Bone mineral density measured by dual-energy x-ray absorptiometry and novel markers of bone formation and resorption in patients on antiepileptic drugs

A Prospective Longitudinal Study of the Effects of Eslicarbazepine Acetate Treatment on Bone Density and Metabolism in Patients with Focal-Onset Epilepsy

BACKGROUND AND OBJECTIVES

Eslicarbazepine acetate (ESL) is a third-generation anti-seizure medication for patients with focal-onset epilepsy. There are known short-term impacts of classic enzyme-inducing drugs on bone health. For oxcarbazepine, which like ESL is a less potent inducer of cytochrome P450 (CYP450) than carbamazepine, some studies have shown that treatment is associated with increased bone metabolic parameters. The effects of ESL on bone health have not been systematically evaluated so the objective of this study was to investigate whether adverse effects of ESL on bone mineral density (BMD) could be measured after a 12-month exposure period. In addition, the effects of ESL on bone turnover were investigated using laboratory indicators of bone metabolism.

METHODS

BONAPARTE was a prospective, longitudinal, observational study that enrolled patients with focal-onset epilepsy with or without secondary generalization who started treatment with ESL, either as adjunctive treatment or monotherapy, at two tertiary epilepsy centres in Germany between February 2018 and July 2020. Standardised osteodensitometry and biochemical bone metabolism parameters at the time of ESL initiation and 1 year after continuation of therapy were assessed. Comparisons between biochemical and densitometric parameters at baseline and after 12 months of treatment were performed using the paired samples t test.

RESULTS

In total, 26 patients (15 male; mean age 41.4 ± 12.5 years) newly treated with ESL were evaluated. Six of these patients had osteopenia at baseline. The mean daily dose of ESL at the 12-month follow-up was 1438 ± 1406 mg. At the group level, there were no significant effects of treatment with ESL on laboratory markers or on BMD. Mean values of BMD in g/cm2 at baseline and after 12 months of ESL treatment were 1.17 (± 0.16) and 1.16 (± 0.16) in the lumbar spine, and 0.98 (± 0.15) and 0.96 (± 0.15) in the proximal femur, respectively. Intra-individually, two patients developed de novo osteopenia measured at the femoral neck associated with relevant changes in bone metabolic parameters.

CONCLUSION

Neither osteodensitometry nor bone metabolism parameters showed significant group effects after 1 year of treatment with ESL. Individual fluctuations were observed, however, which may warrant monitoring for longer follow-up periods. The study was registered in the German register for clinical studies under the number DRKS00010430 with the official name BONAPARTE.

The Effects of Osteoporotic and Non-osteoporotic Medications on Fracture Risk and Bone Mineral Density

Osteoporosis is a highly prevalent bone disease affecting more than 37.5 million individuals in the European Union (EU) and the  United States of America (USA). It is characterized by low bone mineral density (BMD), impaired bone quality, and loss of structural and biomechanical properties, resulting in reduced bone strength. An increase in morbidity and mortality is seen in patients with osteoporosis, caused by the approximately 3.5 million new osteoporotic fractures occurring every year in the EU. Currently, different medications are available for the treatment of osteoporosis, including anti-resorptive and osteoanabolic medications. Bisphosphonates, which belong to the anti-resorptive medications, are the standard treatment for osteoporosis based on their positive effects on bone, long-term experience, and low costs. However, not only medications used for the treatment of osteoporosis can affect bone: several other medications are suggested to have an effect on bone as well, especially on fracture risk and BMD. Knowledge about the positive and negative effects of different medications on both fracture risk and BMD is important, as it can contribute to an improvement in osteoporosis prevention and treatment in general, and, even more importantly, to the individual's health. In this review, we therefore discuss the effects of both osteoporotic and non-osteoporotic medications on fracture risk and BMD. In addition, we discuss the underlying mechanisms of action.

A Literature Review of the Potential Impact of Medication on Vitamin D Status

In recent years, there has been a significant increase in media coverage of the putative actions of vitamin D as well as the possible health benefits that supplementation might deliver. However, the potential effect that medications may have on the vitamin D status is rarely taken into consideration. This literature review was undertaken to assess the degree to which vitamin D status may be affected by medication. Electronic databases were searched to identify literature relating to this subject, and study characteristics and conclusions were scrutinized for evidence of potential associations. The following groups of drugs were identified in one or more studies to affect vitamin D status in some way: anti-epileptics, laxatives, metformin, loop diuretics, angiotensin-converting enzyme inhibitors, thiazide diuretics, statins, calcium channel blockers, antagonists of vitamin K, platelet aggregation inhibitors, digoxin, potassium-sparing diuretics, benzodiazepines, antidepressants, proton pump inhibitors, histamine H2-receptor antagonists, bile acid sequestrants, corticosteroids, antimicrobials, sulphonamides and urea derivatives, lipase inhibitors, hydroxychloroquine, highly active antiretroviral agents, and certain chemotherapeutic agents. Given that the quality of the data is heterogeneous, newer, more robustly designed studies are required to better define likely interactions between vitamin D and medications. This is especially so for cytochrome P450 3A4 enzyme (CYP3A4)-metabolized medications. Nevertheless, this review suggests that providers of health care ought to be alert to the potential of vitamin D depletions induced by medications, especially in elderly people exposed to multiple-drug therapy, and to provide supplementation if required.

The effects of antiepileptic drugs on bone health: A systematic review

PURPOSE

Epilepsy may be treated with antiepileptic drugs (AEDs), which have been reported to decrease bone mineral density (BMD). Current data is conflicting and variable, and little is known with regard to how duration of AED use or specific AEDs, such as CYP-450 enzyme-inducing (EIAEDs) versus non-enzyme inducing (NEIAEDs) drugs affect BMD. We sought to systematically review BMD changes due to AED use to identify trends in reporting.

METHODS

A literature search via Medline (PubMed), EMBASE, and Cochrane databases was performed. Peer-reviewed articles were identified that reported on BMD measurements in conjunction with AEDs.

RESULTS

Twenty-six studies met inclusion criteria. Long-term therapy was shown across multiple, well-controlled studies to have the most significant BMD loss. Carbamazepine had the most frequent reporting of unfavorable effects on bone health and Lamotrigine seemed to show the most bone-protective qualities. Serum biochemical markers of bone turnover did not significantly correlate with measured BMD changes.

