Ability of peripheral DXA measurement to diagnose osteoporosis as assessed by central DXA measurement

Cross-Sectional and Longitudinal Associations between Forearm Bone Mineral Density and Anthropometry in Adult Japanese Men and Women

BACKGROUND

No consensus exists regarding which anthropometric measurements are related to bone mineral density (BMD), and this relationship may vary according to sex and age. A large Japanese cohort was analyzed to provide an understanding of the relationship between BMD and anthropometry while adjusting for known confounding factors.

METHODS

Our cohort included 10,827 participants who underwent multiple medical checkups including distal forearm BMD scans. Participants were stratified into four groups according to age (≥50 years or <50 years) and sex. The BMD values were adjusted for confounding factors, after which single and partial correlation analyses were performed. The prevalence of osteopenia was plotted for each weight index (weight or body mass index [BMI]) class.

RESULTS

Cross-sectional studies revealed that weight was more favorably correlated than BMI in the older group (R=0.278 and 0.212 in men and R=0.304 and 0.220 in women, respectively), whereas weight and BMI were weakly correlated in the younger age groups. The prevalence of osteopenia exhibited a negative linear relationship with weight among older women ≥50 years of age, and an accelerated increase was observed with decreasing weight in older men weighing <50 kg and younger women weighing <60 kg. When weight was replaced with BMI, the prevalence was low in most subgroups classified by weight.

CONCLUSIONS

Weight, rather than BMI, was the most important indicator of osteopenia but it might not be predictive of future bone loss.

Prescreening for osteoporosis with forearm bone densitometry in health examination population

BACKGROUND

Early detection and timely prophylaxis can retard the progression of osteoporosis. The purpose of this study was to determine the validity of peripheral Dual Energy X-ray Absorptiometry (DXA) test for osteoporosis screening. We examined peripheral bone mineral density (BMD) using AKDX-09 W-I DXA densitometer. Firstly, we acquired BMD data from manufacturer-supplied density-gradient phantoms and 30 volunteers to investigate its accuracy and precision, then we measured BMD for 150 volunteers using both AKDX (left forearm) and Hologic Discovery Wi (left forearm, left hip and L1 - L4 vertebrae) simultaneously. Correlation relationship of BMD results acquired from two instruments was assessed by simple linear regression analysis, the Receiver Operating Characteristic (ROC) curves and Areas Under the Curves (AUCs) were evaluated for the diagnostic value of left forearm BMD measured by AKDX in detecting osteoporosis.

RESULTS

In vitro precision errors of AKDX BMD were 0.40, 0.20, 0.19%, respectively, on low-, medium-, and high-density phantom; in vivo precision was 1.65%. Positive correlation was observed between BMD measured by AKDX and Hologic at the forearm (r = 0.670), L1-L4 (r = 0.430, femoral neck (r = 0.449), and total hip (r = 0.559). With Hologic measured T-score as the gold standard, the sensitivity of AKDX T-score < - 1 for identifying suboptimal bone health was 63.0 and 76.1%, respectively, at the distal one-third radius and at any site, and the specificity was 73.9 and 90.0%, respectively; the AUCs were 0.708 and 0.879. The sensitivity of AKDX T-score ≤ - 2.5 for identifying osteoporosis at the distal one-third radius and at any site was 76.9 and70.4%, respectively, and the specificity was 80.4 and 78.0%, respectively; the AUCs were 0.823 and 0.778.

CONCLUSIONS

Peripheral DXA appears to be a reliable tool for prescreening for osteoporosis.

Bone Mineral Density Around the Knee Joint: Correlation With Central Bone Mineral Density and Associated Factors

INTRODUCTION

The aims of this study were to (1) assess the bone mineral density (BMD) around the knee joint, (2) determine the correlation between central and knee BMDs, and (3) investigate the factors associated with BMD around the knee joint in patients with knee osteoarthritis (OA).

