Vertebral Fractures and Role of Low Bone Mineral Density in Crohn’s Disease
2007; Elsevier BV; Volume: 5; Issue: 6 Linguagem: Inglês
10.1016/j.cgh.2007.02.024
ISSN1542-7714
AutoresJesse Siffledeen, Kerry Siminoski, Ho Jen, Richard N. Fedorak,
Tópico(s)Vitamin D Research Studies
ResumoBackground & Aims: Vertebral fractures in Crohn's (CD) patients with low bone mineral density (BMD) have been documented as between 14%–22%. Vertebral fractures in CD patients with normal BMD have not been reported. The objectives were to identify the prevalence of vertebral fractures in CD patients and associated predictive factors. Methods: Two hundred twenty-four CD patients underwent vertebral BMD analysis and radiographs. Fractures were identified by using quantitative height reduction morphometry, and severity was assessed by spinal fracture index. Results: Mean age was 40.6 ± 11.0 years. Sixty percent reported corticosteroid use during the preceding year. Forty-five of 224 (20.0%) patients had 88 vertebral fractures. Sixteen of 45 patients with vertebral fractures had normal BMD (19.0% of all patients with normal BMD). Analysis of patients with or without vertebral fractures did not demonstrate significant differences in BMD or in corticosteroid use. Linear regression analysis demonstrated that elevations in body mass index, C-reactive protein, and parathyroid hormone were significantly predictive of vertebral fractures (r = 0.415, P < .05), and height reduction was >20% (r = 0.417, P < .05). Conclusions: This study demonstrates that vertebral fractures in CD patients occur with an equal frequency in those with low and with normal BMD, regardless of corticosteroid use. The mean age of CD patients with vertebral fractures was much lower than that reported in the general population for these fractures. Elevations in body mass index and C-reactive protein and parathyroid hormone levels were predictive of vertebral fractures. Background & Aims: Vertebral fractures in Crohn's (CD) patients with low bone mineral density (BMD) have been documented as between 14%–22%. Vertebral fractures in CD patients with normal BMD have not been reported. The objectives were to identify the prevalence of vertebral fractures in CD patients and associated predictive factors. Methods: Two hundred twenty-four CD patients underwent vertebral BMD analysis and radiographs. Fractures were identified by using quantitative height reduction morphometry, and severity was assessed by spinal fracture index. Results: Mean age was 40.6 ± 11.0 years. Sixty percent reported corticosteroid use during the preceding year. Forty-five of 224 (20.0%) patients had 88 vertebral fractures. Sixteen of 45 patients with vertebral fractures had normal BMD (19.0% of all patients with normal BMD). Analysis of patients with or without vertebral fractures did not demonstrate significant differences in BMD or in corticosteroid use. Linear regression analysis demonstrated that elevations in body mass index, C-reactive protein, and parathyroid hormone were significantly predictive of vertebral fractures (r = 0.415, P < .05), and height reduction was >20% (r = 0.417, P < .05). Conclusions: This study demonstrates that vertebral fractures in CD patients occur with an equal frequency in those with low and with normal BMD, regardless of corticosteroid use. The mean age of CD patients with vertebral fractures was much lower than that reported in the general population for these fractures. Elevations in body mass index and C-reactive protein and parathyroid hormone levels were predictive of vertebral fractures. Minimal trauma vertebral fractures are an important clinical consequence of low bone mineral density (BMD). In the healthy adult population, these low energy fractures occur almost exclusively among those older than 50 years of age and/or those with abnormal BMD. However, patients with CD have a higher prevalence of osteopenia and osteoporosis, with reports of frequencies up to 55% and 57%, respectively.1Habtezion A. Silverberg M.S. Parkes R. et al.Risk factors for low bone density in Crohn's disease.Inflamm Bowel Dis. 2002; 8: 87-92Crossref PubMed Scopus (112) Google Scholar, 2Dinca M. Fries W. Luisetto G. et al.Evolution of osteopenia in inflammatory bowel disease.Am J Gastroenterol. 