HMG-CoA reductase inhibitors and the risk of vertebral fracture

Association of type 2 Diabetes Mellitus and bone mineral density: a two-sample Mendelian randomization study

BACKGROUND

Observational studies have suggested that type 2 Diabetes Mellitus (DM2) is a potentially modifiable risk factor for lower BMD, but the causal relationship is unclear. This study aimed to examine whether the association of DM2 with lower BMD levels was causal by using Mendelian randomization (MR) analyses.

METHODS

We collected genome-wide association study data for DM2 and BMD of total body and different skeletal sites from the IEU database. Subsequently, we performed a two-sample Mendelian randomization analysis using the Two Sample MR package.

RESULTS

We identified a positive association between DM2 risk (61,714 DM2 cases and 596,424 controls) and total BMD, and other skeletal sites BMD, such as femoral neck BMD, ultra-distal forearm BMD and heel BMD. However, non-significant trends were observed for the effects of DM2 on lumbar-spine BMD.

CONCLUSION

In two-sample MR analyses, there was positive causal relationship between DM2 and BMD in both overall samples. In summary, while observational analyses consistently indicate a strong association between DM2 and low BMD, our MR analysis introduces a nuanced perspective. Contrary to the robust association observed in observational studies, our MR analysis suggests a significant link between DM2 and elevated BMD.

Age- and dose-dependent effect of statin use on the risk of osteoporotic fracture in older adults

Previous studies have revealed the protective effects of statins on bone but the association of statins use with osteoporosis-related measurement has shown controversial results. In this study, we found an age, dose andduration-dependent osteoprotective effect of statins in general older population.

PURPOSE

Previous studies have revealed the protective effects of statins on bone but the association of statins use with osteoporotic fractures has shown controversial results.

METHODS

In this study with Korean National Health Insurance Service-Senior cohort database, a total of 365,656 elderly without previous history of osteoporosis and who were started on statin since January 1 2004 were included and observed until December 31 2012. Hazard rations (HR) for major osteoporotic fractures were calculated using the weighted Cox proportional hazards model with inverse-probability of treatment weighting method.

RESULTS

During 6.27 years of follow-up period, 54,959 osteoporotic fractures occurred and the majority of fractures (69.5%) were vertebral fractures. Compared with non-users, statin use was associated with a decreased risk of all outcomes with adjusted HR (95% CI) of 0.77 (0.72-0.83; P < 0.001) for major osteoporotic fractures, 0.49 (0.38-0.62; P < 0.001) for hip fractures, and 0.70 (0.64-0.77; P < 0.001) for vertebral fractures. When outcomes were examined separately by sex, the results were broadly comparable in terms of patterns of risk reduction by statin use. The patients with statin initiated at age ≥ 80 years had the highest risk reduction for most outcomes relative to non-users. Higher cumulative dose of statin was negatively associated with the osteoporotic fracture risk; 0.97 (0.91-1.02) for 30-364 cumulative daily defined dose (cDDD), 0.45 (0.40-0.51) for 365-1,094 cDDD, and 0.22 (0.15-0.33) for ≥ 1,095 cDDD.

CONCLUSIONS

Our results showed that statin use was associated with significant reduction in the risk of osteoporotic fractures in general older population.

Exposure to statins is associated to fracture risk reduction in elderly people with cardiovascular disease: evidence from the AIFA-I-GrADE observational project

PURPOSE

Conflicting findings were observed from clinical trials and observational studies evaluating the association between the use of statins and the risk of fracture. A case-control study nested into a cohort of elderly patients on treatment with statins for cardiovascular secondary prevention was performed on this issue.

METHODS

The cohort was formed by 13 875 individuals aged ≥65 years from several Italian health units receiving statins after hospital discharge for cardiovascular outcomes. From this cohort, 964 patients who experienced fracture were identified (i.e., cases). Up to five controls were randomly selected for each case from the underlying cohort. Conditional logistic regression was used to model the risk of fracture associated with adherence to statins, which was measured from the proportion of days covered (PDC) by treatment. A set of sensitivity analyses was performed in order to account for sources of systematic uncertainty.

RESULTS

Compared with patients with low adherence (PDC ≤ 40%), those on intermediate (PDC 41-80%) and high (PDC > 80%) adherence exhibited a risk reduction of 21% (95% confidence interval 6% to 23%) and 25% (7% to 40%). Similar effects were observed among patients younger and older than 80 years, as well as among men, while there was no evidence that adherence to statins affected the risk of fracture among women. Sensitivity analyses revealed that the associations were consistent and robust.

CONCLUSIONS

Use of statins for secondary cardiovascular prevention is associated with fracture risk reduction in elderly people. Further studies are required to better clarify the statin-fracture association in postmenopausal women. Copyright © 2017 John Wiley & Sons, Ltd.

Efficacy of statins for osteoporosis: a systematic review and meta-analysis

Our meta-analysis assessed the efficacy of statins on the risk of fracture, bone mineral density (BMD), and the markers of bone metabolism by collecting data from 33 clinical trials. We found that statin treatment was associated with bone metabolism. And statins seemed to be more effective on male patients with osteoporosis. The efficacy of statins for the treatment of osteoporosis has been controversial in previous studies and meta-analyses. Our meta-analysis was conducted to examine in detail the efficacy of statins on osteoporosis. We searched PubMed, Embase, and the Cochrane Library databases for clinical trials from inception to May 2016. We included studies that described the effect of statins on the risk of fracture, BMD, or bone turnover markers. Moreover, we also conducted subgroup analyses according to the skeleton site, patient gender, and length of follow-up. A total of 33 studies which included 23 observational studies (16 cohort studies and 7 case-control studies) and 10 randomized controlled trials (RCTs) were evaluated. These 33 studies included 314,473 patients in statin group and 1,349,192 patients in control group. Statins decreased the risk of overall fractures (OR = 0.81, 95% CI 0.73-0.89) and hip fractures (OR = 0.75, 95% CI 0.60-0.92). Furthermore, the use of statins was associated with increased BMD at the total hip (standardized mean difference (SMD) = 0.18, 95% CI 0.00-0.36) and lumbar spine (SMD = 0.20, 95% CI 0.07-0.32) and improved the bone formation marker, osteocalcin (OC) (SMD = 0.21, 95% CI 0.00-0.42). However, there was no positive effect on vertebral fractures, upper extremity fractures, BMD at the femoral neck, bone-specific alkaline phosphatase (BALP), and serum C-terminal peptide of type I collagen (S-CTX). Also, compared with male subgroups, the effect on female subgroups was only slightly positive or of no statistical significance. Our meta-analysis indicates that statin treatment may be associated with a decreased risk of overall fractures and hip fractures, an increased BMD at the total hip, BMD at the lumbar spine, and OC. Moreover, our results also show that statin treatment may have a greater effect on male patients than on female patients.

Wheelchair use and lipophilic statin medications may influence bone loss in chronic spinal cord injury: findings from the FRASCI-bone loss study

We identified a protective bone effect at the knee with lipophilic statin use in individuals with chronic spinal cord injury. Lipophilic statin users gained bone at the knee compared to non-users and wheelchair users lost bone compared to walkers. Ambulation and or statins may be effective osteogenic interventions in chronic spinal cord injury (SCI).

INTRODUCTION

SCI increases the risk of osteoporosis and low-impact fractures, particularly at the knee. However, during the chronic phase of SCI, the natural history and factors associated with longitudinal change in bone density remain poorly characterized. In this study, we prospectively assessed factors associated with change in bone density over a mean of 21 months in 152 men and women with chronic SCI.

