Thoracic bone mineral density measured by quantitative computed tomography in patients undergoing spine surgery

BACKGROUND CONTEXTThe thoracic spine is a common location for vertebral fractures as well as instrumentation failure after long spinal fusion procedures. The association between those complications and bone mineral density (BMD) are well recognized. Due to the overlying sternum and ribs in the thoracic spine, projectional BMD assessment tools such as dual energy x-ray absorptiometry (DXA) are limited to the lumbar spine. Quantitative computed tomography circumvents several shortcomings of DXA and allows for level-specific BMD measurements. Studies comprehensively quantifying BMD of the entire thoracic spine in patients undergoing spine surgery are limited.PURPOSEThe objective of this study was: (1) to assess the reliability of thoracic QCT measurements, (2) to determine possible level-specific BMD variation throughout the thoracic spine and (3) to assess the correlation between BMDs of the T1-T12 spinal levels.STUDY DESIGN/SETTINGCross-sectional observation study.PATIENT SAMPLEPatients undergoing spine surgery from 2016–2020 at a single, academic institution with available preoperative CT imaging of the thoracic spine were included in this study.OUTCOME MEASURESThe outcome measure was BMD measured by QCT.METHODSPatients undergoing spine surgery from 2016–2020 at a single, academic institution with available preoperative CT imaging of the thoracic spine were included in this study. Subjects with previous instrumentation at any thoracic level, concurrent vertebral fractures, a Cobb angle of more than 20 degrees, or incomplete thoracic spine CT imaging were excluded. Asynchronous quantitative computed tomography (QCT) measurements of T1-T12 were performed. To assess inter- and intra-observer reliability, a validation study was performed on 120 vertebrae in 10 randomly selected patients. The interclass correlation coefficient (ICC) was calculated. A pairwise comparison of BMD was conducted and correlations between each thoracic level were evaluated. The statistical significance level was set at p<.05.RESULTS60 patients (men, 51.7%) met inclusion criteria. The study population was 90% Caucasian with a mean age of 62.2 years and a mean BMI of 30.2 kg/m². The inter- and intra-observer reliability of the thoracic QCT measurements was excellent (ICC of 0.97 and 0.97, respectively). The trabecular BMD was highest in the upper thoracic spine and decreased in the caudal direction (T1 = 182.3 mg/cm³, T2 = 168.1 mg/cm³, T3 = 163.5 mg/cm³, T4 = 164.7 mg/cm³, T5 = 161.4 mg/cm³, T6 = 152.5 mg/cm³, T7 = 143.5 mg/cm³, T8 = 141.3 mg/cm³, T9 = 143.5 mg/cm³, T10 = 145.1 mg/cm³, T11 = 145.3 mg/cm³, T12 = 133.6 mg/cm³). The BMD of all thoracic levels cranial to T6 was statistically higher than the BMD of all levels caudal to T6 (p < .001). Nonetheless, significant correlations in BMD among all measured thoracic levels were observed, with a Pearson's correlation coefficient ranging from 0.74 to 0.97.CONCLUSIONSThere is significant regional BMD variation in the thoracic spine depending on spinal level. This BMD variation might contribute to several clinically relevant phenomena. First, vertebral fractures occur most commonly at the thoracolumbar junction including T12. In addition to mechanical reasons, these fractures might be partially attributed to thoracic BMD that is lowest at T12. Second, the optimal upper instrumented vertebra (UIV) for stopping long fusions to the sacrum and pelvis is controversial. The BMD of surgically relevant upper thoracic stopping points (T2-T4) was significantly higher than the BMD of lower thoracic stopping points (T10-T12). Besides stress concentration at the relatively mobile lower thoracic segments, the low BMD at these levels might contribute to previously suggested higher rates of junctional failures with short fusions.     

Regional bone mineral density differences measured by quantitative computed tomography in patients undergoing anterior cervical spine surgery