1999; 94: 1292-1297Crossref PubMed Scopus (98) Google Scholar, 3Compston J.E. Judd D. Crawley E.O. et al.Osteoporosis in patients with inflammatory bowel disease.Gut. 1987; 28: 410-415Crossref PubMed Scopus (292) Google Scholar, 4Ardizzone S. Bollani S. Bettica P. et al.Altered bone metabolism in inflammatory bowel disease: there is a difference between Crohn's disease and ulcerative colitis.J Intern Med. 2000; 247: 63-70Crossref PubMed Scopus (157) Google Scholar, 5Dressner-Pollak R. Karmeli F. Eliakim R. et al.Femoral neck osteopenia in patients with inflammatory bowel disease.Am J Gastroenterol. 1998; 93: 1483-1490Crossref PubMed Scopus (192) Google Scholar, 6Jahnsen J. Falch J.A. Aadland E. et al.Bone mineral density is reduced in patients with Crohn's disease but not in patients with ulcerative colitis: a population based study.Gut. 1997; 40: 313-319PubMed Google Scholar, 7Robinson R.J. Al Azzawi F. Iqbal S.J. et al.Osteoporosis and determinants of bone density in patients with Crohn's disease.Dig Dis Sci. 1998; 43: 2500-2506Crossref PubMed Scopus (122) Google Scholar, 8Bjarnason I. Macpherson A. Mackintosh C. et al.Reduced bone density in patients with inflammatory bowel disease.Gut. 1997; 40: 228-233PubMed Google Scholar, 9Schoon E.J. Van Nunen A.B. Wouters R.S.M.E. et al.Osteopenia and osteoporosis in Crohn's disease: prevalence in a Dutch population-based cohort.Scand J Gastroenterol. 2000; 35: 43-47Crossref Scopus (22) Google Scholar, 10Schulte C. Dignass A. Mann K. et al.Reduced bone mineral density and unbalanced bone metabolism in patients with inflammatory bowel disease.Inflamm Bowel Dis. 1998; 4: 268-275PubMed Google Scholar, 11Siffledeen J. Fedorak R.N. Siminoski K. et al.Bones and Crohn's: analysis of risk factors associated with low bone mineral density in patients with Crohn's disease.Inflamm Bowel Dis. 2004; 10: 220-228Crossref PubMed Scopus (68) Google Scholar Furthermore, the average age of CD patients with osteoporosis is significantly lower than that seen in the general population.11Siffledeen J. Fedorak R.N. Siminoski K. et al.Bones and Crohn's: analysis of risk factors associated with low bone mineral density in patients with Crohn's disease.Inflamm Bowel Dis. 2004; 10: 220-228Crossref PubMed Scopus (68) Google Scholar Two studies have examined the relationship of CD patient BMDs (assessed by dual energy X-ray absorptiometry [DXA]) to vertebral fracture prevalence (investigated by direct radiography). The first study did not identify a correlation between BMD and fractures, but it did report a 14.2% frequency of asymptomatic vertebral fractures in 272 CD patients with a mean age of 37.2 years.12Stockbrugger R.W. Schoon E.J. Bollani S. et al.Discordance between the degree of osteopenia and the prevalence of spontaneous vertebral fractures in Crohn's disease.Aliment Pharmacol Ther. 2002; 16: 1519-1527Crossref PubMed Scopus (90) Google Scholar Interestingly, 55% of these CD patients with vertebral fractures had normal BMD.12Stockbrugger R.W. Schoon E.J. Bollani S. et al.Discordance between the degree of osteopenia and the prevalence of spontaneous vertebral fractures in Crohn's disease.Aliment Pharmacol Ther. 2002; 16: 1519-1527Crossref PubMed Scopus (90) Google Scholar The second study of 293 CD patients screened for osteopenia or osteoporosis (T score ≤ −1) reported a 22% frequency of asymptomatic vertebral fractures among patients with low BMD, with approximately one third of patients being younger than 30 years.13Klaus J. Armbrecht G. Steinkamp M. et al.High pervalence of osteoporotic vertebral fractures in patients with Crohn's disease.Gut. 2002; 51: 654-658Crossref PubMed Scopus (170) Google Scholar However, this second study did not assess vertebral fractures for those CD patients with normal BMD. Long-range data comparing fractures experienced by CD patients with those of age-matched and gender-matched controls have yielded conflicting results. Four population-based, retrospective studies reported only a slightly increased incidence of spinal fractures (incidence rate ratio, 1.29–2.2), and one of these studies reported that the incidence failed to reach statistical significance when compared with healthy controls.14Loftus E.V.J. Crowson C.S. Sandborn W.J. et al.Long term fracture risk in patients with Crohn's disease: a population-based study in Olmsted County, Minnesota.Gastroenterology. 2002; 123: 468-475Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar, 15Van Staa T.-J. Cooper C. Brusse L.S. et al.Inflammatory bowel disease and the risk of fracture.Gastroenterology. 2003; 125: 1591-1597Abstract Full Text Full Text PDF PubMed Scopus (202) Google Scholar, 16Bernstein C.N. Blanchard J.F. Leslie W. et al.The incidence of fracture among patients with inflammatory bowel disease.Ann Intern Med. 2000; 133: 795-799Crossref PubMed Scopus (401) Google Scholar, 17Vestergaard P. Mosekilde L. Fracture risk in patients with Celiac disease, Crohn's disease and ulcerative colitis: a nationwide follow-up study of 16, 416 patients in Denmark.Am J Epidemiol. 2002; 156: 1-10Crossref PubMed Scopus (269) Google Scholar This is in contrast to a questionnaire-based study that demonstrated a substantially increased risk of vertebral fractures for CD patients as compared with healthy controls (incidence rate ratio, 6.7).18Vestergaard P. Krogh K. Rejnmark L. et al.Fracture risk is increased in Crohn's disease, but not in ulcerative colitis.Gut. 2000; 46: 176-181Crossref PubMed Scopus (172) Google Scholar Current evidence suggests that bone mass and low BMD are among the most important and quantifiable clinical predictors of fracture risk in the general population.19Cooper C. O'Neill T. Silman A. The epidemiology of vertebral fractures.Bone. 1993; 14: S89-S97Abstract Full Text PDF PubMed Scopus (235) Google Scholar, 20Marshall D. Johnell O. Wedel H. Meta-analysis of how well measures of bone mineral density predict occurrence of osteoporotic fractures.Bone. 1996; 312: 1254-1259Google Scholar, 21Black D.M. Steinbuch M. Palermo L. et al.An assessment tool for predicting fracture risk in postmenopausal women.Osteoporos Int. 2001; 12: 519-528Crossref PubMed Scopus (417) Google Scholar, 22Kanis J. Borgstrom F. De Laet C. et al.Assessment of fracture risk.Osteoporos Int. 2005; 16: 581-589Crossref PubMed Scopus (943) Google Scholar, 23Delmas P.D. Genant H.K. Crans G.G. et al.Severity of prevalent vertebral fractures and the risk of subsequent vertebral and nonvertebral fractures: results from the MORE trial.Bone. 2003; 33: 522-532Abstract Full Text Full Text PDF PubMed Scopus (436) Google Scholar, 24Brown J.P. Josse R.G. 2002 clinical practice guidelines for the diagnosis and management of osteoporosis in Canada.CMAJ. 2002; 167: S1-S34PubMed Google Scholar, 25Papaioannou A. Joseph L. Brown J.P. et al.Risk factors associated with incident clinical vertebral and nonvertebral fractures in postmenopausal women: the Canadian Multicentre Osteoporosis Study (CaMos).Osteoporos