Prevalence and risk factors for vitamin D insufficiency among children with epilepsy

Prevalence and predictors of vitamin D deficiency among adults with epilepsy: A cross-sectional study

BACKGROUND

Vitamin D deficiency among adult people with epilepsy (PWE) is scarcely studied, despite its essential role in bone health and maintaining homeostasis. Several studies have studied the relationship between factors related to epilepsy and vitamin D metabolism. We aim to investigate this in our multi-ethnic society.

METHODS

This was a single-center cross-sectional study. We recruited 159 participants diagnosed with epilepsy on antiseizure medications (ASMs). We included those aged 18 years and above, excluding patients with long-term medical conditions that would affect vitamin D metabolism. Sociodemographic data and details of epilepsy were collated. Venous sampling was performed to analyze the levels of albumin-corrected calcium, phosphate, alkaline phosphatase, and 25-hydroxyvitamin D3 [25(OH)D]. Serum 25(OH)D level is defined as deficient (<20 ng/ml), insufficient (20-29 ng/ml), and sufficient (≥30 ng/ml).

RESULTS

The study reported that 73 (45.9%) participants had vitamin D deficiency, 38 (23.9%) had vitamin D insufficiency, and 48 (30.2%) patients had sufficient vitamin D levels. The predictors identified were PWE aged 18 to 44 years old (p = 0.001), female gender (OR 3.396, p = 0.002), and ethnicity (p < 0.001), specifically Malay and Chinese. However, no significant association was identified between types of ASMs, serum calcium, or the prevalence of vitamin D deficiency.

CONCLUSION

Vitamin D deficiency among PWE is prevalent in our local population, suggesting that regular screening should be considered for those at risk. Early identification would allow intervention to reduce the risk of future complications.

Molecular insights into the pathogenic impact of vitamin D deficiency in neurological disorders

Neurological disorders are the major cause of disability, leading to a decrease in quality of life by impairing cognitive, sensorimotor, and motor functioning. Several factors have been proposed in the pathogenesis of neurobehavioral changes, including nutritional, environmental, and genetic predisposition. Vitamin D (VD) is an environmental and nutritional factor that is widely distributed in the central nervous system's subcortical grey matter, neurons of the substantia nigra, hippocampus, thalamus, and hypothalamus. It is implicated in the regulation of several brain functions by preserving neuronal structures. It is a hormone rather than a nutritional vitamin that exerts a regulatory role in the pathophysiology of several neurological disorders, including Alzheimer's disease, Parkinson's disease, epilepsy, and multiple sclerosis. A growing body of epidemiological evidence suggests that VD is critical in neuronal development and shows neuroprotective effects by influencing the production and release of neurotrophins, antioxidants, immunomodulatory, regulation of intracellular calcium balance, and direct effect on the growth and differentiation of nerve cells. This review provides up-to-date and comprehensive information on vitamin D deficiency, risk factors, and clinical and preclinical evidence on its relationship with neurological disorders. Furthermore, this review provides mechanistic insight into the implications of vitamin D and its deficiency on the pathogenesis of neurological disorders. Thus, an understanding of the crucial role of vitamin D in the neurobiology of neurodegenerative disorders can assist in the better management of vitamin D-deficient individuals.

Standard and high dose ergocalciferol regimens for treatment of hypovitaminosis D in epileptic children and adolescents

OBJECTIVES

Children with epilepsy are at increased risk of vitamin D deficiency. We aimed to compare the effect of two ergocalciferol regimens given for 90 days.

METHODS

Epileptic patients aged 5-18 years who received at least one antiepileptic drug (AED) for more than 6 months and had serum 25-OHD <30 ng/mL were randomized to receive 20,000 IU/10 d (standard dose, n=41) or 60,000 IU/10 d (high dose, n=41) of oral ergocalciferol. Serum Ca, P, Mg, ALP, iPTH and urine Ca/Cr ratio were measured at baseline and after 90 days of treatment. Change in serum 25-OHD and vitamin D status after treatment was evaluated.

RESULTS

The initial serum 25-OHD in the standard dose and high dose group was 19.5 ± 4.9 and 18.4 ± 4.6 ng/mL, respectively. Serum 25-OHD after treatment was significantly higher in the high dose group (39.0 ± 11.5 vs. 27.5 ± 8.6 ng/mL, p<0.05). The average increase in serum 25-OHD in the high dose and standard dose group was 20.6 ± 11.4 and 7.2 ± 7.5 ng/mL, respectively (p<0.05). Normalized serum 25-OHD was achieved in 80.5% of the high dose group compared to 36.6% of the standard dose group (p<0.05). No adverse events were found. Patients with a BMI Z-score>0 had a 2.5 times greater risk of continued hypovitaminosis D after treatment compared to those with a BMI Z-score<0 (95% CI: 1.0-5.9, p<0.05).