BACKGROUND CONTEXTClinically, the association between bone mineral density (BMD) and surgical instrumentation efficacy is well recognized. Although several studies have quantified the BMD of the human lumbar spine, comprehensive BMD data for the cervical spine is limited. The few available studies included young and healthy patient samples, which may not represent the typical cervical fusion patient. Currently no large scale study provides detailed BMD information of the cervical and first thoracic vertebrae in patients undergoing anterior cervical spine surgery.PURPOSEThe objective of this study was to determine possible trabecular BMD variations throughout the cervical spine and first thoracic vertebra in patients undergoing anterior cervical discectomy and fusion (ACDF) and to assess the correlation between BMDs of the spinal levels C1–T1.STUDY DESIGN/SETTINGThis is a retrospective case series.PATIENT SAMPLEPatients undergoing ACDF from 2015 to 2018 at a single, academic institution with available preoperative CT imaging were included in this study.OUTCOME MEASURESThe outcome measure was BMD measured by QCT.METHODSPatients that underwent ACDF from 2015 to 2018 at a single, academic institution were included in this study. Subjects with previous cervical instrumentation or missing/incomplete preoperative cervical spine CT imaging were excluded. Asynchronous quantitative computed tomography (QCT) measurements of the lateral masses of C1 and the C2-T1 vertebral bodies were performed. For this purpose, an elliptical region of interest that consisted exclusively of trabecular bone was selected. Any apparent sclerotic levels that might affect trabecular QCT measurements were excluded from the final analysis. Interobserver reliability of measurements was assessed by calculating the interclass correlation coefficients (ICC). Pairwise comparison of BMD was performed and correlations between the various cervical levels were evaluated. The statistical significance level was set at p<.05.RESULTSIn all, 194 patients (men, 62.9%) met inclusion criteria. The patient population was 91.2% Caucasian with a mean age of 55.9 years and mean BMI of 28.2 kg/m². The ICC of cervical QCT measurements was excellent (ICC 0.92). The trabecular BMD was highest in the mid-cervical spine (C4) and decreased in the caudal direction (C1 average=253.3 mg/cm³, C2=276.6 mg/cm³, C3=272.2 mg/cm³, C4=283.5 mg/cm³, C5=265.1 mg/cm³, C6=235.3 mg/cm³, C7=216.8 mg/cm³, T1=184.4 mg/cm³). The BMD of C7 and T1 was significantly lower than those of all other levels. Nonetheless, significant correlations in BMD among all measured levels were observed, with a Pearson's correlation coefficient ranging from 0.507 to 0.885.CONCLUSIONSTo the authors’ knowledge this is the largest study assessing trabecular BMD of the entire cervical spine and first thoracic vertebra by QCT. The patient sample consisted of patients undergoing ACDF, which adds to the clinical relevance of the findings. Knowledge of BMD variation in the cervical spine might be useful to surgeons utilizing anterior cervical spine plate and screw systems. Due to the significant variation in cervical BMD, procedures involving instrumentation at lower density caudal levels might potentially benefit from a modification in instrumentation or surgical technique to achieve results similar to more cephalad levels.     

Diffuse idiopathic skeletal hyperostosis (DISH): relation to vertebral fractures and bone density

Summary

Radiographs and spinal bone mineral density (BMD) were evaluated from 342 elderly men regarding possible effects of diffuse idiopathic skeletal hyperostosis (DISH) on vertebral fractures and densitometry measurements. Prevalent vertebral fractures were more frequent among men with DISH compared to men with no DISH even after fracture prevalence was adjusted for BMD. Paravertebral calcifications should be considered in patients with DISH when interpreting BMD measurements because both dual X-ray absorptiometry (DXA) and quantitative CT (QCT) densitometry may not be reliable.

Introduction

The purpose of this study is to evaluate the prevalence of DISH in older men and its association with vertebral fractures and with BMD determined by DXA and QCT.

Methods

Lateral radiographs of the spine were analyzed in a sample of 342 men aged ??65?years participating in the MrOS Study concerning the presence and grade of DISH and vertebral fractures. Lumbar BMD was measured by both DXA (areal, grams per square centimeter) and QCT (volumetric, grams per cubic centimeter). The association between DISH, BMD, and presence of fractures was studied using ?? ² and t tests.

Results

DISH was present in 52% (178/342) of the men. Men with DISH were older (mean, 75.1 vs 73.3, p?<?0.05) and more likely to have prevalent fractures (28% vs 20%, p?<?p?=?0.09). BMD assessed with DXA (1.08 vs 1.00?g/cm², p????0.0001), but not with QCT (0.11 vs 0.11?g/cm3, p?=?0.65), was significantly higher in men with DISH compared to men without DISH. Significantly lower BMD of men with both DISH and fractures compared to men with DISH but without fractures was only detected by QCT (?25%, 0.09 vs 0.12, p?<?0.05). Both DXA BMD and QCT BMD were significantly higher in severe lumbar DISH (+22% and +31%, p?<?0.0001), respectively.

Conclusion

DISH was associated with a higher prevalence of vertebral fractures in elderly men. Lumbar ossifications related to DISH should be considered when interpreting BMD measurements to predict their fracture risk.     

Discordance in lumbar bone mineral density measurements by quantitative computed tomography and dual-energy X-ray absorptiometry in postmenopausal women: a prospective comparative study

