Prevalence and risk factors of discordance in diagnosis of osteoporosis using spine and hip bone densitometry

Artificial Intelligence-enabled Chest X-ray Classifies Osteoporosis and Identifies Mortality Risk

A deep learning model was developed to identify osteoporosis from chest X-ray (CXR) features with high accuracy in internal and external validation. It has significant prognostic implications, identifying individuals at higher risk of all-cause mortality. This Artificial Intelligence (AI)-enabled CXR strategy may function as an early detection screening tool for osteoporosis. The aim of this study was to develop a deep learning model (DLM) to identify osteoporosis via CXR features and investigate the performance and clinical implications. This study collected 48,353 CXRs with the corresponding T score according to Dual energy X-ray Absorptiometry (DXA) from the academic medical center. Among these, 35,633 CXRs were used to identify CXR- Osteoporosis (CXR-OP). Another 12,720 CXRs were used to validate the performance, which was evaluated by the area under the receiver operating characteristic curve (AUC). Furthermore, CXR-OP was tested to assess the long-term risks of mortality, which were evaluated by Kaplan‒Meier survival analysis and the Cox proportional hazards model. The DLM utilizing CXR achieved AUCs of 0.930 and 0.892 during internal and external validation, respectively. The group that underwent DXA with CXR-OP had a higher risk of all-cause mortality (hazard ratio [HR] 2.59, 95% CI: 1.83-3.67), and those classified as CXR-OP in the group without DXA also had higher all-cause mortality (HR: 1.67, 95% CI: 1.61-1.72) in the internal validation set. The external validation set produced similar results. Our DLM uses CXRs for early detection of osteoporosis, aiding physicians to identify those at risk. It has significant prognostic implications, improving life quality and reducing mortality. AI-enabled CXR strategy may serve as a screening tool.

The association of lipid metabolism with bone metabolism and the role of human traits: a Mendelian randomization study

Background

The impact of lipid metabolism on bone metabolism remains controversial, and the extent to which human traits mediate the effects of lipid metabolism on bone metabolism remains unclear.

Objective

This study utilized mendelian randomization to investigate the effects of blood lipids on bone mineral density (BMD) at various skeletal sites and examined the mediating role of human traits in this process.

Methods

We leveraged genetic data from large-scale genome-wide association studies on blood lipids (n=1,320,016), forearm bone mineral density (FA-BMD) (n=10,805), lumbar spine bone mineral density (LS-BMD) (n=44,731), and femoral neck bone mineral density (FN-BMD) (n=49,988) to infer causal relationships between lipid and bone metabolism. The coefficient product method was employed to calculate the indirect effects of human traits and the proportion of mediating effects.

Results

The results showed that a 1 standard deviation(SD) increase in HDL-C, LDL-C and TC was associated with a decrease in LS-BMD of 0.039 g/cm2, 0.045 g/cm2 and 0.054 g/cm2, respectively. The proportion of mediating effects of systolic blood pressure (SBP) on HDL-C to LS-BMD was 3.17%, but suppression effects occurred in the causal relationship of LDL-C and TC to LS-BMD. Additionally, the proportion of mediating effects of hand grip strength (HGS) on the TC to LS-BMD pathway were 6.90% and 4.60% for the left and right hands, respectively.

Conclusion

In conclusion, a negative causal relationship was established between lipid metabolism and bone metabolism. Our results indicated that SBP and HGS served as mediators for the effects of lipid metabolism on bone metabolism.

Unravelling hip-spine bone mineral density discordance in people living with HIV

INTRODUCTION

In people living with HIV (PLWH), bone mineral density (BMD) discordance between the lumbar spine (LS) and femoral neck (FN) could be frequent given the high frequency of secondary osteoporosis, including HIV-related factors for bone disease.

MATERIALS AND METHODS

Retrospective cohort of PLWH with a dual X-ray absorptiometry scan. Hip-spine BMD discordance was defined as different T-score or Z-scores categories at LS and FN.