Int. 2005; 16: 568-578Crossref PubMed Scopus (62) Google Scholar However, low BMD cannot, by itself, predict fracture risk, as evidenced by the fact that patients with vertebral fractures can have normal BMD at the time of diagnosis.26World Health OrganisationAssessment of fracture risk and its application to screening for postmenopausal osteoporosis: Technical Report Series 843. WHO, Geneva1994Google Scholar Therefore, age, low body mass index (BMI), family history of osteoporotic fractures, low calcium and vitamin D intake, and long-term use of corticosteroids are being investigated for their secondary effects on non-low BMD vertebral fractures.21Black D.M. Steinbuch M. Palermo L. et al.An assessment tool for predicting fracture risk in postmenopausal women.Osteoporos Int. 2001; 12: 519-528Crossref PubMed Scopus (417) Google Scholar, 22Kanis J. Borgstrom F. De Laet C. et al.Assessment of fracture risk.Osteoporos Int. 2005; 16: 581-589Crossref PubMed Scopus (943) Google Scholar, 27Kanis J.A. Johnell O. De Laet C. et al.A meta-analysis of previous fracture and subsequent fracture risk.Bone. 2004; 35: 375-382Abstract Full Text Full Text PDF PubMed Scopus (922) Google Scholar Studies examining risk factors associated with vertebral fractures in CD patients are limited in number and have focused primarily on risk associated with corticosteroid use.14Loftus E.V.J. Crowson C.S. Sandborn W.J. et al.Long term fracture risk in patients with Crohn's disease: a population-based study in Olmsted County, Minnesota.Gastroenterology. 2002; 123: 468-475Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar, 18Vestergaard P. Krogh K. Rejnmark L. et al.Fracture risk is increased in Crohn's disease, but not in ulcerative colitis.Gut. 2000; 46: 176-181Crossref PubMed Scopus (172) Google Scholar Nevertheless, a previous vertebral fracture in the general population has been demonstrated to increase the risk of a second vertebral fracture at least 4-fold.20Marshall D. Johnell O. Wedel H. Meta-analysis of how well measures of bone mineral density predict occurrence of osteoporotic fractures.Bone. 1996; 312: 1254-1259Google Scholar, 21Black D.M. Steinbuch M. Palermo L. et al.An assessment tool for predicting fracture risk in postmenopausal women.Osteoporos Int. 2001; 12: 519-528Crossref PubMed Scopus (417) Google Scholar, 25Papaioannou A. Joseph L. Brown J.P. et al.Risk factors associated with incident clinical vertebral and nonvertebral fractures in postmenopausal women: the Canadian Multicentre Osteoporosis Study (CaMos).Osteoporos Int. 2005; 16: 568-578Crossref PubMed Scopus (62) Google Scholar, 28Ross P.D. Davis J.W. Epstein R.S. et al.Pre-existing fractures and bone mass predict vertebral fracture incidence in women.Ann Intern Med. 1991; 114: 919-923Crossref PubMed Scopus (970) Google Scholar, 29Nevitt M.C. Ettinger B. Black D.M. et al.The association of radiographically detected vertebral fractures with back pain and function: a prospective study.Ann Intern Med. 1998; 128: 793-800Crossref PubMed Scopus (700) Google Scholar, 30Ettinger B. Black D.M. Mitlak B.H. et al.Reduction of vertebral fracture risk in postmenopausal women with osteoporosis treated with raloxifene: results from a 3-year randomized clinical trial: Multiple Outcomes of Raloxifene Evaluation (MORE) investigators.JAMA. 1999; 282: 637-645Crossref PubMed Scopus (3062) Google Scholar Similarly, CD patients have been identified as having an increased risk of fracture associated with a previous vertebral fracture diagnosis.17Vestergaard P. Mosekilde L. Fracture risk in patients with Celiac disease, Crohn's disease and ulcerative colitis: a nationwide follow-up study of 16, 416 patients in Denmark.Am J Epidemiol. 