Evaluation of bone mineral density in children receiving antiepileptic drugs

Slipped capital femoral epiphysis in a 5-year-old boy with cerebral palsy on valproic acid and levetiracetam for epilepsy: a case report

This study presents a rare case of unilateral slipped capital femoral epiphysis treated surgically in a 5-year-old boy with cerebral palsy who was born at 27 weeks' gestation and developed grade III intraventricular haemorrhage and periventricular leucomalacia and was on antiepileptic drugs, including valproic acid and levetiracetam for >3 years. The patient had no history of endocrine, renal, and significant familial diseases.

Evaluation of Bone Metabolism in Children Using Antiseizure Drugs: A Single-Center Experience and Review of the Literature

The effect of anti-seizure drugs (ASDs) on bone mineral density (BMD) is a controversial topic. This study investigated the effect of monotherapy and polytherapy drugs separately. Patients with a history of epilepsy treated with the same ASDs for more than 6 months were included in the study. Data regarding patient demographics, biochemical markers related to bone metabolism (calcium, phosphorus, alkaline phosphatase, parathyroid hormone, vitamin D), and BMD with dual-energy X-ray absorptiometry (DXA) were collected and compared. In total, 104 children with epilepsy using valproic acid (VPA), levetiracetam (LEV), carbamazepine (CBZ) alone or in combination and 22 healthy controls were evaluated. The ages of the children (64 boys, 62 girls) ranged between 2 and 17, with a mean of 9.50 ± 4.03 years. BMD or Z-scores did not differ among the monotherapy groups or between them and the polytherapy group. The lowest mean Z-score was in the VPA group but without statistical significance. Alkaline phosphatase levels were significantly higher in the group using CBZ. Calcium levels significantly differed between the groups (p = 0.001). The CBZ and LEV groups had the lowest calcium levels. However, phosphorus and vitamin D measurements did not significantly differ by ASDs used. Unfortunately, low vitamin D levels were evident in all children with epilepsy and even among controls. Physical activity, sun exposure, and calcium intake might be recommended in children treated with ACDs and in combination with additional risk factors monitoring via DXA should be considered. Further studies in a large population are necessary to judge which ASDs are more at risk to reduce bone mineralization than others.

The effect of carbamazepine on bone structure and strength in control and osteogenesis imperfecta (Col1a2 +/p.G610C ) mice

The inherited brittle bone disease osteogenesis imperfecta (OI) is commonly caused by COL1A1 and COL1A2 mutations that disrupt the collagen I triple helix. This causes intracellular endoplasmic reticulum (ER) retention of the misfolded collagen and can result in a pathological ER stress response. A therapeutic approach to reduce this toxic mutant load could be to stimulate mutant collagen degradation by manipulating autophagy and/or ER‐associated degradation. Since carbamazepine (CBZ) both stimulates autophagy of misfolded collagen X and improves skeletal pathology in a metaphyseal chondrodysplasia model, we tested the effect of CBZ on bone structure and strength in 3‐week‐old male OI Col1a2^+/p.G610C and control mice. Treatment for 3 or 6 weeks with CBZ, at the dose effective in metaphyseal chondrodysplasia, provided no therapeutic benefit to Col1a2^+/p.G610C mouse bone structure, strength or composition, measured by micro‐computed tomography, three point bending tests and Fourier‐transform infrared microspectroscopy. In control mice, however, CBZ treatment for 6 weeks impaired femur growth and led to lower femoral cortical and trabecular bone mass. These data, showing the negative impact of CBZ treatment on the developing mouse bones, raise important issues which must be considered in any human clinical applications of CBZ in growing individuals.

Intermittent administration sodium valproate has a protective effect on bone health in ovariectomized rats

The present work was aimed to evaluate the effect of different administration modes of sodium valproate (VPA) on bone strength, bone mass and bone mineral density in ovariectomized (OVX) rats and further investigation of the possible mechanism. 60 female SD rats were randomly divided into 4 groups: Sham group (Sham, n = 15), OVX group (OVX, n = 15), OVX rats received intermittent VPA treatment group (IVPA, n = 15) and OVX rats received daily VPA treatment group (EVPA, n = 15). After 12 weeks of treatment, the rats were sacrificed, and serum and femur samples were harvested. DEXA, Micro-CT, history, biomechanical testing, biochemical index and western blot analysis were used to observe the therapeutic effect and explore the possible mechanism. Micro-CT and DEXA analysis of bones revealed better BMD and higher BV/TV, Tb. Th, Tb. N, Conn. D and lower Tb. Sp at femoral metaphysis evaluated in IVPA when compared with OVX and EVPA group (P < 0.05). Histological, fluorescent analysis and biological strength revealed more trabecular bone and higher relative mineral apposition rate, maximal load, elastic modulus and energy at break with evaluated in IVPA when compared with OVX and EVPA group (P < 0.05). The levels of P1NP, estrogen, CTX, TRAP-5b and RANKL of the IVPA group showed a significant increase when compared with the OVX and EVPA group (P < 0.05). We confirm adverse effects on protein expressions including Notch1, Jagged1, HEY1, Wnt 1, β-catenin and RUNX2 following daily VPA treatment in OVX female rats. Our current study demonstrated that intermittent administration of sodium valproate has a protective effect on bone health in OVX rats and these effects may be achieved by activating Notch/Wnt/β-catenin/RUNX2 signal axis.

Effects of valproic acid on skeletal metabolism in children with epilepsy: a systematic evaluation and meta-analysis based on 14 studies

BACKGROUND

Previous studies have reported that long-term use of valproic acid can cause changes in bone metabolism in children. We conducted this meta-analysis to determine the effects of valproic acid on bone metabolism and bone mineral density (BMD) in children with epilepsy.

METHODS

Studies were searched from the databases of PubMed, Embase, Ovid, Cochrance Library, Springer Link and Web of Science. The effects of valproic acid on bone metabolism indicators and BMD were assessed through calculating the standardized mean difference (SMD) with 95% confidence interval (CI).

RESULTS

Fourteen studies with 987 individuals were included in this analysis. The long-term use of valproic acid did not affect the levels of serum calcium (p = 0.99), phosphorus (p = 0.28), ALP (p = 0.76), PTH (p = 0.36) and osteocalcin (p = 0.72), but it led to a decrease in 25-OH-VitD (p = 0.01) and BMD (p = 0.002 for the vertebra; p = 0.004 for the femur) in treating children with epilepsy.

CONCLUSION

Long-term use of valproic acid in treating children with epilepsy can lead to a reduction in 25-OH-VitD and BMD. Measurements of 25-OH-VitD and BMD should be performed regularly in children taking the drug to detect early osteopenia caused by the drug.

Effect of carbamazepine on the bone health of people with epilepsy: a systematic review and meta-analysis

Importance

Increasing evidence indicates that carbamazepine (CBZ) treatment in people with epilepsy (PWE) has adverse effects on bone health.

Objective

We conducted a meta-analysis to investigate the effect of CBZ on the bone health of PWE.

Methods

Two independent reviewers systematically searched PubMed and EMBASE for eligible studies. Standard mean deviations (SMDs) with 95% confidence intervals were used as a measure to investigate the effect of CBZ on bone-related outcomes in PWE.

Results

Levels of vitamin D (standardized mean difference [SMD]: −0.62, 95% CI: −0.89 to −0.35) and calcium (SMD: −0.38, 95% CI: −0.67 to −0.09) were significantly lower in the CBZ group than controls. Additionally, significantly higher alkaline phosphatase (SMD: 0.67, 95% CI: 0.52–0.82) was observed in patients using CBZ than controls. However, no significant difference in BMD was found between the two groups (SMD: −0.06, 95% CI: −0.55 to 0.43).