Background ContextLevel-specific lumbar bone mineral density (BMD) evaluation of a single vertebral body can provide useful surgical planning and osteoporosis management information. Previous comparative studies have primarily focused on detecting spinal osteoporosis but not at specific levels.PurposeTo compare the detection rate of lumbar osteoporosis between quantitative computed tomography (QCT) and dual-energy X-ray absorptiometry (DXA); to explore and analyze the distribution models of QCT-derived BMD and DXA T-score at the specific levels; and to evaluate the diagnostic accuracy of level-specific BMD thresholds for the prediction of osteoporotic vertebral compression fracture (OVCF) in postmenopausal women.Study Design/SettingA comparative analysis of prospectively collected data comparing QCT-derived BMD with DXA T-score.Patient SampleA total of 296 postmenopausal women who were referred to the spine service of a single academic institution were enrolled.Outcome MeasuresQCT-derived BMD and DXA T-score at specific levels, with or without osteoporotic vertebral compression fracture.MethodsPostmenopausal women who underwent QCT and DXA within a week of admission from May 2019 to June 2022 were enrolled. The diagnostic criteria for osteoporosis recommended by the World Health Organization and the American College of Radiology were used for lumbar osteoporotic diagnosis. To evaluate differences in lumbar BMD measurements at specific levels, a threshold of T score=-2.5 and QCT-derived BMD = 80 mg/cm³ were used to categorize level-specific lumbar BMD into low and high BMD. Disagreements in BMD categorization between DXA and QCT were classified as a minor or major discordance based on the definition by Woodson. Data between QCT and DXA were visualized in a stacked bar plot and analyzed. Correlations between DXA and QCT at the specific levels were evaluated using Pearson's linear correlation and scatter plots. Curve fitting of BMD distribution, receiver operating characteristic (ROC) and area under the curve (AUC) for each single vertebral level was performed.ResultsOf the 296 patients, QCT diagnosed 61.1% as osteoporosis, 30.4% as osteopenia and 8.4% as normal. For those screened with DXA, 54.1% of the patients had osteoporosis, 29.4% had osteopenia and 16.6% had normal BMD. Diagnoses were concordant for 194 (65.5%) patients. Of the other 102 discordant patients, 5 (1.7%) were major and 97 (32.8%) were minor. Significant correlations in level-specific BMD between DXA and QCT were observed (p<.001), with Pearson's correlation coefficients ranging from 0.662 to 0.728. The correlation strength was in the order of L1 > L2 > L3 > L4. The low BMD detection rate for QCT was significantly higher than that for DXA at the L3 and L4 levels (65% vs. 47.9% and 68.1% vs 43.7, respectively, p<.001). Patients with OVCF showed significantly lower QCT-derived BMD (47.2 mg/cm³ vs. 83.2 mg/cm³, p<.001) and T-score (-3.39 vs. -1.98, p<.001) than those without OVCF. Among these patients, 82.8% (101/122) were diagnosed with osteoporosis by QCT measurement, while only 74.6% (91/122) were diagnosed by DXA. For discrimination between patients with and without OVCF, QCT-derived BMD showed better diagnosed performance (AUC range from 0.769 to 0.801) than DXA T-score (AUC range from 0.696 to 0.753).ConclusionQCT provided a more accurate evaluation of lumbar osteoporosis than DXA. The QCT-derived BMD measurements at a specific lumbar level have a high diagnostic performance for OVCF.     

Preoperative MRI-based vertebral bone quality (VBQ) score assessment in patients undergoing lumbar spinal fusion

BACKGROUND CONTEXTThe importance of bone status assessment in spine surgery is well recognized. The current gold standard for assessing bone mineral density is dual-energy X-ray absorptiometry (DEXA). However, DEXA has been shown to overestimate BMD in patients with spinal degenerative disease and obesity. Consequently, alternative radiographic measurements using data routinely gathered during preoperative evaluation have been explored for the evaluation of bone quality and fracture risk. Opportunistic quantitative computed tomography (QCT) and more recently, the MRI-based vertebral bone quality (VBQ) score, have both been shown to correlate with DEXA T-scores and predict osteoporotic fractures. However, to date the direct association between VBQ and QCT has not been studied.PURPOSEThe objective of this study was to evaluate the correlation between VBQ and spine QCT BMD measurements and assess whether the recently described novel VBQ score can predict the presence of osteopenia/osteoporosis diagnosed with QCT.STUDY DESIGN/SETTINGCross-sectional study using retrospectively collected data.PATIENT SAMPLEPatients undergoing lumbar fusion from 2014-2019 at a single, academic institution with available preoperative lumbar CT and T1-weighted MRIs were included.OUTCOME MEASURESCorrelation of the VBQ score with BMD measured by QCT, and association between VBQ score and presence of osteopenia/osteoporosis.METHODSAsynchronous QCT measurements were performed. The average L1-L2 BMD was calculated and patients were categorized as either normal BMD (>120 mg/cm³) or osteopenic/osteoporotic (≤120 mg/cm³). The VBQ score was calculated by dividing the median signal intensity of the L1-L4 vertebral bodies by the signal intensity of the cerebrospinal fluid on midsagittal T1-weighted MRI images. Inter-observer reliability testing of the VBQ measurements was performed. Demographic data and the VBQ score were compared between the normal and osteopenic/osteoporotic group. To determine the area-under-curve (AUC) of the VBQ score as a predictor of osteopenia/osteoporosis receiver operating characteristic (ROC) analysis was performed. VBQ scores were compared with QCT BMD using the Pearson's correlation.RESULTSA total of 198 patients (53% female) were included. The mean age was 62 years and the mean BMI was 28.2 kg/m². The inter-observer reliability of the VBQ measurements was excellent (ICC of 0.90). When comparing the patients with normal QCT BMD to those with osteopenia/osteoporosis, the patients with osteopenia/osteoporosis were significantly older (64.9 vs. 56.7 years, p<.0001). The osteopenic/osteoporotic group had significantly higher VBQ scores (2.6 vs. 2.2, p<.0001). The VBQ score showed a statistically significant negative correlation with QCT BMD (correlation coefficient = -0.358, 95% CI -0.473 - -0.23, p<.001). Using a VBQ score cutoff value of 2.388, the categorical VBQ score yielded a sensitivity of 74.3% and a specificity of 57.0% with an AUC of 0.7079 to differentiate patients with osteopenia/osteoporosis and with normal BMD.CONCLUSIONSWe found that the VBQ score showed moderate diagnostic ability to differentiate patients with normal BMD versus osteopenic/osteoporotic BMD based on QCT. VBQ may be an interesting adjunct to clinically performed bone density measurements in the future.     