RESULTS

Overall, 865 individuals (mean 49.5 years, female 27%) were included. Osteoporosis diagnosis was four-to-seven times lower when both skeletal sites were affected than when considering the lowest T-score at any site (overall, 21% vs 4%). Hip-spine BMD discordance was observed in 381 (44%) individuals, it increased with age (from 43 to 52%, P = 0.032), and it was mainly due to lower LS-BMD. A lower FN-BMD was associated with older age, lower BMI (P < 0.01), and HIV-related factors, such as low CD4 + T-cell counts, duration of HIV infection, and time on antiretroviral therapy (ART). In a multivariate regression analysis, sex male (Odds Ratio, OR 4.901), hyperparathyroidism (OR, 2.364), and time on ART (OR 1.005 per month) were independently associated with discordance. A higher estimated fracture risk by FRAX equation was observed in individuals with BMD discordance due to lower FN-BMD compared to those with lower LS-BMD (+ 36% for major osteoporotic fracture, P = 0.04; + 135% for hip fracture, P < 0.01).

CONCLUSION

Hip-spine BMD discordance is highly prevalent in PLWH and it is associated with classical and HIV-related risk factors, modifying the rate of osteoporosis and fracture risk estimation.

Evaluation of the bone mineral density in the Mexican female population using the Radiofrequency Echographic Multi Spectrometry (REMS) technology

The bone health status of a Mexican female population, including a cohort of 455 women aged over 40 years, was assessed by Radiofrequency Echographic Multi Spectrometry (REMS).

PURPOSE

Assessment of the bone health status in an average female Mexican population with REMS. The secondary objective investigated age- and body mass index (BMI)-related effects on the diagnostic classification and the influence of risk factors for osteoporosis.

METHODS

Women aged over 40 years underwent a REMS scan at the lumbar spine and both femoral necks. The degree of correlation of the bone mineral density (BMD) across axial sites was assessed by the Pearson correlation coefficient (r), along with the diagnostic discordance. The association between risk factors, age, and BMI and diagnostic classification was determined by the chi-squared test.

RESULTS

Four hundred seventy-one women were enrolled. Osteoporosis was diagnosed in 11.0%, 8.1%, and 8.3% of cases at the lumbar spine and right and left femoral neck, respectively. The diagnostic agreement between the lumbar spine and femoral necks was about 73% (85% considering a 0.3 T-score tolerance), whereas the agreement between the femoral necks was 97.4% (99.6% considering a 0.3 T-score tolerance). Most of discordant cases were minor discordances. The correlation between the lumbar spine and femoral neck was r = 0.82 and 0.85, respectively, whereas both femoral necks correlated with r = 0.97. As expected, the prevalence of osteoporosis increased with age and decreased as BMI increased.

CONCLUSION

The widespread applicability of the non-ionizing REMS technology has been demonstrated in a representative Mexican cohort, covering wide age and BMI ranges. Age and BMI variations correlate with the prevalence of osteoporosis, in line with the recent scientific literature.

Prevalence, Clinical Implication, and Cause of Spine Hip Discordance in Elderly Patients with Fragility Hip Fracture

Background

Spine-hip discordance (SHD) increases fracture risk. However, its prevalence and clinical implications have not been investigated in patients with hip fractures. This study determined the prevalence and association of SHD with mortality and investigated the cause of SHD in patients with hip fractures.

Methods

This study included patients admitted for fragility hip fractures between 2011 and 2020. All patients underwent dual energy X-ray absorptiometry and anteroposterior and lateral views of the lumbosacral spine during admission. Data on demographics, diagnosis, American Society of Anesthesiologists score, and mortality were collected. A T-score difference of more than 1.5 between L1–4 and the femur neck was considered discordant, and 3 groups (lumbar low [LL] discordance, no discordance [ND], and femur neck low [FL] discordance) were compared. In the discordance group, lumbar radiographs were reviewed to determine the cause of discordance.

Results

Among 1,220 eligible patients, 130 were excluded due to patient refusal or bilateral hip implantation; therefore, this study included 1,090 patients (271 male and 819 female). The prevalence of LL, ND, and FL was 4.4%, 66.4% and 29.2% in men and 3.9%, 76.1%, and 20.0% women. Mortality was not associated with discordance. The most common causes of discordance were physiological in the LL group and pathological in the FL group for both sexes.

Conclusions

Patients with hip fractures showed lower rates of ND and higher rates of FL compared to the general population. True discordance should be carefully judged for pathological and artifact reasons. The clinical implications of SHD require further investigation.