Conclusion and significance: This study provided evidence that CBZ treatment has a negative effect on bone health in PWE. Clinical implications are that long-term CBZ treatment may not be a good choice for PWE with skeletal diseases or osteoporosis.

Bone health in pediatric patients with neurological disorders

Patients with neurological disorders are at high risk of developing osteoporosis, as they possess multiple risk factors leading to low bone mineral density. Such factors include inactivity, decreased exposure to sunlight, poor nutrition, and the use of medication or treatment that can cause lower bone mineral density such as antiepileptic drugs, ketogenic diet, and glucocorticoids. In this article, mechanisms involved in altered bone health in children with neurological disorders and management for patients with epilepsy, cerebral palsy, and Duchenne muscular dystrophy regarding bone health are reviewed.

Bone Mineral Density Loss in People With Epilepsy Taking Valproate as a Monotherapy: A Systematic Review and Meta-Analysis

Objective: Data on changes in bone mineral density (BMD) from valproate (VPA) therapy are ambiguous and conflicting. Thus, the aim of this study was to systematically review the existing data and carry out a meta-analysis to investigate the effect of VPA as a monotherapy on BMD in people with epilepsy (PWE). Methods: We systematically searched PubMed, EMBASE, and MEDLINE for eligible studies. We calculated the standardized mean difference (SMD) with 95% confidence interval (CI) to investigate the statistical power of the association between VPA treatment and BMD. Results: Nineteen studies were included in this systematic review and meta-analysis. We found that BMD was lower in the VPA group than in the control group (SMD: -0.44; 95% CI: -0.65 to -0.22). A significant association was found in adult patients (SMD: -0.57; 95% CI: -0.88 to -0.26; I 2 = 69.8%) and pediatric patients (SMD: -0.32; 95% CI: -0.60 to -0.03; I 2 = 67.8%) by subgroup analysis. This study indicated that BMD was significantly lower in patients treated for more than 36 months than in controls (SMD: -0.52; 95% CI: -0.76 to -0.27; I 2 = 61.8%). However, a significant difference was not found between patients who were treated for less than 36 months and controls (SMD: -0.36; 95% CI: -0.72 to 0.01; I 2 = 74.8%). Conclusion and significance: The present study provided evidence that VPA treatment was significantly associated with BMD loss in PWE. Thus, for patients at a high risk of osteoporosis and fracture, especially for patients who need long-term treatment, VPA may not be a good choice.

Decreased bone density induced by antiepileptic drugs can cause accelerated orthodontic tooth movement in male Wistar rats

PURPOSE

The aim of the present study was to evaluate the effect of the carbamazepine and valproic acid on orthodontic tooth movement in male Wistar rats.

METHODS

Evaluation of tooth movement after 21 days of drugs infusion was carried out by feeler gauge. Bone densitometry on lateral cephalograms was conducted on days 1 and 21. After dissection of the maxillae, histologic parameters were evaluated.

RESULTS

Orthodontic tooth movement was accelerated in experimental groups rather than controls. Optical density was significantly increased in these groups. In histologic sections, mesioapical portion of the PDL (Periodontal Ligament) was wider in experimental groups. Also, distoapical portion of the PDL was wider only in valproic acid group.

CONCLUSION

Valproic acid and carbamazepine can decrease the bone density which may induce the accelerated orthodontic tooth movement in rats.

Basics of bone metabolism and osteoporosis in common pediatric neuromuscular disabilities

Bone modeling is a process that starts with fetal life and continues during adolescence. Complex factors such as hormones, nutritional and environmental factors affect this process. In addition to these factors, physical conditioning and medications that have toxic effects on bony tissue should be carefully considered in patient follow-up. Osteoporosis is a significant problem in pediatric population because of ongoing growth and development of skeletal system. Two types of osteoporosis are primary and secondary types and children with neuromuscular disabilities constitute a major group with secondary osteoporosis. Low bone mass in patients with cerebral palsy, spina bifida, and Duchenne muscular dystrophy cause increased bone fragility in even slight traumas. Maximizing peak bone mass and prevention of bone loss are very important to reduce the fracture risk in neuromuscular diseases. This article aims to review the determinants of bone physiology and bone loss in children with cerebral palsy, spina bifida, and Duchenne muscular dystrophy.

Neuron subset-specific Pten deletion induces abnormal skeletal activity in mice

Individuals with a history of epilepsy are at higher risk for bone fractures compared to the general population. Although clinical studies support an association between low bone mineral density (BMD) and anti-seizure medications, little is known on whether a history of seizures is linked to altered bone health. Therefore, in this study we tested the hypothesis that bone mass, morphology, and bone mineralization are altered by seizures in genetically epileptic animals and in animals subjected to an episode of status epilepticus. In this study, we used NS-Pten conditional knockout mice (a well-studied genetic model of epilepsy). We used microCT analysis to measure BMD, morphology, and mineralization in NS-Pten^+/+ (wildtype) and NS-Pten^-/- (knockout) mice at 4 and 8weeks, as well as adult Kv4.2^+/+ and Kv4.2^-/- mice. We measured BMD, bone morphology, and mineralization in adult NS-Pten^+/+ mice that received status epilepticus through kainic acid (20mg/kg intraperitoneal). Further, we measured locomotion for NS-Pten^+/+ and NS-Pten^-/- mice at 4 and 6weeks. We found that NS-Pten^-/- mice exhibited low BMD in the tibial metaphysis and midshaft compared to non-epileptic mice. Morphologically, NS-Pten^-/- mice exhibited decreased trabecular volume fraction, and endocortical expansion in both the metaphyeal and diaphyseal compartments. In the midshaft, NS-Pten^-/- mice exhibited reduced tissue mineral density, indicating impaired mineralization in addition to morphological deficits. NS-Pten^-/- mice exhibited hyperactivity in open field testing, suggesting low bone mass in NS-Pten^-/- mice was not attributable to hypoactivity. Differences in BMD were not observed following kainate-induced seizures or in the Kv4.2^-/- model of seizure susceptibility. Our findings suggest that deletion of Pten in the brain results in impaired bone mass and mineralization, which may contribute to weaker bones and thereby a higher fracture risk.

Relationship between Bone Density and Biochemical Markers of Bone among Two Groups Taking Carbamazepine and Sodium Valproate for Epilepsy in Comparison with Healthy Individuals in Yazd

Introduction

Chronic antiepileptic therapy has been associated with metabolic bone diseases including osteomalacia and osteoporosis. The aim of this study was to determine frequency of changes in biochemical and bone mineral density (BMD) in adults receiving valproaic acid (VPA) & carbamazepine (CBZ).

Methods

In a cross sectional study evaluating adults (age 20–50 y) epileptic patients receiving valproic acid or carbamazepine for at least 2 years. This study was conducted from May 2014 to May 2015 in Shahid Sadoughi Hospital of Yazd University of Medical Science, Yazd, Iran. Bone metabolism was evaluated by measurement of serum calcium (Ca), phosphorus (P), alkaline phosphatase (ALP) and parathormone hormone (PTH), BMD at lumbar and femoral measured by dual energy X ray absorptiometry (DXA). SPSS software (version 18) was used for data analysis. The t-test was used for quantitative data, and the chi-squared test was used for the qualitative variables.