CONCLUSION

The present study provides evidence that long-term AED therapy is the most significant risk factor for BMD loss. Furthermore, there was little compelling evidence to support that EIAEDs, as a class, were more harmful to bone than NEIAEDs, which has been previously suggested in multiple studies. Early clinical concern for significant loss of BMD may not be warranted as lower BMD was less likely to be observed during the initial years of AED therapy. Furthermore, serum markers of bone turnover are not clinically reliable in assessing BMD changes in patients taking AEDs.

The effect of normalization of sodium on bone turnover markers in patients with epilepsy. A randomized single-blinded placebo-controlled trial

Hyponatremia [p[Na]<136 mmol/L] is an independent risk factor for decreased bone mineral density (BMD). However, whether hyponatremia represents a surrogate marker, or a direct causal relationship to bone loss remains unknown. The aim of the study was to investigate the effect of salt replacement therapy on bone turnover markers (BTM) and BMD in patients with epilepsy and chronic hyponatremia. This prospective single-blinded randomized trial investigated serum BTM and BMD, evaluated by Dual Energy X-ray Absorptiometry (DXA), in 21 patients at baseline and following three months of salt replacement therapy. Patients with two consecutive measurements of hyponatremia prior to baseline and no known osteoporosis were included from the epilepsy out-patient clinic at Rigshospitalet, Denmark. Seven patients were randomized to placebo and 14 to salt intervention. The baseline p[Na] was 134 (130.5-140) mmol/L (median (IQR)). All patients had BTM within age-specific reference ranges at baseline. Following 3 months of intervention with 3-9 g of salt daily there was no difference in levels of procollagen type 1 N-terminal propeptide (P1NP) or C-terminal cross-linking telopeptide of type 1 collagen (CTX) between placebo and intervention. Nor was there any difference in BMD evaluated at the lumbar spine (L1-L4) or at the femoral neck or total hip. In our study, salt replacement did neither affect BTM nor BMD. However, due to the small size of the study, more studies are needed to further investigate this.

Does the Vitamin D Deficiency Have Any Role in Severity or Prolongation of Seizure? A Pilot Study in Iran

Background:

Based on previous studies, vitamin D deficiency could lead to nerve stimulation. The purpose of the present study was to determine frequency and duration of seizures in children with idiopathic epilepsy in two groups; normal level of vitamin D versus decreased level of vitamin D.

Methods:

This pilot, comparative study was carried out in Zanjan University of Medical Sciences on total 40 children aging between 2 to 12 years old (23 male and 17 female) with the diagnosis of idiopathic epilepsy. All patients were receiving anti-epileptic drugs. The initial questionnaire was completed by each parent. Total 40 epileptic cases were examined in close follow-ups every three months, during total 9 months. Meanwhile, the frequency and duration of each seizure were recorded in questionnaire at every three-month period. Vitamin D blood samples were analyzed at the beginning of the study and after 9 months following the study. Serum levels of Vitamin D were analyzed by ELISA method (Elecsys2010, RocheCo, Germany; STAR FAX; 2100), simultaneously, Vitamin D level <30 ng/ml (nanogram per milliliter) was defined as Vitamin D deficiency. Cases were divided into two groups based on Vitamin D level. The frequency and duration of convulsions were compared in patients with normal level of vitamin D versus children with decreased level of vitamin D. Data were analyzed by Chi-square and t-test methods.

Results:

In all 40 patients, vitamin D level less than 30 ng/ml was detected in 32% (13 patients) at the beginning of study and 35% (14 patients) in 9 months later (13 patients were common between the two groups). There was no significant relationship between the frequency of seizures, the duration of seizures and vitamin D levels in patients. The relationship between positive family history of epilepsy and the number of seizures was reported significant. The frequency of vitamin D deficiency was higher in female cases in final evaluation.

Conclusion:

In the present study, a considerable correlation was detected between the frequency of seizures and positive history of seizure in the family. The frequency of vitamin D deficiency was higher in female cases in final analysis. No significant relationship was detected between the number of seizures, the mean duration of seizures and serum level of Vitamin D in children who received anticonvulsant drugs. However, vitamin D deficiency in patients was not overlooked in order to prevent known complications. We recommend a randomized clinical trial in the future with an adequate sample size. Moreover, a non-epileptic control group in study would be useful.

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.

The effect of vitamin D3 and paricalcitol on penicillin-induced epileptiform activity in rats

AIM

Epilepsy is a disease characterized by seizures which impair human life considerably. Vitamin D is of different systemic effects on metabolism and its deficiency is known to have a high prevalence among epilepsy patients. Paricalcitol, a vitamin D receptor agonist, has relatively fewer side effects. This study aimed to investigate the anticonvulsant effect of vitamin D₃ (cholecalciferol) and paricalcitol on penicillin-induced epileptiform activity.

METHOD

21 male Wistar rat weighing 180-240 g were used. After anesthetized by 1.25 g/kg urethane intraperitoneally (i.p.), rats were placed in the stereotaxic frame and tripolar electrodes were placed on the skull. The single microinjection of penicillin (2.5 μl, 500 IU, i.c.) into left sensorimotor cortex induced epileptiform activity. A single dose of 60.000 IU/kg (i.p.) vitamin D₃ was administered 14 days before intracortical penicillin (500 IU) injection. Paricalcitol (10 μg/kg, i.p.) was administered 30 min before intracortical penicillin (500 IU) administration and recorded for the following 180 min.

RESULTS

Vitamin D₃ pretreatment and paricalcitol diminished the frequency of epileptiform activity (p < 0.001) without changing the amplitude (p > 0.05) compared to the penicillin-injected group. Vitamin D₃ pretreatment and paricalcitol led to an important delay in the onset of penicillin-induced epileptiform activity (p < 0.001 and p < 0.05, respectively). Vitamin D₃ increased the latency of penicillin-induced epileptic activity compared to paricalcitol group (p < 0.001).

CONCLUSION

Results indicate that vitamin D₃ and paricalcitol decreased the frequency and increased the latency of the penicillin-induced epileptic activity. Vitamin D₃ was more effective than paricalcitol.

Bone Health in Rats With Temporal Lobe Epilepsy in the Absence of Anti-Epileptic Drugs

Rationale: Epilepsy patients often exhibit reduced bone mineral density and are at an increased risk of bone fracture. Whether these bone abnormalities are due to the use of anti-epileptic drugs (AED’s) or the disease itself is unknown. For example, although decreased bone health in epilepsy patients is generally attributed to the use of AED’s, seizures can also trigger a number of physiological processes that have the potential to affect bone. Therefore, to assess whether bone abnormalities occur in epilepsy in the absence of AED’s, the current study investigated mechanical characteristics and trabecular bone morphology in rats with chronic temporal lobe epilepsy.