METHODS

A mixed model procedure with repeated measures was used to assess predictors of change in bone mineral density (PROC MIXED) at the distal femur and proximal tibia. Factors with a p value of <0.10 in the univariate mixed models, as well as factors that were deemed clinically significant (gender, age, and walking status), were assessed in multivariable models. Factors with a p value of ≤0.05 were included in the final model.

RESULTS

We found no association between bone loss and traditional osteoporosis risk factors, including age, gender, body composition, or vitamin D level or status (normal or deficient). In both crude and fully adjusted models, wheelchair users lost bone compared to walkers. Similarly, statin users gained bone compared to nonusers.

CONCLUSIONS

The statin finding is supported by reports in the general population where statin use has been associated with a reduction in bone loss and fracture risk. Our results suggest that both walking and statins may be effective osteogenic therapies to mitigate bone loss and prevent osteoporosis in chronic SCI. Our findings also suggest that loss of mechanical loading and/or neuronal factors contribute more to disuse osteoporosis than traditional osteoporosis risk factors.

Statins and hip fracture risk in men: a population-based case-control study

PURPOSE

To estimate the association between hydroxymethylglutaryl-CoA inhibitor (statin) use and hip fracture.

METHODS

We conducted a population-based case-control study. Cases were 6774 male enrollees in a large managed care organization, aged 45 or more years, with an incident hip fracture from 1997 to 2006. Controls without fracture (n = 6774) were matched to cases on age, race, and medical center. Electronic information on pharmaceutical use was used to identify the dispensing of statins from 1991 forward.

RESULTS

Overall, 1884 (27.8%) cases and 2150 controls (31.7%) used a statin before index date (matched odds ratio [mOR] = 0.81, 95% confidence interval [CI] = 0.74-0.87). Adjustment for comorbidity burden strengthened the magnitude of the overall association (mOR = 0.68, CI = 0.62-0.74). The adjusted association was similar across age groups but was strongest among men aged 80 years or more (mOR = 0.62, CI = 0.54-0.71) and was most pronounced in African Americans (mOR = 0.43, CI = 0.28-0.64). Greater duration of statin use did not alter the odds ratios.

CONCLUSIONS

These data add to the growing evidence of a potential protective effect of statin use on bone health. However, these results need to be replicated in a prospective study that can account for confounding by indication which may explain these findings.

The effects of atorvastatin on the prevention of osteoporosis and dyslipidemia in the high-fat-fed ovariectomized rats

Previous studies reported that statins showed positive effects on bone in both human and animal models. This study aimed to investigate the effects of atorvastatin on the prevention of osteoporosis and dyslipidemia in ovariectomized rats fed with high-fat emulsion. The 3-month-old female rats were subjected to either sham operations (n = 8) or ovariectomized operations (OVX, n = 24). The OVX rats were orally administered deionized water (n = 8) or standardized high-fat emulsion without (n = 8) or with atorvastatin (n = 8). All rats were injected twice with calcein before sacrificed for the purpose of double in vivo labeling. After 12 weeks, all rats were sacrificed under anesthesia. Biochemistry, histomorphometry, mechanical test, micro-computed tomography analysis, mechanical test, histology, and component analysis were performed. We found that high-fat emulsion significantly decreased body weight, bone formation, collagen content of bone, and bone biomechanics, while increased blood, liver, and bone marrow lipids. Atorvastatin treatment prevented dyslipidemia, reversed hepatic steatosis, optimized composition of bone, and improved bone mechanical properties. The current study provided further evidence that atorvastatin might be useful for the treatment of osteoporotic patients with dyslipidemia.

High Cholesterol Deteriorates Bone Health: New Insights into Molecular Mechanisms

Many epidemiological studies show a positive connection between cardiovascular diseases and risk of osteoporosis, suggesting a role of hyperlipidemia and/or hypercholesterolemia in regulating osteoporosis. The majority of the studies indicated a correlation between high cholesterol and high LDL-cholesterol level with low bone mineral density, a strong predictor of osteoporosis. Similarly, bone metastasis is a serious complication of cancer for patients. Several epidemiological and basic studies have established that high cholesterol is associated with increased cancer risk. Moreover, osteoporotic bone environment predisposes the cancer cells for metastatic growth in the bone microenvironment. This review focuses on how cholesterol and cholesterol-lowering drugs (statins) regulate the functions of bone residential osteoblast and osteoclast cells to augment or to prevent bone deterioration. Moreover, this study provides an insight into molecular mechanisms of cholesterol-mediated bone deterioration. It also proposes a potential mechanism by which cellular cholesterol boosts cancer-induced bone metastasis.

Vertebral fractures on routine chest computed tomography: relation with arterial calcifications and future cardiovascular events

Osteoporosis and cardiovascular disease often coexist. Vertebral fractures incidentally imaged in the course of routine care might be able to contribute to the prediction of cardiovascular events. Following a case-cohort design, 5,679 patients undergoing chest CT were followed for a median duration of 4.4 years. Cases were defined as patients who subsequently developed a cardiovascular event (n = 493). The presence and severity of vertebral fractures, as well as aortic, coronary and valvular calcifications on CT were investigated. Cases were more likely to be male (69 vs 60 %) and older (66 vs 61 years old). Prevalent vertebral fractures conferred an elevated risk of cardiovascular events after adjustment for age and gender [hazard ratio (HR) of 1.28, 95 % confidence interval (CI) 1.07 to 1.54]. This effect remained moderate after correction for cardiovascular calcifications (HR 1.20, CI 0.99-1.44). However, in terms of discrimination, vertebral fractures did not have substantial incremental prognostic value after correction (C-index was 0.683 vs 0.682 for models with and without vertebral fractures respectively). Prevalent vertebral fractures on routine clinical chest CT are related to future cardiovascular events but do not have additional prognostic value to models that already include age, gender and cardiovascular calcifications.

Novel applications of statins for bone regeneration

The use of statins for bone regeneration is a promising and growing area of research. Statins, originally developed to treat high cholesterol, are inhibitors of the enzyme 3-hydroxy-3-methylglutaryl, the rate-limiting enzyme of the mevalonate pathway. Because the mevalonate pathway is responsible for the synthesis of a wide variety of important biochemical molecules, including cholesterol and other isoprenoids, the effects of statins are pleiotropic. In particular, statins can greatly affect the process of bone turnover and regeneration via effects on important cell types, including mesenchymal stem cells, osteoblasts, endothelial cells, and osteoclasts. Statins have also been shown to have anti-inflammatory and antimicrobial properties that may be useful since infection can derail normal bone healing. This review will explore the pleiotropic effects of statins, discuss the current use of statins for bone regeneration, particularly with regard to biomaterials-based controlled delivery, and offer perspectives on the challenges and future directions of this emerging area of bone tissue engineering.

Association of Statins and Risk of Fractures in a Military Health System

Background: Contradictory evidence exists regarding statin use and risk of osteoporotic fractures. Objective: The study objective was to examine the effect of statins on fracture risk in a Military Healthcare System (MHS) with similar access and standard of health care for its beneficiaries. Methods: This is a retrospective study of patients enrolled in an MHS encompassing the period from October 1, 2003, to March 1, 2010. Statin users were defined as those receiving a statin for ≥90 days in Fiscal Year 2005, whereas nonusers were defined as individuals not receiving a statin throughout the study period. A propensity score–matched cohort of statin users and nonusers was created using 42 variables. The outcomes were identified using ICD-9-CM codes in the follow-up period (October 1, 2006, to March 1, 2010). In all, 4 outcomes were examined: all fractures, femoral neck fractures, upper-extremity fractures, and lower-extremity fractures. Results: Of 46 249 patients, 6967 pairs of statin users and nonusers were matched. Statin users had a lower risk of femoral neck fracture in comparison to nonusers (odds ratio = 0.58, 95% CI = 0.36-0.94) but similar risk of all fractures, lower-extremity fractures, and upper-extremity fractures. Conclusions: In this cohort of patients managed in an MHS, statin use was associated with a lower risk of femoral neck fractures, but not all fractures, upper-extremity fractures, or lower-extremity fractures.