CONCLUSIONS

Oral ergocalciferol 60,000 IU/10 d for 90 days was more effective at normalizing serum 25-OHD than 20,000 IU/10 d in epileptic children and adolescents who were receiving AEDs.

Association between serum vitamin D status and the anti-seizure treatment in Chinese children with epilepsy

Objective

To compare the serum 25-OH-VitD levels, the major marker of vitamin D (VitD) status, between healthy children and children with epilepsy before initiation of and during anti-seizure medications (ASMs) treatment and to evaluate the potential influence factors on 25-OH-VitD levels. Another major aim was to assess the potential role of VitD supplementation.

Methods

For comparison, we finally enrolled and collected data from 6,338 healthy children presenting to Health Care Department and 648 children visiting primary care pediatricians with symptoms of epilepsy in Children’s Hospital of Nanjing Medical University from January 2019 to June 2021. The demographic and biochemical characteristics of each child were extracted from the hospital information system.

Results

Serum 25-OH-VitD levels in 648 children with epilepsy were significantly lower than those of 6,338 healthy children (P &lt; 0.0001), and the percentage of VitD insufficiency and deficiency status in pediatric patients was 49.19%. Of note, the serum 25-OH-VitD levels in children with newly diagnosed epilepsy before receiving any ASMs treatment were also significantly lower than those in healthy controls. Interestingly, ASMs therapy, alone or in combination, did not consistently reduce baseline serum VitD levels in children with epilepsy. The lower serum VitD levels in pediatric patients than those in healthy children might be related to the disease itself, rather than the ASMs treatment. As expected, VitD supplementation substantially increased the serum 25-OH-VitD levels (P &lt; 0.0001). More critically, children with epilepsy receiving VitD supplementation achieved good seizure control in our study.

Significance

In this retrospective study, the childhood epilepsy before initiation of and during ASMs treatment decreased the serum 25-OH-VitD concentrations, suggesting a clear association between epileptic disease and the risk of VitD deficiency. ASMs coadministration and long-term valproic acid treatment did not worse VitD-deficiency status, but in the small group receiving VitD supplementation, there was a significant improvement in reduction of seizure frequency. Therefore, pediatric clinicians are urged to raise public awareness of epilepsy-associated VitD deficiency.

Association between serum vitamin D levels and age in patients with epilepsy: a retrospective study from an epilepsy center in Saudi Arabia

BACKGROUND

Vitamin D deficiency has been linked to various medical conditions such as bone loss, decreased mineralization, endocrine disorders, and central nervous system disorders, including epilepsy. Vitamin D deficiency is prevalent among patients with epilepsy (PWE). However, the specific association between vitamin D levels and age in PWE is unclear.

OBJECTIVES

Identify the relation between vitamin D level and age in PWE and evaluate factors that may play a role in seizure control.

DESIGN

Retrospective analytical medical record review SETTING: Outpatient epilepsy research clinic in Saudi Arabia PATIENTS AND METHODS: Between November 2016 and April 2020, we selected eligible PWE aged older than 14 years whose vita-min D levels were recorded at least once after reviewing 1550 patient electronic files. We analyzed data on serum vitamin D level by age and other factors, vitamin D supplement use, seizure classification, and conducted a multivariate logistic regression to assess associations with seizure control.

MAIN OUTCOME MEASURES

Relationships between vitamin D levels and age and factors that might affect seizure control.

SAMPLE SIZE

524 patients RESULTS: The prevalence of low serum vitamin D levels was high (86.8%). The median vitamin D level in all patients was low (38 nmol/L), and was lower in young PWE than in adult PWE (P<.01). Only 146 patients received vitamin D supplements. High vitamin D levels were associated with a 40% seizure reduction.

CONCLUSION

Vitamin D deficiency is underestimated in PWE in Saudi Arabia, and is more prevalent among young adults and patients on polytherapy than in other PWE. Patients with high vitamin D levels had good seizure control compared with those with low levels. The effect of vitamin D supplements on seizure control should be further investigated in randomized control trials.

LIMITATIONS

Retrospective study and no categorization by presence of supplementation.

CONFLICT OF INTEREST

None.

Hypovitaminosis D and risk factors in pediatric epilepsy children

Background

Anti-seizure medication (ASM) treatment is one of the significant risk factors associated with abnormal vitamin D status in epilepsy patients. Multiple studies have shown that adult epilepsy patients can exhibit vitamin D deficiency. However, there are few reports investigating pediatric epilepsy patients. In this study, we aimed to identify risk factors related to hypovitaminosis D in pediatric epilepsy patients in Thailand.

Methods

A cross-sectional retrospective cohort study was conducted in 138 pediatric epilepsy patients who received anticonvulsants from April 2018 to January 2019. Demographic data, seizure types, puberty status, physical activity, duration, and types of anti-seizure medications were analyzed. Patients with abnormal liver function, abnormal renal function, and who received vitamin D supplements or ketogenic diet containing vitamin D were excluded. Levels of serum vitamin D (25(OH)D) were measured.