METHODOLOGY

This cross-sectional study included 122 patients who underwent total knee arthroplasty. Central and knee dual-energy X-ray absorptiometry was performed preoperatively. BMD at 6 regions of interest (ROIs) around the knee joint were measured, and their correlations with central BMD were determined using Spearman's correlation analysis. Lower limb alignment, severity of OA, body mass index (BMI), preoperative functional and pain scores were assessed to elucidate the factors associated with knee BMD using linear regression analysis.

RESULTS

Around the knee joint, BMD was the lowest at the distal femoral metaphysis and lateral tibial condyle. Knee BMD was significantly correlated with central BMD. However, the correlation coefficients varied by the ROI. Additionally, multivariate analysis revealed different associations with respect to the regions around the knee joint. Varus alignment of the lower limb was associated with increased BMD of the medial condyles and decreased BMD of lateral condyles. High grade OA was a protective factor; it was associated with increased BMD at the lateral condyles of the femur and tibia. Higher BMI was an independent protective factor in all ROIs around the knee joint except the lateral femoral condyles. Lower functional level was not associated with decreased BMD, whereas a higher pain score was significantly associated with lower BMD at the proximal tibial metaphysis.

CONCLUSIONS

Knee BMD was significantly correlated with central BMD. However, the correlations varied with the regions around the knee joint probably due to their independent association with the alignment of the lower limb, severity of OA, BMI, and preoperative pain level.

A Substruction Approach to Assessing the Theoretical Validity of Measures

BACKGROUND

Validity is about the logic, meaningfulness, and evidence used to defend inferences made when interpreting results. Substruction is a heuristic or process that visually represent the hierarchical structure between theory and measures.

PURPOSE

To describe substruction as a method for assessing the toretical validity of research measures.

METHODS

Using Fawcett's Conceptual-Theoretical-Empirical Structure. an exemplar is presented of substruction from the Individual and Family Self-Management Theory to the Striving to be strong study concepts and empirical measures.

RESULTS

Substruction tables display evidence supporting theoretical validity of the instruments used in the study.

CONCLUSION

A high degree of congruence between theory and measure is critical to support the validity of the theory and to support attributions made about moderating, mediating, causal relationships, and intervention effects.

Peripheral DXA measurement around ankle joint to diagnose osteoporosis as assessed by central DXA measurement

OBJECTIVE

This study evaluated the correlation between central and peripheral bone mineral density (BMD) of the ankle joint, using dual-energy X-ray absorptiometry (DXA). We also investigated whether peripheral ankle BMD could be used to identify individuals who were diagnosed with osteoporosis, using central DXA.

METHODS

We recruited 134 volunteers aged 20-90 years who agreed to participate in this study. Central BMD of the lumbar spine and left femur, and peripheral BMD of the medial malleolus, distal tibia, lateral malleolus, and talus were measured with DXA.

RESULTS

Among the peripheral sites of the ankle, the highest and lowest BMD were observed in the talus and lateral malleolus, respectively. All peripheral DXA measurements of the ankle joint were significantly correlated with central DXA measurements. There was a good correlation (r: 0.656-0.725) between peripheral and central BMD for the older age group (> 50 years), but fair-to-good correlation (r: 0.263-0.654) for the younger age group (< 50 years). The cut-off values for peripheral BMD of the ankle joint between osteoporosis and non-osteoporosis were 0.548 g/cm² (sensitivity, 89.0%; specificity, 69.0%) for the medial malleolus, 0.626 g/cm² (sensitivity, 83.3%; specificity, 82.8%) for the distal tibia, 0.47 g/cm² (sensitivity, 100.0%; specificity, 65.5%) for the lateral malleolus, and 0.973 g/cm² (sensitivity, 72.2%; specificity, 83.6%) for the talus (p < 0.001).

CONCLUSIONS

This study showed good correlation between peripheral BMD around ankle joint and central BMD for older age group. Further study is required to use the ankle DXA as a valid clinical tool for the diagnosis of osteoporosis and fracture risk assessment.