Methods: Ten-week old male Wistar rats underwent kainic acid-induced status epilepticus (SE; n = 7) or a sham procedure (n = 9). Rats were implanted with EEG recording electrodes at nine weeks post-SE, and video-EEG was continuously recorded for one week at 10- and 22-weeks post-SE to confirm that SE rats had spontaneous seizures. Open-field testing to assess locomotion was conducted at 23-weeks post-SE. At 24-weeks post-SE, rats were euthanized and tibia were extracted to determine trabecular morphology by micro-computed tomography (µCT), while femurs were used to investigate mechanical properties via 3-point bending.

Results: All post-SE rats had spontaneous seizures at 10- and 22-weeks post-SE, while none of the sham rats had seizures. µCT trabecular analysis of tibia revealed no differences in total volume, bone volume, bone volume fraction, trabecular number, or trabecular separation between post-SE or sham rats, although post-SE rats did have increased trabecular thickness. There were also no group differences in total distance travelled in the open field suggesting that activity levels did not account for the increased trabecular thickness. In addition, no differences in mechanical properties of femurs were observed between the two groups.

Conclusion: There was a lack of overt bone abnormalities in rats with chronic temporal lobe epilepsy in the absence of AED treatment. Although further studies are still needed, these findings may have important implications towards understanding the source (e.g., AED treatments) of bone abnormalities in epilepsy patients.

An explorative literature review of the multifactorial causes of osteoporosis in epilepsy

PURPOSE

Patients with epilepsy have a greatly increased risk of osteoporosis and fractures. The literature is diverse and contradictory when dealing with the underlying pathophysiological mechanisms. Consequently, the purpose of this review was to shed light on the multifactorial causes behind the increased occurrence of metabolic bone disease in patients with epilepsy and to identify areas for future research.

METHODS

A review of the literature was performed searching PubMed with relevant Medical Subject Headings MeSH terms. The results of the search were evaluated for relevance to the review based on the title and abstract of the publication. Publications in language other than English and publications pertaining only pediatric patients were excluded. For all studies, included reference lists were evaluated for further relevant publications. In total, 96 publications were included in this explorative review.

RESULTS

The high occurrence of metabolic bone disease in patients with epilepsy is multifactorial. The causes are the socioeconomic consequences of having a chronic neurological disease but also adverse effects to antiepileptic drug treatment ranging from interference with calcium and vitamin D metabolism to hyponatremia-induced osteoporosis.

CONCLUSION

The literature supports the need for awareness of bone health in patients with epilepsy. The pathophysiological mechanisms are many and various wanting for further research in the less well-characterized areas. Furthermore, great responsibility rests on the healthcare professionals in implementing comprehensive patient care and in assuring bone protective measures in clinical practice to prevent bone loss in patients with epilepsy.

Carbamazepine adverse drug reactions

INTRODUCTION

Carbamazepine (CBZ) is used for the treatment of epilepsy and other neurological and psychiatric disorders. The occurrence of adverse reactions (ADRs) to CBZ can negatively impact the quality of life of patients, as well as increase health-care costs. Thus, knowledge of CBZ-induced ADRs is important to achieve safer treatment outcomes. Areas covered: This review describes the clinical features, known mechanisms, and clinical management of the main CBZ-induced ADRs. In addition, pharmacogenetic studies focused on ADRs induced by CBZ are cited. Expert commentary: CBZ-induced ADRs are well known in the literature. The metabolite CBZ-10,11-epoxide plays an important role in the mechanism that underlies the ADRs induced by CBZ. Several factors should be considered for a safer use of CBZ, such as monotherapy prescription when possible, an adequate dose titration, knowledge of previous ADRs in the patient, and routine monitoring of CBZ plasma concentrations in symptomatic patients. Pharmacogenetics is a potential tool for CBZ therapy improvement, and the design of multicenter studies focused on the identification of biomarkers for CBZ-induced ADRs could provide useful information for a safer CBZ therapy.

Effects of the Antiepileptic Drugs Phenytoin, Gabapentin, and Levetiracetam on Bone Strength, Bone Mass, and Bone Turnover in Rats

Long-term treatment with antiepileptic drugs (AEDs) is accompanied by reduced bone mass that is associated with an increased risk of bone fractures. Although phenytoin has been reported to adversely influence bone metabolism, little is known pertaining to more recent AEDs. The aim of this study was to evaluate the effects of gabapentin or levetiracetam on bone strength, bone mass, and bone turnover in rats. Male Sprague-Dawley rats were orally administered phenytoin (20 mg/kg), gabapentin (30 or 150 mg/kg), or levetiracetam (50 or 200 mg/kg) daily for 12 weeks. Bone histomorphometric analysis of the tibia was performed and femoral bone strength was evaluated using a three-point bending method. Bone mineral density (BMD) of the femur and tibia was measured using quantitative computed tomography. Administration of phenytoin significantly decreased bone strength and BMD, which was associated with enhanced bone resorption. In contrast, treatment with gabapentin (150 mg/kg) significantly decreased bone volume and increased trabecular separation, as shown by bone histomorphometric analysis. Moreover, the bone formation parameters, osteoid volume and mineralizing surface, decreased after gabapentin treatment, whereas the bone resorption parameters, osteoclast surface and number, increased. Levetiracetam treatment did not affect bone strength, bone mass, and bone turnover. Our data suggested that gabapentin induced the rarefaction of cancellous bone, which was associated with decreased bone formation and enhanced bone resorption, and may affect bone strength and BMD after chronic exposure. To prevent the risk of bone fractures, patients prescribed a long-term administration of gabapentin should be regularly monitored for changes in bone mass.

Evaluation of bone health among epileptic patients using biochemical markers and DEXA scan: an Egyptian study

BACKGROUND

An association between antiepileptic drugs, low bone mineral density (BMD), fractures, and abnormalities in bone metabolism has been suggested for a longer period, although conclusive evidence has not been reported.

METHODS

Thirty epileptic patients and 30 matched healthy subjects participated in the study. Measurements of serum levels of calcium, phosphorus, vitamin D, parathormone, and alkaline phosphatase were done for included subjects. Dual-energy X-ray absorptiometry (DEXA) scan was also performed.

