强直性脊柱炎患者骨密度与骨代谢异常的研究

The relation between bone mineral density and bone turnover markers in ankylosing spondylitis patients

目的 探讨AS患者骨质疏松的发生情况并分析与骨代谢指标之间的相关性.方法 选择在安徽省立医院风湿免疫科就诊的AS患者46例,同时选取年龄、性别相匹配的健康对照25名,详细记录AS患者的临床资料;双能X线吸收法测定腰椎（L2-4）及股骨颈、桡骨的骨密度;AS患者骨代谢指标总Ⅰ型前胶原氨基端延长肽（PINP）和骨钙素采用放射学免疫测定法,β胶原特殊序列采用电化学发光法测定.2组资料符合正态分布采用独立样本t检验,多组之间比较采用方差分析,不符合正态分布采用非参数秩和检验,计数资料采用x3检验,2组数据间的相关性采用Pearson或Spearman相关分析.结果 ①AS组腰椎骨质减少发生率48％（22例）,明显高于对照组20％（χ^2=5.32,P=0.021）;AS组腰椎、股骨颈、桡骨骨密度均较对照组明显减低（t=-3.73,-3.68,-5.24; P＜0.05）;②AS晚期腰椎骨密度较早期升高（t=2.26,P=0.034）,股骨颈骨密度差异无统计学意义.③早晚期患者血清中PINP、骨钙素及β胶原特殊序列差异无统计学意义（P＞0.05）.④腰椎骨密度与β胶原特殊序列、ESR呈负相关（r=-0.325,P=0.047;r=-0.314,P=0.046）;股骨颈骨密度与β胶原特殊序列、骨钙素呈负相关（r=-0.387,P=0.024;r=-0.371,P=0.034）,与病程、Bath AS疾病活动指数（BASDAI）等指标无相关性.结论 AS患者存在骨量减少,以腰椎的发生率最高;β胶原特殊序列可能成为预测AS骨量减少的有价值指标.

Objective To study the pathophysiology of ankylosing spondylitis （AS）-related osteoporosis by investigating the relation between bone mineral density （BMD） and bone turnover markers.Methods Fortysix AS patients were included in this study,including 35 male and 11 female patients.Twenty-five gender and age matched healthy subjects were served as the healthy control group.Informed consents were obtained from all subjects.BMD of lumbar spine （L2-4）,fermoral neck and radius were tested using dual-energy X-ray absorption method.Data about BASDAi,ESR,Ig was collected.Bone formation markers including procollagen type Ⅰ N-terminal peptide （PINP） and osteocalcin （OC） were included for analysis,the formal was measured by radioimmunoassay and the later was measured by immunoradiometric assay and bone resorption marker.β-Crosslaps was measured by electrochemiluminescence immunoassay.Independent-samples t test was used to compare normal distributed data between the two groups.Analysis of variance was used to compare the data between the three groups.For those data which were not normally distributed,Rank sum test was performed.Correlations were determined by Pearson or Spearman＇s ranking.Results ① 48% of AS patients had bone loss,while the percentage in the healthy control group was 20% （χ^2=5.32,P=0.021）.BMD of lumbar spine,fermoral neck and radius of the AS patients were lower than the controls （t=-3.73,-3.68,-5.24; P〈0.05）.② Bone density （BMD） of lumbar spine in patients at the late stage was higher than patients at early disease stage （t=2.26,P=0.034）,however,the BMD in the femoral neck was not.③ The procollagen （PINP）,OC and β-CrossLaps were not significantly different in patients at different stage of diseases （P〉0.05）.④BMD of lumbar spine was negatively correlated with the β-CrossLaps and ESR（r=-0.325,P=0.047; r=-0.314,P=0.046）,The BMD in fermoral neck was negatively correlated with β-CrossLaps and OC （r=-0.387,P=0.024; r=-0.371,P=0.034）,but they were not correlated with disease duration and BADSAI.Conclusion Osteoporosis is common in AS.Bone turnover markers including bone formation and bone resorption are increased in AS.β-CrossLaps is likely to predict bone loss in AS.