Association of IL-6 G-174C polymorphism with bone mineral density

Functional polymorphisms in the promoter region of interleukin-6 (IL-6) are known to be involved in bone mineral density (BMD) and the development of osteoporosis, but the reported results have been inconsistent. Using the meta-analysis approach, the present study is designed to provide a relatively comprehensive picture of the relationship between bone mineral density (BMD) or osteoporosis and polymorphisms in the promoter region of IL-6 (rs1800795 and rs1800796). The difference of bone mineral density (BMD) values between genotypes was examined by mean difference and 95 % confidence intervals (CIs). Association between IL-6 polymorphism and clinical osteoporosis was evaluated by pooled odds ratios (ORs) and 95 % CIs. A total of 13 articles with 11,499 subjects were included in the present study. For ?174 (rs1800795), we found that individuals with the G/G genotype had a significantly lower BMD value than those with C/C genotype at femoral neck (0.02 g/cm², 95 % CI 0.00–0.03) (p = 0.04) and distal radius (0.01 g/cm², 95 %CI 0.01–0.01) (p < 0.0001). However, we did not find a statistically significant difference of BMD at the spine. When analysis was limited to postmenopausal women, similar results were obtained. We further found that the C/C genotype was associated with a reduced risk of osteoporosis compared to G/G genotype, and the pooled OR was 0.72 (95 % CI 0.54–0.95, p = 0.02). In addition, a significant relationship was found between G-634C (rs1800796) polymorphism and distal radius BMD (CC vs. GG: 0.02 g/cm², 95 % CI 0.01–0.03; GC vs. GG: 0.02 g/cm², 95 % CI 0.00–0.03) in the Asian population. These findings suggest that the CC genotype of IL-6 G-174C polymorphism may be associated with high BMD at femoral neck and distal radius and decreased risk of osteoporosis in the Caucasian population whereas G-634C polymorphism was associated with distal radius BMD in Asians.     

Timing of Repeat BMD Measurements: Development of an Absolute Risk‐Based Prognostic Model

This study attempted to address the following questions: for an individual who is at present nonosteoporotic, given their current age and BMD level, what is the individual's risk of fracture and when is the ideal time to repeat a BMD measurement? Nonosteoporotic women (n = 1008) and men (n = 750) over the age of 60 in 1989 from the Dubbo Osteoporosis Epidemiology Study were monitored until one of the following outcomes occurred: (1) BMD reached “osteoporosis” level (i.e., T‐scores ≤ ?2.5) or (2) an incident fragility fracture. During the follow‐up period (average, 7 yr), 346 women (34%) and 160 men (21%) developed osteoporosis or sustained a low‐trauma fracture. The risk of osteoporosis or fracture increased with advancing age (women: RR/10 yr, 1.3; 95% CI, 1.1–1.6; men: RR/10 yr, 2.3; 95% CI, 1.7–2.9) and lower BMD levels (women: RR per ?0.12 g/cm², 3.2; 95% CI, 2.6–4.1; RR per ?0.12 g/cm², 2.6; 95% CI, 2.0–3.3). Using the predicted risk (of osteoporosis or fracture) of 10% as a cut‐off level for repeating BMD measurement, the estimated time to reach the cut‐off level varied from 1.5 (for an 80‐yr‐old woman with a T‐score of ?2.2) to 10.6 yr (for a 60‐yr‐old man with a T‐score of 0). These results suggest that, based on an individual's current age and BMD T‐score, it is possible to estimate the optimal time to repeat BMD testing for the individual. The prognostic model and approach presented in this study may help improve the individualization and management of osteoporosis.     

Low calcaneal bone mineral density and the risk of distal forearm fracture in women and men: A population-based case-control study

ObjectiveWe used dual X-ray absorptiometry (DXA) to measure calcaneal bone mineral density (BMD) and estimate the prevalence of osteoporosis in a population with distal forearm fracture and a normative cohort.MethodsPatients 20 to 80 years of age with distal forearm fracture treated at one emergency hospital during two consecutive years were invited to calcaneal BMD measurement; 270 women (81%) and 64 men (73%) participated. A DXA heel scanner estimated BMD (g/cm²) and T-scores. Osteoporosis was defined as T-score ≤? 2.5 SD. Of the fracture cohort, 254 women aged 40–80 years and 27 men aged 60–80 years were compared with population-based control cohorts comprising 171 women in the age groups 50, 60, 70 and 80 years and 75 men in the age groups 60, 70, and 80 years.ResultsIn the fracture population no woman below 40 years or man below 60 years of age had osteoporosis. In women aged 40–80 years the prevalence of osteoporosis in the distal forearm fracture cohort was 34% and in the population-based controls was 25%; the age-adjusted prevalence ratio (PR) was 1.32 (95% CI 1.00–1.76). In the subgroup of women aged 60–80 years the age-adjusted prevalence ratio of osteoporosis was 1.28 (95% CI 0.95–1.71). In men aged 60–80 years the prevalence of osteoporosis in the fracture cohort was 44% and in the population-based controls was 8% (PR 6.31, 95% CI 2.78–14.4). The age-adjusted odds ratio for fracture associated with a 1-SD reduction in calcaneal BMD was in women aged 40–80 years 1.4 (95% CI 1.1–1.8), in the subgroup of women aged 60–80 years 1.2 (95% CI 0.95–1.6), and in men aged 60–80 years 2.6 (95% CI 1.7–4.1). Among those aged 60–80 years the area under the ROC curve was in women 0.56 (95% CI 0.49–0.63) and in men 0.80 (95% CI 0.70–0.80).ConclusionsThe age-adjusted prevalence of osteoporosis based on calcaneal BMD is higher in individuals with distal forearm fracture than in population-based controls. BMD impairment is associated with increased odds ratio for forearm fracture in both women and men but the differences between cases and controls are more pronounced in men than in women, which may have implications in fracture prevention.     