Unintended effects of statins from observational studies in the general population: systematic review and meta-analysis

BACKGROUND

Efficacy of statins has been extensively studied, with much less information reported on their unintended effects. Evidence from randomized controlled trials (RCTs) on unintended effects is often insufficient to support hypotheses generated from observational studies. We aimed to systematically assess unintended effects of statins from observational studies in general populations with comparison of the findings where possible with those derived from randomized trials.

METHODS

Medline (1998 to January 2012, week 3) and Embase (1998 to 2012, week 6) were searched using the standard BMJ Cohort studies filter. The search was supplemented with reference lists of all identified studies and contact with experts in the field. We included prospective studies with a sample size larger than 1,000 participants, case control (of any size) and routine health service linkage studies of over at least one year duration. Studies in subgroups of patients or follow-up of patient case series were excluded, as well as hospital-based cohort studies.

RESULTS

Ninety studies were identified, reporting on 48 different unintended effects. Statins were associated with lower risks of dementia and cognitive impairment, venous thrombo-embolism, fractures and pneumonia, but these findings were attenuated in analyses restricted to higher quality studies (respectively: OR 0.74 (95% CI 0.62 to 0.87); OR 0.92 (95% CI 0.81 to 1.03); OR 0.97 (95% CI 0.88 to 1.05); OR 0.92 (95% CI 0.83 to 1.02)); and marked heterogeneity of effects across studies remained. Statin use was not related to any increased risk of depression, common eye diseases, renal disorders or arthritis. There was evidence of an increased risk of myopathy, raised liver enzymes and diabetes (respectively: OR 2.63 (95% CI 1.50 to 4.61); OR 1.54 (95% CI 1.47 to 1.62); OR 1.31 (95% CI 0.99 to 1.73)).

CONCLUSIONS

Our systematic review and meta-analyses indicate that high quality observational data can provide relevant evidence on unintended effects of statins to add to the evidence from RCTs. The absolute excess risk of the observed harmful unintended effects of statins is very small compared to the beneficial effects of statins on major cardiovascular events.

Is lipid profile associated with bone mineral density and bone formation in subjects with spinal cord injury?

Purpose. The association between serum lipids and bone mineral density (BMD) has been investigated previously but, up to now, these relationships have not yet been described in spinal cord injury (SCI). We tried to assess the correlation between serum triglyceride (TG), total cholesterol (TC), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) and BMD in male subjects with SCI. Methods. Dual-energy X-ray absorptiometry (DXA) was used to assess BMD in femoral neck, trochanter, intertrochanteric zone, and lumbar vertebras. Blood samples were taken to measure serums lipids and bone biomarkers including osteocalcin, cross-linked type I collagen (CTX), and bone alkaline phosphatase (BALP). Partial correlation analysis was used to evaluate the relationships between mentioned measurements after adjustment for weight and age. Results. We found a positive correlation between HDL and femoral neck BMD (P: 0.004, r = 0.33). HDL was negatively correlated with osteocalcin (P: 0.017, r = -0.31) which was not in consistency with its relationship with BMD. TC and LDL were not related to CTX, BALP and BMD. Conclusion. This study does not support a strong association between serum lipids and BMD in subjects with SCI. Moreover it seems that positive association between HDL and BMD is not mediated through increased bone formation.

Statin use and fracture risk: can we quantify the healthy-user effect?

BACKGROUND

Numerous observational studies show that statin use is associated with lower risk of osteoporotic fractures. However, a causal relationship is not supported by data from randomized trials. Unmeasured confounding is implicated as a likely culprit for the controversy because of failure to measure and adjust for patient-level tendencies to engage in healthy behaviors. However, an alternative explanation is selection bias because of the inclusion of prevalent users of statins in the analysis. The relative importance of either bias has not been investigated in a quantitative sensitivity analysis.

METHODS

We conducted a systematic review to summarize the pattern of association between statin use and fracture risk in observational studies. Our objective was to quantify the magnitude of unmeasured confounding and selection bias in a sensitivity analysis.

RESULTS

In 17 published studies, the pooled relative risk for the association between current use of statins and fracture risk was 0.75 (95% confidence interval = 0.66-0.85). Upon adjustment for individual-level use of preventative health services, the pooled relative risk shifted by less than 5% on the log scale. However, a sensitivity analysis for selection bias revealed that moderate levels of bias could eliminate the association between statins and fracture risk.

CONCLUSIONS

It appears that confounding from unmeasured variables cannot explain the protective association between statins and fractures that has been observed in the literature.

Clinical review: Statins and trauma--a systematic review

Statins, in addition to their lipid-lowering properties, have anti-inflammatory actions. The aim of this review is to evaluate the effect of pre-injury statin use, and statin treatment following injury. MEDLINE, EMBASE, and CENTRAL databases were searched to January 2012 for randomised and observational studies of statins in trauma patients in general, and in patients who have suffered traumatic brain injury, burns, and fractures. Of 985 identified citations, 7 (4 observational studies and 3 randomised controlled trials (RCTs)) met the inclusion criteria. Two studies (both observational) were concerned with trauma patients in general, two with patients who had suffered traumatic brain injury (one observational, one RCT), two with burns patients (one observational, one RCT), and one with fracture healing (RCT). Two of the RCTs relied on surrogate outcome measures. The observational studies were deemed to be at high risk of confounding, and the RCTs at high risk of bias. Three of the observational studies suggested improvements in a number of clinical outcomes in patients taking statins prior to injury (mortality, infection, and septic shock in burns patients; mortality in trauma patients in general; mortality in brain injured patients) whereas one, also of trauma patients in general, showed no difference in mortality or infection, and an increased risk of multi-organ failure. Two of three RCTs on statin treatment in burns patients and brain injured patients showed improvements in E-selectin levels and cognitive function. The third, of patients with radial fractures, showed no acceleration in fracture union. In conclusion, there is some evidence that pre-injury statin use and post-injury statin treatment may have a beneficial effect in patients who have suffered general trauma, traumatic brain injury, and burns. However, these studies are at high risk of confounding and bias, and should be regarded as 'hypothesisgenerating'. A well-designed RCT is required to determine the therapeutic efficacy in improving outcomes in this patient population.

HMG-CoA reductase inhibitors (statins) and bone mineral density: a meta-analysis

CONTEXT

The association between 3-hydroxy-3methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) and bone mineral density (BMD) is controversial because of conflicting findings from previous studies.

OBJECTIVE AND DESIGN

The purpose of the present study was to evaluate the effect of statins on BMD reported in randomized and non-randomized controlled trials. We searched PubMed and Embase, using text, medical subject headings (MeSH) and keywords "bone mineral density" and "statins" or "HMG-CoA reductase inhibitors". Our last PubMed and Embase queries were updated to August 2012. Data on participants, interventions, and outcomes from each study were abstracted independently by two authors.

RESULTS

Five case-control studies, six cohort studies and four randomized controlled trials (RCTs) met the inclusion criteria. Included studies involved 34,877 subjects (3824 in the intervention group and 31,053 in the control group) in 12 different countries with ages ranging from 44 to 66 years. Statins significantly increased BMD at lumbar spine [standardized mean difference (SMD) 0.15, 95% CI 0.09-0.22], total hip (SMD 0.22, 95% CI 0.17-0.27) and femoral neck (SMD 0.19, 95% CI 0.09-0.29). We carried out subgroup analyses on selected populations of the cohorts. Statistically significant increases were also observed in the lumbar spine (SMD 0.12, 95% CI 0.04-0.21), total hip (SMD 0.23, 95% CI 0.17-0.28) and femoral neck BMD (SMD 0.22, 95% CI 0.08-0.36).