Results

Eighty two epileptic patients (mean age: 31.67±10.69 year) treated with either carbamazepine (n=41) or valproate sodium (n=41) were studied. Normal serum Ca and P levels were observed in 98.8% and 97.6% of patients respectively. Serum ALP and PTH were normal in 97.6% and 97.6% of patients. Means of Ca and P in CBZ group were significantly lower than VPA group (Ca: 9.02 vs. 9.1, p-value: 0.03 and P: 3.54 vs. 3.76 p-value: 0.004). BMD values at lumbar spine were not significant in either group (T. score CBZ: −0.43± 0.744 vs. T. score VPA: −0.615± 0.904 and p-value: 0.333) and were significantly higher than Iranian normal population BMD value at femoral neck in CBZ group was lower than VPA group (T. score CBZ: −0.707± 0.896 vs. T. score VPA: − 0.297± 0.850 p-value: 0.04). Dosage of CBZ and VPA did not correlate with BMD and biochemical parameters. Duration of CBZ use had correlation with increased ALP and duration of VPA use had correlation with decreased BMD in adult patients.

Conclusion

long term anti-epileptic drug treatment either with CBZ and VPA which has unknown effects on skeletal mineralization and induces a state of decreased bone mineral density BMD values at femoral neck were significant in CBZ group Therefore regular screening for monitoring of biochemical markers of bone turnover and BMD with DXA during the treat period is recommended. In addition, Ca supplement could be considered for all patients with epilepsy upon initiation of CBZ and VPA therapy.

Potential effects of valproate and oxcarbazepine on growth velocity and bone metabolism in epileptic children- a medical center experience

Background

Children with longstanding use of antiepileptic drugs (AEDs) are susceptible to developing low bone mineral density and an increased fracture risk. However, the literature regarding the effects of AEDs on growth in epileptic children is limited. The aim of this study was to investigate the potential effects of valproate (VPA) and/or oxcarbazepine (OXC) therapy on growth velocity and bone metabolism.

Methods

Seventy-three ambulatory children (40 boys and 33 girls) with epilepsy, aged between 1 and 18 years (mean age 9.8 ± 4.1 years), were evaluated for growth velocity before and for 1 year after VPA and/or OXC treatment. The bone resorption marker serum tartrate-resistant acid phosphatase 5b (TRAcP5b) and the bone formation marker serum bone-specific alkaline phosphatase (BAP) were measured post-AEDs therapy for 1 year.

Results

The difference in growth velocity (ΔHt) and body weight change (ΔWt) between pre- and post-AEDs treatment were -1.0 ± 2.8 cm/year (P < 0.05) and 0.1 ± 3.9 kg/year (P = 0.84), respectively. The study population had serum TRAcP5b-SDS of -1.6 ± 1.2 and BAP-SDS of 1.7 ± 3.7 compared with sex- and age-matched healthy children. Significant correlation between serum TRAcP 5b and BAP activities was noted (r = 0.60, p < 0.001). There was a positive correlation between growth velocity and serum TRAcP 5b activity after AED treatment (r = 0.42, p < 0.01). No correlation was found between ΔHt, ΔWt, serum TRAcP 5b, BAP activity and types of AEDs.

Conclusion

Growth velocity was significantly decreased in epileptic children after 1 year of VPA and/or OXC treatment. The effect of VPA and/or OXC therapy on dysregulation of bone metabolism might play a crucial role in physical growth.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-016-0597-7) contains supplementary material, which is available to authorized users.

Osteoporosis Associated with Epilepsy and the Use of Anti-Epileptics-a Review

The increased rate of fractures associated with epilepsy has been long recognised but remains incompletely understood. Study quality and study results have varied, with some but not all studies showing bone diseases including osteoporosis and/or osteomalacia, and a high prevalence of vitamin D insufficiency and deficiency are also noted. Falls risk can also be higher in patients with epilepsy taking anti-epileptic medications, potentially leading to fracture. Larger research collaborations are recommended to further advance understanding in this field, particularly to examine underlying genetic and pharmacogenomic associations of epilepsy and anti-epileptic medication usage and its association with bone diseases and fractures, as well as further investigation into optimal management of bone health in epilepsy.

The bone mineral content alterations in pediatric patients medicated with levetiracetam, valproic acid, and carbamazepine

AIM

The negative effect of antiepileptic drugs on bone health has been previously documented. However, which antiepileptic drug is safer in regard to bone health is still questionable. Our aims were to investigate the bone mineral density alterations in pediatric patients who receive antiepileptic medication for a minimum of two years and to compare the results of these drugs.

MATERIALS AND METHODS

Fifty-nine patients (32 males, 27 females; mean age: 8.6±4.6years) and a control group (13 males, 7 females; mean age: 7.6±3.3years) were included in the study. The patients were receiving necessarily the same antiepileptic drugs (AEDs) for at least two years, and none of the patients had mental retardation or cerebral palsy. The patients were divided into three groups: group 1 (patients receiving levetiracetam (LEV), n=20), group 2 (patients receiving carbamazepine (CBZ), n=11), and group 3 (patients receiving valproic acid (VPA), n=28). Plasma calcium (Ca), phosphorus (P), parathyroid hormone (PTH), alkaline phosphatase (ALP), vitamin D levels, and bone mineral density (BMD) values of femur and vertebras (L1-4) and z-scores (comparative results of BMD values of the patients with the age- and gender-matched controls in device database) of the groups were compared.

RESULTS

The differences between P, PTH, ALP and age, Ca and BMD results, and vitamin D levels of the patients in all four groups was not statistically significant according to Kruskal-Wallis test (p>0.05). The z-score levels of all the patient and control groups were also not statistically significantly different compared with each other.

CONCLUSION

In contrast to previous reports in pediatric patients, our study has documented that there is not a considerable bone loss in patients receiving long-term AED medication. Although levetiracetam has been proposed as bone-protecting medication, we did not observe any difference between AEDs regarding bone mineral density after two years of treatment.

Effects of antiepileptic drugs on bone mineral density and bone metabolism in children: a meta-analysis

OBJECTIVE

The aim of our meta-analysis was to assess the effects of antiepileptic drugs on bone mineral density and bone metabolism in epileptic children.

METHODS

Searches of PubMed and Web of Science were undertaken to identify studies evaluating the association between antiepileptic drugs and bone mineral density and bone metabolism.

RESULTS

A total of 22 studies with 1492 subjects were included in our research. We identified: (1) a reduction in bone mineral density at lumbar spine (standardized mean difference (SMD)=-0.30, 95% confidence interval (CI) [-0.61, -0.05]), trochanter (mean difference (MD)=-0.07, 95% CI [-0.10, -0.05]), femoral neck (MD=-0.05, 95% CI [-0.09, -0.02]), and total body bone mineral density (MD=-0.33, 95% CI [-0.51, -0.15]); (2) a reduction in 25-hydroxyvitamin D (MD=-3.37, 95% CI [-5.94, -0.80]) and an increase in serum alkaline phosphatase (SMD=0.71, 95% CI [0.38, 1.05]); (3) no significant changes in serum parathyroid hormone, calcium, or phosphorus.

CONCLUSIONS

Our meta-analysis suggests that treatment with antiepileptic drugs may be associated with decreased bone mineral density in epileptic children.

Chronic administration of anticonvulsants but not antidepressants impairs bone strength: clinical implications

Major depression and bipolar disorder are associated with decreased bone mineral density (BMD). Antidepressants such as imipramine (IMIP) and specific serotonin reuptake inhibitors (SSRIs) have been implicated in reduced BMD and/or fracture in older depressed patients. Moreover, anticonvulsants such as valproate (VAL) and carbamazepine (CBZ) are also known to increase fracture rates. Although BMD is a predictor of susceptibility to fracture, bone strength is a more sensitive predictor. We measured mechanical and geometrical properties of bone in 68 male Sprague Dawley rats on IMIP, fluoxetine (FLX), VAL, CBZ, CBZ vehicle and saline (SAL), given intraperitoneally daily for 8 weeks. Distinct regions were tested to failure by four-point bending, whereas load displacement was used to determine stiffness. The left femurs were scanned in a MicroCT system to calculate mid-diaphyseal moments of inertia. None of these parameters were affected by antidepressants. However, VAL resulted in a significant decrease in stiffness and a reduction in yield, and CBZ induced a decrease in stiffness. Only CBZ induced alterations in mechanical properties that were accompanied by significant geometrical changes. These data reveal that chronic antidepressant treatment does not reduce bone strength, in contrast to chronic anticonvulsant treatment. Thus, decreased BMD and increased fracture rates in older patients on antidepressants are more likely to represent factors intrinsic to depression that weaken bone rather than antidepressants per se. Patients with affective illness on anticonvulsants may be at particularly high risk for fracture, especially as they grow older, as bone strength falls progressively with age.