Quantitative ultrasound measurements of the calcaneus and hand phalanges in elderly Spanish men: relationship with peripheral bone mineral density of the hand phalanges

OBJECTIVES

The aims of this pilot study were to describe quantitative ultrasound (US) measurements and peripheral bone mineral density (BMD) of the hand phalanges on dual-energy x-ray absorptiometry and to examine the correlations between them in elderly Spanish men.

METHODS

We studied 199 healthy men (mean age ± SD, 73.31 ± 5.10 years). The participants were not taking any medications, and they reported no diseases, including diseases that are associated with abnormalities in mineral metabolism. Phalangeal and calcaneal quantitative US measurements and phalangeal BMD measurements were performed in all participants.

RESULTS

A bivariate correlation analysis showed no association between quantitative US assessments at the phalanges or the calcaneus (P = .409). After adjustment for potential confounders, the correlation between phalangeal BMD and phalangeal quantitative US measurements was r = 0.417 (P < .0001), and the correlation for calcaneal quantitative US was r = 0.26 (P = .001). Further adjustment by percentage of body fat increased quantitative US correlations with phalangeal BMD: r = 0.450 (P < .0001) at the phalanges; r = 0.291 (P = .001) at the calcaneus.

CONCLUSIONS

There is a small correlation between quantitative US measurements at the calcaneus and phalangeal BMD that increases to a moderate level with quantitative US measurements at the phalanges in elderly Spanish men.

Forearm bone mineral density varies as a function of adiposity in inuit women 40-90 years of age during the vitamin D-synthesizing period

Aging Inuit women are at increased risk for low vitamin D status due to habitation at higher latitudes, darker skin, and ongoing nutrition transition. Lower serum 25-hydroxyvitamin D (25[OH]D) concentration and higher risk of fracture have been separately reported in Inuit women, with particular relevance to postmenopausal women. We evaluated vitamin D status, forearm bone mineral density (fBMD), and nutrition in Inuit women ≥40 years. Women (n = 568) were randomly selected to participate in the 2007-2008 International Polar Year Inuit Health Survey from 36 Arctic communities. fBMD was measured using peripheral dual-energy X-ray absorptiometry. Dietary intakes were derived from 24 h recall and food-frequency questionnaires. Fasting serum 25(OH)D, parathyroid hormone, and osteocalcin (OC) were measured using a LIAISON(®) automated analyzer. The weighted prevalence of women having 25(OH)D concentration below 37.5, 50, and 75 nmol/L was 7.2 %, 17.6 %, and 48.6 %, respectively, with older women having better status. The dietary density of most nutrients increased with age, as did traditional food intake. fBMD was low in 3 (1.4 %) premenopausal (Z score < -2) and 107 (29.6 %) postmenopausal (T score < -1.5) women. Regression revealed that either weight, body mass index, or percent body fat significantly predicted fBMD in premenopausal women, in addition to age and OC in postmenopausal women. Women ≥50 years have higher vitamin D status and more nutrient-dense diets than women 40-49 years. While measures of adiposity predicted fBMD in all women, additional predictors after menopause included age and bone turnover.

Dual energy X-ray absorptimetry: fundamentals, methodology, and clinical applications

Dual-energy X-ray absorptiometry (DXA; DEXA) is the technique of choice to diagnose osteoporosis and to monitor the response to treatment. It is also useful for measuring body composition. In recent years, new applications have been developed, including vertebral morphometry through the study of the lateral spine, prosthesis integration in orthopedics, and lipodystrophy in HIV+ patients, although its use in these cases is not well established. DXA densitometry is accurate and precise. It is essential to optimize each step of the diagnostic process, taking care to ensure the best acquisition, image analysis, and interpretation of the results. Thus, to obtain the greatest utility from DXA, radiologists need to know the technique, its indications, and its pitfalls. This article reviews the fundamentals, modalities, methods, and clinical applications of DXA.

