RETRACTED: Homocysteine as a predictive factor for hip fracture in elderly women with Parkinson's disease

The association of homocysteine, folate, vitamin B12, and vitamin B6 with fracture incidence in older adults: a systematic review and meta-analysis

Background

Diverse conclusions have been drawn regarding the association of homocysteine (HCY) deficiency and supplements of B vitamins with fracture incidence in older adults. The aim of this meta-analysis was to investigate the association of HCY and B vitamins (folate, vitamin B12, and B6) with fracture incidence in older adults and whether supplements of B vitamins reduce the risk of fracture.

Methods

The PubMed, Embase, and Cochrane library databases were systematically searched from their inception dates to 1 July 2019 to identify relevant published articles. Meta-analysis was performed to pool hazard ratios (HRs) or risk ratios (RRs) and 95% confidence intervals (CIs) using a random effects model.

Results

A total of 28 studies fulfilled the inclusion criteria. High serum HCY was an independent risk factor for fractures in older persons (HR =1.25, 95% CI: 1.12 to 1.40), but only at the highest quartile level (>15 µmol/L) (HR =1.71, 95% CI: 1.37 to 2.12), rather than the second and third quartile. Multiple sensitivity and subgroup analyses supported the consistency and stability of this result. A severe deficiency of folate, instead of vitamin B12 and B6, was found to increase the risk of fracture in older adults (HR =1.46, 95% CI: 1.06 to 2.02; 1.24, 95% CI: 0.79 to 1.95; 1.36, 95% CI: 0.90 to 2.06, respectively). For the interventional effect, there was no significant association of combined folate and vitamin B12, combined folate, vitamin B12 and B6, or single vitamin B6 supplementation with the decrease of fracture risk.

Discussion

This meta-analysis revealed that significantly elevated serum level of HCY is positively associated with fracture incidence in older adults, yet the necessity and threshold for intervention by B vitamins require further large-scale high-quality clinical trials to validate.

PROSPERO identifier

CRD42019122586.

Evaluation of the Relationship Between Homocysteine, Parathormone, Vitamin D3, and Bone Mineral Densitometry in Recipients of Kidney Transplant

PURPOSE

In this study, we evaluated the relationship between serum homocysteine level and proteinuria, parathyroid hormone, vitamin D, and bone mineral density in kidney transplant recipients (KTR).

MATERIALS AND METHODS

A total of 117 stable KTR older than 18 years was followed in our outpatient clinic. Demographic data were recorded. Simultaneously biochemical parameters, including glucose, blood urea nitrogenous, creatinine, calcium, phosphorus, sodium, potassium, albumin, parathormone, vitamin D₃, homocysteine, vitamin B₁₂, folate, and 24-hour urine protein, and bone mineral density of the femoral neck and spine by dual-energy x-ray absorptiometry (DEXA) were measured.

RESULTS

DEXA measurements were normal, osteoporotic, and osteopenic (12.3%, 36.3%, and 51.3%, respectively). There was a relationship between the serum homocysteine and usage of rapamycin (P = .05), statins (P = .057), and beta blockers (P = .01), DEXA measurements were not related with serum homocysteine levels and immunosuppressive drugs used. Serum homocysteine levels correlated negatively with blood urea nitrogen (P = .002), creatinine (P = .001), vitamin B₁₂ (P < .001), and a positively daily proteinuria (rho = 0.203, P = .031). There was a negative relationship between proteinuria and serum level of vitamin D.

CONCLUSIONS

The bone mineral density decreased in more than 87% of our KTR. We did not find any relationship between DEXA measurements and levels of homocysteine, vitamin D, parathormone, and immunosuppressive drugs. It should be noted that some drugs used may affect serum homocysteine levels. Interestingly, there was a relationship between proteinuria and serum levels of homocysteine and vitamin D. Therefore, serum levels of homocysteine and vitamin D should be evaluated for preventing renal damage in KTR.

Bazedoxifene Ameliorates Homocysteine-Induced Apoptosis and Accumulation of Advanced Glycation End Products by Reducing Oxidative Stress in MC3T3-E1 Cells

Elevated plasma homocysteine (Hcy) level increases the risk of osteoporotic fracture by deteriorating bone quality. However, little is known about the effects of Hcy on osteoblast and collagen cross-links. This study aimed to investigate whether Hcy induces apoptosis of osteoblastic MC3T3-E1 cells as well as affects enzymatic and nonenzymatic collagen cross-links and to determine the effects of bazedoxifene, a selective estrogen receptor modulator, on the Hcy-induced apoptosis and deterioration of collagen cross-links in the cells. Hcy treatments (300 μM, 3 mM, and 10 mM) increased intracellular reactive oxygen species (ROS) production in a dose-dependent manner. Propidium iodide staining showed that 3 and 10 mM Hcy induced apoptosis of MC3T3-E1 cells. Moreover, the activities of caspases-8, 9, and 3 were increased by 3 mM Hcy. The detrimental effects of 3 mM Hcy on apoptosis and ROS production were partly reversed by bazedoxifene and 17β estradiol. In addition, real-time PCR, immunostaining and Western blot showed that 300 μM Hcy decreased the expression of lysyl oxidase (Lox). Furthermore, 300 μM Hcy increased extracellular accumulation of pentosidine, an advanced glycation end product. Treatment with bazedoxifene ameliorated Hcy-induced suppression of Lox expression and increase in pentosidine accumulation. These findings suggest that high-dose Hcy induces apoptosis of osteoblasts by increasing oxidative stress, and low-dose Hcy decreases enzymatic collagen cross-links and increases pentosidine accumulation, resulting in the deterioration of bone quality. Bazedoxifene treatment effectively prevents the Hcy-induced detrimental reactions of osteoblasts. Thus, bazedoxifene may be a potent therapeutic drug for preventing Hcy-induced bone fragility.

Neuroendocrine abnormalities in Parkinson's disease

Neuroendocrine abnormalities are common in Parkinson's disease (PD) and include disruption of melatonin secretion, disturbances of glucose, insulin resistance and bone metabolism, and body weight changes. They have been associated with multiple non-motor symptoms in PD and have important clinical consequences, including therapeutics. Some of the underlying mechanisms have been implicated in the pathogenesis of PD and represent promising targets for the development of disease biomarkers and neuroprotective therapies. In this systems-based review, we describe clinically relevant neuroendocrine abnormalities in Parkinson's disease to highlight their role in overall phenotype. We discuss pathophysiological mechanisms, clinical implications, and pharmacological and non-pharmacological interventions based on the current evidence. We also review recent advances in the field, focusing on the potential targets for development of neuroprotective drugs in Parkinson's disease and suggest future areas for research.