RESULTS

Serum calcium, phosphorus, and vitamin D were significantly lower, whereas serum parathormone and alkaline phosphatase were significantly higher in epileptic patients compared to control subjects. Bone mineral density (BMD) abnormalities were detected in 22 patients (73.4%). A statistically significant difference in DEXA scan measurements at different regions was detected between epileptic patients and control subjects. Epileptic patients receiving enzyme inducer antiepileptic drugs (AEDs) had significantly lower serum (calcium, phosphorous, and vitamin D) and lower BMD values compared to those receiving enzyme inhibitors. Results of BMD were positively correlated with serum calcium, phosphorous, and vitamin D, while negatively correlated with serum alkaline phosphatase and duration of therapy.

CONCLUSIONS

Abnormal bone health is common in epileptic patients. These abnormalities may be attributed to prolonged intake of AEDs especially enzyme inducers.

Bone loss with antiepileptic drug therapy: a twin and sibling study

Changes in areal bone mineral density (aBMD) and other predictors of bone loss were evaluated in 48 same-sex twin/age-matched sibling pairs discordant for antiepileptic drug (AED) use. AED users had reduced BMD at the hip regions. Prolonged AED users had greater aBMD loss, predicting a higher risk of bone fragility.

INTRODUCTION

To investigate the longitudinal associations of bone mineral measures with antiepileptic drug (AED) use, including enzyme-inducing (EIAED) and non-enzyme-inducing (NEIAED) types, and other predictors of bone loss in a study of 48 same-sex twin/age-matched sibling pairs (40 female, 8 male) discordant for AED use.

METHODS

Using dual-energy X-ray absorptiometry (DXA), areal bone mineral density (aBMD) and content (BMC) at the hip regions, forearm, lumbar spine, and whole body were measured twice, at least 2 years apart. The mean within-pair difference (MWPD), MWPD%, and mean annual rate of aBMD change were adjusted for age, weight, and height. Predictors of bone loss were evaluated.

RESULTS

AED users, compared to non-users, at baseline and follow-up, respectively, had reduced aBMD at the total hip (MWPD% 3.8, 4.4%), femoral neck (4.7, 4.5%), and trochanter regions (4.1, 4.6%) (p < 0.05). For the whole cohort, the annual rate of change in all aBMD/BMC (p > 0.05) regions did not differ within pairs. Nevertheless, EIAED users had greater aBMD loss than non-users (n = 20 pairs) at the total hip (1.7 vs. 0.3%, p = 0.013) and whole body regions (0.7% loss vs. 0.1% BMD gain, p = 0.019), which was not found in NEIAED-discordant pairs (n = 16). AED use >20 years predicted higher aBMD loss at the forearm (p = 0.028), whole body (p = 0.010), and whole body BMC (p = 0.031).

CONCLUSIONS

AED users had reduced aBMD at the hip regions. Prolonged users and EIAED users had greater aBMD loss, predicting a higher risk of bone fragility. Further prospective studies of AED effects on bone microarchitecture are needed.

Biochemical Testing Relevant to Bone

Laboratory biochemical testing is critical to the clinical understanding of bone disorders. Patients with skeletal diseases have underlying themes in their pathophysiology that would be impossible to detect without biochemical assessment of serum and urine minerals, vitamin D, parathyroid hormone, parathyroid hormone-related peptide, and bone turnover markers. Bone disorders are caused by abnormalities in signaling pathways that affect bone formation and resorption. Therapies for common bone diseases were developed in direct response to underlying biochemical abnormalities.

Bone Mineral Changes in Epilepsy Patients During Initial Years of Antiepileptic Drug Therapy

Antiepileptic drug (AED) therapy is associated with decreased bone mineral density; however, the time course for this development is unclear. The aim of this study was to evaluate bone mineral changes during the initial years of AED therapy in AED-naive, newly diagnosed epilepsy patients compared with non-AED users. In 49 epilepsy patients newly started on AEDs and in 53 non-AED users of both genders, bone mineral density (BMD) and bone mineral content were measured using dual-energy X-ray absorptiometry at baseline (within the first year of therapy) and at least 1 yr later. Bone changes between the 2 assessments, adjusted for age, height, and weight, were calculated as the annual rate of change. The median duration of AED therapy was 3.5 mo at baseline and 27.6 mo at follow-up. No overall difference was found in mean BMD and bone mineral content measures between user and nonuser cohorts in both cross-sectional baseline and the annual rate of change (p > 0.05). However, users on carbamazepine monotherapy (n = 11) had an increased annual rate of total hip (-2.1% vs -0.8%, p = 0.020) and femoral neck BMD loss (-2.1% vs -0.6%, p = 0.032) compared to nonusers. They also had a marginally higher rate of femoral neck BMD loss (-2.1%, p = 0.049) compared with valproate (-0.1%, n = 13) and levetiracetam users (+0.6%, n = 13). During the initial years of AED treatment for epilepsy, no difference was found in bone measures between AED users as a group and nonuser cohorts. However, the data suggested that carbamazepine monotherapy was associated with increased bone loss at the hip regions, compared to users of levetiracetam or valproate and nonusers. Larger studies of longer duration are warranted to better delineate the bone effects of specific AEDs, with further consideration of the role of early dual-energy X-ray absorptiometry scanning and careful AED selection in potentially minimizing the impact on bone health in these patients.

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.

Development and validation of an interview-administered FFQ for assessment of vitamin D and calcium intakes in Finnish women

Increased vitamin D fortification of dairy products has increased the supply of vitamin D-containing products with different vitamin D contents on the market in Finland. The authors developed a ninety-eight-item FFQ with eight food groups and with a question on supplementation to assess dietary and supplemental vitamin D and Ca intakes in Finnish women (60ºN). The FFQ was validated in subgroups with different habitual vitamin D supplement use (0-57·5 µg/d) against the biomarker serum 25-hydroxyvitamin D (S-25(OH)D) and against 3-d food records (FR) (n 29-67). Median total vitamin D intake among participants was 9·4 (range 1·6-30·5) µg/d. Spearman's correlations for vitamin D and Ca ranged from 0·28 (P 0·146, FFQ v. S-25(OH)D, persons not using supplements) to 0·75 (P<0·001, FFQ v. FR, supplement use included). The correlations between the FFQ and S-25(OH)D concentrations improved within increasing supplement intake. The Bland-Altman analysis showed wide limits of agreement between FFQ and FR: for vitamin D between -7·8 and 8·8 µg/d and for Ca between -938 and 934 mg/d, with mean differences being 0·5 µg/d and 2 mg/d, respectively. The triads method was used to calculate the validity coefficients of the FFQ for vitamin D, resulting in a mean of 1·00 (95 % CI 0·59, 1·00) and a range from 0·33 to 1·00. The perceived variation in the estimates could have been avoided with a longer FR period and larger number of participants. The results are comparable with earlier studies, and the FFQ provides a reasonable estimation of vitamin D and Ca intakes.

