Skeletal site bone mineral density heterogeneity in women and men

Assessment of fracture risk

Osteoporosis-related fractures (low-trauma, fragility fractures) are associated with significant morbidity, mortality, and health care expenditure worldwide. In the absence of a defining fracture, the diagnosis of osteoporosis is based on the World Health Organization's T-score criteria using central dual-energy x-ray absorptiometry (DXA). Paradoxically, the majority of those patients who will sustain a low-trauma fracture do not meet the T-score definition of osteoporosis. Conversely, younger individuals with bone density in the osteoporotic range but no other risk factors have relatively low fracture rates and yet are frequently considered candidates for osteoporosis therapies. The limited accuracy of bone density testing alone to predict fractures has led to the development of a variety of fracture assessment tools that utilize the combination of bone density and clinical risk factors to improve the prediction of low-trauma fractures. These fracture assessment tools quantitatively predict the 10-year fracture probability of hip and major osteoporosis-related fractures, and can be used to define cost-effective intervention strategies for primary and secondary fracture prevention.

Assessment of fracture risk

Osteoporosis-related fractures are associated with significant morbidity, mortality, and health care expenditure worldwide. The low sensitivity of bone density testing alone to predict fractures has led to the development of a variety of fracture assessment tools that use the combination of bone density and clinical risk factors to improve the prediction of low-trauma fractures. These fracture assessment tools quantitatively predict the 10-year probability of hip and major osteoporosis-related fractures, and can be used with various intervention strategies to effectively intervene with cost-effective therapies to prevent future fractures.

Official Positions for FRAX® Bone Mineral Density and FRAX® simplification from Joint Official Positions Development Conference of the International Society for Clinical Densitometry and International Osteoporosis Foundation on FRAX®

Tools to predict fracture risk are useful for selecting patients for pharmacological therapy in order to reduce fracture risk and redirect limited healthcare resources to those who are most likely to benefit. FRAX® is a World Health Organization fracture risk assessment algorithm for estimating the 10-year probability of hip fracture and major osteoporotic fracture. Effective application of FRAX® in clinical practice requires a thorough understanding of its limitations as well as its utility. For some patients, FRAX® may underestimate or overestimate fracture risk. In order to address some of the common issues encountered with the use of FRAX® for individual patients, the International Society for Clinical Densitometry (ISCD) and International Osteoporosis Foundation (IOF) assigned task forces to review the medical evidence and make recommendations for optimal use of FRAX® in clinical practice. Among the issues addressed were the use of bone mineral density (BMD) measurements at skeletal sites other than the femoral neck, the use of technologies other than dual-energy X-ray absorptiometry, the use of FRAX® without BMD input, the use of FRAX® to monitor treatment, and the addition of the rate of bone loss as a clinical risk factor for FRAX®. The evidence and recommendations were presented to a panel of experts at the Joint ISCD-IOF FRAX® Position Development Conference, resulting in the development of Joint ISCD-IOF Official Positions addressing FRAX®-related issues.

Exclusion of focal vertebral artifacts from spine bone densitometry and fracture prediction: a comparison of expert physicians, three computer algorithms, and the minimum vertebra

Expert physicians and automated methods for the exclusion of vertebral levels in DXA scans containing focal artifacts were compared. All methods of vertebral exclusion led to a small improvement in fracture prediction. Computer algorithms performed at least as well as physicians.

INTRODUCTION

Lumbar spine DXA is often confounded by focal artifacts. Clinical rules and automated methods for vertebral exclusion have been proposed, but their concordance, effect on diagnosis, and fracture prediction is unknown.

MATERIALS AND METHODS

We analyzed clinical DXA scans of the lumbar spine (20,478 women and 1534 men) performed from 1998 to 2002 (Province of Manitoba, Canada). Longitudinal health service records were assessed for the presence of nontrauma fracture codes after BMD testing. The effect of vertebral exclusions by expert physicians and several automated methods on diagnosis and prediction of incident fractures was compared.

RESULTS

Vertebral exclusions were reported by physicians in over one quarter of the scans (31% of women and 29% of men). All methods of vertebral exclusion significantly decreased the mean spine T-score and increased the proportion of women designated as osteoporotic. kappa values and ROC area under the curve (AUC) for physician-computer agreement in the identification of abnormal scans indicated fair to moderate agreement in both women and men. Compared with no vertebral exclusions, a small increase in the hazard ratio and AUC for spine fracture and osteoporotic fracture prediction was seen after physician and computer exclusions. Compared with physician exclusions, AUC for prediction of osteoporotic fractures in men increased significantly with one computer algorithm (p = 0.004). The minimum vertebral T-score enhanced fracture prediction compared with no exclusions but approximately doubled the prevalence of osteoporotic categorization.