Simvastatin rescues homocysteine-induced apoptosis of osteocytic MLO-Y4 cells by decreasing the expressions of NADPH oxidase 1 and 2

Clinical studies have shown that hyperhomocysteinemia is associated with bone fragility. Homocysteine (Hcy) induces apoptosis of osteoblastic cell lineage by increasing oxidative stress, which may contribute to Hcy-induced bone fragility. Statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, ameliorate oxidative stress by regulating oxidant and anti-oxidant enzymes. However, the effects of statins on Hcy-induced apoptosis of osteocytes are unknown. This study was thus aimed to investigate whether or not statins prevent Hcy-induced apoptosis of osteocytic MLO-Y4 cells and regulate NADPH oxidase (Nox) expression. TUNEL staining showed that 5 mM Hcy induced apoptosis of MLO-Y4 cells, and that co-incubation of 10(-9) or 10(-8) M simvastatin significantly suppressed the apoptotic effect. Moreover, we confirmed the beneficial effect of simvastatin against Hcy's apoptotic effect by using a DNA fragment ELISA assay. However, TUNEL staining showed no significant effects of pravastatin, a hydrophilic statin, on the Hcy-induced apoptosis. Real-time PCR showed that Hcy increased the mRNA expressions of Nox1 and Nox2, whereas simvastatin inhibited the stimulation of Nox1 and Nox2 expressions by Hcy. In contrast, neither Hcy nor simvastatin had any effect on Nox4 expression. These findings indicate that simvastatin prevents the detrimental effects of Hcy on the apoptosis of osteocytes by regulating the expressions of Nox1 and Nox2, suggesting that statins may be beneficial for preventing Hcy-induced osteocyte apoptosis and the resulting bone fragility.

HYPERHOMOCYSTEINEMIA AND ITS TREATMENT IN PATIENTS WITH PARKINSON'S DISEASE

Introduction:

Homocysteine is process-product of methionine demethylation. It has proatherogenic, prothrombotic, prooxidative, proapoptotic, osteoporotic, neurotoxic, neuroinflamatory, and neurodegenerative effects. Hyperhomocysteinemia correlates with C667T MTHFR mutation, decrease of folic acid and vitamin B, as well as prolonged use of certain medications.

Materials and Methods:

We measured levels of homocysteine in thirty patients (15::15) with “de novo” Parkinson’s disease, with average age 64.17 ± 13.19 (28-82) years (Department of Neurology, University Clinical Center Tuzla). Normal level of homocysteine for women was 3.36-20.44 micromole/l and 5.9-16 micromole/l for men. We followed the effects of medicament approach (folic acid) every six months for next five years.

Results:

20% of patients with “de novo” Parkinson’s disease exhibited hyperhomocysteinemia. An average level of homocysteine was 13.85 ± 5.82 micromole/l. Differences due to age and homocysteine levels, regardless of sex, were not concluded. For the next five years intake of folic acid (periodically, 1-2 months, 5 mg per day, orally) was effective to normalized levels of homocysteine in all.

Conclusion:

Hyperhomocysteinemia is present in every fifth patient with “de novo” Parkinson’s disease. Folic acid is medication of choice in treatment of hyperhomocysteinemia coexisting with Parkinson’s disease.

Lower Bone Mineral Density in Patients with Parkinson's Disease: A Cross-Sectional Study from Chinese Mainland

KEY POINTS

Significantly lower BMD in PD compared to healthy subjects in both genders.Less than 35 mg(2)/dl(2) of Ca-P product in >80% of PD patients.Significant correlations between BMD and severity of PD.Lower BMD at H&Y stage III/IV than that at H&Y stage I/II.

OBJECTIVES

Although several lines of evidence have suggested that patients with Parkinson's disease (PD) have a higher risk of osteoporosis and fracture, the association between bone mineral density (BMD) and severity of PD patients is unknown.

METHODS

We performed a cross-sectional study of 54 patients with PD and 59 healthy age-matched controls. Multiple clinical scales were used to evaluate the severity of PD, and serum levels of calcium, phosphorus, and homocysteine were measured to determine BMD's association with PD severity.

RESULTS

BMD in PD patients was significantly lower than that in healthy controls. The BMD scores of the spine, femoral neck (FN), and hip were lower in females than in males in the healthy group. In the PD group, BMD in the hip was significantly lower in females compared to males. There was a negative correlation between daily l-DOPA dosage and BMD in the spine and hip in the PD group, while BMD in the spine, neck, and hip was significantly correlated with severity of PD. Besides, we found that among the lumbar spine (LS), FN, and hip, bone loss in the LS was the most severe in PD patients based on the T-scores.

CONCLUSION

Our findings support the hypothesis that patients with PD have a higher risk of osteoporosis, and that low BMD in the spine, FN, and hip may indirectly reflect the severity of PD. Our findings have prompted us to pay more attention to osteoporosis in the LS in Chinese PD patients.

Occurrence, management and outcomes of hip fractures in patients with Parkinson's disease

INTRODUCTION

Hip fractures can be debilitating, especially in patients with pre-existing Parkinson's disease; they have reportedly worse outcomes than non-Parkinson's disease patients.

SOURCES OF DATA

A computerized literature search on PubMed, Medline, Embase, and CINAHL, supplemented by a manual search of related publications.

AREAS OF AGREEMENT

Parkinson's disease patients were found to have significantly lower bone mineral density; higher incidence of falls and hip fractures; delays to receiving their Parkinson's disease medication and surgery; higher risk of pneumonia, urinary infection, pressure sores, post-operative mortality; surgical complications and sequelae, including failed fixation, dislocation, longer hospital stay, re-operation; and increased risk of contralateral hip fracture.

AREAS OF CONTROVERSY

Regain of mobility and return to previous residential status have been variably reported.

GROWING POINTS

All Parkinson's disease patients should be screened and considered for primary prevention treatment. On admission with hip fractures, attention should be paid to avoid delays to medication, ensuring safe anaesthetic and timely surgery, and post-operative chest physiotherapy and mobilization.

RESEARCH

Research is needed in minimizing the bone-resorptive effects of anti-Parkinson's disease medication.

Activation of AMP-activated protein kinase protects against homocysteine-induced apoptosis of osteocytic MLO-Y4 cells by regulating the expressions of NADPH oxidase 1 (Nox1) and Nox2

BACKGROUND

Elevated plasma homocysteine (Hcy) level is associated with the risk of osteoporotic fracture. While Hcy increases oxidative stress, AMP-activated protein kinase (AMPK) activation ameliorates it. This study aimed to investigate whether Hcy induces apoptosis of osteocytic MLO-Y4 cells through regulating expressions of oxidant and anti-oxidant enzymes and determine the effects of AMPK activation by 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) and metformin on the Hcy-induced apoptosis of the cells.

RESULTS

DNA fragment ELISA and TUNEL staining assays showed that Hcy treatments (0.1-5.0 mM) induced apoptosis of MLO-Y4 cells in a dose-dependent manner. The detrimental effect of Hcy was partly but significantly reversed by an antioxidant (N-acetylcysteine) and NADPH oxidase (Nox) inhibitors (apocynin and diphenyleneiodonium). In addition, treatment with AICAR (0.05-0.1 mM) and metformin (10-100 μM) ameliorated Hcy-induced apoptosis of the cells. The favorable effect of metformin on Hcy-induced apoptosis was completely canceled by an AMPK inhibitor Ara-A. Hcy increased the expression levels of Nox1 and Nox2, while it had no effects on the expressions of Nox4 or the anti-oxidant enzymes, superoxide dismutase 1 and 2. Hcy-induced increases in the expressions of Nox1 and Nox2 decreased significantly by treatments with AICAR.