Prevalence and Risk Factors of T-Score Spine-Hip Discordance in Patients with Osteoporotic Vertebral Compression Fracture

Background: T-score discordance between the spine and hip is commonly observed when dual energy X-ray absorptiometry (DXA) is used to diagnose osteoporosis. However, information is scarce regarding the prevalence and risk factors for this problem in Korea. This study evaluated the prevalence of major/minor discordance and associated risk factors in elderly Korean patients with osteoporotic vertebral compression fractures (OVCFs).Methods: This study included 200 patients (37 men, 163 women) treated for thoracic or lumbar compression fractures between January 2015 and August 2021. DXA was performed to examine T‐scores and determine the prevalence of discordance, defined as a difference between the T-score categories of the femur and spine in the same individual. The t-tests, χ2 tests, and regression analyses were used to assess the associated risk factors of T-score discordance among the subjects.Results: T-score concordance, minor discordance, and major discordance were observed in 137 (68.5%), 59 (29.5%), and 4 (2%) patients with OVCFs, respectively. The spinal T-score was lower than the femoral T-score in all major discordance and 81.3% (48/59) of minor discordant cases. Overall, the only factor related to T-score discordance was the age at fracture (odds ratio, -0.01; P=0.014).Conclusions: The results of this study showed that a significant number of subjects (31.5%) showed spine-hip discordance, even with a mean age in their 80s. More attention should be paid to the appropriate evaluation and management of elderly patients with OVCFs. Moreover, a longitudinal study is necessary to verify the clinical importance of T-score discordance in this population.

Discordance in Bone Mineral Density between the Lumbar Spine and Femoral Neck Is Associated with Renal Dysfunction

PURPOSE

Bone mineral density (BMD) determined by dual-energy X-ray absorptiometry is considered a gold standard for diagnosing osteoporosis. Some people show discordance in BMD values measured at the femur and that at the lumbar spine (LS). The aim of the present study was to investigate whether differences in BMD T-scores between the LS and femur neck (FN) are associated with renal dysfunction in the general population of Korea.

MATERIALS AND METHODS

We analyzed national data for 17306 adults from the Korean National Health and Nutrition Examination Survey conducted between 2008 and 2011. BMD T-score differences between LS and FN (termed BMD offset) were calculated by subtracting FN T-scores from LS T-scores. Diminished renal function was defined as estimated glomerular filtration rates (eGFR) less than 60 mL/min/1.73 m².

RESULTS

Among those aged ≥50 years, BMD offset was negatively associated with eGFR levels. Additionally, eGFR levels decreased linearly across increasing BMD offset quartiles. Men and women with an offset of >1.5 showed a 4.79-times and 2.51-times higher risk of renal dysfunction, respectively, compared to individuals with an offset of ≤0, after adjusting for age, body mass index, educational level, current smoking, and physical activity. In contrast, there was little evidence of an association between renal dysfunction and BMD offset in subjects aged <50 years.

CONCLUSION

Discordance between LS and FN BMDs was significantly associated with renal dysfunction in subjects aged ≥50 years. When assessing bone health in older chronic kidney disease patients, physicians should consider the possibility of BMD discordance between LS and FN.

Does Quantitative Ultrasound at the Calcaneus Predict an Osteoporosis Diagnosis in Postmenopausal Women from the Silesia Osteo Active Study?

The aims of the study were to assess the clinical conformity between quantitative ultrasound (QUS) and densitometry with use of the standard World Health Organization T-score thresholds to determine optimal diagnostic cutoff values for QUS T-scores in different age groups. Three hundred sixty-five postmenopausal Caucasian women were enrolled into the study and divided into two age groups (<65 y and ≥65 y). Skeletal status was assessed using QUS measurements at the calcaneus and bone densitometry at the spine and proximal femur (Hologic Explorer, Bedford, MA, USA). QUS measurement results expressed as the stiffness index (SI) correlated significantly with both femoral neck bone mineral density (r = 0.51, p < 0.0001) and lumbar spine bone mineral density (r = 0.52, p < 0.0001). On the basis of receiver operating characteristic curve analyses, the thresholds for correspondence between QUS T-score values and T-score -2.5SD in dual X-ray absorptiometry (DXA) were established. They ranged between -1.63SD and -1.70SD in relation to femoral neck DXA and between -1.22SD and -1.51SD in relation to lumbar spine DXA, depending on age category. In conclusion, the study described here confirmed that QUS measurements at the calcaneus may provide information comparable to DXA examinations at the femoral neck and lumbar spine in postmenopausal women.