Effects of antiepileptic drugs on bone health and growth potential in children with epilepsy

BACKGROUND

Bone health may be impaired in children with epilepsy.

OBJECTIVES

Our objective was to characterize bone mineral density (BMD) and bone growth in children receiving antiepileptic drugs (AEDs) and to assess the effects of co-morbidity, vitamin D deficiency, and type of drugs used.

DATA SOURCES

Data were sourced from PubMed, Embase, and Web of Science.

ELIGIBILITY CRITERIA

Cross-sectional, cohort, case-control, or randomized controlled trials reporting BMD or parameters of bone growth.

PARTICIPANTS

Children with epilepsy compared with controls.

INTERVENTIONS

AEDS or ketogenic diet.

STUDY APPRAISAL

The studies were evaluated by one author.

SYNTHESIS METHODS

Studies were categorized as reporting reduced BMD or not at any skeletal site as outcome. A logistic regression was performed for age, percent boys, study design, type of AED, co-morbidity or not, and signs of vitamin D deficiency/osteomalacia or not.

RESULTS

Carbamazepine and valproate were analyzed as monotherapy in 11 studies, and for both drugs a limited decrease in BMD seemed present. For oxcarbazepine, levetiracetam, phenytoin, phenobarbital, and topiramate, only one study with monotherapy was found for each drug, none of which reported decreased bone density. Polytherapy with AEDs seemed to be associated with a larger decrease in bone density than was monotherapy. Although few studies were available on bone growth, these did indicate that bone growth may be impaired among users of AEDs. Ketogenic diet may be associated with decreased bone density. The main determinant of normal BMD was absence of vitamin D deficiency/osteomalacia.

LIMITATIONS

The studies differed in skeletal sites studied and most were cross-sectional. No head-to-head comparisons of AEDs were performed. Children treated with polytherapy or ketogenic diet may have more complicated and severe disease than those treated with monotherapy. The underlying cause of epilepsy and vitamin D deficiency may contribute to impaired bone growth and density.

CONCLUSIONS

Reduced bone density, impaired bone growth, and vitamin D deficiency may be seen in children treated with drugs against epilepsy.

IMPLICATIONS

Measures to correct vitamin D deficiency, calcium intake should be taken.

Bone mineral density in ambulatory children with epilepsy

OBJECTIVE

To elucidate the effects of antiepileptic drugs (AEDs) on bone health status of ambulatory epileptic children.

METHODS

A total of 120 epileptic children aged 2-15 y were enrolled in three groups. The first group was on therapy with carbamazepine, phenobarbital or primidone. The second was treated with valproic acid and the third group was untreated. Serum calcium, phosphorous, total alkaline phosphatase, and parathyroid hormone levels were compared between groups. Bone mineral density tests were also performed at four sites of the lumbar spine and three sites of femoral neck and results were compared between the groups.

RESULTS

Of all enrolled subjects, 67 patients (55.8 %) were vitamin D deficient. The three groups were not significantly different in terms of vitamin D, calcium, phosphorus, total alkaline phosphatase, and parathyroid hormone levels. While patients in first group had lower Z-score of femoral neck and lumbar spine compared to those on valproic acid, these values were also significantly different than that of the third group.

CONCLUSIONS

It can be concluded that both enzyme-inducing AEDs and non enzyme-inducing AEDs decrease bone mineral density (BMD). Also alkaline phosphatase (ALP) is affected in ambulatory epileptic children on enzyme-inducing AEDs. Nevertheless, valproic acid (a non-enzyme-inducing agent) does not have the mentioned side effects.

Longitudinal change of vitamin D status in children with epilepsy on antiepileptic drugs: prevalence and risk factors

BACKGROUND

Our aim was to evaluate the prevalence and risk factors of vitamin D deficiency and the changes of vitamin D level among children with epilepsy on antiepileptic drugs.

METHODS

The levels of serum 25-hydroxy vitamin D were measured at the start of antiepileptic drugs and at 6- to 12-month intervals in children with epilepsy taking antiepileptic drugs in Pusan National University Children's Hospital. Vitamin D deficiency was defined as 25-hydroxy vitamin D levels <20 ng/mL and insufficiency between 21 and 29 ng/mL.

RESULTS

A total of 143 children (103 boys and 40 girls) with the mean age of 7.4 ± 5.4 years were included. The mean follow-up duration was 1.8 ± 0.8 years. At the start of antiepileptic drugs and the last follow-up, vitamin D deficiency or insufficiency was recognized in 56.6% (81 of 143) and 79.0% (113 of 143), respectively (P < 0.01). The mean value of initial 25-hydroxy vitamin D was 31.1 ± 14.7 ng/mL, which was significantly decreased to 20.2 ± 14.9 ng/mL (P < 0.01) in the last follow-up. Polytherapy (-16.0 ± 13.6 ng/mL), longer duration of ≥2 years (-23.5 ± 9.1 ng/mL), tube feeding (-18.2 ± 14.5 ng/mL), and overweight with body mass index of eighty-fifth percentile or greater (-17.0 ± 12.1 ng/mL) had a significant negative effect for the longitudinal change of 25-hydroxy vitamin D. Age, etiologies, seizure outcomes, and type of antiepileptic drugs (enzyme-inducing versus nonenzyme-inducing antiepileptic drugs) did not affect the longitudinal decrease of 25-hydroxy vitamin D.

CONCLUSIONS

A high proportion of these children on antiepileptic drugs had hypovitaminosis D and a significant decrease between the initial and the last follow-up. Polytherapy and longer duration of antiepileptic drugs, tube feeding, and overweight were independently associated with longitudinally significant decrease of 25-hydroxy vitamin D.

Antiepileptic drugs and bone metabolism in children: data from 128 patients

There are conflicting results concerning bone metabolism in children receiving antiepileptic medication, with data concentrating on neurologically impaired patients. We performed a multicenter cross-sectional study in otherwise healthy children who received monotherapy with valproic acid, oxcarbazepine, lamotrigine, sulthiame, levetiracetam, or topiramate for at least 6 months. Data on calcium, phosphorus, alkaline phosphatase, 25-OH vitamin D, and parathormone were collected. Among 128 patients, 24.4% had hypocalcemia, 25.4% hypophosphatemia, and 13.3% (n = 17) 25-OH vitamin D levels <10 ng/mL. All patients were clinically asymptomatic. Mean calcium concentrations were found to be significantly lower among the study population (2.41 mmol/L) compared with healthy controls (2.53 mmol/L). Lowest mean concentration was observed in patients treated with sulthiame followed by oxcarbazepine and valproic acid. No influence of calcium intake or therapy on bone metabolism was noted. Effects on bone metabolism of anticonvulsive monotherapy are not restricted to neurologically impaired children but also affect otherwise healthy children.

Vitamin D deficiency in children with epilepsy: Do we need to detect and treat it?