Bone status in patients with epilepsy: relationship to markers of bone remodeling

Patients with epilepsy and treated with antiepileptic drugs (AEDs) may develop metabolic bone disease; however, the exact pathogenesis of bone loss with AEDs is still unclear. Included were 75 adults with epilepsy (mean age: 31.90 ± 5.62 years; duration of treatment with AEDs: 10.57 ± 3.55 years) and 40 matched healthy controls. Bone mineral content (BMC) and bone mineral densities (BMD) of the femoral neck and lumbar spine were measured using dual-energy X-ray absorptiometry (DEXA). Blood samples were analyzed for calcium, magnesium, phosphate, alkaline phosphatase (ALP), 25-hydroxy vitamin D (25OHD), soluble receptor activator of nuclear factor-kappa B ligand (sRANKL), osteoprotegerin (OPG), and OPG/RANKL ratio (markers of bone remodeling). Compared to controls, patients had lower BMD, BMC, Z-score, and T-score at the femoral neck and lumbar spine (all p < 0.001). Seventy-two percent and 29.33% of patients had osteoporosis of the lumbar spine and femoral neck. Patients had significantly lower serum calcium, 25(OH)D, and OPG and higher ALP, sRANKL levels, and sRANKL/OPG (all p < 0.001). Fifty-two percent of patients had hypocalcemia, 93% had hypovitaminosis D, 31% had high levels of sRANKL, and 49% had low levels of OPG. No differences were identified between DEXA and laboratory results in relation to the type, dose, or serum levels of AEDs. BMD at the femoral neck and lumbar spine were found to be correlated with the duration of illness (p = 0.043; p = 0.010), duration of treatment with AEDs (p < 0.001; p = 0.012), and serum levels of 25(OH)D (p = 0.042; p = 0.010), sRANKLs (p = 0.005; p = 0.01), and OPG (p = 0.006; p = 0.01). In linear regression analysis and after adjusting for gender, age, weight, duration, and number of AEDs, we observed an association between BMD, 25(OH)D (p = 0.04) and sRANKL (p = 0.03) concentrations. We conclude that AEDs may compromise bone health through disturbance of mineral metabolism and acceleration of bone turnover mechanisms.

The problem of osteoporosis in epileptic patients taking antiepileptic drugs

INTRODUCTION

Epilepsy is a common neurological disorder associated with recurrent seizures. Therapy with antiepileptic drugs (AEDs) helps achieve seizure remission in approximately 70% of epileptic patients. Treatment with AEDs is frequently lifelong and there are reports suggesting its negative influence on bone health. This is especially important in terms of general occurrence of osteoporosis, affecting over 50 million people worldwide.

AREAS COVERED

This study refers to two main groups of AEDs: hepatic enzyme inducers (carbamazepine, oxcarbazepine, phenobarbital, phenytoin, primidone and topiramate) and non-inducers (clobazam, clonazepam, ethosuximide, gabapentin, lacosamide, lamotrigine, levetiracetam, pregabalin, tiagabine, valproate, vigabatrin and zonisamide). Some reports indicate that enzyme inducers may exert a more negative influence on bone mineral density (BMD) compared to non-inducers. Bone problems may appear in both sexes during AED therapy, although women are additionally burdened with postmenopausal osteoporosis. Supplementation of vitamin D and calcium in patients on AEDs is recommended.

EXPERT OPINION

Apart from enzyme inducers, valproate (an even enzyme inhibitor) may also negatively affect BMD. However, the untoward effects of AEDs may depend upon their doses and duration of treatment. Although the problem of supplementation of vitamin D and calcium in epileptic patients on AEDs is controversial, there are recommendations to do so.

The impact of the use of antiepileptic drugs on the growth of children

BACKGROUND

This study investigated whether long-term treatment with antiepileptic drugs (AEDs) had negative effects on statural growth and serum calcium levels in children with epilepsy in Taiwan.

METHODS

Children with epilepsy treated with one prescription of AEDs (monotherapy) for at least 1 year were selected. The AEDs included valproic acid (VPA; Deparkin) in 27 children (11 boys and 16 girls) aged 4-18 years, oxcarbazepine (Trileptal) in 30 children (15 boys and 15 girls) aged 5-18 years, topiramate (Topamax) in 19 children (10 boys and 9 girls) aged 6-18 years, and lamotrigine (Lamicta) in eight children (5 boys and 3 girls) aged 5-13 years. Patients with a history of febrile convulsions were selected as the controls.

RESULTS

One year of VPA treatment significantly impaired the statural growth of pediatric patients with epilepsy (p < 0.005) compared with the control group. The underlying mechanism may have been due to the direct effect of VPA on the proliferation of growth plate chondrocytes rather than alterations of serum calcium.

CONCLUSIONS

These results raise serious concerns about the growth of pediatric epilepsy patients who use AEDs, and potentially the need to closely monitor growth in children with epilepsy and adolescents under AED treatment, especially VPA.

Epilepsy and vitamin D

Several disorders, both systemic and those of the nervous system, have been linked with vitamin D deficiency. Neurological disorders with a vitamin D link include but are not limited to multiple sclerosis, Alzheimer and Parkinson disease, as well as cerebrovascular disorders. Epilepsy which is the second leading neurological disorder received much less attention. We review evidence supporting a link between vitamin D and epilepsy including those coming from ecological as well as interventional and animal studies. We also assess the literature on the interaction between antiepileptic drugs and vitamin D. Converging evidence indicates a role for vitamin D deficiency in the pathophysiology of epilepsy.

Effect of oxcarbazepine on bone mineral density and biochemical markers of bone metabolism in patients with epilepsy

PURPOSE

Antiepileptic drugs (AEDs) may cause adverse effects on bone metabolism and bone mineral density (BMD). The aim of this study is to determine the effect of oxcarbazepine (OXC) monotherapy on biochemical markers of bone metabolism and BMD in epilepsy patients.

METHODS

Forty-one new onset drug naïve epilepsy patients were recruited (19 females, 22 males; mean age: 28.2±8.4 years). We measured biochemical markers of bone metabolism (serum calcium, phosphate, bone alkaline phosphatase, parathyroid hormone, osteocalcin, insulin-like growth factor (IGF)-1, C-telopeptide, Vitamin D3 levels) and BMD by DEXA (dual energy X-ray absorptiometry) method in all patients before and after a long-term OXC monotherapy.