Changes in bone mineral density after allogenic stem cell transplantation

ObjectiveOsteoporosis is a complication after allogenic stem cell transplantation (alloSCT). The purpose of this study was to assess changes in bone mineral density (BMD) 6 months and 3 years after alloSCT, as well as predictors of bone loss.MethodsA longitudinal, prospective, single-center study was conducted at Lille University Hospital between 2005 and 2016. Clinical, biological, radiologic (thoracic and lumbar spine) and densitometric (DXA) assessments were carried out at baseline (pre-transplant), 6 months and 3 years. Patients with myeloma were not included.ResultsTwo hundred and fifty-eight patients were included (144 men). Among them, 60.1% had leukemia and 65.8% of them, acute myeloid leukemia. At baseline, 6 months and 3 years, DXA-confirmed that osteoporosis was observed in 17%, 22.8% and 17.5% of the patients, respectively, mainly at the femoral neck. At baseline, 6 months and 3 years, 9 (8.5%), 53 (21.5%) and 38 (16.7%) patients, respectively, were receiving anti-osteoporotic treatment. From baseline to 6-month follow-up, BMD decreased significantly (p < 0.001) at the lumbar spine (?36 [95%CI; ?51 to ?20] mg/cm² of hydroxyapatite), femoral neck (?43 [95%CI; ?57 to ?29] mg/cm² of hydroxyapatite) and total hip (?53 [95%CI; ?68 to ?39] mg/cm² of hydroxyapatite). From 6-month to 3-year follow-up, a significant increase in BMD was observed at the lumbar spine only (+31 [95%CI; 20 to 42] mg/cm² of hydroxyapatite, p < 0.001). At all 3 sites, changes in BMD did not differ between patients treated or untreated by anti-osteoporotic treatment from 6-month to 3 year follow-up. Incident fractures were found in 4.1% and 5.7% of the patients at 6 months and 3 years, respectively. Between baseline and 6 months, bone loss at all 3 sites was associated with corticosteroid intake. At the total hip, 23.3% of the decrease in BMD from baseline to 6 months was due to an active hematological disease (p < 0.05), a bone marrow stem cells (p < 0.01) and a corticosteroid intake (p < 0.01).ConclusionOur study found evidence of bone fragility in alloSCT patients. Low BMD persisted at the hip 3 years after transplantation due to slower improvement at this site.     

MTHFR Polymorphism and Bone Mineral Density: Meta-Analysis of Published Studies

The C677T (rs1801133) polymorphism of methylenetetrahydrofolate reductase (MTHFR) has been associated with bone status in some studies, but the results have been mixed. In order to have a better understanding of this issue, we performed a meta-analysis of studies about the association of the C677T polymorphism and bone mineral density (BMD). Eight studies analyzed the relationship with spine BMD. When their results were combined, individuals with TT genotype showed a small but significantly reduced BMD compared to those with TC and CC genotypes. The weighted mean difference (WMD) was 18.0 mg/cm² (P = 0.001, 95% confidence interval [CI] 7.1–28.9), without statistical evidence for between-study heterogeneity (P = 0.28, I² = 17%). Six studies analyzed femoral neck BMD. A test for heterogeneity was significant (P = 0.03, I² = 56%). Individuals with TT alleles tended to have somewhat lower BMD, but the difference was not statistically significant. In random effects model, the WMD between the TT and TC/CC genotypes was 6.4 mg/cm² (95% CI –7.8 to 21.2, P = 0.36). Total hip BMD was measured in four studies. They showed a significantly lower BMD in subjects with TT alleles: WMD 19.7 (95% CI 5.3-34.1) mg/cm², P = 0.007, in comparison with TC/CC subjects. When we considered only studies on women, the WMD in BMD between TT and TC/CC genotypes was significant at the spine (22.1 mg/cm², 95% CI 8.6-35.6; P = 0.001) and the femoral neck (15.5 mg/cm², 95% CI 4.3-26.7; P = 0.007). There was no evidence for heterogeneity. The small number of studies did not allow a meaningful sex-stratified analysis of total hip BMD or a separate analysis of male data. In conclusion, the C677T polymorphism of the MTHFR gene is associated with small differences in BMD, at least in women.     