CONCLUSION

These findings suggest that Hcy induces apoptosis of osteocytes by increasing the expressions of Nox1 and Nox2, and AMPK activation by AICAR and metformin effectively prevents the detrimental reactions. Thus, AMPK activation may be a potent therapeutic candidate for preventing Hcy-induced osteocyte apoptosis and the resulting bone fragility.

Effect of ibandronate therapy on serum homocysteine and leptin in postmenopausal osteoporotic females

A significant change in serum leptin level and no change in homocysteine were observed with ibandronate treatment. No correlation of homocysteine and leptin was found with bone mass density (BMD). Results indicate that ibandronate reduces serum leptin levels but how does it help in reducing the osteoporosis. It needs to be explored.

INTRODUCTION

The current study was planned to determine the effects of ibandronate on serum homocysteine and leptin levels in postmenopausal osteoporotic females and to correlate these with BMD.

METHODS

Forty-two newly diagnosed and untreated postmenopausal osteoporotic females were selected on the basis of their BMD (BMD < -2.5) from Orthopaedic Out Patient Department of Shaikh Zayed Hospital, Lahore, Pakistan, and 36, age and BMI matched non-osteoporotic postmenopausal females, were also selected as a control group. Baseline physical and biochemical parameters were compared. In osteoporotic patients, changes in circulating leptin and homocysteine levels were studied after 6 months of therapy with ibandronate (150 mg). The collected data were analyzed on SPSS 16.

RESULTS

There was no significant difference observed in the mean value of all baseline parameters except BMD in both groups. After 6 months of treatment with ibandronate (150 mg), a significant change was observed in serum leptin levels (19.48 ± 1.60 ng/ml vs. 14.09 ± 0.85 ng/ml, p < 0.002), while no considerable change observed in serum homocysteine levels (16.22 ± 0.95 μmol/l vs. 16.80 ± 1.03 μmol/l, p < 0.63). Serum leptin was found significantly correlated with anthropometric parameters. No correlation of serum leptin and homocysteine was found with BMD (r = 0.09, p value = 0.54; r = -0.17, p value = 0.27).

CONCLUSION

Our results show that ibandronate reduces serum leptin levels while it has no effect on serum homocysteine levels. Further studies are needed to explain how the decrease in serum leptin level may help in reducing the progression of osteoporosis.

Bone health in Parkinson's disease: a systematic review and meta-analysis

OBJECTIVE

Parkinson's disease (PD) and osteoporosis are chronic diseases associated with increasing age. Single studies have reported associations between them and the major consequence, namely, increased risk of fractures. The aim of this systematic review and meta-analysis was to evaluate the relationship of PD with osteoporosis, bone mineral density (BMD) and fracture risk.

METHODS

A literature search was undertaken on 4 September 2012 using multiple indexing databases and relevant search terms. Articles were screened for suitability and data extracted where studies met inclusion criteria and were of sufficient quality. Data were combined using standard meta-analysis methods.

RESULTS

23 studies were used in the final analysis. PD patients were at higher risk of osteoporosis (OR 2.61; 95% CI 1.69 to 4.03) compared with healthy controls. Male patients had a lower risk for osteoporosis and osteopenia than female patients (OR 0.45; 95% CI 0.29 to 0.68). PD patients had lower hip, lumbar spine and femoral neck BMD levels compared with healthy controls; mean difference, -0.08, 95% CI -0.13 to -0.02 for femoral neck; -0.09, 95% CI -0.15 to -0.03 for lumbar spine; and -0.05, 95% CI -0.07 to -0.03 for total hip. PD patients were also at increased risk of fractures (OR 2.28; 95% CI 1.83 to 2.83).

CONCLUSIONS

This systematic review and meta-analysis demonstrate that PD patients are at higher risk for both osteoporosis and osteopenia compared with healthy controls, and that female patients are at greater risk than male patients. Patients with PD also have lower BMD and are at increased risk of fractures.

Homocysteine Level and Mechanisms of Injury in Parkinson's Disease as Related to MTHFR, MTR, and MTHFD1 Genes Polymorphisms and L-Dopa Treatment

An elevated concentration of total homocysteine (tHcy) in plasma and cerebrospinal fluid is considered to be a risk factor for Alzheimer's disease (AD) and Parkinson's disease (PD). Homocysteine (Hcy) levels are influenced by folate concentrations and numerous genetic factors through the folate cycle, however, their role in the pathogenesis of PD remains controversial. Hcy exerts a neurotoxic action and may participate in the mechanisms of neurodegeneration, such as excitotoxicity, oxidative stress, calcium accumulation, and apoptosis. Elevated Hcy levels can lead to prooxidative activity, most probably through direct interaction with N-methyl-D-aspartate (NMDA) receptors and sensitization of dopaminergic neurons to age-related dysfunction and death. Several studies have shown that higher concentration of Hcy in PD is related to long-term administration of levodopa (L-dopa). An elevation of plasma tHcy levels can also reflect deficiencies of cofactors in remethylation of Hcy to methionine (Met) (folates and vitamin B12) and in its transsulfuration to cysteine (Cys) (vitamin B6). It is believed that the increase in the concentration of Hcy in PD can affect genetic polymorphisms of the folate metabolic pathway genes, such as MTHFR (C677T, A1298C and G1793A), MTR (A2756G), and MTHFD1 (G1958A), whose frequencies tend to increase in PD patients, as well as the reduced concentration of B vitamins. In PD, increased levels of Hcy may lead to dementia, depression and progression of the disease.

Five-year fracture risk estimation in patients with Parkinson's disease

BACKGROUND

Previous studies have shown that patients with Parkinson's disease (PD) are at increased risk of fractures. However, no specific prediction model for fracture estimation among PD patients is currently available. Therefore, the aim of this study was to develop a simple score for estimating the 5-year osteoporotic and hip fracture risks among patients with PD.

METHODS

The U.K. Clinical Practice Research Datalink (1987-2011) was used to identify incident PD patients. Cox proportional-hazards models were used to calculate the 5-year risks of osteoporotic and hip fracture among PD patients. The regression model was fitted with various risk factors for fracture and the final Cox model was converted into integer risk scores.

RESULTS

We identified 4411 incident PD patients without a history of osteoporotic treatment. The 5-year risks of osteoporotic and hip fracture were plotted in relation to the risk score. Risk scores increased with age, female gender, history of renal disease and history of dementia. The C-statistic, which is a parameter to test the internal validity of the model, was reasonable for the prediction of osteoporotic fracture (0.69) and hip fracture (0.73).

CONCLUSION

In this study, we developed a simple model to estimate 5-year fracture risk among incident PD patients. It may be useful in daily practice after external validation.

Homocysteine level and risk of fracture: A meta-analysis and systematic review

AIMS

Previous studies have reported inconsistent findings regarding the association between elevated plasma Hcy levels and fracture risk. We investigated this association between homocysteine (Hcy) levels in patients with fracture and unaffected controls by conducting a meta-analysis and systematic review.