Children and adolescents treated with antiepileptic drugs are known to have problems with bone metabolism, bone mineral density loss, and 2-3 times the fracture risk of healthy controls. We reviewed the literature regarding bone mineral density in children with epilepsy and vitamin D therapy in children treated with anti-epileptic drugs. Studies of bone mineral density markers in children with epilepsy have mostly found little significant difference in bone mineral density markers in children with epilepsy. They have been limited by small sample size and many of the studies have not corrected for confounding factors such as comorbidities, mobility, nutrition, and obesity. Studies of vitamin D therapy in children with epilepsy have shown little evidence of effect and have been similarly limited by lack of stratification with regard to confounding factors. There is a need for larger studies, using clinically significant outcomes such as fractures, including at risk populations such as symptomatic generalised epilepsy, impaired mobility, and polytherapy. At the present time in the absence of good evidence to the contrary, there remains concern that children with epilepsy are at risk of poor bone health and that vitamin D therapy may be beneficial. As low-dose vitamin D supplementation (400 IU per day) is now recommended for healthy children and it is biologically feasible that children with epilepsy may be at higher risk of clinically significant deficiency, it is important that neurologists ensure that low-dose vitamin D supplementation should be prescribed and compliance followed up in children with epilepsy.

Vitamin D and bone health among children with epilepsy

The lay media and scientific literature have focused increasing attention on vitamin D deficiency and insufficiency in recent years. Low vitamin D levels confer increased an risk of abnormal bone mineralization, and are linked to poor bone health in epilepsy patients. However, vitamin D is not the only determinant of bone health in children with epilepsy. Anticonvulsant medications, in addition to features and comorbidities of epilepsy and coexisting neurologic diseases, are important factors in this complex topic. We review the basic metabolism of vitamin D in terms of bone health among children with epilepsy. We also discuss the literature regarding vitamin D and bone mineral density in this population. Finally, we suggest algorithms for screening and treating vitamin D insufficiency in these patients.

Chronic antiepileptic monotherapy, bone metabolism, and body composition in non-institutionalized children

AIM

The aim of this study was to determine the influence of chronic monotherapy with antiepileptic drugs (AEDs) on vitamin D levels, bone metabolism, and body composition.

METHOD

Eighty-five children (38 males, 47 females; mean age 12 y 5 mo, SD 3 y 4 mo) were treated with valproate and 40 children (28 males, 12 females; mean age 11 y 10 mo, SD 3 y) were treated with other AEDs (lamotrigine, sulthiame, or oxcarbazepine), comprising the non-valproate group. Forty-one healthy children (29 males 12 females; mean age 12 y 1 mo, SD 3 y 5 mo) served as a comparison group. Height, weight, body impedance analysis, 25-hydroxyvitamin D, calcium, phosphate, two bone resorption markers (receptor activator of nuclear factor kappaB ligand [RANKL] and tartrate-resistant acid phosphatase 5b [TRAP5b]), osteoprotegerin, and leptin were measured.

RESULTS

No child was vitamin D deficient as defined by a 25-hydroxyvitamin D (25OHD) level of less than 25 nmol/l (<10 ng/ml). Leptin, body fat, weight standard deviation score (SDS), and body mass index (BMI) SDS were all significantly higher (each p<0.001) in valproate-treated children than in the non-valproate group, as were calcium (p=0.027) and RANKL (p=0.007) concentrations. Similarly, leptin was significantly higher in the valproate group than in control participants (p<0.001), as were body fat (p=0.023), weight SDS (p=0.046), BMI SDS (p=0.047), calcium (p<0.001), and RANKL (p<0.001), whereas TRAP5b concentrations were significantly lower in the valproate-treated group (p=0.002). Furthermore, calcium and RANKL levels were significantly higher in the non-valproate group than in comparison participants (p<0.001 and p=0.016 respectively).

INTERPRETATION

Non-enzyme-inducing or minimal enzyme-inducing AED monotherapy does not cause vitamin D deficiency in otherwise healthy children with epilepsy. Valproate therapy is associated with increases in weight, body fat, and leptin concentration, as well as with a bone metabolic profile that resembles slightly increased parathyroid hormone action.

The effects of oxcarbazepine treatment on vitamin B12 and folate levels, thyroid functions, sex hormones, and bone mineral density in epileptic patients

The aim of this study was to evaluate vitamin B12 and folate levels, thyroid functions, sex hormones and bone mineral density in idiopathic epileptic patients taking oxcarbazepine as monotherapy. Newly diagnosed pediatric patients with idiopathic partial epilepsy taking oxcarbazepine (OXC) as monotherapy were enrolled in this study. The pre-treatment and 6 months post-treatment values of vitamin B12, folate, thyroid functions, sex hormones, and bone mineral density (BMD) were obtained from all patients. A total of 32 patients (22 (68.8%) males and 10 (31.2%) females) were included in this study. The mean age was 7.4 ± 3.2 years (range: 2–14 years). There were no significant differences between the pre-treatment and 6 months post-treatment values of vitamin B12, folate, thyroid functions, sex hormones, and BMD. However, the 6 month post-treatment sex hormone binding globulin (SHBG) values (159.92 ± 48.14 nmol/L) were significantly higher than the pre-treatment values (137.88 ± 43.12 nmol/L) (p=0.009). We found that OCX treatment in children did not have an effect on serum folate and vitamin B12 levels, thyroid functions, sex hormones and BMD but caused increased SHBG. Over time, the increase in serum SHBG levels may lead to diminished bioactivity of sex steroids, and thus to reduced fertility. The further studies are needed to demonstrate the clinical importance of increased SHBG levels.

The effect of oxcarbazepine on bone metabolism

OBJECTIVE

Long term use of several antiepileptic drugs is known to cause alteration in bone metabolism. Therefore, we investigated the effect of new antiepileptic drug, oxcarbazepine, on bone metabolism.

METHODS

Twenty eight patients who were on oxcarbazepin therapy (18 female, 10 males; mean age: 27.82 +/- 10.98 years (range: 15-45)) with no additional antiepileptic drug use history in one year period prior to the study and 28 control subjects were involved in the study. Measurement of calcium, phosphate, alkaline phosphatase and Vitamin D3 levels and bone density measurements with DEXA method were performed in patient and age-matched control groups. The baseline parameters were compared with the control group and with those measured at the end of one year.

RESULTS

The biochemical (calcium, phosphate, alkaline phosphatase and Vitamin D3) parameters and densitometry values after one year of therapy were not different than the baseline values indicating that those were not affected by the therapy (P > 0.05).

CONCLUSIONS

In previous studies, anticonvulsant drugs that induce enzymes increase bone degradation by causing vitamin D deficiency. According to the results of this study, oxcarbazepin with little effect on enzyme induction was shown not to affect bone mineral metabolism.

Prevalence and risk factors of low bone mineral density and 25-hydroxyvitamin D status in young healthy epileptic adult patients in a tropical Asian country taking antiepileptic drug

PURPOSE

Antiepileptic drugs have been reported to reduce bone mineral density (BMD) in several countries with varying prevalence but in studies with small sample size and inadequate assessment of confounders, and rarely including young adults. We sought to determine the prevalence, vitamin D status and risk factors for low BMD in young adult epileptic patients in a tropical setting.

METHODS

We prospectively examined left femoral neck and spine with dual-energy X-ray absorption. Demographic data, basic laboratory studies, history of clinical epilepsy, parathyroid hormone and vitamin D level were obtained.

RESULTS

One hundred and twenty three patients were included. The mean (+/-SD) T-score was -0.31+/-1.24 at the spine and -0.19+/-1.11 at the left femoral neck. 36% had osteopenia and 4.1% had osteoporosis at either site. Four patients had vitamin D deficiency. Vitamin D levels were not correlated with BMD. Twenty-five patients had vitamin D insufficiency. Multivariate logistic regression analysis identified low body mass index (BMI) and male sex as risk factors for low BMD at the spine and low BMI and duration of treatment as risk factors for low BMD at the left femoral neck.