A Body Shape Index Has a Good Correlation with Postoperative Complications in Gastric Cancer Surgery

Background

The relationship between obesity and surgical complications has been controversial. A Body Shape Index (ABSI) is a newly developed anthropometric index based on waist circumference adjusted for height and weight. The aim of this study was to investigate the relationship between ABSI and surgical complications.

Methods

From November 2001 to September 2012, 4,813 patients underwent curative resection for gastric cancer. ABSI was defined as waist circumference divided by (BMI^2/3height^1/2). Data of clinicopathologic characteristics and morbidity were collected by retrospective review. Binary logistic regression was used for multivariable analyses to determine whether ABSI was independently associated with postoperative complications.

Results

The incidence of overall surgical complications was 13.4 %, and the most common complication was ileus (2.8 %). In the multivariable analysis, ABSI was an independent factor for overall complications [odds ratio (OR), 1.22; 95 % confidence interval (CI) 1.01–1.48; P = 0.041). However, BMI showed no statistical significance (OR, 1.03; 95 % CI 1.00–1.06; P = 0.063). In the subgroup analyses, ABSI was significantly associated with overall complications regarding open gastrectomy (OR, 1.26; 95 % CI 1.01–1.57; P = 0.039). Regarding laparoscopy-assisted gastrectomy, ABSI had no significant effect on overall complications (P = 0.844).

Conclusions

ABSI shows good correlation with surgical complications in patients with gastric cancer. Further studies are needed for the various clinical roles of ABSI, and the results could be helpful to determine the effect of abdominal obesity on gastric cancer surgery and the clinical usefulness of ABSI.     

Prevalence and Predictors of Reduced Bone Density in Child and Adolescent Patients With Crohn's Disease

Reduced bone mineral density (BMD) has broadly been found to be associated with inflammatory bowel disease across a number of geographical locations and cultures. We aimed to estimate the prevalence of reduced BMD and identify clinical predictors in a cohort of Crohn's disease patients (CD) in Saudi Arabia. We conducted a retrospective study involving children and adolescents with CD between 2013 and 2018. BMD was evaluated using dual-energy X-ray absorptiometry scans of the spine and body. A multivariate analysis was performed for the detection of predictors of low BMD. Sixty-four patients were enrolled. The median age was 16 years (range, 8–19 years) and 55% of patients were males. Total body BMD scanning identified 25 patients (39%) with osteoporosis. Twenty patients (31.3%) were found to have z scores consistent with osteopenia. A multivariate regression analysis identified a low weight-for-age z score (B coefficient = 0.347, 95% confidence interval [CI] = 0.211–0.482, p < 0.001 for Spine BMD and B coefficient = 0.321, 95% CI = 0.170–0.472, p < 0.001 for total body BMD), a low height-for-age z score (B coefficient = 0.187, 95% CI = 0.035–0.338, p = 0.017 for spine BMD and B coefficient = 0.0.258, 95% CI = 0.089–0.427, p = 0.004 for total body BMD), a low 25-hyroxyvitamin D level (B coefficient = 0.026, 95% CI = 0.013–0.038, p < 0.001 for spine BMD and B coefficient = 0.016, 95% CI = 0.002–0.031, p = 0.026 for total body BMD), and a higher number of corticosteroid induction courses (B coefficient = ?0.567, 95% CI = ?0.923 to ?0.212, p = 0.003 for spine BMD and B coefficient = ?0.566, 95% CI = 0.963–0.169, p = 0.007 for total body BMD) as predictors of low BMD. In the spine BMD analysis, older age at the time of presentation was identified as a significant predictor for low bone density (B coefficient = 0.254, 95% CI = 0.141–0.368, p < 0.001). In conclusion, Saudi Arabian children and adolescents with CD have a high prevalence rate of low bone density compared to Western populations. Several clinical characteristics are identified as significant predictors for low BMD.     

Prevalence of Alpha-1 antitrypsin deficiency in COPD patients in Argentina. The DAAT.AR study

IntroductionAlpha-1 antitrypsin deficiency (AATD) is still underdiagnosed, despite the recommendation to determine AAT in patients with chronic obstructive pulmonary disease (COPD).ObjectiveTo estimate the prevalence of AATD in COPD patients adjusted according to the population of the COPD prevalence study in Argentina (EPOC.AR).Material and methodsThis was a multicenter prospective cross-sectional study of a population aged ≥ 30 years of age diagnosed with COPD, involving AAT quantification in dry blood spot and subsequent genotyping in subjects with < 1.5 mg/dl AAT in dry blood spot (< 80 mg/dl in serum). AAT was defined as the detection of variants ZZ or SZ on genotyping. The EPOC.AR study population was used to calculate local adjusted prevalence.ResultsWe included 3254 patients (544 with AAT < 80 mg/dL) with a spirometric diagnosis of COPD. The prevalence of AATD in the total study population was 1.29% (95% CI 0.93–1.74), of which 0.92% (95% CI 0.62–1.31) were Pi*ZZ and 0.37% (95% CI 0.19−0.64) Pi*SZ. The adjusted prevalence of AATD in COPD patients ≥ 40 years of age was 0.83% (95% CI 0.23–2.08). We found that AATD was negatively associated with age (OR 0.94; 95% CI 0.90−0.98; P = .006), smoking habit (OR 0.98; 95% CI 0.96−0.99; P = .009), and FEV₁% (OR 0.95; 95% CI 0.91−0.99; P = .015).ConclusionsThe prevalence of AATD in the adult population with COPD in Argentina is estimated to be 0.83%, which could represent 17,000 cases in our country.     

