Osteoporosis In Turkish HIV/AIDS patients: comparative analysis by dual energy X-ray absorptiometry and digital X-ray radiogrammetry

Bone mineral density in people living with HIV: a narrative review of the literature

Bone health status is largely absent in South Africa, the main reasons being the absence and cost-effectiveness of specific screening equipment for assessing bone mineral density (BMD). Various risk factors seem to play a role, some of which can be modified to change bone health status. Urbanisation is also a public health concern. Changing nutritional, as well as social behaviour, play integral roles in the prevalence and incidence of decreased BMD. Furthermore, human immunodeficiency virus (HIV) specifically, has a negative impact on BMD and although highly active antiretroviral therapy increases the prognosis for HIV-infected individuals, BMD still seem to decrease further. Dual energy X-ray absorptiometry is considered the gold standard for BMD assessment; however, recent developments have provided more cost-effective screening methods, among which heel quantitative ultrasound appears to be the most widely used in resource limited countries such as South Africa.

Reference values for digital X-ray radiogrammetry parameters in children and adolescents in comparison to estimates in patients with distal radius fractures

The first objective of this study was to determine normative digital X-ray radiogrammetry (DXR) values, based on original digital images, in a pediatric population (aged 6-18 years). The second aim was to compare these reference data with patients suffering from distal radius fractures, whereas both cohorts originated from the same geographical region and were evaluated using the same technical parameters as well as inclusion and exclusion criteria. DXR-BMD and DXR-MCI of the metacarpal bones II-IV were assessed on standardized digital hand radiographs, without printing or scanning procedures. DXR parameters were estimated separately by gender and among six age groups; values in the fracture group were compared to age- and gender-matched normative data using Student's t tests and Z scores. In the reference cohort (150 boys, 138 girls), gender differences were found in bone mineral density (DXR-BMD), with higher values for girls from 11 to 14 years and for boys from 15 to 18 years (p < 0.05). Girls had higher normative metacarpal index (DXR-MCI) values than boys, with significant differences at 11-14 years (p < 0.05). In the case-control investigation, the fracture group (95 boys, 69 girls) presented lower DXR-BMD at 15-18 years in boys and 13-16 years in girls vs. the reference cohort (p < 0.05); DXR-MCI was lower at 11-18 years in boys and 11-16 years in girls (p < 0.05). Mean Z scores in the fracture group for DXR-BMD were -0.42 (boys) and -0.46 (girls), and for DXR-MCI were -0.51 (boys) and -0.53 (girls). These findings indicate that the fully digital DXR technique can be accurately applied in pediatric populations ≥ 6 years of age. The lower DXR-BMD and DXR-MCI values in the fracture group suggest promising early identification of individuals with increased fracture risk, without the need for additional radiation exposure, enabling the initiation of prevention strategies to possibly reduce the incidence of osteoporosis later in life.

Application of geometrical measurements in the assessment of vertebral strength

Background:

The study was aimed at the development of parameters that could be used as predictors of vertebral strength. Proposed parameters describing vertebral geometry and/or shape can be established on the basis of routine spine roentgenograms, making roentgenography a novel tool for vertebral fracture risk assessment in the future.

Material/Methods:

20 human cadaveric L3 vertebrae were included in the study. Dual-energy X-ray absorptiometry (DXA) was used for an assessment of bone mineral density (BMD). Quantitative computed tomography (QCT) was performed to measure the volumetric bone density as the most reliable parameter in vertebral fracture risk assessment. Geometrical measurements were performed on the basis of high quality and high resolution computer tomography 3-dimensional images. Biomechanical tests were performed to measure vertebral strength. Two parameters were defined on the basis of extensive research: the ratio between vertebral base area and its height (A/H), and the ratio of vertebral coronal width to coronal height (W/H). Correlations between vertebral mechanical strength – its BMD, QCT density, A/H and W/H were calculated.

Results:

The best correlation to bone durability was achieved for QCT density (r=0.882), while correlation strength for BMD (r=0.779) and A/H (r=–0.773) were comparable. W/H correlated better than BMD to mechanical strength (–0.788).

Conclusions:

Geometrical parameters of vertebrae potentially measured on spine radiograms could be used as predictors of vertebral durability. The calculated correlation coefficients suggest that one of the proposed parameters works better than the commonly used BMD.