CONCLUSIONS

We observed fair to moderate agreement between the physician and computer methods for vertebral level exclusion. All methods of vertebral exclusion led to a small improvement in fracture prediction using the lumbar spine measurement. The automated algorithms performed at least as well as physicians when fractures were used as the endpoint.

Biomarkers of bone turnover can be assayed from human saliva

The purpose of this study was to determine if biomarkers of bone turnover [deoxypyridinium (D-PYR) or osteocalcin (OC)] could be detected in human saliva. These biomarkers have been measured in ovariectomized sheep saliva, but not in human saliva. Saliva was collected from 37 women. The bone mineral density of the calcaneus was assessed by quantitative ultrasound and expressed as a T score. Salivary D-PYR and OC concentrations were determined by enzyme-linked immunosorbent assay. Data were analyzed by a Spearman's rho correlation test and factorial analysis of variance was followed by a post hoc Tukey's test. There were significant correlations between age, body mass index, D-PYR, or OC concentration and calcaneus T scores (p<.05), suggesting that saliva could be used as a fluid for assay of human biomarkers of bone turnover. Our data suggest a beneficial use of saliva in situations where a large number of patients are to be screened for metabolic bone diseases.

Avaliação do diagnóstico densitométrico de osteoporose/osteopenia conforme o sítio ósseo

O objetivo deste estudo foi avaliar a freqüência de osteoporose de acordo com os sítios ósseos avaliados, utilizando um estudo transversal de base clínica. Foram avaliados 610 exames densitométricos em relação a freqüência de osteoporose/osteopenia e concordância do diagnóstico de acordo com o local avaliado. Apesar de alta correlação da DMO entre os sítios ósseos, a freqüência de osteoporose variou de acordo com o sítio avaliado. Osteoporose esteve presente em 14 e 18% dos pacientes, quando considerado o colo do fêmur e fêmur total, e 42 e 30% quando considerados o triângulo do Ward e coluna (p< 0,05). Um quarto das mulheres consideradas em risco aumentado de fratura pelo exame da coluna lombar foi classificado como normal pelo estudo do colo do fêmur; 16% com risco aumentado pelo estudo do colo do fêmur foi classificado como normal no estudo da coluna. Este estudo demonstra que existe discordância nos resultados densitométricos de acordo com a área estudada, afetando a ocorrência de osteoporose. Para julgamento clínico de risco de fratura, a avaliação combinada de dois sítios ósseos é o procedimento mais adequado.

Assessment of periodontal conditions and systemic disease in older subjects. I. Focus on osteoporosis

BACKGROUND

Osteoporosis (OPOR) is a common chronic disease, especially in older women. Patients are often unaware of the condition until they experience bone fractures. Studies have suggested that OPOR and periodontitis are associated diseases and exaggerated by cytokine activity. Panoramic radiography (PMX) allows studies of mandibular cortical index (MCI), which is potentially diagnostic for OPOR.

AIMS

i). To study the prevalence of self-reported history of OPOR in an older, ethnically diverse population, ii). to assess the agreement between PMX/MCI findings and self-reported OPOR, and iii). to assess the likelihood of having both a self-reported history of OPOR and a diagnosis of periodontitis.

MATERIALS AND METHODS

PMX and medical history were obtained from 1084 subjects aged 60-75 (mean age 67.6, SD +/- 4.7). Of the films, 90.3% were useful for analysis. PMXs were studied using MCI. The PMXs were used to grade subjects as not having periodontitis or with one of three grades of periodontitis severity.

RESULTS

A positive MCI was found in 38.9% of the subjects, in contrast to 8.2% self-reported OPOR. The intraclass correlation between MCI and self-reported OPOR was 0.20 (P < 0.01). The likelihood of an association between OPOR and MCI was 2.6 (95%CI: 1.6, 4.1, P < 0.001). Subjects with self-reported OPOR and a positive MCI had worse periodontal conditions (P < 0.01). The Mantel-Haentzel odds ratio for OPOR and periodontitis was 1.8 (95%CI: 1.2, 2.5, P < 0.001).

CONCLUSIONS

The prevalence of positive MCI was high and consistent with epidemiological studies, but only partly consistent with a self-reported history of osteoporosis with a higher prevalence of positive MCI in Chinese women. Horizontal alveolar bone loss is associated with both positive self-reported OPOR and MCI.