METHODS

We conducted a systematic literature search (up to April 2012) of the PubMed database and Embase. We selected observational studies that evaluated Hcy levels in subjects with fracture compared to unaffected controls. We also included randomized clinical trials (RCTs) on the effect of Hcy-lowering therapy in fracture patients. Criteria for inclusion were the assessment of baseline Hcy and risk of fracture as an outcome. The results were presented as relative risk (RR) and corresponding 95% confidence intervals (CI) comparing fracture patients to the control subjects or the highest Hcy quartile group to the lowest Hcy quartile group.

RESULTS

Nine studies with 14,863 participants were identified and analyzed. The pooled RR from a random effect model of participants with all fractures compared with the control subjects was 1.59 (95% CI 1.30-1.96). The pooled RR from a random model for hip fractures in the highest Hcy quartile group compared with the lowest Hcy quartile group was 1.67 (95% CI 1.17-2.38). The effect of Hcy-lowering therapy on fracture was tested in two clinical trials, but clinically important end points were not reported in a consistent way.

CONCLUSIONS

This meta-analysis and systematic review suggested that Hcy significantly increased the risk of fracture, and the increase was independent of risk factors.

Homocysteine, folate, and vitamin B12 levels and vertebral fracture risk in postmenopausal women

The objective of this study was to examine the influence of homocysteine, vitamin B(12), and folate on the prevalence of asymptomatic osteoporotic vertebral fractures (VFs) using vertebral fracture assessment (VFA) in postmenopausal women. The study cohort consisted of 188 consecutive postmenopausal women (mean age, weight, and body mass index of 57.9 ± 8.5 [41-91]yr, 74.4 ± 13.5 [38-150]kg, and 30.4 ± 5.2 [17.1-50.7]kg/m(2), respectively). Lateral VFA images and scans of the lumbar spine and proximal femur were obtained using a Lunar Prodigy Vision densitometer (GE Healthcare Inc., Waukesha, WI). VFs were defined using a combination of Genant's semiquantitative approach and morphometry. Fifty-eight (30.9%) patients had densitometric osteoporosis. VFs were identified using VFA in 76 (40.4%) patients: 61 women had grade 1 VFs and 15 had grade 2 or 3 VFs. No statistical difference was shown between the 3 groups (absence of VFs, VFs grade 1, and VFs grade 2/3) concerning the biological parameters. Comparison of patients according to quartiles of homocysteine levels showed that women in the highest quartile were older and had a lower bone mineral density (BMD); however, the prevalence of VFs was not statistically different from that of women in the other quartile groups. Stepwise regression analysis showed that homocysteine was not independently associated with the presence of VFs, which was mainly related to the osteoporotic status. Although a weak association was observed between hyperhomocysteinemia and low BMD and a trend to higher prevalence of grade 2/3 VFs was observed, our study did not confirm that homocysteine, vitamin B(12), and folate status are important determinants of prevalent asymptomatic VFs in postmenopausal women.

Nutritional therapies in Parkinson's disease

Advise patients with Parkinson's disease (PD) to consume a balanced diet, with special attention to adequate intake of dietary fiber, fluids, and macro- and micronutrients. Regularly reassess patients' nutritional history and anthropomorphic measures (height and weight), particularly in patients with advanced disease. PD-related psychosocial as well as physical and cognitive limitations increase susceptibility to subacute and chronic malnutrition. Nutritional requirements may change with PD progression or after surgical therapy for PD. Patients and caregivers may benefit from counseling by a dietician who is knowledgeable about the nutritional risks and needs of PD. Regularly inquire about dysphagia symptoms, and consider speech therapy consultation for clinical and modified barium-swallowing evaluations and management recommendations. Although non-oral delivery options of dopaminergic therapy are increasing, severe dysphagia may warrant percutaneous endoscopic gastrostomy tube placement for nutritional support and more reliable PD medication dosing. Analyze vitamin B(12) and D concentrations at regular intervals. Both vitamins are frequently deficient in elderly persons but may not be routinely checked by primary care physicians. Record over-the-counter and nutritional supplement medications at each visit, and assist patients in periodically re-evaluating their potential benefits, side effects, drug interactions, and costs. To date, clinical trials of antioxidant vitamins and nutritional supplements have provided insufficient evidence to support routine use for PD in the clinic. Data from several clinical trials of antioxidant vitamins/nutritional supplements are expected in the near future. Consider altering medication dosing in relation to meals to help with mild to moderate motor fluctuations. Patients with severe motor fluctuations may benefit from adapting the 5:1 carbohydrate-to-protein ratio in their daily meals and snacks. Following a "protein redistribution" diet is logistically more difficult and less palatable, and therefore less frequently recommended. To ensure adequate protein intake, a registered dietician should supervise patients who follow either of these diets.

Dopaminergic drugs and the risk of hip or femur fracture: a population-based case-control study

SUMMARY

The effect of dopaminergic medication on the risk of hip/femur fractures is not clear. Our results showed a nearly twofold increased risk of hip/femur fractures in current dopaminergic drug users. Concomitant use of antidepressants further increased this risk. Fracture risk assessment may be warranted in elderly users of dopaminergic drugs.

INTRODUCTION

Dopaminergic drugs, often used in the treatment of Parkinson's disease, have several pharmacological effects that may increase or decrease the risk of falling and fractures. Thus, the effect of dopaminergic medication on the risk of hip/femur fractures is not clear. The objective of the study was to examine the effect of dopaminergic medication and concomitant use of psychotropics on the risk of hip/femur fractures taking into account the timing of dopaminergic drug use.

METHODS

A population-based case-control study in the PHARMO database was conducted for the period 1991 to 2002. Cases were patients aged 18 years and older with a first hip or femur fracture and matched to four control patients by year of birth, sex and geographical region.

RESULTS

The study population included 6,763 cases and 26,341 controls. Current use of dopaminergic drugs (1-30 days before the index date) was associated with an increased risk of hip/femur fractures compared to never use (OR(adj) 1.76, 95% CI = 1.39-2.22), but this excess risk rapidly dropped to baseline levels when treatment had been discontinued >1 year ago. Concomitant use of antidepressants among current dopaminergic drug users further increased the risk of hip/femur fractures (OR(adj) 3.51, 95% CI = 2.10-5.87) while there was no additional risk with concomitant use of other psychotropics.

CONCLUSIONS

Although the observed association between dopaminergic drugs and fracture risk may not be entirely causal, due to absence of information on the (severity of the) underlying disease, fracture risk assessment may be warranted in elderly users of dopaminergic drugs.

Influences of bone and mineral metabolism in epilepsy

INTRODUCTION

Patients with epilepsy are at increased risk for metabolic bone disease, low bone mineral density and fractures.