CONCLUSION

The results of this study suggest that statins may help improve and maintain BMD at the lumbar spine, hip and femoral neck, especially in Caucasians and Asians. It also provides justification for prospective RCTs to evaluate the possible role of statins in BMD in different ethnic populations, such as Latin American and Africans.

Mechanisms of bone anabolism regulated by statins

Osteoporosis is a common disease in the elderly population. The progress of this disease results in the reduction of bone mass and can increase the incidence of fractures. Drugs presently used clinically can block the aggravation of this disease. However, these drugs cannot increase the bone mass and may result in certain side effects. Statins, also known as HMG-CoA (3-hydroxy-3-methylglutaryl-CoA) reductase inhibitors, have been widely prescribed for CVD (cardiovascular disease) for decades. Nonetheless, several studies have demonstrated that statins exert bone anabolic effect and may be helpful for the treatment of osteoporosis. Several experiments have analysed the mechanisms of bone anabolism regulated by statins. In the present paper, we review the mechanisms of promoting osteogenesis, suppressing osteoblast apoptosis and inhibiting osteoclastogenesis.

Vitamin E as an Antiosteoporotic Agent via Receptor Activator of Nuclear Factor Kappa-B Ligand Signaling Disruption: Current Evidence and Other Potential Research Areas

Osteoporosis is a growing healthcare burden that affects the quality of life in the aging population. Vitamin E is a potential prophylactic agent that can impede the progression of osteoporosis. Various in vivo studies demonstrated the antiosteoporotic potential of vitamin E, but evidence on its molecular mechanism of action is limited. A few in vitro studies showed that various forms of vitamin E can affect the receptor activator of nuclear factor kappa-B ligand (RANKL) signaling and their molecular targets, thus preventing the formation of osteoclasts in the early stage of osteoclastogenesis. Various studies have also shown that the effects of the different isoforms of vitamin E differ. The effects of single isoforms and combinations of isoforms on bone metabolism are also different. Vitamin E may affect bone metabolism by disruption of free radical-mediated RANKL signaling, by its oestrogen-like effects, by its effects on the molecular mechanism of bone formation, by the anti-inflammatory effects of its long-chain metabolites on bone cells, and by the inhibition of 3-hydroxyl-3-methyglutaryl coenzyme A (HMG-CoA). In conclusion, the vitamin E isoforms have enormous potential to be used as prophylactic and therapeutic agents in preventing osteoporosis, but further studies should be conducted to elucidate their mechanisms of action.

Hypercholesterolemia promotes an osteoporotic phenotype

A role for hypercholesterolemia in the development of osteoporosis has been suggested in published reports. However, few studies contain direct evidence of a role for maintenance of cholesterol homeostasis in bone health. Using isocaloric high-fat/high-cholesterol and low-fat/no-cholesterol diets in a 4-month feeding study combined with micro computed tomography analysis, we demonstrated in two different mouse strains that mice with hypercholesterolemia lose cortical and trabecular bone in the femurs and vertebrae (bone mineral density was decreased on average by ≈90 mg/mL in the cortical vertebrae in one strain) and cortical bone in the calvariae (bone mineral density was decreased on average by ≈60 mg/mL in one strain). Mechanical testing of the femurs demonstrated that loss of bone in the mice with hypercholesterolemia caused changes in the mechanical properties of the bone including loss of failure load (failure load was decreased by ≈10 N in one strain) and energy to failure. Serologic and histomorphologic analyses suggested that hypercholesterolemia promotes osteoclastogenesis. These studies support a role for hypercholesterolemia in the development of osteoporosis and provide a model with which to test intervention strategies to reduce the effects of hypercholesterolemia on bone health.

Heart drugs that affect bone

There have been important developments in our understanding of the mechanisms underlying the development of osteoporosis, and several of these mechanisms also underlie atherosclerosis. Drugs given to treat cardiovascular disease may impact on bone health in either a beneficial or a harmful way. There is evidence that nitrates are beneficial to bone, but evidence for the benefit of statins, thiazide diuretics, and β-blockers is weaker. By contrast, it is likely to be that some drugs such as loop-acting diuretics are harmful to bone, whereas evidence for harm caused by drugs such as warfarin is weaker. These observations point towards opportunities for new drug development for bone diseases, and possibly the development of treatments that will benefit more than one disease.

Association between bone mineral density and type 2 diabetes mellitus: a meta-analysis of observational studies

Type 2 diabetes mellitus (T2DM) influences bone metabolism, but the relation of T2DM with bone mineral density (BMD) remains inconsistent across studies. The objective of this study was to perform a meta-analysis and meta-regression of the literature to estimate the difference in BMD (g/cm²) between diabetic and non-diabetic populations, and to investigate potential underlying mechanisms. A literature search was performed in PubMed and Ovid extracting data from articles prior to May 2010. Eligible studies were those where the association between T2DM and BMD measured by dual energy X-ray absorptiometry was evaluated using a cross-sectional, cohort or case–control design, including both healthy controls and subjects with T2DM. The analysis was done on 15 observational studies (3,437 diabetics and 19,139 controls). Meta-analysis showed that BMD in diabetics was significantly higher, with pooled mean differences of 0.04 (95% CI: 0.02, 0.05) at the femoral neck, 0.06 (95% CI: 0.04, 0.08) at the hip and 0.06 (95% CI: 0.04, 0.07) at the spine. The differences for forearm BMD were not significantly different between diabetics and non-diabetics. Sex-stratified analyses showed similar results in both genders. Substantial heterogeneity was found to originate from differences in study design and possibly diabetes definition. Also, by applying meta-regression we could establish that younger age, male gender, higher body mass index and higher HbA_1C were positively associated with higher BMD levels in diabetic individuals. We conclude that individuals with T2DM from both genders have higher BMD levels, but that multiple factors influence BMD in individuals with T2DM.

Association between bone mineral density and type 2 diabetes mellitus: a meta-analysis of observational studies

Type 2 diabetes mellitus (T2DM) influences bone metabolism, but the relation of T2DM with bone mineral density (BMD) remains inconsistent across studies. The objective of this study was to perform a meta-analysis and meta-regression of the literature to estimate the difference in BMD (g/cm(2)) between diabetic and non-diabetic populations, and to investigate potential underlying mechanisms. A literature search was performed in PubMed and Ovid extracting data from articles prior to May 2010. Eligible studies were those where the association between T2DM and BMD measured by dual energy X-ray absorptiometry was evaluated using a cross-sectional, cohort or case-control design, including both healthy controls and subjects with T2DM. The analysis was done on 15 observational studies (3,437 diabetics and 19,139 controls). Meta-analysis showed that BMD in diabetics was significantly higher, with pooled mean differences of 0.04 (95% CI: 0.02, 0.05) at the femoral neck, 0.06 (95% CI: 0.04, 0.08) at the hip and 0.06 (95% CI: 0.04, 0.07) at the spine. The differences for forearm BMD were not significantly different between diabetics and non-diabetics. Sex-stratified analyses showed similar results in both genders. Substantial heterogeneity was found to originate from differences in study design and possibly diabetes definition. Also, by applying meta-regression we could establish that younger age, male gender, higher body mass index and higher HbA(1C) were positively associated with higher BMD levels in diabetic individuals. We conclude that individuals with T2DM from both genders have higher BMD levels, but that multiple factors influence BMD in individuals with T2DM.