Bone health in healthy Indian population aged 50 years and above

One thousand six hundred healthy subjects aged more than 50 years, residing in Delhi, were evaluated for bone mineral metabolic parameters. High prevalence of osteoporosis (35.1% subjects) was observed in this population. Bone mineral density (BMD) correlated positively with body mass index (BMI) and negatively with PTH levels. No correlation was observed with serum 25(OH)D levels.

INTRODUCTION

To assess the bone health status in elderly Indians and compare peripheral DXA (pDXA) with central DXA in evaluation of osteoporosis.

METHODS

The study involved 1,600 healthy subjects more than 50 years of age residing in Delhi, India, who underwent anthropometric, biochemical, and hormonal evaluation. BMD was measured by DXA at lumbar spine, hip, and distal radius; and by pDXA at forearm and calcaneum.

RESULTS

Seven hundred ninety-two males and 808 postmenopausal females, with a mean age of 57.67 ± 9.46 years were evaluated. Osteoporosis was present in 35.1% subjects (M-24.6%, F-42.5%) and osteopenia in 49.5% (M-54.3%, F-44.9%). Prevalence of osteoporosis increased with age in females, but not in males. BMD at all sites, except distal radius, was positively correlated with BMI (r=0.037, p=0.14). Total body BMD was negatively correlated with alkaline phosphatase (r= -0.184, p<0.00001) and PTH levels (r= -0.099, p<0.00001), respectively. No significant correlation was observed between serum 25(OH)D levels and BMD at any site. BMD at forearm and calcaneum, measured using pDXA, showed strong positive correlation with BMD measured by central DXA. pDXA had sensitivity of 88%, specificity of 55%, and negative and positive predictive values of 89% and 52%, respectively, at T-score -2.5 at peripheral sites compared to central DXA.

CONCLUSIONS

A high prevalence of osteoporosis was observed in elderly Indian subjects. pDXA has high negative predictive value, making it a useful tool in population screening for osteoporosis.

Refinement of an osteoporosis risk-assessment questionnaire for use in community pharmacy

Objective

To explore the influence of bone mineral density (BMD) tests in osteoporosis risk categorisation in community pharmacies, and to develop a simple tool for pharmacists to use as a pre-BMD test screen.

Method

A secondary data analysis was conducted on the responses of 193 participants to a risk-assessment questionnaire, used in previous osteoporosis research that included a BMD test. To explore the impact of the BMD test on pharmacists' categorisation of risk, the researchers made an independent assessment based on responses of the questionnaire. The influence of risk factors on BMD scores/bone status was explored using multiple and logistic regression respectively.

Key findings

A total of responses of 193 participants were available for study, with 113 in the BMD group and 80 from the non-BMD group. In the BMD group, both researchers and pharmacists identified a similar proportion of patients in the moderate/high-risk category when BMD results were incorporated in the risk assessments (X2 = 0.78, degrees of freedom (df) = 1, 0.3 &lt; P &lt; 0.5). A statistically significant difference in risk categorisation was found between the pharmacists and researchers in the non-BMD group (X2 = 23.9, df = 1, P &lt; 0.001). Risk factors identified to be significantly affecting BMD and of use for identifying patients at high risk for osteopenia/osteoporosis were age, weight, postmenopause and absence of hormone replacement therapy (HRT). These four factors were used to construct a simple risk index to guide pharmacists' initial risk categorisation.

Conclusion

The findings of this study suggested that BMD testing may increase the effectiveness of risk assessments and enhance the screening procedures in the community pharmacy. The simple risk index could serve as a pre-BMD test screen, with a BMD test recommended when necessary. A refined risk-assessment questionnaire could serve to guide pharmacists in directing individualised counselling and advice for at-risk patients, through identification of modifiable risk factors and conditions.

Patient responses to an integrated service, initiated by community pharmacists, for the prevention of osteoporosis

Objective

This study aimed to develop, implement and evaluate an integrated service provided by pharmacists to consumers based on the results of a risk-assessment survey carried out by the pharmacist and testing of bone mineral density (BMD) by a radiographer. It also investigated whether measurement of BMD in the pharmacy increased the effectiveness of the service and pharmacist referral in terms of adherence to advice and uptake of referral compared with the same service offered without BMD testing.