AREAS COVERED

This article reviews the predictors and mechanisms of bone loss in patients with epilepsy. It provides information regarding the basic bone biology, evidences of osteopathy with epilepsy and the potential mechanisms of its pathogenesis. This review shows that long-term use of antiepileptic drugs (AEDs) is associated with the risk of osteopathy. However, age, gender, low body mass, severity of epilepsy, co-morbid conditions, institutionalization and calcium and vitamin D deficiencies are additional and modified risk factors. AEDs may indirectly accelerate bone loss through hypovitaminosis D, hypocalcemia and hyperparathyroidism or reduce bone accrual through decreasing the levels of calcitonin, growth factors and vitamin K. Also, AEDs may directly accelerate osteoclastic (bone loss) and/or reduce osteoblastic (bone formation) activities, the main cells involved in bone remodeling.

EXPERT OPINION

Understanding the basic bone biology and the pathophysiology of the disturbed bone and mineral metabolism in epilepsy will aid in identification and monitoring of patients at risk and in planning appropriate prophylactic and therapeutic measures.

The relationship between plasma homocysteine levels and bone mineral density in post-menopausal women

BACKGROUND

Whether or not mild hyperhomocysteinemia and low serum levels of folates or vitamin B12 are risk factors for osteoporosis in the elderly is controversial.

AIMS AND METHODS

To investigate whether or not plasma levels of total homocysteine (tHcy) and serum levels of folates and vitamin B12 are associated with bone mineral density (BMD), we carried out a cross-sectional study on 446 post-menopausal women (mean age: 65.1+/-9.4 years), consecutively seen at the Siena Unit (Tuscany region, Central Italy) for BMD evaluation over a two-year period. BMD of the total femur, femoral neck and lumbar spine was detected by dual-energy X-ray absorptiometry.

RESULTS

The age-adjusted geometric mean of plasma tHcy levels (micromol/L) was 9.96+/-1.29 in women with normal BMD, 11.06+/-1.32 in those with osteopenia and 11.88+/-1.35 in those with osteoporosis (p<0.0001). On multiple linear regression analysis, adjusting for age, body mass index, folates, vitamin B12, creatinine clearance, smoking habit and alcohol intake, tHcy was negatively related to BMD of the total femur [beta estimate for log-homocysteine: -0.050 (95% CI: -0.100 to -0.001, p=0.048; R(2)=0.02)], but not of femoral neck or lumbar spine. There was no significant association between BMD and serum levels of folates and vitamin B12.

CONCLUSIONS

tHcy is negatively associated with BMD of the total femur. The contribution of tHcy to explain the variance of BMD is small (2% of the total variance) but clinically relevant, considering the high prevalence of osteoporosis among post-menopausal women and the possibility to lower tHcy by vitamin supplementation.

Homocysteine-lowering therapy or antioxidant therapy for bone loss in Parkinson's disease

We investigated whether homocysteine (Hcy)- lowering therapy or an antioxidant prevented bone loss in Parkinson's disease (PD) patients taking levodopa. Forty-two PD patients with low bone mineral density (BMD) taking levodopa were randomly assigned to Hcy-lowering therapy (5 mg folate and 1500 microg vitamin B(12) daily), alpha-lipoic acid (alpha-LA) therapy (1200 mg daily), or control groups. Primary outcomes were BMD changes from baseline to 12 months. Secondary outcomes were changes in Hcy level, and C-telopeptide (CTX) levels at 12 months. Forty-one patients completed the study. Hcy-lowering therapy resulted in significantly greater BMD changes at the lumbar spine (4.4%), total femur (2.8%), and femur shaft (2.8%) than control (P = 0.005-0.023). BMD changes in the alpha-LA therapy group were similar to those of the control group, but changes at the trochanter (4.6%) were significantly greater in the alpha-LA therapy group than in the control group after adjustment for body mass index changes. Hcy concentrations decreased to 35.2% +/- 13.4% in the Hcy-lowering therapy group, but increased in other groups. Serum CTX levels at 12 months tended to be lower in the Hcy-lowering group (0.442 +/- 0.024 ng/mL) than control group (0.628 +/- 0.039 ng/mL) (P = 0.159). This small trial suggests that Hcy-lowering therapy may prevent bone loss in PD patients taking levodopa.

Differential effects of homocysteine and beta aminopropionitrile on preosteoblastic MC3T3-E1 cells

Compounds, like beta-aminopropionitrile (bAPN) and homocysteine (hcys), are known to inhibit a stable matrix formation. Osteoblast-synthesized collagen matrix regulates the differentiation of precursor cells into mature osteoblasts. They express lysyl oxidase, an enzyme involved in the collagen cross-linking process. Lately, plasma hcys levels have recently been strongly correlated with fracture in humans. We have previously shown that bAPN not only disturbs collagen cross-links but also affects osteoblastic differentiation in a cell culture system. The aim of the present study was to investigate the effects of bAPN and hcys on collagen cross-links and gene expression at the mRNA level by FTIR and quantitative RT-PCR, respectively. We found that bAPN and hcys down-regulated cell multiplication. While bAPN also down-regulated the metabolic activity of MC3T3-E1 cells, hcys down-regulated it by lower concentrations but up-regulated it by higher; both substances up-regulated alkaline phosphatase activity. The substances increased the ratio of pyr/divalent cross-links of collagen, and down-regulated mRNA expression of lysyl hydroxylase (Plod2) and lysyl oxidase (Lox), genes which play an important role in the formation of a stable matrix. Furthermore, we demonstrate that both substances stimulated the expression of Runx2, an indispensable regulator of osteoblastic differentiation. However, analysis of genome wide mRNA expression suggests that hcys and bAPN have differential effects on genes involved in osteoblastic differentiation and phenotype regulation. The results indicate that although both bAPN and hcys affect collagen cross-link post-translational modifications in a similar manner as far as pyr and divalent cross-links are concerned, they have differential effects on the monitored genes expression at the mRNA level, with hcys exerting a broader effect on the genome wide mRNA expression.

Hyperhomocysteinemia due to levodopa treatment as a risk factor for osteoporosis in patients with Parkinson's disease

Parkinson's disease (PD) patients have been reported to have lower bone mineral density (BMD) and higher fracture risk than individuals without PD. We assessed the association between hyperhomocysteinemia due to levodopa intake and BMD in PD patients. We measured serum homocysteine (Hcy) concentrations and BMD in the proximal femur and lumbar spine of PD patients aged 55 years or older (n = 95) and three age-/gender-matched control subjects (n = 285). The prevalence of osteoporosis was higher in both men (2.5-fold) and women (1.7-fold) with PD than in controls, and adjusted odds ratios for osteoporosis were 3.57 (95% confidence interval [CI], 1.25-10.20) for men and 2.54 for women (95% CI, 1.31-4.93) with PD. Serum Hcy concentrations were significantly higher in PD patients (median = 13.0 micromol/l) than controls (median = 11.5 micromol/l) (P = 0.005). Serum Hcy concentrations were independently associated with BMD values at all proximal femur sites in all subjects (P = 0.005 to 0.012). In PD patients, higher serum Hcy concentrations were independently associated with higher fracture risk (P = 0.029). PD patients taking higher doses of levodopa had significantly higher serum Hcy concentrations (P = 0.013), and greater levodopa intake was associated with lower BMD values in some areas (P = 0.008 to 0.029). In conclusion, these findings indicate that hyperhomocysteinemia due to levodopa intake may be one additional risk factor for osteoporosis and fracture in PD patients. Reducing Hcy may be a therapeutic modality for treating osteoporosis in PD patients taking levodopa.