Bone Mineral Density Predicts Fractures in Chronic Kidney Disease

Fractures are common in chronic kidney disease (CKD). The optimal methods by which to assess fracture risk are unknown, in part, due to a lack of prospective studies. We determined if bone mineral density (BMD) by dual‐energy X‐ray absorptiometry (DXA), and/or high‐resolution peripheral quantitative computed tomography (HRpQCT) could predict fractures in men and women ≥18 years old with stages 3 to 5 CKD. BMD was measured by DXA (at the total hip, lumbar spine, ultradistal, and 1/3 radius) and by HRpQCT (at the radius), and subjects were followed for 2 years for incident morphometric spine fractures and low‐trauma clinical fractures. The mean age of the subjects was 62 years with equal numbers having stages 3, 4, and 5 CKD. Over 2 years there were 51 fractures in 35 subjects. BMD by DXA at baseline was significantly lower at all sites among those with incident fractures versus those without. For example, the mean BMD at the total hip in those with incident fractures was 0.77 g/cm² (95% confidence interval [CI], 0.73 to 0.80) and in those without fracture was 0.95 g/cm² (95% CI, 0.92 to 0.98). Almost all baseline HRpQCT measures were lower in those with incident fracture versus those without. For example, volumetric BMD in those with incident fractures was 232 mg HA/cm³ (95% CI, 213 to 251) and in those without fracture was 317.6 mg HA/cm³ (95% CI, 306 to 329.1). Bone loss occurred in all subjects, but was significantly greater among those with incident fractures. Our data demonstrate that low BMD (by DXA and HRpQCT) and a greater annualized percent decrease in BMD are risk factors for subsequent fracture in men and women with predialysis CKD. © 2014 American Society for Bone and Mineral Research.     

Bone densitometry of excised vertebrae; Anatomical relationships

Summary Bone mineral density (BMD) was determined in 32 excised vertebrae using three methods: (1) dual-energy quantitative computed tomography (QCT), (2) dual-photon absorptiometry (DPA) with 153-Gd in an anteriorposterior projection and (3) scanning slit X-ray absorptiometry (SSXA) in both AP and lateral projections. The QCT region-of-interest in the anterior vertebral body had a lower density than that of the total trabecular portion of the body, but was highly correlated to this larger region (r=0.96; SEE=8 mg/cm³). The anterior QCT region also correlated moderately with BMD from DPA (r=0.77; SEE=18 mg/cm³). Measurements of the vertebral body in lateral projection were less well correlated (r=0.5–0.7) to QCT densities. Both the anterior QCT region (r=0.81; SEE=18 mg/cm³) and the BMD from DPA (r=0.86; SEE=16 mg/cm³) were similarly predictive of density of the integral vertebral body. Differences among densitometric methods on the spine depend on the projection used and the region examined.     

Vertebral Bone Mineral Density Measured by Quantitative Computed Tomography With and Without a Calibration Phantom: A Comparison Between 2 Different Software Solutions

Quantitative computed tomography (CT) can be used to quantify bone mineral density (BMD) in the spine from clinical CT scans. We aimed to determine agreement and precision of BMD measurements by 2 different methods: phantom-less internal tissue calibration and asynchronous phantom-based calibration in a cohort of patients with chronic kidney disease (CKD). Patients with CKD were recruited for CT angiography of the chest, abdomen, and pelvis. BMD was analyzed by 2 different software solutions using different calibration techniques; phantom-based by QCT Pro (Mindways Inc.) and phantom-less by Extended Brilliance Workspace (Philips Healthcare). Intraoperator reanalysis was performed on 53 patients (36%) for both methods. An interoperator reanalysis on 30 patients (20%) using the phantom-based method and 29 patients (19%) using the phantom-less method was made. XY- and Bland-Altman plots were used to evaluate method agreement. Phantom-based measured BMD was systematically higher than phantom-less measured BMD. Despite a small absolute difference of 3.3 mg/cm³ (CI: -0.2–6.9?mg/cm³) and a relative difference of 5.1% (CI: 2.2%–8.1%), interindividual differences were large, as seen by a wide prediction interval (PI: -47–40?mg/cm³). The Bland-Altman plot showed no systematic bias, apart from 5 outliers. Intraoperator variability was high for the phantom-less method (5.8%) compared to the phantom-based (0.8%) and the interoperator variability was also high for the phantom-less method (5.8%) compared to the phantom-based (1.8%). Despite high correlation between methods, the between-method difference on an individual level showed great variability. Our results suggest agreement between these 2 methods is insufficient to allow them to be used interchangeably in patients with CKD.     