Association between bone mineral density and type 2 diabetes mellitus: a meta-analysis of observational studies

Type 2 diabetes mellitus (T2DM) influences bone metabolism, but the relation of T2DM with bone mineral density (BMD) remains inconsistent across studies. The objective of this study was to perform a meta-analysis and meta-regression of the literature to estimate the difference in BMD (g/cm(2)) between diabetic and non-diabetic populations, and to investigate potential underlying mechanisms. A literature search was performed in PubMed and Ovid extracting data from articles prior to May 2010. Eligible studies were those where the association between T2DM and BMD measured by dual energy X-ray absorptiometry was evaluated using a cross-sectional, cohort or case-control design, including both healthy controls and subjects with T2DM. The analysis was done on 15 observational studies (3,437 diabetics and 19,139 controls). Meta-analysis showed that BMD in diabetics was significantly higher, with pooled mean differences of 0.04 (95% CI: 0.02, 0.05) at the femoral neck, 0.06 (95% CI: 0.04, 0.08) at the hip and 0.06 (95% CI: 0.04, 0.07) at the spine. The differences for forearm BMD were not significantly different between diabetics and non-diabetics. Sex-stratified analyses showed similar results in both genders. Substantial heterogeneity was found to originate from differences in study design and possibly diabetes definition. Also, by applying meta-regression we could establish that younger age, male gender, higher body mass index and higher HbA(1C) were positively associated with higher BMD levels in diabetic individuals. We conclude that individuals with T2DM from both genders have higher BMD levels, but that multiple factors influence BMD in individuals with T2DM.

The Rotterdam Study: 2012 objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, oncological, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in over a 1,000 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy ). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

A systems approach to bone pathophysiology

With evolving interest in multiscalar biological systems one could assume that reductionist approaches may not fully describe biological complexity. Instead, tools such as mathematical modeling, network analysis, and other multiplexed clinical- and research-oriented tests enable rapid analyses of high-throughput data parsed at the genomic, proteomic, metabolomic, and physiomic levels. A physiomic-level approach allows for recursive horizontal and vertical integration of subsystem coupling across and within spatiotemporal scales. Additionally, this methodology recognizes previously ignored subsystems and the strong, nonintuitively obvious and indirect connections among physiological events that potentially account for the uncertainties in medicine. In this review, we flip the reductionist research paradigm and review the concept of systems biology and its applications to bone pathophysiology. Specifically, a bone-centric physiome model is presented that incorporates systemic-level processes with their respective therapeutic implications.

Correlates of osteoporosis in chronic obstructive pulmonary disease: An underestimated systemic component

RATIONALE

Chronic obstructive pulmonary disease (COPD) patients are at increased risk of osteoporosis. Osteoporosis is under diagnosed and under treated in these patients and the underlying mechanisms remain unclear. To date, screening recommendations for osteoporosis in COPD patients are not available.

OBJECTIVES

To examine the prevalence of drug treatment of bone abnormalities as well as the clinical determinants of osteoporosis in COPD.

METHODS

COPD patients (n=554) consecutively entering pulmonary rehabilitation were included in this cross-sectional study. Medical history, current medication use, smoking status, lung function, bone mineral density, body composition and other clinical characteristics were assessed before entering pulmonary rehabilitation. Univariate- and multivariate multinomial logistic regression analyses were used to determine correlates of osteoporosis.

MAIN RESULTS

Twenty-one percent of patients had osteoporosis and 41% had osteopenia. Osteoporosis was pharmacologically under treated (82% of osteoporotic patients were not receiving bone medication). Independent predictors of osteoporosis were cachexia (OR: 12.1; 95%CI: 4.5-32.7; p<0.001), age between 55 and 65 years (OR: 6.0; 95%CI: 2.2-16.3; p<0.001) and over 65 years (OR: 11.7; 95%CI: 4.1-33.1; p=<0.001). Overweight (OR: 0.1; 95%CI: 0.05-0.4; p=0.001) and obesity (OR: 0.78; 95%CI: 0.02-0.4; p=0.002) showed a substantial protective effect.

CONCLUSIONS

The majority of COPD patients with osteoporosis entering pulmonary rehabilitation did not receive pharmacological treatment for osteoporosis. Cachectic COPD patients should be screened for osteoporosis, especially when over 55 years of age.

Can low doses of simvastatin enhance fracture healing? An experimental study in rabbits

Several observational and experimental studies have investigated the potential anabolic effects of statins on undisturbed bone but only a few recent studies have examined the effect of statins on skeletal repair. The goal of the study is to investigate any potential early anabolic effect of the systemic administration of simvastatin in low doses (based on earlier safety and efficacy studies on undisturbed bone) on fracture healing. Fifty-four skeletally mature male New Zealand White rabbits were used for the study. The rabbits were assigned to one of three experimental groups: a control group, and two groups that were orally administrated a diet with 10 and 30 mg/kg/day of simvastatin, respectively. A complete biochemical blood count was performed to exclude drug-induced complications. Half of the animals of each group were sacrificed at 15 days and the other half at 30 days after surgery at which time intervals healing quality was assessed. The bones were subjected to biomechanical testing, histomorphometric analysis and peripheral quantitative computed tomography. In animals received simvastatin of 30 mg/kg/day a significant reduction of BMD, stiffness, and energy absorbed to failure were observed. At 15 days, the amount of cartilaginous callus formation was reduced, and the void space was significantly increased, in the animals of both groups that received simvastatin when compared to the control group (p<.05). Our results suggest that simvastatin doses of 30 mg/kg/day may have a negative anabolic effect on callus formation in rabbits, whereas doses of 10 mg/kg/day seem not to produce a significant positive or a negative effect, especially at the early stages of fracture remodeling.

Effects of mevastatin on grafted bone in MRL/MpJ mice

Statins, lipid-lowering drugs, have been reported to influence bone metabolism. However, the available information about their effects on bone formation and resorption in vivo is still limited. The present study was undertaken to determine whether the topical administration of mevastatin could increase the bone mass of isografted bone. The tibiae were bilaterally dissected from a donor MRL/MpJ mouse and transplanted subcutaneously in the dorsal region of a recipient mouse. One grafted tibia was topically infused for either 1, 2, 3, or 4 weeks with mevastatin, using an osmotic minipump at a dose of 2.5 pmol/hr. The other tibia was infused with 0.9% NaCl (control). Our three results were: (1) Topical mevastatin stimulated bone formation and numerous cuboidal osteoblasts appeared on the surface of newly formed bone. Bone mineral density and bone area in mevastatin-treated bone were significantly increased. (2) Topical mevastatin increased the number of osteoclasts. (3) The expression of bone morphogenetic protein-2 (BMP-2) mRNA and receptor activator of NF-kB ligand (RANKL) mRNA were upregulated in mevastatin-treated bone. These results suggest that the topical infusion of mevastatin increases bone mass of isografted bone by increasing bone turnover and, at least in part, by promoting the expression of BMP-2 and RANKL mRNA.

Simvastatin locally applied from a biodegradable coating of osteosynthetic implants improves fracture healing comparable to BMP-2 application

Many clinical and experimental investigations address the influence of statins on bone formation and fracture healing. Simvastatin was shown to increase the expression of Bone morphogenetic protein (BMP-2), which is one of the most potent growth factors targeting bone formation. In this study, the effect of simvastatin locally applied from a bioactive polymer coating of implants on fracture healing was investigated. A closed fracture of the right tibia of 5-month-old Sprague-Dawley rats was performed. Intramedullary stabilization was achieved with uncoated vs. polymer-only coated vs. polymer plus drug coated titanium Kirschner wires. Test substances (either simvastatin low- or high dosed or BMP-2) were incorporated into a biodegradable layer of poly(d,l-lactide). Tibiae were harvested after 28 or 42 days, respectively and underwent biomechanical testing (torsional stiffness and maximum load) and histomorphometric analysis. Radiographic results demonstrated progressed callus consolidation in the BMP-2- and simvastatin-treated groups compared to the uncoated group at both timepoints. The simvastatin-high-dosed group revealed an increased torsional stiffness and significantly elevated maximum load (d 28) compared to control group as well as a significant increase in both parameters at d 42. BMP-2-treated animals showed significantly elevated maximum load and stiffness at the early timepoint and elevated torsional stiffness after d 42. The histomorphometric analysis revealed a significantly decreased cartilage area for BMP-2 treated animals at d 28. Even though an increase of mineralized areas among periosteal callus was found at d 42 for simvastatin-high as well as BMP-2 treated animals, no significant difference could be detected at both timepoints compared to the uncoated group. However, simvastatin-high treated animals revealed significantly reduced cartilage areas within the periosteal callus at d 42. The present study revealed a dose-dependent effect and improved fracture healing under local application of simvastatin. Biomechanical, radiographic and histomorphometric properties showed comparable results to BMP-2- treated animals in this study.