Bone tissue and hyperhomocysteinemia

Bone tissue quality is determined not only by multiple architectural variables, but also by the mechanical properties of collagen type 1. Homocysteinuria is a genetic disease whose manifestations include severe hyperhomocysteinemia and decreased bone strength. The effects of smaller homocysteine elevations on bone tissue are difficult to demonstrate in clinical studies. Studies in animals and in humans suggest that homocysteine may weaken collagen crosslinks and, if present in large amounts, interfere with bone remodeling. Whether routine homocysteine assays should be performed to detect bone frailty remains unclear. In clinical practice, the focus should be on identifying patients with potential causes of homocysteine elevation (e.g., medications), who should then be given vitamin D and folic acid supplementation if needed. This approach may improve not only bone health, but also vascular and general health.

Collagen cross-linking influences osteoblastic differentiation

Osteoblasts synthesize collagen matrix, which itself regulates the differentiation of precursor cells into mature osteoblasts. They express lysyl oxidase (LOX), which is involved in the collagen cross-linking process. Lathyrogens, like ss-aminopropionitrile (ssAPN), inhibit the formation of a stable matrix. The aim of the present study was to investigate the influence of cross-linking on osteoblastic differentiation. MC3T3-E1 cells were seeded and treated with or without 400 muM ssAPN for 1 week. Thereafter, living cells were removed and, on this extracellular matrix, new MC3T3-E1 cells were seeded and cultured for 1 week without ssAPN. RNA was isolated, and expression of specific marker genes was determined by quantitative reverse transcription-polymerase chain reaction. Changes in specific cross-links after ssAPN treatment were measured with Fourier-transform infrared spectroscopy. The collagen matrix that formed showed a significant reduction of two major cross-links of bone collagen, deH-DHLNL and pyr, compared to control cultures. Gene expression studies showed an increase of collagen alpha1 (I) (COL1A1) to 150%. Expression of LOX and osteocalcin (OCN) mRNA was significantly downregulated to about 75%. When fresh MC3T3-E1 cells were seeded on this altered matrix without ssAPN, COL1A1 mRNA expression was upregulated (140%), OCN was downregulated (60%), and LOX mRNA expression remained unaffected. These results indicate that ssAPN treatment not only disrupts collagen cross-link formation but also affects osteoblastic activity and expression. In conclusion, the disrupted matrix produced in the presence of lathyrogen influences, even in its absence, the expression of osteoblastic genes.

The effect of B-vitamins on biochemical bone turnover markers and bone mineral density in osteoporotic patients: a 1-year double blind placebo controlled trial

BACKGROUND

Hyperhomocysteinemia is a new risk factor for osteoporosis. This study analyzed the effect of a homocysteine (HCY)-lowering treatment in osteoporotic individuals.

METHODS

Osteoporotic subjects (n=47, 55-82 years) were treated with either a combination of 2.5 mg folate, 0.5 mg vitamin B(12) and 25 mg vitamin B(6) or placebo. Bone mineral density (BMD) at lumbar spine and hip was measured at baseline and after 1 year. Urinary desoxypyridinoline cross-links (DPD) and plasma levels of tartrate resistant acid phosphatase (TRAP), C-terminal cross-links of collagen I (CTx), pro-collagen type I N-terminal peptide (PINP) and osteocalcin (OC) were measured after 0, 4, 8 and 12 months.

RESULTS

B-vitamin supplementation significantly reduced HCY (0 vs. 12 months: 13.6+/-4.8 vs. 8.9+/-2.4 micromol/L). Placebo treatment had no effect on HCY (0 vs. 12 months: 12.0+/-3.4 vs. 12.7+/-3.9 micromol/L). BMD, TRAP, CTx, OC and PINP did not change throughout the study in both groups. Vitamin treatment decreased urinary DPD by -13% (p<0.01) after 8 and 12 months. In a sub-group analysis of hyperhomocysteinemic subjects (HCY>15 mumol/L, n=8), B-vitamin treatment tended to increase BMD at the lumbar spine, with a t-score from -2.7 to -1.7, and to decrease OC and PINP by approximately 50%.

CONCLUSIONS

B-vitamin supplementation had no consistent effects on bone turnover or BMD. However, the situation may be different in patients with hyperhomocysteinemia.

The role of hyperhomocysteinemia and B-vitamin deficiency in neurological and psychiatric diseases

Hyperhomocysteinemia (HHcy) is related to central nervous system diseases. Epidemiological studies show a positive, dose-dependent relationship between plasma total homocysteine (tHcy) concentration and neurodegenerative disease risk. tHcy is a marker of B-vitamin (folate, B(12), B(6)) status. Hypomethylation, caused by low B-vitamin status and HHcy, is linked to key pathomechanisms of dementia; B-vitamin supplementation could potentially reduce neurological damage. In retrospective studies, the association between tHcy and cognition is impressive; there is also evidence that tHcy-lowering treatment could be effective in primary and secondary stroke prevention. Increased tHcy and low serum folate occur in patients with Parkinson's disease, especially those receiving L-dopa. There is also an association between HHcy and multiple sclerosis, and between B-vitamin status and depression. Studies also confirm a causal role for tHcy in epilepsy, and certain anti-epileptics enhance HHcy. B-vitamin status should be optimized by ensuring sufficient intake in patients with neuropsychiatric diseases. HHcy occurs commonly in the elderly and can contribute to age-related neurodegeneration. Treatment with folic acid, B(12) and B(6) lowers tHcy. For secondary and primary prevention from several neuropsychiatric disorders, it seems prudent to actively identify deficient subjects and ensure sufficient vitamin intake.

The role of hyperhomocysteinemia as well as folate, vitamin B(6) and B(12) deficiencies in osteoporosis: a systematic review

Hyperhomocysteinemia (HHCY) has been suggested as a new risk factor for osteoporosis. Recent epidemiological, clinical and experimental studies provide a growing body of data, which is reviewed in this article. Epidemiological and (randomized) clinical trials suggest that HHCY increases fracture risk, but has minor effects on bone mineral density. Measurement of biochemical bone turnover markers indicates a shift of bone metabolism towards bone resorption. Animal studies confirm these observations showing a reduced bone quality and stimulation of bone resorption in hyperhomocysteinemic animals. Homocysteine (HCY) has been found to accumulate in bone by collagen binding. Cell culture studies demonstrate that high HCY levels stimulate osteoclasts but not osteoblasts, indicating again a shift of bone metabolism towards bone resorption. Regarding B-vitamins, only a few in vivo studies with equivocal results have been published. However, two large cell culture studies confirm the results obtained with exogenous HCY administration. In addition, HHCY seems to have adverse affects on extracellular bone matrix by disturbing collagen crosslinking. In conclusion, existing data suggest that HHCY (and possibly B-vitamin deficiencies) adversely affects bone quality by a stimulation of bone resorption and disturbance of collagen crosslinking.