Setting

Community pharmacists in urban and rural settings in New South Wales, Australia, delivered the service.

Method

The adherence to advice or referral given by 12 community pharmacists during 2003 to 217 participants about the prevention of osteoporosis following screening with either a BMD test plus risk-assessment questionnaire or a risk-assessment questionnaire only was compared.

Key findings

No significant between-group differences in adherence to advice or referral were found. However, participants valued the BMD service significantly more highly than the non-BMD service as measured by satisfaction scores.

Conclusions

Consumers were interested in receiving information about osteoporosis and their own risk of it and even greater interest in BMD testing in the pharmacy. There was no difference in uptake of referral or advice following either questionnaire only or questionnaire plus BMD testing. Low uptake of referral and advice overall by those deemed to be at high risk is of concern. Far greater education and encouragement for consumers to follow through is required.

Lifestyle impact on lifetime bone loss in women and men: the Tromsø Study

A physically active, nonsmoking lifestyle with weight maintenance positively influences bone health. The authors estimated the effect of lifestyles on peak bone mass and lifetime bone loss in the Tromsø Study, Norway. Bone mineral density (BMD) was measured at distal and ultradistal forearm sites with single x-ray absorptiometric devices in 7,948 men and women aged 24-84 years in 1994-1995 and repeated in 2001 in 6,182 subjects. BMD was significantly higher at peak than at old age. However, the difference, estimated as lifetime loss, varied between lifestyle groups. Lifetime loss in nonsmoking, physically active men with a body mass index of 25 kg/m(2) compared with smoking, inactive, and lean men was 15.9% and 25.9% at the distal site and 17.5% and 29.7% at the ultradistal site, respectively. In women, the corresponding loss estimates were 34.4% and 45.7% and 35.6% and 55.7%, respectively. The differences in BMD at the age of 80 years correspond to an increased forearm fracture risk of 69% in men and 85% in women with greatest bone loss. A lifestyle including nonsmoking, a high physical activity level, and a high body weight reduces bone loss and fracture risk in both sexes, with increasing effect from peak bone mass to old age.

Age-related trends in phalangeal bone mineral density in Sri Lankan men and women aged 20 years or more

To establish normative reference values and to study the age-related trends in phalangeal bone mineral density (BMD), 4504 male and 5215 female volunteers aged 20 yr or more were recruited from 7 provinces from October 2004 to October 2005. Subjects suffering from diseases and those who were taking medications, which could affect BMD were excluded from the analysis (n=530). Phalangeal BMD was measured in the nondominant hand using an AccuDXA. Men and women were categorized to age groups of 20-29 (1087 men and 1079 women), 30-39 (1122 men and 1146 women), 40-49 (1148 men and 1455 women), 50-59 (810 men and 1111 women), 60-69 (250 men and 335 women), and 70 yr or more (87 men and 94 women). Mean BMDs (SD) of men in above categories were 0.595 (0.057), 0.603 (0.061), 0.591 (0.066), 0.576 (0.069), 0.558 (0.077), and 0.522 (0.079) g/cm2, respectively. The corresponding BMDs (SD) in women were 0.495 (0.057), 0.506 (0.062), 0.502 (0.064), 0.462 (0.072), 0.406 (0.072), and 0.340 (0.055) g/cm2, respectively. Peak BMD was seen in 30-39-age category in both sexes. Women after 50 yr lost BMD at a rate of 0.006 (standard error 0.0003) g/cm2/yr, whereas the corresponding value in men was 0.002 (standard error 0.0001) g/cm2/yr. These data provide normative reference data for the calculation of T-score and Z-score for phalangeal BMD in Sri Lankan men and women aged more than 20 yr.