Results

All 138 subjects were enrolled, the age ranged from 1.04 – 19.96 years; (mean = 9.65 ± 5.09), the mean serum 25(OH) D level was 26.56 ± 9.67 ng/ml. The prevalence of vitamin D deficiency was 23.2% and insufficiency was 47.8% respectively. Two risk factors—puberty status (OR 5.43, 95% CI 1.879-15.67) and non-enzyme-inhibiting ASMs therapy (OR 3.58, 95% CI 1.117-11.46)—were significantly associated with hypovitaminosis D, as shown by multivariate analyses.

Conclusions

Our study reports the high prevalence of hypovitaminosis D in pediatric epilepsy patients in Thailand despite being located in the tropical zone. These findings can guide clinicians to measure vitamin D status in pediatric epilepsy patients particularly when they reach puberty and/or are using non-enzyme-inhibiting ASMs therapy. Early detection of vitamin D status and prompt vitamin D supplementation can prevent fractures and osteoporosis later in life.

Trial registration

TCTR20210215005 (http://www.clinicaltrials.in.th/).

Valproic acid therapy decreases serum 25-hydroxyvitamin D level in female infants and toddlers with epilepsy- a pilot longitudinal study

To evaluate if valproic acid (VPA) therapy is associated with vitamin D deficiency among infants and toddlers with epilepsy, a cross-sectional clinical study was conducted in 25 children with epilepsy taking VPA. Blood levels of calcium, phosphorus, alkaline phosphatase, and 25-hydroxy vitamin D [25(OH)D] and plasma VPA level were measured at 1- to 3-month intervals. At the initial and final measurements, vitamin D deficiency or insufficiency was recognized in 8 (32%) and 12 (42%), respectively. In girls, a decreasing trend in serum 25(OH)D levels (P<0.05) was observed. Polytherapy had a significant negative effect on the longitudinal change of 25(OH)D (P<0.05) in girls. In conclusion, our study indicates that a high proportion of girls after VPA therapy had hypovitaminosis D.

Vitamin D deficiency in pediatric patients using antiepileptic drugs: systematic review with meta-analysis

OBJECTIVES

To measure the prevalence of vitamin D deficiency (through the 25-hydroxyvitamin D metabolite) in pediatric patients using antiepileptic drugs.

SOURCE OF DATA

Meta-analysis of studies identified through search in the PubMed, Embase, LILACS, and Cochrane Library databases, on February 19, 2019.

SUMMARY OF DATA

A total of 748 articles were identified, 29 of which were relevant to the objectives of this study. The prevalence of vitamin D deficiency found was 0.32 (95% CI=0.25-0.41; I²=92%, p<0.01). In the subgroup analyses, the most significant results were observed in the group of patients using cytochrome P450-inducing antiepileptic drugs, with a prevalence of 0.33 (95% CI=0.21-0.47; I²=86%, p<0.01) and, considering the study design, in the subgroup of cohort studies, with a prevalence of 0.52 (95% CI=0.40-0.64; I²=76%, p<0.01).

CONCLUSIONS

Taking into account the deleterious effects of vitamin D deficiency on the bone health of individuals using antiepileptic drugs, it is suggested to include in their care 25-hydroxyvitamin D monitoring, cholecalciferol supplementation, and treatment of the deficiency, when present.

Vitamin D Deficiency, Hypocalcemia, and Hearing Loss in Children

OBJECTIVE

Characterize relations between vitamin D deficiency (VDD), hypocalcemia, and hearing loss (HL) in children.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary referral hospital.

PATIENTS

Children in the Audiological and Genetic Database with a diagnosis of VDD, rickets, or osteomalacia.

INTERVENTION

None.

MAIN OUTCOME MEASURES

Prevalence, type, severity (4-tone pure-tone average, PTA), and progression of HL. HL was defined as greater than 15 dB HL at any threshold by pure tone, greater than 20 dB HL by sound field audiometry, or greater than 25 dB in infants less than 1 year of age.

RESULTS

Of 888 children with VDD, 474 (53.4%) had HL, with 17% having moderate-profound HL. Compared with an age-matched cohort of 13,320 children drawn from the same database, children with VDD were significantly more likely to have sensorineural HL (SNHL) (adjusted odds ratios [aOR] 1.26 [95% confidence interval [CI] 1.01-1.58]). Among children with VDD, children with femur fracture had a significantly higher rate of HL (81% versus 53%, p = 0.008) and children with hypocalcemia had a significantly higher rate of moderate-profound HL (36% versus 18%, p = 0.016). Additionally, hypocalcemia with and without VDD was associated with SNHL (aOR 2.30 [1.07-4.56]).