Calcifications in the abdominal aorta predict fractures in men: MINOS study

In a cohort of 781 men >or=50 yr of age followed up for 10 yr, extended calcifications in the abdominal aorta were associated with a 2- to 3-fold increase in the risk of osteoporotic fractures regardless of BMD and falls.

INTRODUCTION

Cardiovascular disease and osteoporotic fractures are public health problems that frequently coexist.

MATERIALS AND METHODS

We assessed the relation of the severity of aortic calcifications with BMD and the risk of fracture in 781 men >or=50 yr of age. During a 10-year follow-up, 66 men sustained incident clinical fractures. Calcifications in the abdominal aorta expressed as an aortic calcification score (ACS) were assessed by a semiquantitative method. BMD was measured at the lumbar spine, hip, whole body, and distal forearm.

RESULTS

ACS > 2 was associated with a 2-fold increase in the mortality risk after adjustment for age, weight, smoking, comorbidity, and medications. After adjustment for age, body mass index (BMI), smoking, and comorbidity, men in the highest quartile of ACS (>6) had lower BMD of distal forearm, ultradistal radius, and whole body than men in the lower quartiles. Log-transformed ACS predicted fractures when adjusted for age, BMI, age by BMI interaction, prevalent fractures, BMD, and history of two or more falls (e.g., hip BMD; OR = 1.44; p < 0.02). ACS, BMD at all the skeletal sites, and history of two or more falls were independent predictors of fracture. Men with ACS > 6 had a 2- to 3-fold increased risk of fracture after adjustment for confounding variables (OR = 2.54-3.04; p < 0.005-0.001 according to the site).

CONCLUSIONS

This long-term prospective study showed that elevated ACS (>6) is a robust and independent risk factor for incident fracture in older men regardless of age, BMI, BMD, prevalent fractures, history of two or more falls, comorbidities, and medications.

Homocysteine and fracture risk in postmenopausal women: the OFELY study

Homocysteine has recently been described as an independent risk factor for osteoporotic fractures in the elderly. We prospectively followed 671 postmenopausal women belonging to the OFELY study, mean age 62 years, during a mean follow-up of 10 years. After adjustment for age, there was no significant relation between the plasma level of homocysteine and the subsequent risk of fracture.

INTRODUCTION

Plasma homocysteine increases with age. Recent studies have described homocysteine as an independent risk factor for osteoporotic fractures in elderly. We investigated the role of plasma homocysteine in the subsequent risk of fractures in healthy ambulatory postmenopausal women.

METHODS

Homocysteine was measured at baseline in 671 postmenopausal women from the OFELY cohort (mean age 62.2 +/- 9 years). Incident clinical fractures were recorded during annual follow-up and vertebral fractures were evaluated with radiographs every four years. A cox proportional hazards model based on time to first fracture was used to calculate hazard ratios for quartiles of homocysteine values.

RESULTS

Mean homocysteine was 10.6 +/- 3.4 mumol/l, increasing with age. After adjustment for age, homocysteine was significantly associated with physical activity, calcium intake, serum albumin and serum creatinine but not with bone turnover markers and bone mineral density. During a mean follow-up of 10 years, 183 fractures occurred among 134 women. After adjustment for age, the overall relative risk of fracture for each 1 SD increment of homocysteine was 1.03 (95%CI 0.87-1.31). Fracture risk was higher in women with homocysteine in the highest quartile without adjustment but no longer after adjustment for age.

CONCLUSIONS

Homocysteine is not an independent risk factor of osteoporotic fractures in healthy postmenopausal women from the OFELY cohort with a broad age range.

Fracture risk associated with parkinsonism and anti-Parkinson drugs

We studied fracture risk associated with parkinsonism (including Parkinson's disease) and drugs used to treat these conditions in a case-control study. Cases were all subjects with any fracture during the year 2000 (n = 124,655). For each case, three controls (n = 373,962) matched on age and gender were randomly drawn from the background population. Exposure was a diagnosis of parkinsonism or use of anticholinergic drugs, levodopa alone or in combination with carbidopa, and/or catechol-O-methyl transferase (COMT) inhibitors, dopamine agonists, or monoamine oxidase B (MAO-B) inhibitors and a number of other confounders. Parkinsonism was associated with a crude odds ratio (OR) of any fracture of 2.2 (95% confidence interval [95% CI] 2.0-2.5) and an adjusted OR of 1.2 (95% CI 1.0-1.4), the risk being higher especially in males younger than 75 years. Levodopa was associated with an increased overall fracture risk and an increased risk of hip fractures in high doses. Dopamine agonists, anticholinergic drugs, and MAO-B inhibitors were not associated with increased fracture risk except for hip fractures at high doses for MAO-B inhibitors and hip fractures at median doses for dopamine agonists. Neuroleptics were associated with increased risk of fractures in almost all skeletal sites and doses. In conclusion, parkinsonism was associated with increased risk of fractures, especially among males younger than 75 years, and the risk was significantly attenuated upon adjustment for confounders. Use of neuroleptics and, to some degree, levodopa was associated with increased risk of fractures.

Experimental hyperhomocysteinemia reduces bone quality in rats

BACKGROUND

Recently, hyperhomocysteinemia (HHCY) has been suggested as a new risk factor for osteoporosis. This study investigated if HHCY is a causal osteoporotic factor in vivo.

METHODS

We used 3 groups of rats: a control group (n = 20), a moderate HHCY group (induced by a 2.4% methionine-enriched diet, n = 10), and an intermediate HHCY group (induced by a 2% homocystine-enriched diet, n = 10). We measured bone fragility [maximum force of an axial compression test (F(max))], bone area as percentage of total area (BAr/TAr, histomorphometry), and biochemical bone turnover markers [osteocalcin (OC) and collagen I C-terminal crosslaps (CTx)].

RESULTS

Compared with controls, 3 months of moderate or intermediate HHCY increased mean (SD) bone fragility at the femoral neck by 18% (6%) in methionine-fed (P = 0.001) and 36% (13%) in homocystine-fed rats (P <0.001). Mean (SD) BAr/TAr at the distal femur in methionine and homocystine groups was decreased by 45% (21%; P = 0.001) and 93% (9%; P = 0.001), respectively. At the femoral neck, BAr/TAr was decreased by 19% (11%; P <0.001) and 55% (19%; P <0.001). At the lumbar spine, the reduction of BAr/TAr was 17% (23%; P = 0.099) and 44% (19%; P <0.001). Plasma OC (bone formation marker) was decreased by 23% (20%; P = 0.006) and 34% (21%; P <0.001). Plasma CTx (bone resorption marker) did not differ between groups.

CONCLUSION

Bone quality is consistently decreased in the presence of increased circulating homocysteine. The results provide evidence that HHCY is a causal osteoporotic factor.

Homocysteine and Parkinson's disease: a dangerous liaison?