2002; 156: 1-10Crossref PubMed Scopus (269) Google Scholar Complicating the assessment of vertebral fractures is the fact that more than 70% go undetected.22Kanis J. Borgstrom F. De Laet C. et al.Assessment of fracture risk.Osteoporos Int. 2005; 16: 581-589Crossref PubMed Scopus (943) Google Scholar, 31Grigoryan M. Guermazi A. Roemer F.W. et al.Recognizing and reporting osteoporotic vertebral fractures.Eur Spine J. 2003; 12: S104-S112Crossref PubMed Scopus (137) Google Scholar, 32van Staa T.P. Dennison E.M. Leufkens H.G. et al.Epidemiology of fractures in England and Wales.Bone. 2001; 29: 517-522Abstract Full Text Full Text PDF PubMed Scopus (788) Google Scholar, 33Majumdar S.R. Kim N. Colman I. et al.Incidental vertebral fractures discovered with chest radiography in the emergency department: prevalence, recognition, and osteoporosis management in a cohort of elderly patients.Arch Intern Med. 2005; 165: 905-909Crossref PubMed Scopus (150) Google Scholar The primary objective of the current study was to identify the cross-sectional prevalence of vertebral fractures, by using 2 standardized and well-described measurement techniques, in a representative cohort of CD patients residing in Alberta, Canada. The secondary objective was to identify clinical and biochemical factors associated with these fractures. Two hundred twenty-four consecutively encountered patients who had either active or quiescent CD and who were attending the Inflammatory Bowel Disease Referral Clinic at the University of Alberta Hospital (Edmonton, Alberta, Canada) were identified as possible experiment participants between September 2000–July 2001. They completed a questionnaire documenting age, CD diagnosis date, gender, smoking status, and number of flare-ups requiring a visit to the physician and/or corticosteroid use during the preceding year. After a baseline BMD, patients were classified into 3 groups: normal bone density (T ≥ −1.0), osteopenia (−1.0 > T > −2.5), and osteoporosis (T < −2.5). At baseline, 70 of 224 patients (36%) had normal BMD. The remaining 154 of 224 patients (64%) had decreased BMD; 31 (13%) of this latter group had osteoporosis, and 123 (51%) had osteopenia. All patients were assessed for vertebral fractures by using anterior-posterior and lateral thoracic and lumbar spine radiographs. The following exclusion criteria were applied at baseline: age < 18 years, known bone disorders other than osteoporosis (such as hyperparathyroidism, Paget's disease, renal osteodystrophy, and documented osteomalacia), abnormal thyroid function, significant renal impairment (serum creatinine ≥ 2× normal), clinical short bowel syndrome, total parenteral or enteral nutrition feeding or supplementation, and spinal anatomies that did not allow adequate DXA assessment. In addition, patients were excluded if they had received (1) any bisphosphonate during the 24 months before the data collection program entry, (2) fluoride supplement during the 24 months before entry, (3) calcium supplements of more than 1.0 g/day during the 6 months before entry, or (4) vitamin D supplements greater than 1000 IU/day during the 6 months before entry. Postmenopausal women were not excluded from the study, and women using oral contraceptives or hormone replacement therapy were not excluded as long as the therapy had been initiated 3 months before baseline and was continued throughout the study period. The primary objective of this study was to identify the cross-sectional prevalence of vertebral fractures in a prospective cohort of CD patients. The secondary objective was to identify clinical, bone density, and biochemical factors associated with these fractures in an effort to find ways to better predict the risk of vertebral fractures for patients with CD. Blood samples were