Correlation Between Serum 25-hydroxyvitamin D And Lipid Metabolism Index In Middle-aged And Elderly Patients With Subclinical Hypothyroidism

Subclinical hypothyroidism(SCH)is a common endocrine and metabolic disease.Its onset is insidious and it is the early stage of hypothyroidism.If it is not treated in time,it will develop into hypothyroidism.Thyroxine is involved in many metabolic processes in the body,such as glucose metabolism,lipid metabolism,and energy metabolism.SCH increases the incidence and mortality of coronary heart disease,and it is speculated that it has a certain relationship with blood lipid metabolism.Studies have shown that SCH patients with elevated serum thyroid stimulating hormone(TSH)levels,showing elevated low-density lipoprotein cholesterol(LDL-C)and total cholesterol(TC)levels,decreased high-density lipoprotein cholesterol(HDL-C)levels.However,the results about the correlation with the components of blood lipids are not very consistent.In addition to regulating calcium-phosphorus metabolism and maintaining bone health,vitamin D(VitD)also has a wider range of extra-osseous biological effects.Besides,studies have suggested that hyperhomocysteinemia is an independent risk factor for cardiovascular and cerebrovascular disease,and the occurrence of SCH is associated with hyperhomocysteinemia and blood lipids.In recent years,it has been demonstrated that blood lipids are associated with low serum VitD levels and hyperhomocysteinemia.Objective:Aim to explore serum 25-hydroxyvitamin D[25(OH)D] levels in middle-aged and elderly patients with SCH and investigate the relationship with lipid metabolism.Furthermore,to analyze SCH related risk factors and the influence mechanism within them,providing clinical basis for the prevention and treatment of SCH.Methods:The middle-aged and elderly SCH patients who were admitted to the Endocrinology Department of the First Central Hospital of Baoding City from December 2017 to June 2018 was collected as the SCH group(n=100)in chronological order.The healthy subjects during the same period were the normal control group(NC,n=70).SCH patients were further divided into VitD-sufficient group,insufficient group,and lacked group according to 25(OH)D levels.Comparison of 25(OH)D,blood lipid index,homocysteine(Hcy),TSH,thyroglobulin antibody(TGAb),thyroid peroxidase antibody(TPOAb),renal function,liver function,blood phosphorus,blood calcium levels within groups were meatured,and analysis of the correlation of these indicators with 25(OH)D were conducted,respectively.Results:1.The level of 25(OH)D in the SCH group was lower than that in the NC group.The levels of TC,TG,LDL-C,VLDL-C,TSH,Hcy,TGAb and TPOAb were higher than those in the NC group.The differences of the indicators above between the two groups were statistically significant,respectively(P<0.05).2.There were significant differences of TG,LDL-C,Hcy and TSH levels within the VitD-sufficient group,insufficient group,and lacked group(P<0.05).3.After Pearson correlation analyses,the results showed that VitD level was negatively correlated with TG,LDL-C,Hcy and TSH levels(r=-0.38,-0.57,-0.85,-0.67,respectively,P <0.05).4.After multiple linear regression analyses,the results showed that TG,VLDL-C,25(OH)D,Hcy levels were relevant influencing factors to SCH patients(t=3.21,-2.26,-6.27,7.43,respectively,P <0.05).Conclusion:1.Middle-aged and elderly SCH patients had lower 25(OH)D levels,and higher TC、TG、LDL-C、VLDL-C and Hcy levels when compared to the NC group.2.Blood lipids and Hcy levels were significantly different in middle-aged and elderly SCH patients with different VitD levels.The more abundant the VitD,the lower the LDL-C,TG,and Hcy levels.3.Changes of TG,LDL-C,Hcy,and TSH levels in middle-aged and elderly SCH patients may have an effect on 25(OH)D levels.