and high TSH level groups [ 27 ]. On the other hand, one study identified a significant difference in TSH levels between osteoporosis and normal groups.…”