CONCLUSION

Chronic use of antiepileptic drug (AED) in young adult patients is associated with low BMD.

Bone mineral density in children, adolescents, and young adults with epilepsy

PURPOSE

The aim of this study was to assess bone mineral density (BMD) in a large population of children, adolescents, and young adults with epilepsy alone or in association with cerebral palsy and/or mental retardation.

METHODS

Ninety-six patients were enrolled in the study. The group comprised 50 males and 46 females, aged between 3 and 25 years (mean age 11 years). The control group consisted of 63 healthy children and adolescents (23 males, 40 females), aged between 3 and 25 years (mean age 12.1 years). Patients underwent a dual-energy x-ray absorptiometry (DEXA) scan of the lumbar spine (L1-L4) and the z scores were calculated for each patient; the t score was considered for patients 18 years of age or older.

RESULTS

Abnormal BMD was found in 56 patients (58.3%), with values documenting osteopenia in 42 (75%) and osteoporosis in 14 (25%). A significant difference emerged between epileptic patients and the control group in BMD, z score, and body mass index (BMI) (p = <0.001). Lack of autonomous gait, severe mental retardation, long duration of antiepileptic treatment, topiramate adjunctive therapy, and less physical activity significantly correlated with abnormal BMD.

DISCUSSION

This study detected abnormal BMD in more than half of a large pediatric population with epilepsy with or without cerebral palsy and/or mental retardation. The clinical significance of these findings has yet to be clarified.

Effects of antiepileptic drug therapy on vitamin D status and biochemical markers of bone turnover in children with epilepsy

Reports of decreased serum 25-hydroxyvitamin D (25-OHD) and altered bone metabolism associated with antiepileptic drug (AED) treatment are inconsistent and predominantly restricted to adults. In this cross-sectional observational study, the aim was to evaluate the influence of AED treatment on vitamin D status and markers of bone turnover in children with epilepsy. In 38 children taking AEDs and 44 healthy control subjects, blood samples were collected to determine the levels of serum 25-OHD, intact parathyroid hormone (iPTH), calcium (Ca), phosphate (P), bone alkaline phosphatase (BAP), osteocalcin (OC) and C terminal telopeptide of type I collagen (ICTP). More than 75% of the patients were vitamin D deficient (serum 25-OHD<20 ng/mL) and 21% of the patients had an insufficient vitamin D status (serum 25-OHD=20-30 ng/mL). In the patients, the serum levels of OC (p = 0.002) and BAP (p < 0.001) were significantly increased, but ICTP (p = 0.002) concentrations were significantly decreased compared with the control group. When patients where divided into two groups according to their medication (mono- or polytherapy), significantly lower 25-OHD (p = 0.038) and ICTP (p = 0.005) levels and elevated BAP (p = 0.023) concentrations were found in patients under polytherapy. An association between 25-OHD and the measured bone markers could not be determined. Our results indicate that the prevalence of vitamin D deficiency in epilepsy patients under AED treatment is high, especially under polytherapy, and alteration markers of bone formation and resorption suggests an accelerated skeletal turnover. The routine monitoring of serum 25-OHD and vitamin D supplementation on an individual basis should be considered.

Predictors of bone density in ambulatory patients on antiepileptic drugs

BACKGROUND AND AIM

Antiepileptic drugs are associated with bone loss and fractures. Data in children is scarce and the impact of new therapies and of low vitamin D is not clear. This study assessed predictors of bone mineral density (BMD) in 225 ambulatory patients with epilepsy.

METHODS

BMD and detailed clinical information were obtained from 137 adults mean age of 31 years, on therapy for a mean of 11.7 years, and 88 children mean age of 13 years, on therapy for an average of 4.7 years.

RESULTS

Hypovitaminosis D was common in epileptic patients. BMD was reduced in adults but not children with epilepsy, by 0.3-0.6 SD depending on the skeletal site measured, compared to controls. Duration of treatment, but not vitamin D levels, was negatively correlated with BMD at the hip in adults. Bone density was reduced with the use of both enzyme and non-enzyme-inducing drugs, with both mono- and polytherapy, and was most severely reduced at the spine and hip with the use of enzyme-inducing drugs. In the multivariate analyses, polytherapy in children and duration of therapy and enzyme-inducing drugs in adults were independent predictors of BMD.

CONCLUSION

Antiepileptic drug therapy is associated with low bone density at clinically relevant skeletal sites, projecting into a possible doubling of fracture risk. Age, therapy duration, polypharmacy and the use of enzyme-inducing drugs were risk factors. Newer drugs may be associated with deleterious effects on bone. Skeletal monitoring with varying intervals, depending on the individual risk profile, is indicated.

Bone mineral density in angelman syndrome

Our aim was to evaluate bone mineral densitometry in patients with Angelman syndrome with or without antiepileptic therapy. Eighteen patients (9 females, 9 males), aged 4.0-24.3 years (mean age, 10.1 years), and two control groups consisting of 18 epileptic and 24 healthy patients, underwent dual-energy X-ray absorptiometry at the lumbar spine (L(1)-L(4)), and z score was evaluated for each patient; the t score was considered for patients aged > or = 18 years. Abnormal bone mineral density was present in 8/18 (44.5%) of patients with Angelman syndrome, in 7/18 (38.9%) of the epileptic group, and in none of the healthy controls. Furthermore, a significant difference regarding mean age of patients (6 versus 15 years, P = 0.008, by Fisher exact test), and mean length of drug treatment (3.5 versus 11.1 years, P = 0.005 by Fisher exact test), appeared in the group with Angelman syndrome. Most of these patients (94.4%) were receiving antiepileptic drugs, mainly valproic acid, for many years. In conclusion, our study revealed osteopenia in almost half the children and young patients with Angelman syndrome. Dual-energy X-ray absorptiometry should be performed in all patients with Angelman syndrome, particularly if they are treated with antiepileptic drugs.

Adverse effects of antiepileptic drugs on bone mineral density in children

Bone mineral content (BMC) or density (BMD) may be decreased in children with epilepsy either as a consequence of the epilepsy, the condition that caused the epilepsy or the treatment for epilepsy. This paper investigates the effects of antiepileptic drugs (AEDs) on BMD in children. A systematic search of Pubmed resulted in 14 papers that described changes in BMD in children on AEDs. For phenytoin, one study failed to show a decrease in femur BMD, whereas another study reported a decrease in total body and spine BMD, but only with the use of phenytoin for > 2 years. With phenytoin combined with a ketogenic diet, a decrease in forearm BMC was seen. For phenobarbital, one study showed a decrease in spine and total body BMD, but only among those who had used phenobarbital for > 2 years. Six studies were available for carbamazepine, and none of these showed a decrease in BMD in any skeletal site. For valproate, results were diverse; two studies reported a decrease in spine BMD, whereas two other studies did not. Two studies reported a decrease in hip BMD with valproate, whereas one did not. All three studies on forearm BMD in users of valproate described a decrease. Three studies reported an improvement in BMC with vitamin D supplementation in children on AEDs. No reports on changes in BMD among users of newer AEDs are available. In conclusion, more evidence is needed for the effects on BMD in children, especially for newer AEDs. The available studies have all been cross-sectional, and longitudianal studies are needed along with studies on potential interventions in children with decreased BMD.