Factors associated with low bone mineral density in a Brazilian cohort of vertically HIV-infected adolescents

OBJECTIVE

To assess the prevalence and factors associated with low bone mineral density (BMD) in HIV-infected adolescents.

METHODS

This was a cross-sectional study of a Brazilian cohort of vertically HIV-infected adolescents. Body composition and lumbar spine (LS) and total body (TB) BMD were estimated by dual-energy X-ray absorptiometry (DXA). Low BMD was considered for a Z-score ≤-2 standard deviations. Pubertal development, anthropometric data, laboratory measurements, antiretroviral regimen, and time of immunological and virological recovery were evaluated as factors associated with a low BMD.

RESULTS

Seventy-four adolescents aged 17.3 ± 1.8 years were studied. Low BMD was present in 32.4% of them. LS and TB BMD Z-scores were positively correlated with weight, body mass index (BMI), BMI Z-score, total body fat, and nutritional status. Patients on tenofovir had lower LS and TB BMD Z-scores. Time on tenofovir was indirectly correlated with LS and TB BMD Z-scores. No difference was found regarding levels of calcium, parathyroid hormone, or 25-hydroxyvitamin D according to BMD status.

CONCLUSIONS

Control of the HIV infection, especially before the initiation of puberty, might have a positive influence on bone gain. Body composition and nutritional status had a positive influence on BMD that was more evident in females, suggesting that nutritional intervention may have a positive impact on BMD.

[Bone mineral loss in patients with human immunodeficiency virus infection]

Life expectancy and quality of life among patients infected with human immunodeficiency virus (HIV) has dramatically improved with the advent of highly active antiretroviral therapy. Nonetheless, with the transformation of HIV infection into a chronic disease, a series of long-term consequences have been observed, among them osteoporosis. The prevalence of this condition is increasing among individuals with HIV infection. Although an epidemic of fragility fractures has not been described in these patients, an increase in the incidence of such fractures is anticipated as the HIV population ages, and this will undoubtedly have an impact on their quality of life. The numerous factors that favor the development of osteoporosis in these patients are related to the infection, itself, and the treatment received.

Bone mineral density remains stable in HAART-treated HIV-infected men over 2 years

OBJECTIVE

Recently we reported that human immunodeficiency virus (HIV)-infected Caucasian men treated with highly active antiretroviral therapy (HAART) have normal weight-adjusted bone mineral density (BMD), in contrast to most other cross-sectional analyses, which have reported low BMD in HIV-infected patients. We have now addressed the question of whether there is accelerated BMD loss over time in HIV-infected men.

DESIGN

A 2-year, prospective, longitudinal study.

SUBJECTS

Twenty-three HAART-treated, HIV-infected men and 26 healthy controls.

MEASUREMENTS

All participants had measurements of BMD and bone-related laboratory parameters at baseline, and a repeat measurement of BMD at 2 years.

RESULTS

In the HIV-infected men the mean age was 47 years, the mean duration of infection was 8.2 years, and the mean duration of HAART was 54 months. Over 2 years of follow-up, BMD increased from baseline in the HIV-infected men by 2.6% at the lumbar spine (P = 0.05 vs. baseline), and remained stable at the total hip (mean change 0.1%, P > 0.99) and total body (mean change 0.6%, P = 0.39). Mean changes in BMD in the control group were 1.4% at the lumbar spine, -0.1% at the total hip, and -0.8% at the total body. The HIV-infected men lost less total body BMD than the control group (P = 0.01). In the HIV-infected men, body weight remained stable over 2 years while fat mass decreased and lean mass tended to increase, whereas in the controls, body weight and fat mass increased while lean mass remained stable.

CONCLUSIONS

Accelerated bone loss does not occur in HIV-infected men treated with HAART. Monitoring of BMD in HIV-infected men may not be necessary.

Antiretroviral therapy and the prevalence of osteopenia and osteoporosis: a meta-analytic review

INTRODUCTION

Prevalence estimates of osteopenia and osteoporosis (reduced bone mineral density; BMD) in HIV-infected patients and the role of antiretroviral therapy (ART) varies in the literature.

METHODS

We conducted a meta-analytical review of cross-sectional studies published in English to determine the pooled odds ratios (OR) of reduced BMD and osteoporosis in the following groups: HIV-positive versus HIV-negative; ART-treated versus ART-naive; protease inhibitor (PI)-treated versus PI-untreated. We searched the MEDLINE, PubMed, and EMBASE databases for eligible references between January 1966 and November 2005. Random effects models were used to generate pooled OR estimates and confidence intervals.