The Rotterdam Study: 2010 objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in close to a 1,000 research articles and reports (see www.epib.nl/rotterdamstudy). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

Scavenger receptor of class B expressed by osteoblastic cells are implicated in the uptake of cholesteryl ester and estradiol from LDL and HDL3

Lipoproteins transport many vitamins and hormones that have been shown to be necessary for bone formation. However, the metabolism of LDL and HDL3 by bone-forming osteoblastic cells remains unknown. Here we report that osteoblastic cells express scavenger receptors of class B that are implicated in the uptake of cholesterol and estradiol from LDL and HDL3.

INTRODUCTION

The bone tissue is continuously remodeled, and its integrity requires a balance between osteoclastic bone resorption and osteoblastic bone formation. Recent studies have reported the importance of triglyceride-rich lipoproteins for the delivery of lipophilic vitamins necessary for normal bone metabolism. However, the ability of osteoblastic cells to process low- and high-density lipoproteins (LDL and HDL3) and the receptors involved remain unknown.

MATERIALS AND METHODS

Binding, competition, degradation, and selective uptake assays with LDL and HDL3 radiolabeled in their protein and lipid moieties or with [3H]estradiol were conducted on human osteoblasts (MG-63 cell line and primary cultures of human osteoblasts [hOB cells]) and on mouse osteoblasts (MC3T3-E1 cell line and primary cultures of murine osteoblasts [mOB cells]). The expression of scavenger receptors (SRs) by osteoblastic cells was determined by RT-PCR and Western immunoblotting, and cellular localization was assessed by sucrose gradient fractionation.

RESULTS

Osteoblastic cells were able to bind, internalize, and degrade HDL3 and LDL and are capable of selectively taking up cholesteryl esters (CEs) from these lipoproteins. Also, we provide evidence that osteoblastic cells express SR-BI, SR-BII, and CD36 (SR-Bs receptors) and that these receptors are localized in membrane lipid rafts or caveolin-rich membranes. The selective uptake of CE from LDL and HDL3 by osteoblastic cells was strongly inhibited by the known SR-B ligand oxidized LDL, indicating that SR-B receptors are responsible for the selective uptake. Finally, estradiol carried by LDL and HDL3 was selectively transferred to the osteoblastic cells also through SR-B receptors.

CONCLUSIONS

Overall, our results suggest a novel mechanism for the routing of cholesterol and estradiol to osteoblasts involving the metabolism of LDL and HDL3 by SR-B receptors.

Influence of oxidized low-density lipoproteins (LDL) on the viability of osteoblastic cells

Cardiovascular diseases have recently been noted as potential risk factors for osteoporosis development. Although it is poorly understood how these two pathologies are related, it is a known fact that oxidized low-density lipoproteins (OxLDL) constitute potential determinants for both of them. The current study investigated the metabolism of OxLDL by osteoblasts and its effect on osteoblastic viability. The results obtained show that OxLDL are internalized but not degraded by osteoblasts while they can selectively transfer their CE to these cells. It is also demonstrated that OxLDL induce proliferation at low concentrations but cell death at high concentrations. This reduction of osteoblast viability was associated with lysosomal membrane damage caused by OxLDL as demonstrated by acridine orange relocalization. Accordingly, chloroquine, an inhibitor of lysosomal activity, accentuated cell death induced by OxLDL. Finally, we demonstrate that osteoblasts have the capacity to oxidize LDL and thereby potentially increase the local concentration of OxLDL. Overall, the current study confirms the potential role of OxLDL in the development of osteoporosis given its influence on osteoblastic viability.

Association of lower serum cholesterol levels with higher risk of osteoporosis in type 2 diabetes

OBJECTIVE

To determine whether a correlation exists between bone mineral density and circulating lipoprotein levels and whether these variables are independently associated with osteoporosis in patients with type 2 diabetes.

METHODS

In a cross-sectional analysis, 159 patients with type 2 diabetes were compared with 70 patients without diabetes selected from an outpatient endocrinology clinic in a tertiary care institute during a 1-year period. Variables were gathered through history, physical examination, and laboratory findings, including blood chemistry studies and dual-energy x-ray absorptiometry.

RESULTS

Of the 229 study patients, 86 (37.6%) had osteoporosis. In the patients with diabetes, the mean +/- SD of age, weight, total cholesterol, and low-density lipoprotein (LDL) cholesterol in those with and without osteoporosis was 72.3 +/- 10.4 years versus 63.6 +/- 11.0 years, 74.2 +/- 14.4 kg versus 83.7 +/- 15.5 kg, 178.4 +/- 33.7 mg/dL versus 194.1 +/- 33.9 mg/dL, and 100.0 +/- 27.1 mg/dL versus 114.2 +/- 30.2 mg/dL, respectively (P<0.01 for all variables). After adjustment for other variables, multiple logistic regression analysis showed that the presence of diabetes was associated with a lower risk of osteoporosis. Similarly, older age and lower body weight, LDL levels, and serum calcium levels were independently associated with lumbar spine osteoporosis in patients with diabetes, in comparison with older age and lower weight in patients without diabetes. Lower weight and older age were associated with femoral neck and total hip osteoporosis in patients with diabetes, in comparison with only older age in patients without diabetes.

CONCLUSION

The presence of type 2 diabetes is associated with a lower risk of osteoporosis. In patients with type 2 diabetes, a lower LDL level is more likely to be associated with osteoporosis at the lumbar spine.

Locally applied simvastatin promotes fracture healing in ovariectomized rat

Simvastatin solution was injected subcutaneously to the site of fractured tibiae of ovariectomized rats. Afterwards healing quality was evaluated by morphologic, radiographic, biomechanical, histological and histomorphometric methods at 1, 2 and 4 weeks after fracture. Results showed that locally applied simvastatin improved fracture healing.

INTRODUCTION

Many studies have documented an anabolic effect of hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, statins, on undisturbed bone. Reports of their effects, however, on fractured skeletal systems have been limited. A study was, therefore, conducted to check the effects of statins on fracture healing.

METHODS

Simvastatin (10 mg/kg/day) was injected subcutaneously to tissue overlying the site of fractured tibiae of ovariectomized rats for a treatment period of 5 days. Vehicle reagent was used as a control. Healing quality was evaluated at 1, 2 and 4 weeks after fracture.

RESULTS

Compared with that in the vehicle group, the callus cross-section area in simvastatin-treated rats was significantly enlarged by 21.3% (p < 0.05) at 1 week and by 21.5% (p < 0.05) at 2 weeks; new woven bone was relatively substantive and arranged more tightly and regularly at 2 and 4 weeks; and maximal load was increased by 57.5% (p < 0.05) at 2 weeks and by 31.4% (p < 0.05) at 4 weeks. Histomorphometrically, simvastatin was associated with a significant (p < 0.05) increase of mineralization width (MLW), mineralization volume (MLV) and mineral apposition rate (MAR).