Anti-epileptic medication and bone health

BACKGROUND

Epilepsy is a common chronic neurological disorder, usually requiring long-term treatment with anti-epileptic drugs (AED). Many studies have reported that AED therapy is associated with metabolic bone disease and is a major iatrogenic risk factor for fractures. There remains uncertainty about the type(s) of bone disease due to AED treatment, and the pathogenesis of AED-associated fractures.

RATIONALE

Deficits in bone mineral density (BMD) are widely reported in AED-treated patient populations. However, much of the research conducted to date has been limited by factors such as small sample size, potentially biased subject selection, a lack of selection of appropriate control data, and failure to take account of important confounding influences. The pathogenesis of AED-associated fractures is likely to be multifactorial, due to factors including reduced BMD, impaired bone quality (due to osteoporosis and/or osteomalacia), increased propensity to fall, and fractures associated with seizures or loss of consciousness.

RECOMMENDATIONS

Patients receiving long-term AED should be monitored for indices of bone health, including BMD and vitamin D status. Lifestyle factors should be optimized, vitamin D status maintained, and fall prevention strategies introduced as appropriate. Good seizure control is important. The use of additional, specific osteoporosis therapy is not evidence-based in this setting, but would appear reasonable in patients with clinically significant decreases in BMD, applying current treatment guidelines for osteoporosis.

CONCLUSION

There is a pressing need for improved understanding of the pathogenesis of AED-associated bone disease, for better definition of the risk associated with specific AED regimens, and for the development of evidence-based preventive and treatment approaches in this common but neglected disorder.

Fractures in children with cerebral palsy

INTRODUCTION

We studied the fracture history in a large population of patients with cerebral palsy to determine which children were at the highest risk for fracture.

METHODS

The International Classification of Diseases (Ninth Revision) coding identified 763 children with cerebral palsy. Patients and caregivers were contacted for information about fracture history and risk factors for low bone density. Of the 763 children identified, 418 children (54.8%) were available for this study; 243 (58%) had quadriplegia, 120 (29%) diplegia, and 55 (13%) hemiplegia. Three hundred sixty-six children were spastic, 23 mixed tone, 13 athetoid, and 16 classified as others. We identified 50 children (12%) who fractured; 15 of these same children had, over time, multiple fractures.

RESULTS

The number of fractures showed a normal distribution by age, with a mean of 8.6 (SD, 4.0). Children with cerebral palsy with mixed tone had a higher rate of fracture (chi = 14.7, P < 0.01); chi analysis indicated that the children who fractured were, as a group, more likely to use a feeding tube, have a seizure disorder, take valproic acid (VPA), and use standing equipment in therapy. Multiple regression analysis demonstrated older age and VPA use as predictive of fracture and gave the following equation: fracture = -0.01 + (VPA x 0.17) + (age x 0.15). The subgroup that sustained multiple fractures were older at the time of first fracture than the children who had only one reported fracture (t = -2.3, P < 0.05).

CONCLUSIONS

The main finding of our article is that older age at first fracture and use of VPA are predictive of fractures and define a group of children with cerebral palsy who may benefit from treatment interventions to increase bone density.

Carbamazepine and valproate for the treatment of bipolar disorder: a review of the literature

There are an increasing number of pharmacologic therapies for bipolar disorder. Two of these agents, the anticonvulsants carbamazepine (CBZ) and valproate (VPA), were first developed over 30 years ago for the treatment of epilepsy, and subsequent studies demonstrated that they are also effective in the treatment of acute mania and suggest efficacy as maintenance therapy in bipolar disorder. Because VPA and CBZ have been in use for many years, the psychiatric community is familiar with the adverse event profiles of these agents. A review of the clinical data evaluating VPA and CBZ monotherapy for the treatment of acute mania suggests that VPA and CBZ are similarly effective in acute mania. However, when their respective adverse event profiles are considered, VPA may be more tolerable than CBZ for short-term use, while CBZ may be better suited for long-term therapy. Controlled and direct comparative studies, both short and long term, are needed to further clarify the differences between VPA and CBZ.

Adverse effects of antiepileptic drugs on bone mineral density

The aim of this study is to determine the frequency of changes in biochemical markers of bone metabolism in children who are receiving valproic acid, carbamazepine, and oxcarbazepine. Thirty healthy children and 68 children with idiopathic epilepsy treated with either carbamazepine (n = 23), valproic acid (n = 31), or oxcarbazepine (n = 14) for more than 1 year were enrolled into the study. Blood samples were obtained in order to determine biochemical parameters (calcium, phosphorus, alkaline phosphates, parathormone, and 25-hydroxyvitamin D). Bone mineral density was measured with the dual-energy x-ray absorptiometry method. There were no significant differences in the serum concentrations of calcium, phosphorus, aspartate aminotransferase, alanine aminotransferase, and albumin levels between the four groups. However, serum alkaline phosphatase concentrations were higher in the patient group as compared with the control subjects. In patients receiving antiepileptic drugs, bone mineral density values were significantly lower than the healthy control group. In conclusion, long-term antiepileptic drug treatment either with valproic acid, carbamazepine, or with oxcarbazepine which has unknown effects on skeletal mineralization, induces a state of decreased bone mineral density.

Bone mineral status in pediatric outpatients on antiepileptic drug monotherapy

Drug-induced osteopenia has been reported in institutionalized children on chronic antiepileptic drug therapy. The aim of this study was to assess longitudinally bone mineral status in pediatric outpatients on antiepileptic drug monotherapy. The study group consisted of 30 ambulatory children on a normal diet: 15 on valproic acid, 11 on carbamazepine, and 4 on phenobarbital monotherapy. Bone mineral density, serum active vitamin D (1,25-dihydroxyvitamin D), and certain biochemical markers of bone formation (calcium, phosphorus, alkaline phosphatase, intact parathyroid hormone, osteocalcin, calcitonin, and urinary calcium to serum creatinine and urinary phosphorus to serum creatinine ratios) were studied at the beginning of antiepileptic drug monotherapy and at the end of 2 years of treatment. Age- and sex-specific Z-scores of bone mineral density were measured at anterior-posterior L2-L4 by dual-energy x-ray absorptiometry. Drug-induced osteopenia was defined in only two patients (one on carbamazepine and the other on phenobarbital monotherapy), with Z-scores of bone mineral density less than -1.5. Serum levels of active vitamin D and biochemical markers were not significantly correlated with the Z-scores of bone mineral density. We detected a frequency of antiepileptic drug-induced osteopenia of 6.7% in pediatric outpatients after 2 years of monotherapy. However, osteopenia was not attributed to a defect in serum active vitamin D production owing to hyperparathyroidism in children on antiepileptic drug monotherapy.

Bone mineral density in subjects using central nervous system-active medications

PURPOSE

Decreased bone mineral density defines osteoporosis according to the World Health Organization and is an important predictor of future fractures. The use of several types of central nervous system-active drugs, including benzodiazepines, anticonvulsants, antidepressants, and opioids, have all been associated with increased risk of fracture. However, it is unclear whether such an increase in risk is related to an effect of bone mineral density or to other factors, such as increased risk of falls. We sought to examine the relationship between bone mineral density and the use of benzodiazepines, anticonvulsants, antidepressants, and opioids in a representative US population-based sample.

SUBJECTS AND METHODS

We analyzed data on adults aged 17 years and older from the Third National Health and Nutrition Examination Survey (NHANES III, 1988-1994). Total femoral bone mineral density of 7114 male and 7532 female participants was measured by dual-energy x-ray absorptiometry. Multivariable linear regression models were used to quantify the relation between central nervous system medication exposure and total femoral bone mineral density. Models controlled for relevant covariates, including age, sex, and body mass index.