Metabolic activities affect femur and lumbar vertebrae remodeling, and anti-resorptive risedronate disturbs femoral cortical bone remodeling

Metabolic activities are closely correlated with bone remodeling and long-term anti-resorptive bisphosphonate treatment frequently causes atypical femoral fractures through unclear mechanisms. To explore whether metabolic alterations affect bone remodeling in femurs and lumbar vertebrae and whether anti-osteoporotic bisphosphonates perturb their reconstruction, we studied three mouse strains with different fat and lean body masses (BALB/c, C57BL6, and C3H mice). These mice displayed variable physical activity, food and drink intake, energy expenditure, and respiratory quotients. Following intraperitoneal calcein injection, double calcein labeling of the femoral diaphysis, as well as serum levels of the bone-formation marker procollagen type-I N-terminal propeptide and the bone-resorption marker C-terminal telopeptide of type-I collagen, revealed increased bone turnover in mice in the following order: C3H > BALB/c ≥ C57BL6 mice. In addition, bone reconstitution in femurs was distinct from that in lumbar vertebrae in both healthy control and estrogen-deficient osteoporotic mice with metabolic perturbation, particularly in terms of femoral trabecular and cortical bone remodeling in CH3 mice. Interestingly, subcutaneous administration of bisphosphonate risedronate to C3H mice with normal femoral bone density led to enlarged femoral cortical bones with a low bone mineral density, resulting in bone fragility; however, this phenomenon was not observed in mice with ovariectomy-induced femoral cortical bone loss. Together, these results suggest that diverse metabolic activities support various forms of bone remodeling and that femur remodeling differs from lumbar vertebra remodeling. Moreover, our findings imply that the adverse effect of bisphosphonate agents on femoral cortical bone remodeling should be considered when prescribing them to osteoporotic patients.

Prevalence and factors of T-score discordance between hip and spine among middle-aged and elderly Malaysians

T-score discordance between hip and spine is a common problem in the diagnosis of osteoporosis based on dual-energy X-ray absorptiometry. Not much information on the prevalence and risk factors of this problem is available in Malaysia. Our study found that factors like age, height, physical activity and menopausal status should be taken into account in the diagnosis of osteoporosis.

INTRODUCTION AND OBJECTIVE

T-score discordance between hip and spine is a common problem in bone mineral density assessment. A difference ≥ 1 standard deviation (SD) (regardless of diagnostic class) is considered minor, and a difference more than one diagnostic class is considered major discordance. This study aimed to determine the prevalence and factors of hip and spine T-score discordance in a population aged ≥ 40 years in Klang Valley, Malaysia.

SUBJECTS AND METHODS

In this cross-sectional study, subjects answered a demographic questionnaire and underwent body composition and bone health assessment using dual-energy X-ray absorptiometry. Chi-square and binary logistic regression analysis were used to assess the prevalence of T-score discordance among the subjects.

RESULTS

A total of 786 Malaysians (382 men, 404 women) subjects were recruited. The prevalence of minor and major discordance was 30.3% and 2.3%, respectively. Overall, factors related to T-score discordance were advanced age, decreased height, and being physically active. Sub-analysis showed that decreased height and being physically active predicted T-score discordance in men, being menopausal and Indian (vs Chinese) were predictors in women.

CONCLUSIONS

T-score discordance between hip and spine is common among Malaysian middle-aged and elderly population. Diagnosis of osteopenia/osteoporosis should be based on the T-score of more than one skeletal site as per the current recommendations.

Metabolic characteristics of subjects with spine-femur bone mineral density discordances: the Korean National Health and Nutrition Examination Survey (KNHANES 2008-2011)

The diagnosis of osteoporosis is determined based on the lowest bone mineral density (BMD) T-score at the lumbar spine (LS) and hip. However, there are occasional marked discordances between the T-score of LS and femur neck (FN). We aimed to examine the prevalence and characteristics of individuals with spine-femur BMD discordance using a nationwide survey. A total of 3233 men aged ≥ 50 years and 2915 postmenopausal women were included from the Korean National Health and Nutrition Examination Surveys (2008-2011). The spine-femur discordance was defined as a difference of ≥ 1.5 SD between LS and FN BMD. Subjects were divided into three groups: low LS (LS < FN), low FN (LS > FN), and no discordance. Four-hundred and seventeen men (12.9%) and two hundred and ninety women (10%) exhibited spine-femur BMD discordance. The prevalence of hypertension and diabetes was higher in men and women with low FN BMD than in any other group. Fasting plasma glucose and homeostasis model assessment of insulin resistance was the highest in subjects with low FN BMD among the three groups. Low FN BMD revealed higher serum parathyroid hormone and lower 25-hydroxyvitamin D3 levels compared to any other group in women, but this was not observed in men. Osteoporosis was prevalent in subjects with discordance in both genders, particularly, in those with low LS BMD (31.6% in men and 63.5% in women). Given the high prevalence of spine-femur BMD discordance, low FN BMD may be associated with vitamin D deficiency and insulin resistance, but low LS BMD may present severe osteoporosis.