CONCLUSIONS

Both vitamin D deficiency and hypocalcemia were found to be independently associated with SNHL, a type of HL that is less likely to improve over time. Recognition of VDD and hypocalcemia as independent risk factors for the development of SNHL could allow for better evaluation and treatment of this patient population. Routine audiological evaluation should be considered in this population.

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.

Vitamin D status among patients with drug-resistant and non-drug-resistant epilepsy

Background & Aims: Epilepsy affects nearly 70 million people worldwide. Vitamin D deficiency may influence the balance of certain epilepsies. The purpose of this study was to determine the vitamin D status and anthropometric measurements of people with epilepsy (PWE), according to their pharmacosensitivity. Methods: Forty-six PWE, with or without drug resistance, underwent nutritional assessment after giving consent. Weight, body mass index (BMI), triceps skinfold thickness (TSF), fat mass (FM) and free fat mass (FFM) by bioelectrical impedance analysis were measured. Serum vitamin D was determined without supplementation. Deficiency was defined as a level < 30 ng/mL. Statistical analysis involved Student t test, ANOVA and Chi². Results: Patients were aged 44.5 ± 14.3 years, with 60.9% of drug-resistance. BMI was 28.7 ± 7.0, 2.2% were malnourished and 30.4% obese according to the BMI. The average vitamin D level was 15.3 ± 9.9 ng/mL, with 87.0% of deficiency, and 40.0% of severe deficiency (<10 ng/mL). The TSF was higher in drug-resistant cases (p = 0.03). There was no link between drug resistance and anthropometric measurements, FM, FFM or vitamin D concentration. Conclusions: Although limited in size, this study showed that PWE are more often obese. Vitamin D deficiency is more common than in the general population, with a much higher prevalence of severe deficiency.

Vitamin D Status of Epileptic Children in India: A Prospective Cross-Sectional Study from a Tertiary Care Centre

Vitamin D deficiency is prevalent all over the world, especially in tropical countries. In epileptics, antiepileptic drugs (AED) and associated comorbidities further impact vitamin D status. The aim of this study is to estimate the prevalence of 25(OH) vitamin D deficiency in epileptic children and evaluate probable risk factors. A cross-sectional study of 200 children between 1 and 18 years of age on AED was undertaken in the pediatric neurology clinic of a tertiary care center of Northern India. In all children, serum 25(OH) vitamin D levels, calcium, phosphorus, and alkaline phosphatase were estimated. The deficiency levels of vitamin D were categorized as: deficiency <20 ng/mL, insufficiency 20 to 30 ng/mL, and sufficiency >30 ng/mL. The potential risk factors for hypovitaminosis D, including type of epilepsy, AED regimen (specific medications, polytherapy vs. monotherapy), cerebral palsy, ambulatory status, intellectual disability, body mass index, gender, and vegetarianism were examined. Among the 200 enrolled children (60% boys), 106/200 (53%) were vitamin D deficient. There was no significant relation of vitamin D levels with gender, type of epilepsy, neurological deficit, and type of AED. An inverse relationship of higher phenytoin doses during monotherapy associated with lower vitamin D levels in monotherapy was found, thereby suggesting adverse effect of high doses of phenytoin on vitamin D levels. VDD is common among epileptic children on AED therapy. Vitamin D deficiency is common prevalent among epileptic children on AED therapy, and its detection and treatment correction should be an integral part of epilepsy management.

Bone Health Screening Practices Among Neurologists in Patients on Antiepileptic Drugs: A Quality Improvement Project

BACKGROUND

Pediatric patients with epilepsy are at risk for low vitamin D levels, increasing the risk for bone fractures, yet standardized bone health screening is not part of routine care.

METHODS

We surveyed pediatric neurologists (n = 68) at our center regarding screening practices, using an 11-item survey; constructed a bone health treatment algorithm; and developed a training intervention to improve screening rates.

RESULTS

The overall survey response rate was 47%. Among respondents, 64% estimated that they screened for bone health less than 25% of the time. Chart review before the intervention demonstrated an overall screening rate of 25.1% (n = 50/199). One year after implementation of a standardized algorithm, the overall screening rates increased to 53.8% (n = 100/186). The frequency of prescribing vitamin D for patients treated with antiepileptic medications increased among general neurologists (preintervention rate 16%, postintervention rate 51%, P < 0.01) as well as among epileptologists (preintervention rate 45%, postintervention rate 57%, P = 0.04).

CONCLUSION

In a relatively short follow-up period, there were significant changes in care patterns regarding screening for bone health in pediatric patients with epilepsy. Further implementation measures are underway to increase bone health screening and care in this population.

Vitamin D supplementation and bone markers in ambulatory children on long-term valproic acid therapy. A prospective interventional study

PURPOSE

Our aim was to investigate any adverse effects of long-term valproic acid (VPA) therapy on bone biochemical markers in ambulatory children and adolescents with epilepsy, and the possible benefits of vitamin D supplementation on the same markers.