RESULTS

Most of biochemical markers were not changed significantly, but serum calcium (p=0.0087) and bone specific ALP was reduced (p=0.0499) significantly after OXC monotherapy in epilepsy patients. BMD at the lumbar spine (L2 to L4) was significantly increased after OXC monotherapy (p=0.0001), revealed by repeated measures ANOVA with Bonferroni's correction of confounders including sex, age, average dose, and treatment duration. However, BMD at the lumbar spine (L2 to L4) was significantly increased (p=0.012) only in female patients in each gender analysis.

CONCLUSIONS

This study demonstrates that a long-term OXC monotherapy does not appear to have harmful effect on bone health in drug naïve epilepsy patients.

Effects of carbamazepine on serum parathormone, 25- hydroxyvitamin D, bone specific alkaline phosphatase, C-telopeptide, and osteocalcin levels in healthy rats

It is still not completely clear whether carbamazepine causes alterations in vitamin D status and in bone metabolism. The objective of this study was to investigate the effects of carbamazepine on serum levels of 25-hydroxyvitamin D and on biomarkers of bone formation and resorption in healthy rats. Levels of calcium, 25- hydroxyvitamin D, parathormone, C-telopeptide, bone specific alkaline phosphatase and osteocalcin were measured in 3 groups of rats consisting of controls (n=10), isotonic saline solution group (n=10) and carbamazepine group (n=10). Mean calcium levels were found to be significantly lower in healthy controls in comparison to isotonic saline solution and carbamazepine groups (10.0±0.24, 10.81±0.16, 10.93±0.22 mg/dL, respectively, p<0.05). Mean levels of 25- hydroxyvitamin D, were found to be significantly higher in control group compared to isotonic saline solution group (25- hydroxyvitamin D; 25.91±1.12, 19.99±0.99 ng/mL, respectively, p<0.01). Mean levels of parathormone and osteocalcin were found to be significantly higher in control group compared to isotonic saline solution group and carbamazepine group. Parathormone levels were measured as 3.46±0.83, 1.08±0.08, 0.94±0.02 pg/mL, respectively (p<0.01). Osteocalcine levels were measured as 1.66±0.001, 1.32±0.002, 1.32±0.001 ng/mL, respectively (p<0.001). A significant difference in terms of mean serum bone specific alkaline phosphatase and C-telopeptide levels among groups was not observed. The main outcome of this prospective study in healthy rats showed no change in biochemical parameters of bone turnover during treatment with carbamazepine.

Bone density characteristics and major depressive disorder in adolescents

OBJECTIVE

Major depressive disorder (MDD) is common during adolescence, a period characterized by rapid bone mineral accrual. MDD has recently been associated with lower bone mineral density (BMD) in adults. Our objective was to determine whether MDD is associated with BMD, bone turnover markers, vitamin D, and gonadal steroids in adolescents.

METHODS

Sixty-five adolescents 12 to 18 years of age (32 boys: 16 with MDD and 16 controls; 33 girls: 17 with MDD and 16 controls) were included in a cross-sectional study. BMD and body composition were obtained by dual-energy x-ray absorptiometry. Estradiol, testosterone, 25-hydroxy vitamin D levels, N-terminal propeptide of Type 1 procollagen (a marker of bone formation), and Type I collagen C-telopeptide (a marker of bone resorption) were measured.

RESULTS

Boys with MDD had a significantly lower BMD at the hip (mean [standard deviation]=0.99 [0.17] g/cm2 versus 1.04 [0.18] g/cm2, body mass index [BMI] adjusted, p=.005) and femoral neck (0.92 [0.17] g/cm2 versus 0.94 [0.17] g/cm2; BMI adjusted, p=.024) compared with healthy controls after adjusting for BMI. This significant finding was maintained after also adjusting for lean mass and bone age (hip: p=.007; femoral neck: p=.020). In girls, there were no significant differences in BMD between the girls with MDD and the controls after adjusting for BMI (p>.17).

CONCLUSIONS

Male adolescents with MDD have a significantly lower BMD as compared with healthy controls after adjusting for body mass and maturity. This association is not observed in girls.

Drug-vitamin D interactions: a systematic review of the literature

Extensive media coverage of the potential health benefits of vitamin D supplementation has translated into substantial increases in supplement sales over recent years. Yet, the potential for drug-vitamin D interactions is rarely considered. This systematic review of the literature was conducted to evaluate the extent to which drugs affect vitamin D status or supplementation alters drug effectiveness or toxicity in humans. Electronic databases were used to identify eligible peer-reviewed studies published through September 1, 2010. Study characteristics and findings were abstracted, and quality was assessed for each study. A total of 109 unique reports met the inclusion criteria. The majority of eligible studies were classified as class C (nonrandomized trials, case-control studies, or time series) or D (cross-sectional, trend, case report/series, or before-and-after studies). Only 2 class C and 3 class D studies were of positive quality. Insufficient evidence was available to determine whether lipase inhibitors, antimicrobial agents, antiepileptic drugs, highly active antiretroviral agents, or H2 receptor antagonists alter serum 25(OH)D concentrations. Atorvastatin appears to increase 25(OH)D concentrations, whereas concurrent vitamin D supplementation decreases concentrations of atorvastatin. Use of thiazide diuretics in combination with calcium and vitamin D supplements may cause hypercalcemia in the elderly or those with compromised renal function or hyperparathyroidism. Larger studies with stronger study designs are needed to clarify potential drug-vitamin D interactions, especially for drugs metabolized by cytochrome P450 3A4 (CYP3A4). Healthcare providers should be aware of the potential for drug-vitamin D interactions.

Effect of epidural steroid injection on bone mineral density and markers of bone turnover in postmenopausal women

STUDY DESIGN

A prospective, observational study.

OBJECTIVE

To evaluate the effect of epidural steroid injection (ESI) on bone mineral density (BMD) in postmenopausal women.

SUMMARY OF BACKGROUND DATA

ESIs are used to treat the pain associated with radiculopathy. Although it is known that exogenous steroid use can disrupt skeletal architecture, it is less clear whether ESIs result in a decrease of BMD.

METHODS

Twenty-eight postmenopausal women experiencing radiculopathy elected L4-L5 ESI treatment. We had a 50% dropout rate due to noncompliance with study requirements. BMD of the hip, femoral neck, and spine along with markers of bone turnover, bone specific-alkaline phosphatase and serum C-telopeptide of collagen I (CTX), was evaluated at baseline preinjection and 3 and 6 months postinjection.