T-Score Discordance of Bone Mineral Density in Patients with Atypical Femoral Fracture

BACKGROUND

Although atypical femoral fracture (AFF) occurs more frequently in patients taking bisphosphonates and longer treatment is associated with higher risk, the causal relationship between AFF and bisphosphonates has not been established. Most patients with AFF have osteoporosis that is being treated with bisphosphonates, but we are not aware of any reports regarding the areal bone mineral density (aBMD) and discordance between the T-scores of the femur and spine in such patients. We investigated the prevalence of aBMD discordance and the characteristics of patients with AFF.

METHODS

Medical records for 63 consecutive patients treated for AFF were retrospectively evaluated, and 48 patients, all female, were eligible for the study. The average age at the time of fracture was 73.0 years, the average duration of bisphosphonate use was 68.5 months, and the average presumed age at bisphosphonate initiation was 67.2 years. We evaluated the prevalence of discordance, defined as a difference between the T-score categories of the femur and spine in the same individual as well as demographic differences between the discordance and concordance groups. We also compared the prevalence of discordance in patients with AFF with that in 114 female patients with intertrochanteric femoral fracture (ITFF).

RESULTS

T-score concordance, minor discordance, and major discordance were seen in 14 (29%), 32 (67%), and 2 (4%) of the patients with AFF, respectively. The prevalence of discordance was significantly higher in those with AFF (71%) than in those with ITFF (23%) (p < 0.001). The average age at bisphosphonate initiation in the AFF group was lower in the discordance group (65.7 years) than in the concordance group (70.7 years) (p = 0.04).

CONCLUSIONS

The prevalence of T-score discordance between the hip and lumbar spine was relatively high in patients with AFF, and the presumed age at the initiation of bisphosphonate therapy was younger in patients with discordant T-scores in this study.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Z-score discordance and contributing factors in healthy premenopausal women with low bone mineral density: the Korean National Health and Nutrition Examination Survey 2008-9

The premenopausal period is important for bone health and prevention of future fractures, but measuring bone mineral density (BMD) at only one site may not be sufficient to determine therapeutic strategies for low BMD in premenopausal women due to the presence of Z-score discordance. In this study, we investigated Z-score discordance in addition to contributing factors of idiopathic low BMD in healthy premenopausal Korean women. We studied 3003 premenopausal women aged 18-50 years, without secondary causes for low BMD and history of fragility fracture, who had participated in the Fourth Korean National Health and Nutrition Examination Surveys (2008-2009). Low body mass index (BMI), low vitamin D level, and low body muscle mass were associated with low BMD even in premenopausal women. Risk factors differed depending on the anatomic site. Low BMI and low vitamin D level were risk factors for low femoral neck BMD (FN-BMD), but not for low lumbar spine BMD (LS-BMD). Only total muscle mass had a slight effect on low LS-BMD. Z-score discordance was much higher than expected, in 75 and 73.8 % of the low LS-BMD and low FN-BMD groups, respectively. Our findings suggest the need to consider BMD discordance in premenopausal women and also to provide information on correctable factors affecting low BMD in younger populations. Long-term follow-up is needed to evaluate the possible effect of Z-score discordance on the prognosis of osteoporosis and subsequent fracture risk.

Is It Possible to Increase the Clinical Effectiveness of the Fracture Risk Assessment Tool in Osteopenia Patients by Taking Into Account Bone Mineral Density Values?

