Analysis Of The Relationship Between 25 (OH) D?FGF-23 And Bone Metabolism In Young Adult Patients With Graves' Disease

Objective:Hyperthyroidism is one of the common endocrine disease caused secondary osteoporosis. With the introduction of new diagnostic techniques in recent years,people begin to pay more attention to the effect of hyperthyroidism on bone metabolism. There are few studies on bone metabolism in young adult patients with Graves disease, and the effect of sex hormone on bone metabolism can be excluded.So our study selected young adult patients with GD and analyzed the characteristics of their bone metabolism. Fibroblast growth factor-23(FGF-23) is a new type of regulation of phosphorus metabolism of cytokine found in the recent years. Many diseases are accompanied by changes in the FGF-23. Hyperthyroidism is a well-described cause of hyperphosphatemia, therefore we clarify the change of FGF-23 and the role of serum phosphorus homeostasis in patients with GD. At the same time, we evaluate the vitamin D status and the relationship between vitamin D and bone mineral homeostasis and BMD in young adult patients with GD. The new ideas and methods for the diagnosis and treatment of hyperthyroidism osteopathy are provided.Methods:69 young adult patients with GD were involved(male, n=17,age: 38.47±6.27,less than 50 years old;female, n=52,age: 37.50±8.59,menstruation normal and less than 50 years old) as GD group. In addition, 35 healthy subjects were recruited(male,n=8,age: 37.67±7.35;female, n=27,age: 39.05±7.55,menstruation normal)as control group, matched age, sex with GD group. All subjects were detected free thyroid function, blood routine, blood calcium, blood phosphorus, parathyroid hormone, 25(OH) D and FGF-23. BMD of lumbar vertebra(L1-L4), femoral neck and total hip were measured by dual-energy X-ray absorption. Compared the difference of each parameter between GD group and control group. According to the 2012 International Osteoporosis Foundation(IOF) in the diagnosis of osteoporosis in young adult patients with hyperthyroidism, the patients with GD were divided into the normal bone mass group and the abnormal bone mass group(including osteoporosis and osteopenia, osteoporosis due to fewer), compared the levels of the various parameters between the two groups. According to the application guideline for vitamin D and bone health in adult chinese( 2014 Standard Edition), the patients with GD were divided into three groups. In the end, the correlation between 25(OH)D, FGF-23 and thyroid function, serum calcium and phosphorus, PTH, bone mineral density were analysed.Results:1?Serum concentration of FT3?FT4?P?PTH and FGF-23 in GD group were significantly higher than control group, TSH and 25(OH)D lower than control group(P<0.05).2?BMD of L1, L2, L3, L4 and L1-L4 in female patients with GD were significantly lower than that of the female control group(P < 0.05), femoral neck and total hip BMD also decreased, but the difference was not statistically significant; There was no significant difference in BMD of L1-L4, femoral neck and total hip between the two groups in male; BMD of L1-L4, femoral neck and total hip in female patients with GD were significantly lower than male patients with GD(P<0.01).3 ? In young adult patients with GD, BMI in abnormal bone mass group was significantly lower than normal bone mass group,FT3 and FT4 were higher than bone mass group(P<0.05); Serum concentration of Ca, P, PTH and FGF-23 were also increased and 25(OH) D was reduced in the abnormal bone mass group, but there was no significant difference between the two groups.4?In GD patients,the incidence of abnormal bone mass in female patients(42.31%)was greater than that male(17.65%). The incidence of abnormal bone mass femoral neck and total hip(26.09%)were greater than that L1-L4(17.39%),but there was no significant difference between the two groups.5?In GD patients, there were no significant differences in BMD of L1-L4, femoral neck and total hip between different groups of vitamin D.6?In GD patients, the level of 25(OH)D was negatively correlated with the level of FT3, FT4 and PTH(P < 0.05),and not correlated with age, BMI,TSH, Ca,Pi,FGF-23 and BMD of L1-L4, femoral neck and total hip. A significant positive correlation was between FGF-23 and serum Pi(P < 0.01), no correlation with other indicators.Conclusion:1?Thyroid hormone in young adult patients with GD is involved in the development of osteopenia / osteoporosis, and thyroid stimulating hormone do not participate in this process.2?Body mass index is one of the factors that affect the bone mass in patients with GD,and there is no correlation between duration and bone mass.3?Young adult patients with GD prone to bone loss. The decline in bone mass of female patients is more obvious, so once the diagnosis of GD, especially in female patients, it should be a comprehensive assessment of BMD and bone metabolism.4?In young adult patients with GD, Vitamin D deficiency is prevalent,and 25(OH) D deficiency might be involved in the occurrence of Graves disease.5?The level of 25(OH) D was not directly related to the changes of bone mineral density, which indicated 25(OH) D might be through regulating the level of PTH indirectly affected the bone metabolism of GD patients.6?In young adult patients with GD, FGF-23 plays an important role in the regulation of the phosphorus homeostasis and increased serum phosphate may be associated with a compensatory rise in circulating FGF-23 level, in a manner the increase of FGF-23 would enable phosphate homeostasis.