RESULTS

There was a significant decline in the hip BMD of 0.018 g/cm (0.028 ± 0.007, P = 0.002) at 6 months compared with baseline. We compared this decline with an age-matched control population that exhibited a decline of 0.003 g/cm(2), significantly less than our study population (P = 0.007). Bone-specific alkaline phosphatase increased significantly by 2.33 U/L from 3 to 6 months (P = 0.012), but the rise of CTX was not significant.

CONCLUSION

A single ESI in postmenopausal women adversely affects BMD of the hip. This is in conjunction with a rise in bone remodeling activity, as evidenced by an increase in bone-specific alkaline phosphatase and CTX. In addition, when compared with an age-matched control population, our study population exhibited a greater decline in BMD. Our findings show that epidural administration of corticosteroids has a deleterious effect on bone, which should be considered when contemplating treatment options for radiculopathy. The resulting decrease in BMD, while slight, suggests that ESIs should be used with caution in those at a risk for fracture.

Antiepileptics and bone health

In recent years there has been increasing evidence suggesting that epilepsy and its treatment can have adverse effects on bone mineralization and calcium metabolism. Many studies have shown a significant reduction in bone mineral density (BMD) and an increased fracture risk in patients treated with enzyme-inducing antiepileptics (phenobarbital, carbamazepine, phenytoin). It is assumed that CYP450-inducing antiepileptic drugs (AEDs) upregulate the enzymes which are responsible for vitamin D metabolism, with the effect of converting 25(OH) vitamin D into inactive metabolites, resulting in reduced calcium absorption with consecutive secondary hyperparathyroidism. Data on bone-specific effects of newer AEDs are limited; nevertheless, alterations of bone metabolism have been reported for oxcarbazepine, gabapentin and, in preclinical studies, for levetiracetam. Prophylactic administration of adequate amounts of calcium and vitamin D is recommended for all patients. For patients with long-term AED exposure, BMD measurement is recommended as part of osteoporosis investigation (especially for patients treated with enzyme-inducing AEDs and where there are major risk factors for fractures). Drug therapy (bisphosphonates) is reserved for the treatment of patients who have a high fracture risk; there are no specific intervention studies available in patients with epilepsy.

May long term oxcarbazepine treatment be lead to secondary hyperparathyroidism?

Background and Purpose

The adverse effects of newer antiepileptic drugs are not well-known. This study assessed the impact of oxcarbazepine (OXC) treatment on bone turnover.

Methods

Forty-four children with idiopathic focal (and/or secondarily generalized) epilepsy who had been treated with OXC for more than 1 year were compared with 33 healthy, age- and sex-matched children. Serum calcium, phosphorus, alkaline phosphatase, parathyroid hormone, osteocalcin, calcitonin, and 25-hydroxyvitamin D, and bone mineral density were measured to evaluate and compare bone mineralization between the two groups.

Results

The serum levels of calcium, osteocalcin, 25-hydroxyvitamin D, and bone mineral density did not differ significantly between the study and control groups. However, serum levels of parathyroid hormone, alkaline phosphatase, phosphorus, and calcitonin differed significantly between the two groups.

Conclusions

These findings suggest that OXC treatment leads to secondary hyperparathyroidism with high-turnover bone disease and/or impaired intestinal calcium absorption.

Neuroendocrinological aspects of epilepsy: important issues and trends in future research

Neuroendocrine research in epilepsy focuses on the interface among neurology, endocrinology, gynecology/andrology and psychiatry as it pertains to epilepsy. There are clinically important reciprocal interactions between hormones and the brain such that neuroactive hormones can modulate neuronal excitability and seizure occurrence while epileptiform discharges can disrupt hormonal secretion and promote the development of reproductive disorders. An understanding of these interactions and their mechanisms is important to the comprehensive management of individuals with epilepsy. The interactions are relevant not only to the management of seizure disorder but also epilepsy comorbidities such as reproductive dysfunction, hyposexuality and emotional disorders. This review focuses on some of the established biological underpinnings of the relationship and their clinical relevance. It identifies gaps in our knowledge and areas of promising research. The research has led to ongoing clinical trials to develop hormonal therapies for the treatment of epilepsy. The review also focuses on complications of epilepsy treatment with antiepileptic drugs. Although antiepileptic drugs have been the mainstay of epilepsy treatment, they can also have some adverse effects on sexual and reproductive function as well as bone density. As longevity increases, the prevention, diagnosis and treatment of osteoporosis becomes an increasingly more important topic, especially for individuals with epilepsy. The differential effects of antiepileptic drugs on bone density and their various mechanisms of action are reviewed and some guidelines and future directions for prevention of osteoporosis and treatment are presented.

Bisphosphonates in phenytoin-induced bone disorder

Chronic administration of phenytoin (PHT) has been associated with bone loss. Bisphosphonates [alendronate (ALD), ibandronate (IBD) and risedronate (RSD)] are potential candidates to prevent PHT-induced bone disorders, and the present study evaluated their effect on the antiepileptic efficacy of PHT. The PHT-induced depletion in folic acid (FA), vitamin B6 and vitamin B12 results in hyperhomocysteinemia. The elevated circulating homocysteine (hcy) could be a risk indicator for micronutrient-deficiency-related osteoporosis via generation of free radicals. Thus, an attempt was also made to unravel the PHT's and bisphosphonates' effect on hcy. Male mice received PHT (35 mg/kg, p.o.) for 90 days to induce bone loss. ALD, RSD and IBD were administered orally at doses 0.65 mg/kg, 0.33 mg/kg, and 0.17 mg/kg respectively, for prevention and 1.3mg/kg, 0.65 mg/kg, and 0.33 mg/kg respectively, for treatment of PHT-induced bone loss. The bone loss was confirmed by bone mineral density (BMD) analysis and bone turnover markers. Serum levels of hcy and FA were estimated along with hydrogen peroxide levels and total antioxidant capacity in order to assess the antioxidant profile of bisphosphonates. The induction of bone loss by PHT was marked by lowered BMD and altered bone turnovers. ALD and RSD administration to PHT treated groups significantly reverted the bony adverse effects. No such effects were observed with IBD. In the bisphosphonates treated groups, hcy levels were statistically at par with the control group. PHT at 35 mg/kg, p.o. could compromise bone mass and thus, could be a model of bone demineralization in mice. The ALD, IBD and RSD have no pharmacodynamic interaction when administered along with PHT at the experimental level. Thus, their usage in the management of PHT-induced bone disease could be worthwhile if clinically approved.