The study aimed to investigate the effectiveness of the clinical use of the Fracture Risk Assessment Tool (FRAX(®)) developed by the World Health Organization identifying patients at risk of osteoporotic fracture and to evaluate changes in osteoporotic fracture risk prediction according to bone mineral density (BMD) values. We identified the occurrence of osteoporotic fracture among patients whose BMD was measured in our hospital between April 2003 and March 2013. We then analyzed FRAX(®) scores obtained with or without BMD on the day before the occurrence of an osteoporotic fracture in actual osteoporotic fracture patients. According to the National Osteoporosis Foundation high-risk criteria, we identified the percentage of high-risk patients before the actual fracture. Among 445 osteoporotic fracture patients, when FRAX(®)-BMD was used, 281 patients (63%) were identified as high-risk before an actual osteoporotic fracture, and when FRAX(®) without BMD was used, 258 patients (58%) were identified (p = 0.115). In the 84 osteopenia patients, 39 patients (46.4%) were identified as high-risk when FRAX(®) without BMD was used, and 19 patients (22.6%) were identified when FRAX(®)-BMD was used (p = 0.001). The use of BMD in FRAX(®) does not seem to increase the clinical effectiveness of predicting osteoporotic fracture in osteopenia patients.

Prevalence and associated factors of T-score discordance between different sites in Iranian patients with spinal cord injury

OBJECTIVES

The present study was conducted to determine the prevalence of T-score discordance and its risk factors in a group of patients with spinal cord injury in a university teaching hospital in the Iranian capital of Tehran.

METHODS

This cross-sectional study was conducted on paraplegic men undergoing bone density testing in an outpatient clinic at a hospital in the Iranian capital, Tehran, between March 2011 and 2012. A questionnaire on demographic and anthropometric characteristics, including age, height, weight, engagement in physical activity and personal smoking habits, was filled out for each subject. All the subjects underwent bone mineral density measurement and blood samples were sent for laboratory testing.

RESULTS

Major T-score discordance between two sites was noted in 54 (41.22%) patients. Multivariate logistic regression revealed that every unit increase in serum calcium levels, as the only factor influencing T-score discordance, was associated with a 2.49-fold increased risk in T-score discordance in the area. As for the spine and radius, BMI was the only influencing factor as every unit increase in BMI was associated with a 14% lower risk for T-score discordance in these regions. Body mass index was the only factor, based on the multivariate model, affecting the risk of developing T-score discordance between two sites.

CONCLUSION

Our study revealed the high prevalence of T-score discordance in patients with spinal cord injury. Physicians should therefore be encouraged to perform BMD at three sites when visiting patients with such injuries.

Prevalence and Risk Factors of Discordance between Left- and Right-Hip Bone Mineral Density Using DXA

To determine the prevalence of significant left-right differences in hip bone mineral density (BMD), and the impact of this difference on osteoporosis diagnosis, we measured bilateral proximal femora using dual energy X-ray absorptiometry (DXA) in 3481 subjects (608 males, 2873 females). The difference between left and right hip was considered significant if it exceeded the smallest detectable difference (SDD) for any of the three hip subregions. Contralateral femoral BMD was highly correlated at all measuring sites (r = 0.92-0.95). However, significant left-right differences in BMD were common: the difference exceeded the SDD for 54% of patients at total hip, 52.1% at femoral neck, and 57.7% at trochanter. The prevalence of left-right differences was greater in participants >65 years. For 1169 participants with normal spines, 22 (1.9%) had discordant left-right hips in which one hip was osteoporotic; for 1349 patients with osteopenic spines, 94 (7%) had osteoporosis in one hip. Participants with BMI < 20 kg/m(2) were more likely to show major T-score discordance (osteoporosis in one hip and normal BMD in the other). Multiple regression analysis showed that the only significant statically parameter that persists after adjusting for all potential confounding parameters were age over 65 years.

Lumbar spine bone mineral density in US adults: demographic patterns and relationship with femur neck skeletal status

This analysis examines lumbar spine bone mineral density (BMD) of US adults from NHANES 2005-2008 by age, sex, and race/ethnicity. Prevalence of low spine BMD and agreement between the prevalence of low BMD at the spine and femur neck in older adults are also assessed.

INTRODUCTION

Lumbar spine BMD data from a representative sample of the US population have not been previously available.

METHODS

We used data from the National Health and Nutrition Examination Survey 2005-2008 to examine demographic patterns in lumbar spine BMD among US adults age ≥20 years and the prevalence of low lumbar spine BMD in adults age ≥50 years. Agreement between the prevalence of low BMD at the femur neck and spine in older adults was also assessed. Dual-energy X-ray absorptiometry was used to measure lumbar spine and femur neck BMD. World Health Organization definitions were used to categorize skeletal status as normal, osteopenia, or osteoporosis.