METHODS

In this single center, the prospective interventional study levels of 25-hydroxyvitamin D (25OHD) and the bone turnover indices of Crosslaps (CTX), total alkaline phosphatase (tALP), osteoprotegerin (OPG), and the receptor activator for nuclear factor kB (RANK) ligand (sRANKL) were assessed before and after one year of vitamin D intake (400 IU/d) and were compared with those of clinically healthy controls. Fifty-four ambulatory children with mean (±standard deviation [SD]) age 9.0 ± 4.5 yrs on VPA (200-1200 mg/d) long-term monotherapy (mean: 3.2 ± 2.6 yrs) were studied, before and after a year's vitamin D intake (400 IU/d).

RESULTS

Nearly half of the cases were vitamin D insufficient/deficient with mean levels 23.1 ± 12.8 vs 31.8 ± 16.2 ng/mL of controls (p = 0.004) and after the year of vitamin D intake increased to 43.2 ± 21.7 ng/mL (p < 0.0001). In parallel, serum CTX and tALP had a decreasing trend approaching control levels but OPG and sRANKL did not change and were not different from controls. However, after vitamin D intake, a positive correlation was seen between 25OHD and OPG but not before.

CONCLUSIONS

The findings imply a higher bone turnover in the young patients on long-term VPA therapy that decreased after vitamin D intake.

Densidad mineral ósea e indicadores bioquímicos y hormonales en niños con parálisis cerebral cuadripléjica

Introduction: children with cerebral palsy (CP) have multiple risk factors for low bone mineral density or osteoporosis. Objective: to explore the association between bone mineral density (BMD) and biochemical and hormonal indicators of bone metabolism in children with quadriplegic cerebral palsy (CP). Methods: a cross-sectional analytical study included 59 participants from six to 18 years of age with quadriplegic CP. Serum concentrations of calcium, phosphorus, 25OHD metabolite, parathyroid hormone (PTH), alkaline phosphatase, and thyroid hormones were determined using standardized methods. The BMD measurement was obtained from the lumbar spine expressed in g/cm2 and Z-score. Unpaired Student's t-test, Chi-square test, odds ratio and Pearson's correlation were performed. Results: participants with CP and malnutrition had lower serum concentrations of calcium, phosphorus and alkaline phosphatase. Those who had low BMD showed lower serum concentrations of calcium, phosphorus and alkaline phosphatase. Most participants with low and normal BMD had vitamin D deficiency (27.1% and 10%) and insufficiency (35.4% and 30%), respectively. There was a significant correlation between BMD and serum concentrations of calcium, phosphorus, alkaline phosphatase, vitamin D and thyroid-stimulating hormone (TSH). There were no differences in the biochemical and hormonal indicators by level of gross motor function, use of anticonvulsants and oral versus enteral feeding method. Conclusion: malnutrition and alteration of vitamin D nutritional status were associated with low BMD and alterations of biochemical indicators of bone metabolism in pediatric patients with quadriplegic CP. The relationship between BMD and biochemical indicators of bone metabolism in children with quadriplegic CP was also demonstrated.

Vitamin D supplementation to prevent vitamin D deficiency for children with epilepsy: Randomized pragmatic trial protocol

BACKGROUND

Vitamin D deficiency is highly prevalent among children with epilepsy. Lack of high-quality evidence led to variability among scientific societies recommendations. Therefore, we aim to determine the efficacy of different common doses used in the pediatric practice to maintain optimal 25-hydroxy vitamin D (25 [OH] vitamin D) level in children with epilepsy and normal baseline 25 (OH) vitamin D level over 6 months of supplementation.

METHODS

This is a protocol for phase IV pragmatic randomized superiority controlled open-label trial at King Saud University Medical City in Riyadh. Children with epilepsy and receiving chronic antiepliptic medication and normal baseline 25 (OH) vitamin D level will be randomly assigned to receive Cholecalciferol 400 IU/day versus 1000 IU/day for 6 months. Our primary outcome is the proportion of children with vitamin D insufficiency (25 (OH) vitamin D level < 75nmol/L) at 6 months. Secondary outcomes include seizure treatment failure, seizure frequency, parathyroid hormone (PTH) levels, bone mineral density, and safety.

DISCUSSION

Our trial is set out to evaluate the efficacy of common different vitamin D maintenance doses on 25 (OH) vitamin D level, seizure control, and bone health for children with epilepsy. The results of our study will possibly help in shaping current vitamin D guidelines for vitamin D supplementation in children with epilepsy and provide a link between 25 (OH) vitamin D level and seizure control.

The Impact of Psychotropic Medications on Bone Health in Youth

PURPOSE OF REVIEW

Psychotropics are prescribed to youth at rapidly growing rates and may negatively impact bone health. Little awareness exists of this association among prescribing providers. Childhood and adolescence are critical times for bone development. Understanding these effects and their management is important to informed psychotropic use.