Treatment of postmenopausal osteoporosis

Osteoporosis is a skeletal disease characterized by low bone mass and microarchitectural deterioration with a resulting increase in bone fragility and hence susceptibility to fracture. Calcium and vitamin D are the most commonly used therapies for osteoporosis, although their efficacy in osteoporotic fracture prevention remains uncertain. Biphosphonates are the most frequently prescribed medication for treatment of osteoporosis and are often considered as first-line therapy for the treatment of osteoporosis. Currently, hormone replacement therapy is only approved by the Food and Drug Administration (FDA) for short-term treatment of severe postmenopausal symptoms with the lowest dose used for the shortest time. In view of its lack of effect on the prevention of nonvertebral fractures, the use of raloxifene should be limited to women with spinal osteoporosis. Most experts agree that it is preferable to treat osteoporosis with a more potent agent than calcitonin and manage the pain separately. Currently, the FDA recommends the use of parathyroid hormone for treatment of osteoporosis for a maximum of 2 years because of the concern of development of osteosarcoma.

Update on Osteoporosis Management in Long-term Care: Focus on Bisphosphonates

Osteoporotic fractures are potentially devastating and associated with high morbidity and substantial economic burden. Residents of long-term care facilities are at greater risk of osteoporosis and its related fractures than those living in the community, yet osteoporosis is underdiagnosed and undertreated in these settings. Bisphosphonates are approved by the Food and Drug Administration for the treatment and prevention of osteoporosis in postmenopausal women. As a class, bisphosphonates have been shown to increase bone mineral density, decrease the markers of bone resorption, and reduce the risk of osteoporotic fractures. The 3 approved bisphosphonates are alendronate, risedronate, and ibandronate. Alendronate and risedronate are dosed daily or weekly and ibandronate, the most recently approved bisphosphonate, has been approved for monthly oral dosing or as an intravenous formulation to be given intermittently (every 3 months). In addition, other products with different mechanisms of action are in the pharmaceutical pipeline and may offer additional management options.

Peripheral bone densitometry: Clinical applications

Technologies for the measurement of bone mineral density and other parameters of bone strength at peripheral skeletal sites have been studied since the 1960s. Single-energy Photon Absorptiometry (SPA), Radiographic Absorptiometry (RA), Radiogrametry (RG), Single-energy X-ray Absorptiometry (SXA), Peripheral Dual-energy X-ray Absorptiometry (pDXA), and Quantitative Ultrasonometry (QUS) have been successively evaluated. These technologies and their clinical applications are discussed in this article. The available scientific evidence supports the clinical use of these technologies at peripheral skeletal for assessment of fracture risk. Peripheral measurements other than the 33% (one-third) radius by DXA cannot be used to diagnose osteoporosis according to current standards. Peripheral skeletal sites are not clinically useful for monitoring changes in BMD with natural evolution of the disease and its treatment. Peripheral BMD measurement can theoretically be used to screen patients for selection to central DXA testing, although device-specific cut-points should be developed before this is implemented. When central DXA testing is not available, peripheral BMD testing may be considered to identify individuals who might benefit from pharmacological intervention.

Correlations between bone mineral density of the hand and other skeletal sites as measured by DXA in Chinese women and men

This study was aimed at assessing the correlations between the bone mineral density (BMD) of the hand and other skeletal sites in Chinese women and men. We measured the BMD of the total body, the anteroposterior lumbar spine (L2-L4), bilateral proximal femurs (i.e., total hip, femoral neck, and trochanter), and bilateral total hands in 363 Chinese adults (96 males, 267 females) using dual-energy X-ray absorptiometry (DXA). Data were analyzed by descriptive statistics, Student's t tests, and Pearson's correlation coefficients (r). We found that bilateral hand measurements reduced precision error by 36% as compared with a single hand measurement. Dominant hand BMD was significantly higher than nondominant hand BMD. For both the dominant and nondominant sides, hand BMD was significantly higher in males than in females. Hand BMD correlated significantly (p<0.001) with the BMD of all skeletal sites for all subjects (r=0.681-0.848), the male group (r=0.568-0.857), and the female group (r=0.687-0.859). After normal references for the Chinese population have been established, further investigations may determine the clinical usefulness of hand BMD measurement in the diagnosis of osteoporosis and the prediction of fracture risk.

