High-resolution Peripheral Quantitative Computed Tomography for the Assessment of Bone Strength and Structure in Obstructive Sleep Apnea Patients

Abstract

Objective To evaluate the bone strength and structure of patients with obstructive sleep apnea(OSA)by the high-resolution peripheral quantitative computed tomography(HR-pQCT)and to explore the relationship between OSA and osteoporosis. Methods Male patients who visited the Sleep Respiratory Center of our hospital from August 2017 to January 2019 were consecutively recruited.Clinical data including the results of Epworth sleep scale(ESS)scoring and overnight polysomnography were collected.HR-pQCT was used to compare the differences in bone geometry,density,and microstructure between OSA patients and non-OSA people;also,the radius and tibia on the non-dominant side were measured to explore the relationship between OSA and osteoporosis. Results A total of 83 subjects were enrolled in the study.The number of patients in the mild,moderate,and severe OSA groups and non-OSA group were 21,18,34,and 10,respectively.There was no significant difference in age,blood pressure,ESS score,sleep stage,and sleep efficiency among these four groups(P>0.05).Body mass index(BMI)and neck circumference were significantly different among these groups(F=4.234,P=0.008;F=3.100,P=0.031).There was no significant difference in the radius indicators(P>0.05).For tibia,there were significant differences among the four groups in the cortical area(Ct.Ar)(F=3.937,P=0.011).There were also significant differences in the bone microstructural indicators including trabecular thickness(Tb.Th)and cortical thickness(Ct.Th)(F=6.247,P=0.001;F=3.746,P=0.014),which were significantly lower in the three OSA groups than in the control group.Pairwise comparisons showed that the Ct.Ar in the severe OSA group was significantly higher than that in the mild OSA group(P=0.019)and Tb.Th in the control group was significantly higher than those in the mild and moderate OSA groups(P=0.006,P=0.001).Correlation analysis showed that,within a certain range,total volumetric bone mineral density(Tt.vBMD)and Tb.Th of radius and tibia were negatively correlated with age(r=-0.312,P=0.004;r=-0.328,P=0.002;r=-0.265,P=0.015;r=-0.280,P=0.010)and positively correlated with BMI(r=0.240,P=0.029;r=0.369,P=0.004;r=0.299,P=0.006;r=0.416,P=0.010).Stepwise multiple regression analysis showed that Tb.Th of radius and tibia were mostly correlated with BMI(β=0.262,P=0.008,R 2=0.243,F=6.270,P=0.000;β=0.494,P=0.000,R 2=0.186,F=7.243,P=0.000)and age(β=-0.216,P=0.030,R 2=0.243,F=6.270,P=0.000;β=-0.306,P=0.003,R 2=0.186,F=7.243,P=0.000).Tt.vBMD of radius had a certain correlation with sleep efficiency and with the decreasing nocturnal mean oxygen saturation caused by OSA(β=0.312,P=0.002, β=-0.249,P=0.012,R 2=0.327,F=7.482,P=0.000). Conclusions In non-elderly male populations,OSA mainly causes a decrease in Tb.Th and Ct.Th of the tibia.The changes in bone strength and structure are mainly related with age and body size and also have certain correlations with sleep efficiency and with the decreasing nocturnal mean oxygen saturation caused by OSA.