Liquid Calibration Phantoms in Ultra-Low-Dose QCT for the Assessment of Bone Mineral Density

Introduction: Cortical bone is affected by metabolic diseases. Some studies have shown that lower cortical bone mineral density (BMD) is related to increases in fracture risk which could be diagnosed by quantitative computed tomography (QCT). Nowadays, hybrid iterative reconstruction-based (HIR) computed tomography (CT) could be helpful to quantify the peripheral bone tissue. A key focus of this paper is to evaluate liquid calibration phantoms for BMD quantification in the tibia and under hybrid iterative reconstruction-based-CT with the different hydrogen dipotassium phosphate (K₂HPO₄) concentrations phantoms. Methodology: Four ranges of concentrations of K₂HPO₄ were made and tested with 2 exposure settings. Accuracy of the phantoms with ash gravimetry and intermediate K₂HPO₄ concentration as hypothetical patients were evaluated. The correlations and mean differences between measured equivalent QCT BMD and ash density as a gold standard were calculated. Relative percentage error (RPE) in CT numbers of each concentration over a 6-mo period was reported. Results: The correlation values (R² was close to 1.0), suggested that the precision of QCT-BMD measurements using standard and ultra-low dose settings were similar for all phantoms. The mean differences between QCT-BMD and the ash density for low concentrations (about 93 mg/cm³) were lower than high concentration phantoms with 135 and 234 mg/cm³ biases. In regard to accuracy test for hypothetical patient, RPE was up to 16.1% for the low concentration (LC) phantom for the case of high mineral content. However, the lowest RPE (0.4 to 1.8%) was obtained for the high concentration (HC) phantom, particularly for the high mineral content case. In addition, over 6 months, the K₂HPO₄ concentrations increased 25% for 50 mg/cm³ solution and 0.7 % for 1300 mg/cm³ solution in phantoms. Conclusion: The excellent linear correlations between the QCT equivalent density and the ash density gold standard indicate that QCT can be used with submilisivert radiation dose. We conclude that using liquid calibration phantoms with a range of mineral content similar to that being measured will minimize bias. Finally, we suggest performing BMD measurements with ultra-low dose scan concurrent with iterative-based reconstruction to reduce radiation exposure.     

Osteoporosis in Indian women aged 40–60 years

Summary

The study investigates BMD pattern in Indian women aged 40–60 years through a retrospective assessment using DEXA scan of hip and spine of 1,282 asymptomatic Indian women. The Study group indicated high incidence of decreased bone mass and significantly lower BMD as compared to western and other Asian counterparts.

Introduction

An understanding of BMD pattern in women aged 40–60 years is crucial for prevention, diagnosis of osteoporosis and management of its complications in later life. Hence, the present study investigates BMD in Indian women aged 40–60 years for which no data exists in literature.

Method

A retrospective assessment of BMD by DEXA scan of hip and spine of 1,282 asymptomatic women in age group 40–60 was performed. Standardized BMD was calculated and compared with other population groups.

Results

Osteoporosis and osteopenia are widely prevalent among females of the 40–60 age group as a meager 35% of subjects had normal bone density. Average BMD of spine was 0.89 (SD 0.14) gm/cm² and average BMD of hip was 0.85(0.15) gm/cm². The correlation between BMD and age was negative. Spine DEXA was found to be more significant than hip DEXA (p value?<?0.0001) for osteoporosis assessment. Similarly, T scores of spine were more significantly correlated in this age group (p value?<?0.0001) for osteoporosis than hip T scores.

Conclusion

The study group indicated high incidence of decreased bone mass, and significantly lower BMD as compared to western and other Asian counterparts. This study emphasizes on early screening and treatment in study group to avoid long-term complications.     

Change in hip bone mineral density and risk of subsequent fractures in older men

Low bone mineral density (BMD) increases fracture risk; how changes in BMD influence fracture risk in older men is uncertain. BMD was assessed at two to three time points over 4.6 years using dual‐energy X‐ray absorptiometry (DXA) for 4470 men aged ≥65 years in the Osteoporotic Fractures in Men (MrOS) Study. Change in femoral neck BMD was estimated using mixed effects linear regression models. BMD change was categorized as “accelerated” (≤?0.034 g/cm²), “expected” (between 0 and ?0.034 g/cm²), or “maintained” (≥0 g/cm²). Fractures were adjudicated by central medical record review. Multivariate proportional hazards models estimated the risk of hip, nonspine/nonhip, and nonspine fracture over 4.5 years after the final BMD measure, during which time 371 (8.3%) men experienced at least one nonspine fracture, including 78 (1.7%) hip fractures. Men with accelerated femoral neck BMD loss had an increased risk of nonspine (hazard ratio [HR] = 2.0; 95% confidence interval [CI] 1.4–2.8); nonspine/nonhip (HR = 1.6; 95% CI 1.1–2.3); and hip fracture (HR = 6.3; 95% CI 2.7–14.8) compared with men who maintained BMD over time. No difference in risk was seen for men with expected loss. Adjustment for the initial BMD measure did not alter the results. Adjustment for the final BMD measure attenuated the change in BMD‐nonspine fracture and the change in BMD‐nonspine/nonhip relationships such that they were no longer significant, whereas the change in the BMD‐hip fracture relationship was attenuated (HR = 2.6; 95% CI 1.1–6.4). Total hip BMD change produced similar results. Accelerated decrease in BMD is a strong, independent risk factor for hip and other nonspine fractures in men. © 2012 American Society for Bone and Mineral Research.