Longitudinal changes in forearm bone mineral density in women and men aged 45-84 years: the Tromso Study, a population-based study

The aim of this study was to describe changes in bone mineral density in Norwegian women and men aged 45-84 years in a population-based, longitudinal study. Bone mineral density (g/cm2) was measured at distal and ultradistal forearm sites with single x-ray absorptiometric devices in 3,169 women and 2,197 men at baseline in 1994-1995 and at follow-up in 2001 (standard deviation, 0.4 years). The mean annual bone loss was -0.5% and -0.4% in men and -0.9% and -0.8% in women not using hormone replacement therapy at the distal and ultradistal sites, respectively. In men, age was a negative predictor of bone mineral density change at both sites. Women not using hormone replacement therapy had the highest bone loss at the ultradistal site 1-5 years after menopause. The correlation between the two measurements was high: r = 0.93 and r = 0.90 in women and r = 0.96 and r = 0.93 in men for the distal and ultradistal sites, respectively. More than 70% kept their quartile positions, indicating a high degree of tracking of bone mineral density measurements. Although the study population live above the polar circle, the rate of bone loss was not higher at the distal and ultradistal forearm sites compared with that of other cohorts.

Osteoporosis diagnosis and screening

Osteoporosis and osteoporotic fracture are major causes of morbidity and mortality in the United States and worldwide. Nearly half of all women and one quarter of men >50 years of age will experience an osteoporosis-related fracture during their lifetime. The diagnosis of osteoporosis in postmenopausal women and older men can be made definitively by comparing bone mineral density (BMD) measurements from dual-energy x-ray absorptiometry (DXA) to mean peak bone mass in young adults. Efforts to increase access to DXA and improve the sensitivity and specificity of osteoporosis risk assessment instruments may help ensure that individuals with osteoporosis are diagnosed early. The early identification of individuals with low BMD and/or clinical risk factors, accurate diagnosis of osteoporosis and osteopenia, and initiation of appropriate treatment are crucial to reducing the incidence of vertebral and nonvertebral fractures. The World Health Organization is moving toward absolute risk assessment and this may help to better identify patients for screening and treatment in the future.

Comparison between the Klemetti index and heel DXA BMD measurements in the diagnosis of reduced skeletal bone mineral density in the elderly

Osteopenia/osteoporosis affect many elderly people and might not be detected until symptoms of fractures occur. Early detection of osteopenia/osteoporosis is important and would allow preventive measures and treatment. Access to screening for osteopenia/osteoporosis is often limited, whereas panoramic radiography is commonly used in dentistry. The aim of this study was to determine the validity of the Klemetti index (KI), measured on panoramic radiographs, in the diagnosis of osteopenia/osteoporosis as defined by a bone mineral density (BMD) measurement below -1.5 standard deviations (SDs) of a community based sample. In total, 211 consecutive participants (102 men and 109 women) 60-96 years in the SNAC-Blekinge study (Swedish National Study on Ageing and Care) underwent bone densitometry [by dual-energy X-ray absorptiometry (DXA)] of both heels. A panoramic radiograph was taken of each participant, and mandibular cortex on a panoramic radiograph was classified as '0' or normal (even and sharp endosteal margin), '1', moderately eroded (evidence of lacunar resorption or endosteal cortical residues), or '2', severely eroded (unequivocal porosity). From logistic regression, the odds ratio of having a BMD measurement below -1.5 SD was 8.04 (95% CI 2.39 to 27.12, P<0.001) in the 'osteopenic' (KI category 2), compared with the 'normal' group (KI categories 0 and 1). Receiver operating characteristic (ROC) curve analysis was used to measure the validity of the KI indicating osteopenia (KI category 2) in predicting reduced BMD. This point provided a sensitivity of 50% and a specificity of 89%. Positive and negative predictive values were 21% and 97%, respectively. There were 87% correctly classified subjects. The area under the ROC curve was 0.64. The present study demonstrated that a negative finding (KI category <2) is highly predictive of the absence of osteopenia/osteoporosis as defined by the DXA measurements.