RECENT FINDINGS

Through a variety of mechanisms, antidepressants, benzodiazepines, mood stabilizers, neuroleptics, and stimulants may all negatively impact pediatric bone health. This confers added risk of osteoporosis in a population already at high risk for suboptimal bone health. Awareness of psychotropic-mediated effects on pediatric bone development is clinically relevant to the use and monitoring of these agents. Clinicians can manage these effects through informed consent, vitamin D supplementation, lifestyle modifications, and reducing polypharmacy. For mood stabilizers, vitamin D level monitoring and secondary prevention is indicated. Future longitudinal studies and development of monitoring guidelines regarding psychotropic impact on bone health are necessary.

Expression Analysis of Vitamin D Signaling Pathway Genes in Epileptic Patients

Vitamin D deficiency has been detected in epileptic patients. Vitamin D participates in neuroprotection, brain cell proliferation, and differentiation. Consequently, vitamin D supplementation has been suggested as an alternative treatment in epileptic patients. We aimed at assessment of vitamin D signaling pathway in epileptic patients. In the present study, we evaluated vitamin D serum concentration as well as expression of vitamin D receptor (VDR) gene and genes encoding for vitamin D activating enzyme 1-alpha-hydroxylase (CYP27B1) and deactivating enzyme 24-hyroxylase (CYP24A1) in epileptic patients compared with healthy individuals. We found significant lower levels of vitamin D in epileptic patients compared with healthy subjects. Expression analyses showed significant downregulation of VDR expression in peripheral blood of epileptic patients compared with healthy subjects (relative expression (REx) = 0.16, P < 0.001). However, there was no significant difference in CYP24A1 expression between epileptic patients and normal subjects. CYP27B1 expression analysis showed significant upregulation in male patients aged between 30 and 40 (REx = 5.43, P = 0.013). After using two-way ANCOVA for adjusting the effects of sex and age, there was a statistically significant difference in the VDR expression values between patient and control groups (P < 0.001). Spearman's correlation analysis showed no significant correlation between genes expression levels and patients' age or vitamin D serum concentrations. However, we found significant correlations between VDR expression levels and CYP24A1/ CYP27B1 expression levels in epileptic patients (r = 0.435 and P < 0.001; r = 0.26 and P = 0.02 respectively). There was also a significant correlation between the expression levels of CYP24A1 and CYP27B1 (r = 0.349 and P = 0.001). Our study shows a possible role for VDR in the pathogenesis of epilepsy.

Vitamin D status of children with cerebral palsy: Should vitamin D levels be checked in children with cerebral palsy?

OBJECTIVE:

We aimed to investigate the vitamin D status of children with cerebral palsy (CP).

METHODS:

A total of 274 children (111 females and 163 males), aged between 1 and 19 years with CP, who came to the Physical Medicine and Rehabilitation, Pediatric Rehabilitation Outpatient Clinic between October 2013 and March 2017, were included in our study. Demographics, data concerning the details of each child’s comorbidity, the Gross Motor Function Classification System (GMFCS), and Manual Ability Classification System (MACS) scores were recorded. The serum 25 hydroxy vitamin D [25(OH)D], calcium (Ca), phosphate (P), and parathormone (PTH) levels were also recorded.

RESULTS:

The mean age of children with CP was 7.59±6.09 years. The distribution by the CP type was 24.8% spastic unilateral, 59.8% spastic bilateral, 1.4% dyskinetic, 0.7% ataxic, 7.6% mixed, and 5.1% unclassified. The serum 25(OH)D levels of the 235 children with CP were measured. There were 79 children at the 25(OH)D level ≤12 ng/ml, regarded as vitamin D deficiency; 62 children at the 25(OH)D level 12-≤20 ng/ml, considered as vitamin D insufficiency, 43 children at the 25(OH)D level 20-≤30 ng/ml, considered as vitamin D sufficiency, and 15 children at the 25(OH)D level >30 ng/ml. A total of 36 children were already taking vitamin D supplements. There was a significant correlation between the 25(OH)D levels and GMFCS and MACS levels and associated impairments such as the epilepsy history, intellectual delay, teeth problems, and growth retardation (p<0.05).

CONCLUSION:

Our results revealed that the children with CP who are not ambulatory (GMFCS levels IV–V) and have associated impairments were prone to vitamin D deficiency, and thus should be checked for vitamin D.

Association of 25-Hydroxyvitamin D Deficiency in Pediatric Epileptic Patients

OBJECTIVE

Epilepsy is a chronic neurological disorder requiring long-term therapy using antiepileptic medications. Reports have incriminated long-term antiepileptic drugs use in deficiency of vitamin D and bone diseases in all age groups. We aimed to investigate the association between serum 25-hydroxyvitamin D levels and pediatric epilepsy in Indian patients.