Homocysteine, a sulphur-containing amino acid formed by demethylation of methionine, is involved in numerous processes of methyl group transfer, all playing pivotal roles in the biochemistry of the human body. Increased levels of plasma homocysteine (hyperhomocysteinemia) - which may result from a deficiency of folate, vitamin B6 or B12 or mutations in enzymes regulating the catabolism of homocysteine - are associated with a wide range of clinical manifestations, mostly affecting the central nervous system (e.g., mental retardation, cerebral atrophy and epileptic seizures). Recent evidence suggests that changes in the metabolic fate of homocysteine, leading to hyperhomocysteinemia, may also play a role in the pathophysiology of neurodegenerative disorders, particularly Parkinson's disease (PD). The nervous system might be particularly sensitive to homocysteine, due to the excitotoxic-like properties of the amino acid. However, experimental findings have shown that homocysteine does not seem to posses direct, cytotoxic activity, while the amino acid has proven able to synergize with more specific neurotoxic insults. Hyperhomocysteinemia has been repeatedly reported in PD patients; the increase, however, seems mostly related to the methylated catabolism of l-Dopa, the main pharmacological treatment of PD. Therefore, hyperhomocysteinemia may not be specific to movement disorders or other neurological diseases, the condition being, in fact, rather the result of the combinations of different factors, mainly metabolic, but also genetic and pharmacological, intervening in the neurodegenerative process.

Associations between homocysteine, bone turnover, BMD, mortality, and fracture risk in elderly women

Homocysteine has been suggested to be a risk factor for fracture, but the causal relationship is not clear. In 996 women from the OPRA study, high homocysteine level was associated with high bone marker levels and low BMD at baseline. During a mean 7-year follow-up, high homocysteine level was associated with mortality, but no clear association to fracture risk existed.

INTRODUCTION

Recently, the association between high serum homocysteine (Hcy) levels and an increased risk of fracture has been described.

MATERIALS AND METHODS

Hcy levels were measured at baseline in 996 women, all 75 years old. Vitamin B(12), folate, serum cross-linking telopeptide of type I collagen (CTX), serum TRACP5b, serum osteocalcin, urine deoxypyridinoline, PTH, areal BMD (aBMD), calcaneal quantitative ultrasound (QUS), and physical performance were assessed at baseline. Fractures and mortality were recorded during a mean follow-up of 7.0 years.

RESULTS

Bone marker levels were higher in women with Hcy in the highest quartile compared with all other women (p < 0.05). The most evident correlation between Hcy and a bone marker was seen with CTX (r = 0.19, p < 0.001). aBMD (hip) was 4% lower, QUS was up to 2% lower, and gait speed was 11% slower among women with Hcy in the highest quartile compared with the other women (p < 0.05). During the follow-up, 267 women sustained at least one low-energy fracture (including 69 hip fractures). When women in the highest Hcy quartile were compared with all other women, the hazard ratios (HRs) for sustaining any type of fracture was 1.18 (95% CI, 0.89-1.36) and for hip fracture was 1.50 (95% CI, 0.91-1.94). For the same group of women, the mortality risk was 2.16 (95% CI, 1.58-2.55). Adjustments for confounders did not substantially change these associations. Adjustment for PTH increased the HR for hip fracture to 1.67 (95% CI, 1.01-2.17). Low vitamin B(12) or folate was not associated with increased fracture risk or mortality.

CONCLUSIONS

High Hcy levels were associated with higher bone turnover, poor physical performance, and lower BMD. There was no clear association to fracture risk. The increased mortality among women with high Hcy levels indicates that a high Hcy level may be a marker of frailty.

Homocysteine and bone loss in epilepsy

Epidemiological studies reveal fracture incidence in epilepsy is twice that of the normal population. Much interest has been focused on Vitamin D, however, considering mixed results on non-enzyme inducing anti-epileptic drugs (AEDs) and bone mineral density (BMD) additional metabolic effects may be to blame. AEDs increase serum homocysteine (s-Hcy) by lowering blood folate levels. An association between elevated homocysteine, BMD and increased fracture incidence has been found in non-epilepsy populations. Additionally, folate and Vitamin B12 levels are independently related to bone mineral density in various non-epilepsy populations. This study supports previous research, which found elevated s-Hcy in subjects taking AEDs and that bone loss is related to the use of enzyme-inducing AEDs and changes in alkaline phosphatase. By one-way ANOVA, subjects on phenytoin monotherapy had significantly higher levels of s-Hcy than those on other AEDs (F=5.89, p=.016). Regression analyses revealed homocysteine, fracture history, length of years on AEDs, ethnicity were predictors of spine T scores. Weight and BMI were predictors of both BMD and DEXA T scores. Use of enzyme-inducing AEDs was a negative predictor of spine BMD and T scores, while phenytoin monotherapy was a positive predictor of spine BMD. Lamotrigine was found to be a negative predictor of spine T score. Ambulatory status, menopause and alcohol consumption were predictors of BMD but not T scores. In this study, persons with epilepsy who take nutritional supplementation have 25% lower s-Hcy levels than those who do not. Supplementation continues to be important in preventative epilepsy care.

Bone Mineral Density in Hip-Fracture Patients With Parkinson’s Disease: A Case-Control Study

OBJECTIVE

To investigate bone mineral density (BMD) levels in patients with Parkinson's disease (PD) who sustained a hip fracture.

DESIGN

Case-control study.

SETTING

Rehabilitation hospital in Italy.

PARTICIPANTS

We investigated 831 out of 887 white patients consecutively admitted to a rehabilitation hospital because of an original hip fracture resulting from a fall. Twenty-eight (3.37%) of the 831 patients were affected by PD. Twenty-eight controls matched for sex, age, and hip-fracture type (cervical or trochanteric) were found among the 803 non-PD patients.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

BMD was assessed by dual-energy x-ray absorptiometry (DXA) at the unfractured femur. Five sites were investigated in each subject: total proximal femur, femoral neck, trochanter, intertrochanteric area, and Ward's triangle. DXA scan was performed a mean +/- standard deviation of 22.2 +/- 7.8 days after fracture occurrence in the 28 patients and 22.0 +/- 5.3 days after fracture occurrence in the 28 controls.

RESULTS

BMD expressed as a T score did not differ significantly between the 28 PD patients and the 28 controls, whereas z score in the PD patients was significantly lower than 0 +/- 1 in the age- and sex-matched general population at 4 of the 5 sites of BMD assessment.

CONCLUSIONS

A sample of PD fallers who sustained a hip fracture had femoral BMD levels similar to those found in matched hip-fracture fallers who did not suffer from PD and significantly lower than those found in the matched reference population.

Role of lifestyle factors on plasma homocysteine levels in Parkison's disease patients treated with levodopa

Many papers documented that Parkinson's disease (PD) patients treated with levodopa (L-dopa) shows elevated plasma homocysteine (Hcy) levels. Several lifestyle factors are able to influence plasma Hcy levels. We review the evidence that L-dopa therapy is related with an increase in plasma Hcy levels and that several behaviours could be able to cause changes in plasma Hcy concentrations. Therefore, there are reasons to suggest that a healthy lifestyle lowering Hcy may prevent this potential iatrogenic complication during L-dopa therapy. Moreover, at present, no controlled prospective studies have evaluated this phenomenon.