RESULTS

Compared to non-Hispanic whites, non-Hispanic blacks had higher and Mexican Americans had lower lumbar spine BMD. Lumbar spine BMD declined with age in women, but not in men. Approximately 4.7 million (10%) older US women and 1 million (3%) older men had lumbar spine osteoporosis in 2005-2008. Roughly one third of them differed in skeletal status at the spine and hip but most were normal at one site and osteopenic at the other. Only 3-10%, depending on sex, had osteoporosis at one skeletal site but not at the other skeletal site. Between 76% and 87% with discordant skeletal status had lumbar spine T-scores within 1 unit of the category threshold.

CONCLUSIONS

These findings suggest that measuring either the femur neck or the lumbar spine will correctly classify the majority of individuals who present for care as osteoporotic or not.

FSHR gene polymorphisms influence bone mineral density and bone turnover in postmenopausal women

OBJECTIVE

FSH, via its receptor (FSHR), influences bone remodeling and osteoclast proliferation and activity. The aim of this study was to evaluate the influence of two single nucleotide polymorphisms (SNPs) of the FSHR gene on bone mineral density (BMD) and bone turnover markers (bone alkaline phosphatase and type I collagen C-telopeptides) in postmenopausal women.

METHODS

Two hundred and eighty-nine unrelated postmenopausal women were genotyped for the SNPs rs1394205 and rs6166. BMD was estimated using dual-energy X-ray absorptiometry and quantitative ultrasound (QUS) methodologies.

RESULTS

AA rs6166 women showed a lower BMD (femoral neck and total body), lower stiffness index (calcaneal QUS), and higher serum levels of bone turnover markers compared to GG rs6166 women. The prevalence of osteoporosis was significantly higher in AA rs6166 women compared with GG rs6166 women. These results were not influenced by circulating levels of FSH and estrogens.

CONCLUSION

The SNP rs6166 of the FSHR gene significantly influences BMD in postmenopausal women. In particular, AA rs6166 women are at increased risk of postmenopausal osteoporosis compared with GG rs6166 women, independently of circulating levels of FSH and estrogens. Previous studies have demonstrated that this SNP influences cell and tissue response to hyperstimulation of FSHR in vivo and in vitro. Our study results appear in agreement with these experimental data and with known biological actions of FSH/FSHR system in bone homeostasis.

DXA scanning in clinical practice

Dual-energy X-ray absorptiometry (DXA) is recognized as the reference method to measure bone mineral density (BMD) with acceptable accuracy errors and good precision and reproducibility. The World Health Organization (WHO) has established DXA as the best densitometric technique for assessing BMD in postmenopausal women and based the definitions of osteopenia and osteoporosis on its results. DXA allows accurate diagnosis of osteoporosis, estimation of fracture risk and monitoring of patients undergoing treatment. However, when DXA studies are performed incorrectly, it can lead to major mistakes in diagnosis and therapy. This article reviews the fundamentals of positioning, scan analysis and interpretation of DXA in clinical practice.

Prevalence and risk factors of osteoporosis in patients with Parkinson's disease

Parkinson's disease (PD) is the most common cause of disability in the elderly. It is currently recognized as a cause of secondary osteoporosis. To evaluate the prevalence of osteoporosis in PD and detect its risk factors, 52 patients with PD (36 men/16 women) and 52 controls paired for age and sex were recruited. Clinical data including demography, disease duration and disease severity were collected. All subjects had bone mineral density (BMD) measured by dual energy X-ray absorptiometry, dorsal and lumbar spine X-ray, and biological exams (osteocalcin, CTX, parathormon). The mean age of the patients was 60.0 +/- 9.25 years [30-77], and the mean disease duration was 4.9 +/- 4.5 years [0.2-17]. Nine patients (17.3%) were osteoporotic and 28 (53.8%) osteopenic. BMD at the lumbar spine and the hip was lower among patients than controls (spine: 1.031 vs. 1.175 g/cm(2); P < 0.001; hip: 0.968 vs. 1.054; P = 0.02). PD patients with low BMD presented a more severe disease and an insufficient sun exposure and calcium intake. There was a positive statistically significant correlation between patients BMD and body mass index and negative correlation with age, severity of PD, and osteocalcin levels. The prevalence of osteoporosis/osteopenia is high in PD patients and seems related to the severity of the disease, an insufficient sun exposure and calcium intake. This osteoporosis constitutes with falls the major risk factors of fracture in PD patients.