MATERIALS & METHODS

We prospectively recruited 100 pediatric epilepsy patients, on monotherapy for minimum one-year duration, and 50 age and sex matched controls. This study was carried out at Yashoda Hospital, India from 2011-2014. All cases and controls underwent tests for serum 25-hydroxyvitamin D, alkaline phosphatase, serum calcium and phosphorus levels.

RESULTS

Patients with 25-hydroxyvitamin D deficiency were significantly higher among cases (45%) than controls (24%). Mean alkaline phosphatase was significantly higher in cases and mean serum calcium was significantly lower (8.3±1.5) in cases. Amongst antiepileptic drugs, carbamazepine and sodium valproate were significantly associated with 25-hydroxyvitamin D deficiency. Risk of vitamin D deficiency was highest with sodium valproate usage (odds:4.0;95%CI 1.4-11.6) followed by carbamazepine use (odds: 2.7; 95%CI 1.0-6.8). After adjustment using multiple logistic regression, antiepileptic drugs showed independent association with 25-hydroxyvitamin D deficiency (odds:2.2;95%CI 0.9-4.5).

CONCLUSION

25-hydroxyvitamin D deficiency was significantly associated with use of carbamazepine and sodium valproate in pediatric epilepsy.

Bone Mineral Status in Children with Epilepsy: Biochemical and Radiologic Markers

Objective:

The aim of this study is to assess bone mineral status in children with epilepsy, on different antiepileptic drugs (AEDs) regimen, using dual-energy X-ray absorptiometry (DXA) and routine biochemical bone markers.

Patients and Methods:

This is observational prospective controlled cohort study, conducted at Mansoura University Children Hospital, from January 2014 to June 2015. In this study, we had 152 participants with ages 3–13 years, 70 children diagnosed with epilepsy and 82 were controls. Children classified into two groups according to the duration of treatment, Group 1 children maintained on AEDs for 6–24 months, Group 2 children ≥24 months. Bone mineral density (BMD) measured by DXA and biochemical markers includes serum calcium, phosphorus, alkaline phosphatase (ALP), and parathyroid hormone (PTH).

Results:

In this study, we found that the serum level of calcium and phosphate were significantly low (P > 0.05) in total cases versus control. We found that the serum level of and ALP and PTH were significantly high (P > 0.05) in total cases versus control. Regarding the DXA markers, there was a significant decrease of BMD and Z-score for the total body and lumbar area in the total cases versus control (P > 0.05).

Conclusion:

The present study showed that all AEDs (new and old) affect bone mineral status in children receiving therapy for more than 6 months, altering both biochemical markers (serum calcium, phosphorus, ALP, and PTH) and radiologic markers (BMD assessed using DXA). Children on AEDs for a longer duration (≥2 years) showed more severe side effects on BMD. Children receiving multiple AEDs are more prone to altered bone mineral status, especially with long duration of therapy. The study also highlights the role of DXA as a safe noninvasive method to assess BMD in children on long-term AEDs.

Risk factors of vitamin D deficiency in children with epilepsy taking anticonvulsants at initial and during follow-up

PURPOSE

Vitamin D status was evaluated in children with epilepsy taking anticonvulsants to determine the prevalence and risk factors of vitamin D deficiency.

METHODS

This study was designed as both a cross-sectional and a retrospective cohort study. A sum of 198 children who were diagnosed with epilepsy at the Department of Pediatrics in Dankook University Hospital was included. Their serum vitamin D levels were reviewed based on clinical information, and analyzed using IBM SPSS ver. 20.0.

RESULTS

One hundred twenty-four children (62.6%) had vitamin D deficiency. Two risk factors were associated: winter to spring season (odds ratio [OR], 3.71; 95% confidence interval [CI], 1.835-7.492) and age more than 12 years (OR, 3.22; 95% CI, 1.377-7.542). Out of the 57 patients who were not vitamin D deficient at the time of initial assay, 47 patients (82.5%) became vitamin D deficient during followup. The change of serum 25-hydroxy vitamin D3 (25(OH)D) levels during follow up showed a weak negative correlation with the duration of medication (r=-0.283, P=0.033). Medication duration was longer and brain magnetic resonance imaging (MRI) abnormality, abnormal underlying conditions, and nonambulatory status were more frequently present in twenty-five patients (44%) who showed a decline of more than 15 ng/mL during follow-up (P<0.05).

CONCLUSION

Vitamin D deficiency is common in children with epilepsy taking anticonvulsants, especially in adolescents more than 12 years of age. This study emphasizes the regular monitoring of vitamin D level, especially in the presence of longer duration of medication, brain MRI abnormality, abnormal underlying conditions, and nonambulatory status.

Vitamin D supplementation in children with epilepsy and intellectual disability

BACKGROUND

Children with epilepsy and intellectual disability have an increased risk of vitamin D deficiency. In this patient group, it is neither clear which factors are associated with the level of 25-hydroxyvitamin D nor what the therapeutic results are when Dutch guidelines are followed.