RESULTS

In linear regression models, significantly reduced bone mineral density was found in subjects taking anticonvulsants (0.92 g/cm2; 95% confidence interval [CI]: 0.89 to 0.94) and opioids (0.92 g/cm2; 95% CI: 0.88 to 0.95) compared with nonusers (0.95 g/cm2; 95% CI: 0.95 to 0.95) after adjusting for several potential confounders. The other central nervous system-active drugs--benzodiazepines or antidepressants--were not associated with significantly reduced bone mineral density.

CONCLUSION

In cross-sectional analysis of NHANES III, anticonvulsants and opioids (but not benzodiazepines or antidepressants) were associated with significantly reduced bone mineral density. These findings have implications for fracture-prevention strategies.

Epilepsy, osteoporosis and fracture risk - a meta-analysis

This meta-analysis assesses the effects of epilepsy on fracture risk and changes in bone mineral density (BMD) in patients with epilepsy. A search of PubMed was conducted using the key words epilepsy, fracture, and bone mineral. A weighted estimate of relative risk of fractures and changes in BMD (Z-score) was calculated. From the changes in BMD, expected increase in relative fracture risk was calculated. A total of 11 studies on fracture risk and 12 studies on BMD were retrieved. The relative risk of any fracture was increased (2.2, 95% CI: 1.9-2.5, five studies), as was the risk of hip (5.3, 3.2-8.8, six studies), forearm (1.7, 1.2-2.3, six studies), and spine fractures (6.2, 2.5-15.5, three studies). A large proportion of fractures (35%) seemed related to seizures. Spine (mean +/- SEM: -0.38 +/- 0.06) and hip (-0.56 +/- 0.06) BMD Z-scores were significantly decreased, hip more than spine (2P < 0.05). The expected increases in relative risk of any fracture from BMD Z-scores were 1.2-1.3, and significantly lower than observed (2P < 0.05). The deficit in BMD in patients with epilepsy is too small to explain the observed increase in fracture risk. The remainder of the increase in fracture risk may be linked to seizures.

Early alteration in bone metabolism in epileptic children receiving carbamazepine monotherapy owing to the induction of hepatic drug-metabolizing enzymes

The purpose of this study was to investigate, by a prospective, self-controlled method, whether early treatment with carbamazepine monotherapy can alter bone metabolism in ambulatory epileptic children with adequate sun exposure, based on the determination of total serum alkaline phosphatase and its bone isoenzyme activities. Serum total alkaline phosphatase and its bone, liver, and intestinal isoenzyme activities were evaluated in 22 epileptic ambulatory children (13 males and 9 females, aged from 5 to 12 years) before and at 3, 6, and 12 months of carbamazepine monotherapy. Serum concentrations of other biochemical markers of bone and liver metabolism, such as calcium, phosphorus, magnesium, gamma-glutamyltransferase, alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase, were also measured in the study participants before and at 6 and 12 months of treatment. Carbamazepine was prescribed at normal dosages (16.4-20 mg/kg/day). Serum total alkaline phosphatase activities were significantly increased at 3 (P = .000), 6 (P = .024), and 12 (P = .037) months of treatment; serum bone alkaline phosphatase activities at 3 (P = .000), 6 (P = .008), and 12 (P = .017) months of treatment; and serum liver alkaline phosphatase activities at 3 (P = .000), 6 (P = .049), and 12 (P = .008) months of treatment, whereas serum intestinal alkaline phosphatase isoenzyme activity was significantly increased only at 3 months of treatment (P = .035). Serum gamma-glutamyltransferase activities were also significantly increased at 6 (P = .000) and 12 (P = .000) months of treatment. No significant changes in the concentrations of serum calcium, phosphorus, magnesium, alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase were noted at 6 and 12 months of treatment. There was a significant correlation between serum gamma-glutamyltransferase activities and serum total alkaline phosphatase activities (r = .689, P = .000 at 6 months; r = .493, P = .020 at 12 months), bone alkaline phosphatase activities (r = .700, P = .000 at 6 months; r = .466, P = .029 at 12 months), and liver alkaline phosphatase activities (r = .427, P = .047 at 6 months; r = .425, P = .048 at 12 months). These findings indicate that ambulatory children who receive carbamazepine monotherapy, even when residing in a country with adequate sunlight, can have their bone metabolism altered early in the course of treatment, as indicated by the elevated activities of serum bone alkaline phosphatase isoenzyme. This early alteration in bone metabolism is probably due to the hepatic enzyme-inducing character of carbamazepine.

Endocrine and metabolic changes in epileptic patients receiving valproic acid

It has been well known for many years that valproic acid (VPA) therapy can induce obesity and important endocrine dysfunctions; among these dysfunctions, the most common are hyperandrogenism, menstrual disorders, polycystic ovary syndrome, hyperinsulinism, and changes in LH, FSH, and sexual and thyroid hormones. Moreover, abnormalities in pubertal development and impaired skeletal growth have been reported. The aim of this review is to analyze the main effects of VPA on endocrinological functions in patients with epilepsy in order to understand in depth the pathophysiological mechanisms and, consequently, to improve the care of these patients.

Current drug treatment of epilepsy in adults

The choice of antiepileptic drugs (AEDs) is rapidly increasing. This review looks at the evidence that guides the decision of which AED to start as monotherapy and aims to aid the choice of treatment if monotherapy fails. Unfortunately, the evidence supporting the prescribing of new drugs is sparse, because most randomised controlled trials answer questions focused on regulatory requirements rather than on clinical use. Ultimately, the choice of one AED will be determined by an individual risk-benefit assessment in which the most effective drug for an individual patient is chosen, and one that would have the lowest risk of significant harm. It is the risk of chronic toxic effects and issues of teratogenicity for women that may affect the choice of drug therapy to the greatest degree. In the future there is a need to improve the quality of clinical data on efficacy and harmful effects of AEDs.

Fracture Risk Associated with Use of Antiepileptic Drugs

PURPOSE

To assess fracture risk associated with different antiepileptic drugs (AEDs). An increased fracture risk has been reported in patients with epilepsy. Classical AEDs have been associated with decreased bone mineral density. The effects of newer AEDs are unknown.

METHODS

We undertook a population-based pharmacoepidemiologic case-control study with any fracture as outcome and use of AEDs as exposure variables (124,655 fracture cases and 373,962 controls).

RESULTS

All AEDs were associated with an increased fracture risk in an unadjusted analysis. After adjustment for prior fracture, use (ever) of corticosteroids, comorbidity, social variables, and diagnosis of epilepsy, carbamazepine [CBZ; odds ratio (OR), 1.18; 95% confidence interval (CI), 1.10-1.26], [and oxcarbazepine (OXC; 1.14, 1.03-1.26)], clonazepam (CZP; 1.27, 1.15-1.41), phenobarbital (PB; 1.79, 1.64-1.95), and valproate (VPA; 1.15, 1.05-1.26) were statistically significantly associated with risk of any fracture. Ethosuximide (0.75, 0.37-1.52), lamotrigine (1.04, 0.91-1.19), phenytoin (1.20, 1.00-1.43), primidone (1.18, 0.95-1.48), tiagabine (0.75, 0.40-1.41), topiramate (1.39, 0.99-1.96), and vigabatrin (0.93, 0.70-1.22) were not statistically significantly associated with fracture risk after adjustment for confounders. The relative increase was modest and in the same range for the significant and nonsignificant results. CBZ, PB, OXC, and VPA displayed a dose-response relation. Fracture risk was more increased by liver-inducing AEDs (OR, 1.38; 95% CI, 1.31-1.45) than by noninducing AEDs (1.19; 95% CI, 1.11-1.27).

CONCLUSIONS

A very limited increased fracture risk is present in users of CBZ, CZP, OXC, PB, and VPA. A limited significant increase cannot be excluded for the other AEDs because of the statistical power.