CONCLUSION

The current study suggests that local application of simvastatin could promote fracture healing in ovariectomized rats.

Effects of atorvastatin on bone in postmenopausal women with dyslipidemia: a double-blind, placebo-controlled, dose-ranging trial

CONTEXT

In preclinical models, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase have been shown to positively affect bone remodeling balance. Observational studies and secondary analyses from lipid-lowering trials have yielded inconsistent results regarding the effect of these agents on bone mineral density and fracture risk.

OBJECTIVE

Our objective was to determine whether clinically significant skeletal benefits result from hydroxymethylglutaryl-coenzyme A reductase inhibition in postmenopausal women.

DESIGN AND SETTING

We conducted a prospective, randomized, double-blind, placebo-controlled, dose-ranging comparative clinical trial at 62 sites in the United States.

PARTICIPANTS

Participants included 626 postmenopausal women with low-density lipoprotein cholesterol levels of at least 130 mg/dl (3.4 mmol/liter) and less than 190 mg/dl (4.9 mmol/liter), and lumbar (L1-L4) spine bone mineral density T-score between 0.0 and -2.5.

INTERVENTION

Once-daily placebo or 10, 20, 40, or 80 mg atorvastatin was administered.

MAIN OUTCOME MEASURES

We assessed percent change from baseline in lumbar (L1-L4) spine bone mineral density with each dose of atorvastatin compared with placebo.

RESULTS

At 52 wk, there was no significant difference between each atorvastatin and placebo group or change from baseline at any tested dose of atorvastatin or placebo in lumbar (L1-L4) spine bone mineral density. Nor did atorvastatin produce a significant change in bone mineral density at any other site. Changes in biochemical markers of bone turnover did not differ significantly between each atorvastatin and placebo group. All doses of atorvastatin were generally well tolerated, with similar incidences of adverse events across all dose groups and placebo.

CONCLUSIONS

Clinically relevant doses of atorvastatin that lower lipid levels had no effect on bone mineral density or biochemical indices of bone metabolism in this study, suggesting that such oral agents are not useful in the prevention or treatment of osteoporosis.

The Rotterdam Study: objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in the Netherlands. The study targets cardiovascular, neurological, ophthalmological and endocrine diseases. As of 2008 about 15,000 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in some 600 research articles and reports (see http://www.epib.nl/rotterdamstudy). This article gives the reasons for the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

Statins and fracture risk. A systematic review

PURPOSE

To summarize current evidence on statin use and fracture risk and to explore potential sources of heterogeneity among study results.

METHODS

A computerized search was conducted on MEDLINE, EMBASE, and the Cochrane databases using the keywords HMG-CoA reductase inhibitor, osteoporosis, and fractures. A meta-analysis was performed to summarize results of studies identified.

RESULTS

Statin use was associated with a 23% lower fracture risk (OR = 0.77, 95%CI: 0.66-0.90). An effect of statins was found in case-control (OR = 0.62, 0.45-0.85, n = 6) and cohort (OR = 0.77, 0.59-1.00, n = 8) studies, but not in post hoc analyses of randomized trials (OR = 1.03, 0.91-1.16, n = 4). A reduced risk with statin use was found for fractures of the hip (OR = 0.58, 0.46-0.74, n = 16), spine (OR = 0.65, 0.48-0.88, n = 8) and other sites (OR = 0.77, 0.60-1.00, n = 7), and both in women (OR = 0.80, 0.66-0.96, n = 11) and men (OR = 0.62, 0.36-1.08, n = 3). Among the observational studies that also evaluated the effect of other lipid-lowering drugs, no reduced fracture risk was found for these agents (OR = 0.96, 0.85-1.09, n = 10). The test for heterogeneity was significant for study results of statin use versus no-use (p < 0.01). Meta-regression analyses suggested that study design might partly account for the heterogeneity. There was an indication of publication bias by examining Begg's plot, although Egger's test was not significant (p = 0.13).

CONCLUSIONS

Current evidence does not support an effect of statins in preventing fractures given (i) the lack of association in randomized trials, (ii) the heterogeneity among observational studies, (iii) the potential residual confounding, and (iv) the potential publication bias.

Increased formation of 8-iso-prostaglandin F(2alpha) is associated with altered bone metabolism and lower bone mass in hypercholesterolaemic subjects

OBJECTIVES

To investigate the relationship of 8-iso-prostaglandin (PG) F(2alpha) levels, a reliable marker of in vivo oxidative stress and lipid peroxidation, with bone mineral density (BMD), bone turnover markers, osteoprotegerin (OPG) and receptor activator of nuclear factor-kappa B ligand (RANKL) in hypercholesterolaemia.

DESIGN

Cross-sectional study.

SETTING

University hospital centre.

METHODS

Serum 8-iso-PGF(2alpha) levels were measured in 173 hypercholesterolaemic subjects and in 152 age- and sex-matched normocholesterolaemic controls. Femoral neck and lumbar spine BMD, serum bone-specific alkaline phosphatase (BAP), osteocalcin (OC), OPG and RANKL levels, as well as urinary levels of C-terminal telopeptides of type I collagen (CTX-I), were also assessed.

RESULTS

Hypercholesterolaemic subjects showed higher (P < 0.0001) serum 8-iso-PGF(2alpha) levels than controls. They also had decreased (P < 0.0001) femoral neck and lumbar spine BMD, and lower (P < 0.0001) serum BAP and OC levels. No significant differences between hypercholesterolaemic and control subjects were found when comparing urinary CTX-I levels, or serum OPG and RANKL levels. In multivariate linear regression analysis, serum 8-iso-PGF(2alpha) was the only negative predictor for femoral neck BMD and serum BAP and OC levels in hypercholesterolaemic subjects. No significant correlation (all P > 0.25) was present between serum 8-iso-PGF(2alpha) levels and urinary CTX-I levels, or serum OPG and RANKL levels, in hypercholesterolaemic subjects.

CONCLUSIONS

We found an association between increased serum 8-iso-PGF(2alpha) levels and lower bone mass and reduced serum BAP and OC concentrations in hypercholesterolaemic subjects. These results would suggest a possible role for oxidative stress in the development of lower bone mass in hypercholesterolaemia.

Effects of statins on bone mineral density: a meta-analysis of clinical studies

CONTEXT

Statins inhibit HMG-CoA reductase, preventing synthesis of mevalonate but also of isoprenoids, which affect osteoclast activity. Amino-bisphosphonates share this effect. In vitro and in vivo, statins show convincing anabolic and anti-resorptive bone effects. However, in a clinical meta-analysis (MA), they did not prevent hip fractures.

OBJECTIVE AND DESIGN

Our meta-analysis studied the impact of statins on bone mineral density (BMD) at various sites and compared the effects of lipophilic and more hydrophilic statins.

DATA SOURCES

Our PubMed and Embase queries using two keywords (statins, BMD) were updated to October 2006.

DATA COLLECTION

Two readers independently collected BMDs from studies.

DATA SYNTHESIS

Twenty-one studies, mostly observational (three randomized controlled trials and one pseudo-randomized study), were assessed. Two studies were excluded (no control groups). Three studies could not be analyzed. The sixteen studies analyzed mainly included postmenopausal osteopenic women (2971 patients under statins). Statins significantly increased BMD at total hip (TH) and femoral neck (FN). Effect sizes (ESs) were modest: 0.21 at TH (95% confidence interval [CI]: 0.16-0.25) and 0.20 at FN (CI: 0.08-0.28). Among women, statins acted similarly (ES: 0.20 for TH and 0.18 for FN; CI: 0.14-0.25 and 0.06-0.31 respectively); lipophilic statins (simvastatin, lovastatin) almost entirely caused this effect, at both TH (ES: 0.20; CI: 0.15-0.26) and FN (ES: 0.22; CI: 0.06-0.37).