taken at baseline to determine the following serum values: serum alkaline phosphatase (IU/L), phosphorous (mmol/L), calcium (mmol/L), parathyroid hormone (PTH) (pmol/L), 25-OH vitamin D (nmol/L), albumin (g/L), sodium (mmol/L), potassium (mmol/L), chloride (mmol/L), creatinine (μmol/L), random glucose (mmol/L), platelet count (*109/L), white blood cell (WBC) count (*109/L), hemoglobin (g/L), total protein (g/L), magnesium (mmol/L), C-reactive protein (CRP) (mg/L), iron (μmol/L), total iron-binding capacity (μmol/L), ferritin (μg/L), carotene (μmol/L), vitamin B12 (pmol/L), RBC folate (nmol/L), testosterone (nmol/L), follicle-stimulating hormone (U/L), luteinizing hormone (U/L), estradiol (pmol/L), and thyroid-stimulating hormone (U/L). Urine samples were also collected for a 24-hour period at baseline to measure levels of N-telopeptide (nmol N-Telopeptides/mmol urine creatinine), a biochemical marker of bone resorption. BMD (g/cm2) of the lumbar spine (L1–L4), the left total hip and trochanteric region, and the right ultradistal radius was determined through DXA (Hologic 4500; Hologic Inc, Bedford, MA) by using standard protocols. All BMD measurements were completed on the same DXA machine. BMD values were normalized (to derive T scores and Z scores) by using the Hologic reference database. The coefficients of variation for the lumbar spine, total hip, and trochanter were 1.0%, 1.5%, and 0.9%, respectively.34Looker A.C. Orwoll E.S. Johnston C.C. et al.Prevalence of low femoral bone density in older US adults from NHANES III.J Bone Miner Res. 1997; 12: 1761-1768Crossref PubMed Scopus (947) Google Scholar Investigators (K.S., H.J.) who were blinded to the treatment allocation determined the BMD category for each subject by using the lowest T score of those taken from the lumbar spine (L1–L4 inclusive, unless there was a specific reason to exclude a given vertebra), total hip, trochanter, and ultradistal radius. Total body height was measured to the closest millimeter with a wall-mounted digital stadiometer (Holtain Ltd, Crymych, Dyfed, UK). Vertebral fracture analysis was assessed with 2 independent methods. First, quantitative morphometry was performed on radiographs of vertebrae T4–L4 by measuring 6 points on each vertebra to determine anterior, mid-vertebral, and posterior heights, as seen in lateral projection. Height reductions (HRs) for each vertebra were recorded as the lowest ratio of these measures as compared with the greatest posterior vertebral height. Vertebral deformities assessed according to this method were classified by HR into 4 categories: (1) >15%, (2) >20%, (3) >20% + 4 mm, and (4) >25%. A vertebra was considered to have a significant deformity if HR was reduced by more than 20%.35Melton III, L.J. Kan S.H. Frye M.A. et al.Epidemiology of vertebral fractures in women.Am J Epidemiol. 1989; 129: 1000-1011PubMed Google Scholar Second, semiquantitative analysis of vertebral fractures was performed according to the Genant semiquantitative method.36Ferguson S.J. Steffen T. Biomechanics of the aging spine.Eur Spine J. 2003; 12: S97-S103Crossref PubMed Scopus (162) Google Scholar, 37Kleerekoper M. Nelson D.A. Vertebral fracture or vertebral deformity.Calcif Tissue Int. 1992; 50: 5-6Crossref PubMed Scopus (79) Google Scholar, 38Genant H.K. Wu C.Y. Van Kuijk C. et al.Vertebral fracture assessment using a semiquantitative technique.J Bone Miner Res. 1993; 8: 1137-1148Crossref PubMed Scopus (2557) Google Scholar, 39Genant H.K. Jergas M. Palermo L. et al.Comparison of semiquantitative visual and quantitative morphometric assessment of prevalent and incident vertebral fractures in osteoporosis.J Bone Miner Res. 1996; 11: 984-996Crossref PubMed Scopus (518) Google Scholar, 40Wu C.Y. Li J. Jergas