Correlation Of Plasma Inactive Matrix Gla Protein With Osteoporosis In Patients With Type 2 Diabetes Mellitus

Background AND Objective:Type 2 diabetic osteoporosis is one of the common and serious chronic complications of diabetes mellitus and a growing number of researches suggests that osteoporosis is mainly due to a decrease in bone mass leading to increased bone fragility and fracture risk.Matrix Gla protein（MGP）is a non-collagenous protein of the bone matrix and has previously been found to be associated with osteoporosis and bone loss.In this study we will investigate the association of plasma inactive MGP（dp-uc MGP）with osteoporosis in type 2 diabetes.Methods:In this study,we enrolled patients from September 2019 to September 2020 in Department of Endocrinology and Metabolism of the Second Affiliated Hospital of Nanchang University,and screening for T2DM in menopausal women or men aged>50years.The area bone mineral density（a BMD）measured by dual-energy X-ray absorptiometry（DXA,US）was divided into normal bone mass group（n=41）,osteopenia group（n=50）and osteoporosis group（n=24）.The results showed that the plasma dp-uc MGP content was significantly higher in the osteoporosis group than that of the normal group and the low bone mass group.The general condition,biochemical indexes and bone metabolism indexes were compared among the three groups,and plasma dp-uc MGP levels were measured by double antibody sandwich enzyme-linked immunosorbent assay（ELISA）.To analyze the relationship between plasma dp-uc MGP and type 2 diabetic osteoporosis,R version 3.4.3 and Empowerstates were used for statistical analysis.Bilateral P<0.05 was considered statistically significant.Results:1.A total of 131 patients with T2DM were included in this study,of whom 115underwent DXA examination.41 in the normal group,with a mean age of 57.85±9.55years and 63.41%males;50 in the low bone mass group,with a mean age of 65.12±9.28 years and 40%males;and 24 in the osteoporosis group,with a mean age of 69.50±8.65 years and 8.33%males.2.There was no significant difference in T2DM cycles,FPG,Hb A1c,25（OH）VD₃,PTH,and adjusted Ca levels among the three groups（P>0.05）,but age,gender,weight,height,BMI,DBP,smoking,and alcohol consumption were among the three groups,HDL,E2,and s UA were significantly different（P<0.05）.Compared with the normal group,the low bone mass group and the osteoporosis group had higher CTX,BGP,and lower serum phosphorus,the difference was significant（P<0.05）.3.After gender grouping the two groups showed that the content of female dp-uc MGP was higher than that of male,the difference was not significant（P>0.05）.BMI,25（OH）D₃,s UA,lumbar L2-L4,HP and FN BMD were lower in women than in men,and PINP,CTX and BGP were higher than in men,and the differences were statistically significant（P<0.05）.After dp-uc MGP was divided into three equal parts,it was found that FPG,s UA,HOMA2-IR and lumbar L2-L4 BMD were significantly different among the three groups（P<0.05）.4.After adjusting for age and gender factors,it was found that log10 dp-uc MGP was significantly correlated with E2 and s UA（P<0.01）.At the same time,it was found that log10 dp-uc MGP was correlated with the BMD of the lumbar spine.The same results were not found with BMD in other parts.5.A linear relationship between dp-uc MGP and BMD without curve inflection was found by smoothing the curve,and this result was only significantly different for lumbar spine BMD（P<0.01）.Multiple regression analysis after adjusting for covariates revealed that for each unit increase in log10 dp-uc MGP,lumbar spine BMD decreased by 0.41 g/cm2 and L2-L4.T values decreased by 0.05（P<0.01）.Compared to the normal bone group,log10 dp-uc MGP increased by 0.12 units in the low bone mass group（P<0.05）and by 0.14 units in the osteoporosis group（P>0.05）.6.Subgroup analysis revealed a fixed negative correlation between dp-uc MGP and lumbar spine BMD after correction for different models（P<0.01）.When dp-uc MGP was trisected,in the fully corrected model（model 3）,the T3 correctedβwas-0.23（-0.38,-0.09）compared to T1（P<0.01）and the P trend was significant for all models（P for trend<0.01）,suggesting a dose-response relationship.Subgroup analysis revealed a more significant correlation between increased dp-uc MGP levels and decreased lumbar spine BMD in middle-aged and older men with T2DM than in postmenopausal women.Conclusion:In this study,we found for the first time that plasma dp-uc MGP levels in patients with type 2 diabetes are negatively correlated with lumbar bone mineral density,especially in middle-aged and elderly men.