CONCLUSION

Our findings of modest but statistically significant beneficial effects of statins on hip BMD should promote large double-blind randomized controlled trials on their bone effects, in view of their major beneficial cardiovascular effects with excellent safety profile.

Toward a core nutraceutical program for cancer management

As previously suggested, it may be feasible to impede tumorevoked angiogenesis with a nutraceutical program composed of glycine, fish oil, epigallocatechin-3-gallate, selenium, and silymarin, complemented by a low-fat vegan diet, exercise training, and, if feasible, a salicylate and the drug tetrathiomolybdate. It is now proposed that the scope of this program be expanded to address additional common needs of cancer patients: blocking the process of metastasis; boosting the cytotoxic capacity of innate immune defenses (natural killer [NK] cells); preventing cachexia, thromboembolism, and tumor-induced osteolysis; and maintaining optimal micronutrient status. Modified citrus pectin, a galectin-3 antagonist, has impressive antimetastatic potential. Mushroombeta-glucans and probiotic lactobacilli can amplify NK activity via stimulatory effects on macrophages. Selenium, beta-carotene, and glutamine can also increase the number and/or cytotoxic activity of NK cells. Cachectic loss of muscle mass can be opposed by fish oil, glutamine, and beta-hydroxy-beta-methylbutyrate. Fish oil, policosanol, and vitamin D may have potential for control of osteolysis. High-dose aspirin or salicylates, by preventing NF-B activation, can be expected to aid prevention of metastasis and cachexia while down-regulating osteolysis, but their impacts on innate immune defenses will not be entirely favorable. A nutritional insurance formula crafted for the special needs of cancer patients can be included in this regimen. To minimize patient inconvenience, this complex core nutraceutical program could be configured as an oil product, a powder, and a capsule product, with the nutritional insurance formula provided in tablets. It would be of interest to test this program in nude mouse xenograft models.

Statins, Fracture Risk, and Bone Remodeling: What Is True?

Besides the action on plasma lipid levels, statins show a series of ancillary effects defined as all of their vascular and nonvascular effects independent from the cholesterol reduction. It has been recently hypothesized that one of these ancillary effects could be the improvement of bone health, due to the interference with bone metabolism. This may potentially represent the rationale for statins' use in the treatment of osteoporosis, the most common disease of the bone. Both experimental observations and clinical studies on this topic generated a number of conflicting results; however, the largest randomized clinical trials, the Scandinavian Simvastatin Survival Study (4S), Long Term Intervention with Pravastatin in Ischemic Disease (LIPID), and Heart Protection Study (HPS), indicate that statins do not prevent or reduce fracture risk.

Statin but not non-statin lipid-lowering drugs decrease fracture risk: a nation-wide case-control study

INTRODUCTION

Discrepant results have been reported on association between treatment with lipid lowering drugs and fracture risk. Several studies have failed to demonstrate an effect of statins on bone mineral density. Therefore, the epidemiological findings of a reduced fracture risk may be due to selections bias, e.g. a healthy drug user effect. If so, the reduced fracture risk is most likely independent of type of lipid lowering drug.

AIM

We assessed fracture risk in users of various lipid-lowering drugs.

METHODS

In a case-control design, we compared 124,655 fracture cases with 373,962 age- and gender-matched controls. We used computerized registers to assess individual drug use and related these data to individual fracture data and information on potential confounders.

RESULTS

Use of statins was associated with a reduced risk of any fracture (adj. OR 0.87; 95% CI, 0.83-0.92) and hip fractures (adj. OR 0.57; 95% CI, 0.48-0.69). Risk of hip fracture decreased with increased accumulated dose of statins. This was true in men and in women and in subjects younger and older than 65 years of age. However, fracture risk was not reduced in patients treated with pravastatin (adj. OR 1.02; 95% CI, 0.89-1.17) or non-statin lipid lowering drugs (adj. OR 0.99; 95% CI, 0.86-1.15).

CONCLUSIONS

The reduced fracture risk in users of lipid lowering drugs is apparently specifically related to users of non-pravastatin statins. Our findings do not support the hypothesis of a healthy drug user effect as an explanation for the reduced fracture risk in users of statins.

Statins and osteoporosis: new role for old drugs

Osteoporosis is the most common bone disease, affecting millions of people worldwide and leading to significant morbidity and high expenditure. Most of the current therapies available for its treatment are limited to the prevention or slowing down of bone loss rather than enhancing bone formation. Recent discovery of statins (HMG-CoA reductase inhibitors) as bone anabolic agents has spurred a great deal of interest among both basic and clinical bone researchers. In-vitro and some animal studies suggest that statins increase the bone mass by enhancing bone morphogenetic protein-2 (BMP-2)-mediated osteoblast expression. Although a limited number of case-control studies suggest that statins may have the potential to reduce the risk of fractures by increasing bone formation, other studies have failed to show a benefit in fracture reduction. Randomized, controlled clinical trials are needed to resolve this conflict. One possible reason for the discrepancy in the results of preclinical, as well as clinical, studies is the liver-specific nature of statins. Considering their high liver specificity and low oral bioavailability, distribution of statins to the bone microenvironment in optimum concentration is questionable. To unravel their exact mechanism and confirm beneficial action on bone, statins should reach the bone microenvironment in optimum concentration. Dose optimization and use of novel controlled drug delivery systems may help in increasing the bioavailability and distribution of statins to the bone microenvironment. Discovery of bone-specific statins or their bone-targeted delivery offers great potential in the treatment of osteoporosis. In this review, we have summarized various preclinical and clinical studies of statins and their action on bone. We have also discussed the possible mechanism of action of statins on bone. Finally, the role of drug delivery systems in confirming and assessing the actual potential of statins as anti-osteoporotic agents is highlighted.

Lipid levels and bone mineral density

PURPOSE

There has been considerable debate about the potential relationship between the use of statin lipid-lowering drugs and fracture risk; several observational studies suggest a protective effect but no randomized controlled trials have confirmed such a benefit. Because statins are given preferentially to persons with hyperlipidemia, if lipid levels were associated with bone mineral density, this could explain the discrepancy between epidemiological observations and randomized controlled trials. The aim of this study was to examine the relationship between lipid levels and bone mineral density.

SUBJECTS AND METHODS

We included the 13592 participants in the National Health and Nutritional Examination Survey (NHANES) III who had bone mineral density and lipid levels measured; participants who reported the use of a lipid-lowering therapy were excluded. We examined the unadjusted bone mineral density across quintiles of total cholesterol, low-density lipoprotein (LDL), and high-density lipoprotein (HDL). We then constructed multivariable models, including age, sex, body mass index, and other potential confounders.

RESULTS

In crude analyses, higher total cholesterol and LDL levels were associated with lower bone mineral densities (both P values for trend <.001), whereas higher HDL levels were associated with higher bone mineral densities (P value for trend <.001). However, in fully adjusted models, there was no significant relationship between total cholesterol, LDL, or HDL levels and bone mineral density (all P values for trend >.1).

CONCLUSIONS

These results do not support a relationship between lipid levels and bone mineral density.

Statins in rheumatology

Statins were developed for the treatment of lipid disorders and have been proved to reduce cardiovascular morbidity and mortality when used for primary or secondary prevention. Beneficial effects in patients with osteoporotic fractures or rheumatoid arthritis (RA) have been suggested but remain unproven. Cardiovascular morbidity and mortality are increased in patients with RA or systemic lupus erythematosus, who should undergo serum lipid assays. When these show dyslipidemia, statin therapy should be started according to current recommendations.