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 effect of anti epileptic drug therapy on serum 25-hydroxyvitamin D and parameters of calcium and bone metabolism--a longitudinal study

BACKGROUND

Chronic antiepileptic drug use is associated with bone loss. We sought to assess the longitudinal effect of antiepileptic drug on serum 25-hydroxyvitamin D [25(OH)D] levels and bone mineral metabolism markers.

METHODS

Patients in the emergency services or those in neurology outpatient department with history of seizure were characterized and included in the study prospectively. Daily dietary intake of calories, calcium, phosphorus and phytates were characterized by dietary recall method. Base line bone mineral parameters - serum calcium, phosphorus, alkaline phosphatase (SAP), tartrate resistant acid phosphatase (TRACP), 25(OH)D levels, parathyroid hormone (PTH) and urinary calcium creatinine ratio (Ca.Cr), urinary calcium/kg/bodyweight (BW) and phosphate excretion index (PEI) were determined. Patients on AED therapy with normal 25(OH)D levels were followed up and were re-evaluated at the end of 6 months.

RESULTS

The daily dietary calcium intake of the subjects was lower than the RDA (Recommended Dietary Allowance) by ICMR (Indian Council of Medical Research). The diet was high in phytates. Two-thirds of the recruited subjects were vitamin D deficient. Subjects with normal 25(OH)D levels at base line showed a significant fall of 25(OH)D levels, urinary calcium, urinary calcium/kg/BW and TRACP levels at the end of 6 months irrespective of the AED used or the plasma level of AED.

CONCLUSIONS

Hypovitaminosis D is common in our population. Subjects with normal 25(OH)D levels, irrespective of the type of antiepileptic medications even at sub-therapeutic serum levels of the drug, went into 25(OH)D deficiency and insufficiency states. Theoretically it can be worthwhile to supplement calcium and vitamin D even before initiation of antiepileptic therapy.

Influence of season, ethnicity, and chronicity on vitamin D deficiency in traumatic spinal cord injury

BACKGROUND

Inadequate levels of vitamin D increase the risk of osteoporosis, a highly prevalent condition in patients with traumatic spinal cord injury (SCI). Reduced sunlight and dark skin further contribute to low vitamin D levels.

OBJECTIVES

To compare serum 25-hydroxy vitamin D [vitamin D25(OH)] levels in acute and chronic SCI and to explore seasonal and ethnic differences among patients with acute and chronic SCI.

PATIENTS/METHODS

Patients (N=96) aged 19 to 55 years with C3-T10 motor complete SCI participated. Acute SCI was 2 to 6 months after injury, whereas chronic SCI was at least 1 year from injury. Serum vitamin D25(OH), calcium, and parathyroid hormone were drawn dUring summer or winter months. Vitamin D deficiency (<13 ng/mL), insufficiency (<20 ng/mL), and subtherapeutic (<32 ng/mL) levels were compared for all groups. A 3-way analysis of covariance was adopted to determine significant main effects of season, chronicity, and ethnicity. Interactions between season and chronicity, season and ethnicity, and chronicity and ethnicity were evaluated. Evaluation of a 3-way interaction among season, chronicity, and ethnicity was completed.

RESULTS

In summer, 65% of patients with acute SCI and 81% of patients with chronic SCI had subtherapeutic vitamin D levels, whereas in winter, 84% with acute SCI and 96% with chronic SCI had vitamin D25(OH) (<32 ng/mL). Lower vitamin D25(OH) levels were observed in African Americans relative to whites. Significant main effects were noted for season (P = 0.017), chronicity (P = 0.003), and ethnicity (P < 0.001). However, interactions between 2 or more factors were not found.

CONCLUSIONS

Vitamin D insufficiency and deficiency are found in the majority of patients with chronic SCI and in many with acute SCI. Initial screening for serum vitamin D25(OH) levels should be performed early in rehabilitation. Periodic monitoring in the chronic setting is highly recommended.

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.

A review of drug-induced hypocalcemia

Hypocalcemia (defined as total serum calcium lower than 8.5 mg/dl or as ionized serum calcium lower than 4.7 mg/dl) is a relatively common metabolic abnormality observed in hospitalized patients. Although it is associated with certain pharmacological agents such as bisphosphonates and cisplatin, hypocalcemia may occasionally develop in the course of treatment with drugs used in everyday clinical practice, including antiepileptics, aminoglycosides, and proton pump inhibitors. Hypocalcemia associated with drug treatment can be easily missed as a consequence of coexistence of multiple factors contributing to low serum calcium levels. Drug-related hypocalcemia is usually mild and asymptomatic but may be severe as well. Effective clinical management can be handled through awareness of this adverse effect induced by certain pharmaceutical compounds on serum calcium concentrations. Herein, we review pertinent clinical information on the incidence of hypocalcemia associated with specific drug treatment and discuss the underlying pathophysiological mechanisms.

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.

Antiepileptic drug use and rates of hip bone loss in older men: a prospective study

OBJECTIVE

To test the hypotheses that older community dwelling men taking non-enzyme-inducing antiepileptic drugs (NEIAEDs) and those taking enzyme-inducing antiepileptic drugs (EIAEDs) have increased rates of hip bone loss.

METHODS

We ascertained antiepileptic drug (AED) use (interviewer-administered questionnaire with verification of use by containers) and measured hip bone mineral density (BMD) (using dual energy x-ray absorptiometry) at baseline and an average of 4.6 years later in a cohort of 4,222 older community-dwelling men enrolled in the Osteoporotic Fractures in Men study. Men were categorized as nonusers (no AED use at either examination, n = 4060), NEIAED user (use of NEIAED only at either examination, n = 100), or EIAED user (use of EIAED only at either examination, n = 62).

RESULTS

After adjustment for multiple potential confounders (age, race, clinic site, health status, pain interfering with work or activity, physical activity, smoking status, alcohol use, total calcium intake, diabetes, chronic kidney disease, vitamin D supplement use, bisphosphonate use, selective serotonin reuptake inhibitor use, inability to rise from a chair, body mass index, and baseline BMD), the average rate of decline in total hip BMD was -0.35%/year among nonusers compared with -0.53%/year among NEIAED users (p = 0.04) and -0.46%/year among EIAED users (p = 0.31). Multivariable adjusted rate of loss was -0.60%/year among men taking NEIAED at both examinations, -0.51%/year among men taking NEIAED at one examination only, and -0.35%/year among nonusers (p for trend = 0.03). Findings were similar at hip subregions.

CONCLUSION

Use of non-enzyme-inducing antiepileptic drugs was independently associated with increased rates of hip bone loss in this cohort of older community-dwelling men.

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.