RESULTS

Of 37 articles identified, 20 met the inclusion criteria. Of the 884 HIV-infected patients, 67% had reduced BMD, of whom 15% had osteoporosis, yielding a pooled OR of 6.4 and 3.7, respectively, compared with HIV-uninfected controls (n = 654) using 11 studies with available data. Compared with ART-naive patients (n = 202, 10 studies), ART-treated individuals (n = 824) had a 2.5-fold increased odds of prevalent reduced BMD. The risk of prevalent osteoporosis (seven studies) was similarly elevated in ART-treated individuals. Compared with non-PI-treated HIV patients (n = 410, 14 studies), PI-treated patients (n = 791) had increased odds of reduced BMD and osteoporosis (12 studies). Few studies adjusted for important covariates such as HIV disease severity or treatment duration.

CONCLUSION

The prevalence of osteoporosis in HIV-infected individuals is more than three times greater compared with HIV-uninfected controls. ART-exposed and PI-exposed individuals had a higher prevalence of reduced BMD and osteoporosis compared with their respective controls. The influence of other disease and treatment variables on these estimates could not be determined.

Normative data for digital X-ray radiogrammetry from a female and male German cohort

This study presents German reference data for digital X-ray radiogrammetry (DXR) differentiated by males as well as females, and quantifies for gender-specific and age-related differences including all DXR parameters. This study also documents the effects of different X-ray settings (e.g., radiographs of the wrist or the hand) on DXR measurements. There were 2085 patients who were prospectively enrolled (954 females and 1131 males) from a data pool of 11,915 patients with radiographs of the nondominant hand or wrist. All patients underwent measurements of bone mineral density (BMD), cortical thickness, bone width, and the metacarpal index (MCI) using DXR technology. These data showed a continuous age-related increase of the DXR parameters to the point of peak bone mass, then a continuous decline beyond the peak bone mass with accentuated age-related cortical bone loss in women. Peak bone mass is reached at approximately 30-34 yr for women and 45-49 yr for men. In addition, men had a significantly higher DXR BMD (mean: +12.8%) compared with woman in all age groups. Regarding the impact of various X-ray settings (e.g., X-ray(wrist) vs. X-ray(hand)), no significant difference was observed between both groups, men as well as women. The development of digital imaging technology has enabled more precise measurements of several radio-geometric features. The present study estimated normative reference values for DXR in German Caucasian women and men. Based on this reference data, a valid and reliable quantification of disease-related demineralization based on measurements of DXR BMD and MCI is now available for the Caucasian ethnic group.

The potential of digital X-ray radiogrammetry (DXR) in the assessment of osteopenia in children with chronic inflammatory bowel disease

BACKGROUND

Loss of bone mass is a known complication of chronic inflammatory bowel disease (IBD) in children. The gold standard in the evaluation of bone mineral density (BMD) is dual energy X-ray absorptiometry (DXA).

OBJECTIVE

In this preliminary study we evaluated digital X-ray radiogrammetry (DXR) which estimates BMD (DXR-BMD) from hand radiographs in children with IBD.

MATERIALS AND METHODS

A total of 26 children with IBD (10 girls, 16 boys; age range 10-18 years) underwent DXR for the calculation of DXR-BMD and metacarpal index (DXR-MCI) using the Pronosco X-posure system. The results were compared with a local reference database and correlated with the results of DXA.

RESULTS

DXR-BMD was 0.36-0.56 g/cm(2) (median 0.46 g/cm(2)) in Crohn disease patients and 0.38-0.63 g/cm(2) (median 0.48 g/cm(2)) in ulcerative colitis patients. DXR-MCI was 0.29-0.49 in Crohn disease patients and 0.28-0.53 in ulcerative colitis patients. The Z-scores were reduced to <-1 SD in five Crohn disease patients and in six ulcerative colitis patients. The coefficients (r) for the correlations between DXR-BMD and DXA-BMD were 0.78 for the lumbar spine and 0.61 for the proximal femur (P<0.01), and between DXR-MCI and DXA-BMD were 0.78 for the lumbar spine and 0.51 for the proximal femur (P<0.01).

CONCLUSIONS

DXR seems to be able to estimate cortical osteopenia in children with chronic IBD. The DXR results showed a positive correlation with DXA results.