Ethnic differences in bone mineral density between inuit and Caucasians in north Greenland are caused by differences in body size

Data on bone mineral density (BMD) in living Inuit are limited and BMD measurements in Arctic Inuit using Dualenergy X-ray Absorptiometry (DXA) are lacking. Ethnicity may be important for bone mass. The aim of this study was to validate DXA in rural Arctic Greenland, to measure BMD in Greenland Inuit and Caucasians, and to estimate the importance of ethnicity for BMD. We measured the BMD in 80 healthy subjects living in Ilulissat and Saqqaq in North Greenland twice in both distal forearms and in both heels using peripheral DXA (pDXA). Participants were stratified by origin (Inuit[settlement])/Caucasians, n = 33 [19]/28), gender (men/women, n = 37/43), and age (30-39/40-49, n = 32/48). Caucasians were bigger than Inuit (men/women, height p < 0.001/p < 0.001; weight p = 0.01/ p = 0.026), but had similar BMI (p = 0.42/0.70). Triplicate pDXA measurements showed individual CV% = 0.16-1.79%; overall CV% = 1.1% (forearm)/1.0% (heel). Data followed the normal distribution (p = 0.65-0.99) with identical variances between Inuit and Caucasians (p = 0.12-0.63). Mean BMD in right forearm/left forearm/right heel/left heel was: Inuit men 0.570/0.568/0.549/0.536 g/cm2; Inuit women 0.484/0.474/0.473/0.464 g/cm2; Caucasian men 0.580/0.570/0.646/0.638 g/cm2; Caucasian women 0.495/0.496/0.552/0.553 g/cm2. An ethnic difference in heel BMD (p < 0.001) disappeared when adjusted for weight (p = 0.30). No difference was found in forearm BMD. In conclusion, pDXA is feasible and reliable in rural Greenland. Ethnic differences in BMD are small and may reflect differences in body size.

Forearm single X-ray absorptiometry in the identification of postmenopausal women with osteoporosis at the hip and spine: a correlation study

The International Society for Clinical Densitometry (ISCD) has stated that forearm bone mineral density (BMD) testing combined with a thorough clinical evaluation may be an option for the diagnosis of osteoporosis when central bone density (CBD) testing is not available. This study assessed the performance of two different forearm sites in identifying subjects with spinal and femoral osteoporosis, and defined the 90% sensitivity point for the DTX-100 bone densitometer in the detection of central osteoporosis. Four hundred and two postmenopausal Bulgarian women between the ages of 50 and 81 yr (mean age 60.24 +/- 10.48 yr) participated in this study. Forearm BMD (distal and ultradistal forearm) was measured with a DTX-100 device (Osteometer Meditech, USA) and central BMD (lumbar spine and proximal femur) with a Hologic QDR 4500 A device. Linear T-score correlations among sites, sensitivity and specificity of the forearm site were analyzed. T-score correlations between the forearm and the central sites ranged from 0.32 to 0.69 (p < or = 0.05 for all correlations in age group 50-59). The forearm site sensitivity increased slightly with advancing age, but specificity decreased. When the distal forearm BMD cut point (0.340 g/cm2) was set to achieve 90% sensitivity to identify total hip osteoporosis, specificity was 40%; when the distal forearm BMD cut point (0.410 g/cm2) was set to achieve 90% sensitivity to identify spinal osteoporosis, specificity was 55.4%; when ultradistal forearm BMD cut points (0.280 and 0.320 g/cm2) were set to achieve 90% sensitivity to identify total hip and spinal osteoporosis, specificity was 40.8 and 59.2%, respectively. Forearm bone density measures may be useful to selectively screen for patients with central osteoporosis.