M. et al.Semiquantitative and quantitative assessment of incident fractures: comparison of methods.J Bone Miner Res. 1994; 9: S157Google Scholar, 41Crans G.G. Genant H.K. Krege J.H. Prognostic utility of a semiquantitative spinal deformity index.Bone. 2005; 37: 175-179Abstract Full Text Full Text PDF PubMed Scopus (97) Google Scholar A vertebra was considered to have a significant fracture deformity if its height was reduced by greater than 20%, and it had a loss of surface area greater than 10% in the presence of a biconcave, crush, or wedge deformity. Vertebrae were graded as normal, mildly deformed (grade 1: reduction of 20%–25% vertebral height and 10%–20% loss of projected vertebral area), moderately deformed (grade 2: 26%–40% HR and 21%–40% loss of projected vertebral area), or severely deformed (grade 3: >40% reduction in height and area). Results were reported as a spinal fracture index (SFI), defined as the sum of all vertebral fracture deformities in an individual patient. Mild deformities were given a score of 1, whereas moderate and severe deformities were given grades of 2 and 3, respectively. This study's protocol was approved by the Ethics Committee for Medical Research at the University of Alberta. Written and oral informed consent was obtained from all participants before they entered the study. The trial was performed in accordance with the International Conference on Harmonisation Good Clinical Practice guidelines, which have their origins in the Declaration of Helsinki. Descriptive statistics were reported as mean ± standard deviation for continuous variables that were normally distributed, unless otherwise stated. Clinical and biochemical variables collected for CD patients without vertebral fractures were compared with those of the patient group with radiographically prevalent vertebral fractures. Continuous variables were analyzed for significant differences between the 2 groups with an unpaired t test. If the data were not normally distributed, then the Mann-Whitney rank test was used. Comparison of discontinuous variables was performed with a χ2 test (or Fisher exact test for non-tabulated data). To determine whether any continuous variables were predictive of vertebral fracture risk in the CD study cohort, a univariate analysis of the data from the 224 patients was first performed with Pearson correlation test. All significantly associated variables were then subjected to multivariate regression analysis. These tests were also performed on patient data stratified according to sex. For all tests, significance was defined as P <.05 (95% confidence interval), with normality and variance defined as P <.01. The statistical program Sigma Stat (version 2.03; SPSS Inc, Chicago, IL) was used for all statistical procedures. Descriptive statistics for 224 patients enrolled in this study are outlined in Table 1. Fifty-six percent of the study population was female, and 23% was postmenopausal. The average age of the study population was 38.7 ± 11.8 years. Approximately fifty percent of the group reported corticosteroid use during the year preceding enrollment in the current study. The median lumbar spine T score was −0.71 (25th percentile, −1.47; 75th percentile, −0.07). Median T scores (25th and 75th percentiles) for the femoral neck, trochanter, and total hip were −0.95 (−1.55, −0.12), −0.41 (−1.14, 0.27), and −0.46 (−1.04, 0.27), respectively. Of the 224 patients enrolled in the present study and having obtained DXA assessment, 8 patients did not obtain spinal radiographic assessment and were not included in further analysis.Table 1Baseline Characteristics of 224 Consecutive Patients With CD Presenting at the Inflammatory Bowel Disease Clinic, University of Alberta, Edmonton, Canada, Between September 2000–July 2001Descriptive characteristicsBaseline statistics (N = 224)Age (y ± SD)38.7 ± 11.8Disease duration (y ± SD)11.1 ± 8.3Gender (M/F)98/126Smokers (Y/N)81/127Corticosteroid use in the year preceding baseline (Y/N)109/107Disease distribution (%) Ileum only40.3 Ileocolonic38.3 Colon only21.4No. of postmenopausal women29Median T score by site (25th, 75th percentiles) Lumbar spine−0.71 (−1.47, −0.07) Femoral neck−0.95 (−1.55, −0.12) Trochanter−0.41 (−1.14, 0.27) Total hip−0.46 (−1.04, 0.27)Total no. of vertebral fractures (N = patients)88 (N = 45)SD, standard deviation. Open table in a new tab SD, standard deviation. Forty-five patients were shown to collectively have 88 significant vertebral fractures (Table 2). Twenty-three patients had more than 1 fracture. Overall, 26 men accounted for 53 of the vertebral fractures. Of the 45 patients with vertebral fractures, only 3 women and 7 men were older than 50 years. The prevalence of vertebral fractures was not related to BMD, with similar rates occurring in patients with normal BMD, osteopenia, and osteoporosis (P = .653) (Table 2). Furthermore, vertebral fracture prevalence was not significantly different in the premenopausal female versus the postmenopausal female population segments (data not shown).Table 2Comparison of Clinical Variables in Patients With and Without Vertebral FracturesCharacteristicPatients with no vertebral fracture deformity (N = 171)Patients with ≥1 vertebral fracture deformity (N = 45)P valueBMI⁎P <.05. (kg/m2)24.8 ± 4.326.6 ± 4.8.02Magnesium⁎P <.05. (mmol/L)0.85 ± 0.080.82 ± 0.08.02Estradiol⁎P <.05. (pmol/L)230 ± 211118 ± 71.03PTH⁎P <.05. (pmol/L)3.34 ± 1.444.46 ± 2.77.03Gender (M/F)68/10325/19.06Ferritin (μg/L)62.0 ± 59.089.7 ± 94.4.09Steroid use (Y/N)80/8525/17.27Testosterone (nmol/L)15.6 ± 6.214.0 ± 5.3.29Age (y)38.5 ± 12.040.6 ± 11.0.33Disease duration (y)10.8 ± 8.412.0 ± 8.2.38Vitamin B12 (pmol/L)303 ± 173335 ± 210.3925 OHD (nmol/L)57.2 ± 27.252.4 ± 20.6.44CRP (mg/L)7.9 ± 9.111.1 ± 15.1.51N-telopeptides (nmol/mmol uCr)48.0 ± 42.440.8 ± 23.2.56Calcium (mmol/L)2.3 ± 0.12.3 ± 0.1.58Age at diagnosis (y)27.6 ± 11.628.6 ± 11.1.60Thyroid-stimulating hormone (U/L)1.9 ± 1.1001.8 ± 1.0.61WBC (⁎P <.05.109/L)7.3 ± 2.37.2 ± 2.4.61No. postmenopausal25 (14.6%)4 (9.1%).61RBC folate (nmol/L)963 ± 333943 ± 401.74Smoker anytime (Y/N)63/9915/24.89Trochanter BMD0.69 ± 0.120.68 ± 0.12.44Lumbar BMD0.98 ± 0.120.98 ± 0.14.58Total hip BMD0.93 ± 0.140.93 ± 0.15.90Femoral neck BMD0.78 ± 0.120.78 ± 0.16.91No. normal BMD (%)68 (39.8)16 (35.6).85No. osteopenia (%)86 (50.3)23 (51.1).93No. osteoporosis (%)17 (9.9)6 (13.3).75NOTE. A vertebral fracture is defined as an HR >20% and a loss of surface area >10%, in the presence of a biconcave, crush, or wedge deformity (see Methods).25 OHD, 25-hydroxyvitamin D. P <.05. Open table in a new tab NOTE. A vertebral fracture is defined as an HR >20% and a loss of surface area >10%, in the presence of a biconcave, crush, or wedge deformity (see Methods). 25 OHD, 25-hydroxyvitamin D. Figure 1 represents vertebral fracture prevalence according to the specific vertebra determined to have a deformity fracture. Vertebrae T7–T9 accounted for a significant proportion of the total fractures identified (37/88), whereas vertebrae T11–L1 accounted for 28 of 88 fractures. Table 2 demonstrates clinical, biochemical, and BMD parameters for patients with or without vertebral fracture on baseline assessment. In comparison to patients without fractures, patients with vertebral fractures had significantly higher serum levels of PTH (4.46 ± 2.77 vs 3.34 ± 1.44, respectively; P = .03), lower serum magnesium levels (0.85 ± 0.08 vs 0.82 ± 0.08, respectively; P = .02), higher BMIs (26.6 ± 4.8 vs
Referência(s)