METHODS

This retrospective study included 30 patients who, in October 2012, were residents of the children's wards of a tertiary epilepsy center in The Netherlands (Kempenhaeghe). From November 2012 onward they received cholecalciferol supplementation in doses that met or exceeded Dutch guidelines. At baseline, after 6, and 15 months, serum 25-hydroxyvitamin D concentration was measured.

RESULTS

At baseline, the vitamin D status in 11 (36.7%) residents was found to be deficient, in 10 (33.3%) to be insufficient and in 9 (30.0%) sufficient. Supplementation dose, diet, body mass index, intellectual disability, and mobility were significantly associated with baseline 25-hydroxyvitamin D concentrations. The mean 25-hydroxyvitamin D concentration increased significantly from 57.40 ± 22.00 nmol/L at baseline to 89.47 ± 26.77 nmol/L after 15 months (P < 0.001). In spite of supplementation ranging from 400 to 1200 IU/day, 64% of the residents in the deficient category and 30% of those with an insufficient level at baseline failed to attain a sufficient vitamin D status after 15 months.

CONCLUSIONS

Not all residents reached a sufficient vitamin D status after supplementation at least equal to the amount recommended by the Dutch guidelines. In a high-risk population, such as our residents, we advise monitoring 25-hydroxyvitamin D concentrations, adjusting supplementation accordingly and following patients to ensure they reach sufficiency.

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.

Adverse skeletal effects of drugs - beyond Glucocorticoids

Osteoporotic fractures are an important public health problem with significant individual and societal costs. In addition to the major risk factors for osteoporotic fracture, low bone mineral density (BMD), age, low body weight and history of fracture or falls, some drugs are now considered to be important secondary risk factor for bone loss and fracture, particularly amongst predisposed individuals. Currently available data are often generated from small observational clinical studies, making risk assessment and development of management guidelines difficult. In many cases, the exposed population has a low baseline risk for fracture and additional assessment and treatment may not be necessary. In this review, we focus on drugs other than glucocorticoids identified as potentially causing adverse skeletal effects, summarizing the existing evidence from preclinical and clinical studies, and suggest recommendations for patient management.

Ginsenoside-mediated blockade of 1α,25-dihydroxyvitamin D3 inactivation in human liver and intestine in vitro

The beneficial effects of vitamin D3 are exerted through 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3], the dihydroxy metabolite of vitamin D3. Hepatic and intestinal biotransformation of 1α,25(OH)2D3 and modifiers of metabolic capacity could be important determinants of bioavailability in serum and tissues. Ginsenosides and their aglycones, mainly 20(S)-protopanaxadiol (aPPD) and 20(S)-protopanaxatriol (aPPT), are routinely ingested as health supplements. The purpose of the present study was to investigate the potential of ginsenosides and their aglycones to block hepatic and intestinal inactivation of 1α,25(OH)2D3, which is the most potent ligand of vitamin D receptor. In vitro biotransformation reactions were initiated with NADPH regenerating solutions following initial preincubation of pooled human hepatic or intestinal microsomal protein or human recombinant CYP3A4 supersomes with 1α,25(OH)2D3 or midazolam. Formation of hydroxylated metabolites of 1α,25(OH)2D3 or midazolam was analyzed using liquid chromatography-mass spectrometry. Co-incubation of 1α,25(OH)2D3 with various ginsenosides (Rg1, Rh2, aPPD, aPPT and total ginsenosides) led to differential inhibition (30-100%) of its hydroxylation. Results suggest that aPPD, aPPT and Rh2 strongly attenuated the hydroxylation of 1α,25(OH)2D3. Follow up inhibition studies with aPPD and aPPT at varying concentrations (0.5-100μM) led to up to 91-100% inhibition of formation of hydroxylated metabolites of 1α,25(OH)2D3 thus preventing inactivation of active vitamin D3. The IC50 values of aPPD or aPPT for the most abundant hydroxylated metabolites of 1α,25(OH)2D3 ranged from 3.3 to 9.0μM in human microsomes. The inhibitory mechanism of aPPD or aPPT for CYP3A4-mediated biotransformation of 1α,25(OH)2D3 was competitive in nature (apparent Ki: 1.7-2.9μM). Similar inhibitory effects were also observed upon addition of aPPD or aPPT into midazolam hydroxylation assay. In summary, our results suggest that ginsenosides, specifically aPPD and aPPT, inhibit the CYP3A4-mediated catabolism of active vitamin D3 in human liver and intestine, potentially providing additional vitamin D-related benefits to patients with cancer, neurodegenerative and metabolic diseases.

Epilepsy treatment by sacrificing vitamin D

Epilepsy is one of the most common neurologic disorders in childhood that often requires long term treatment with antiepileptic drugs. Both antiepileptic treatment and the comorbidities associated with epilepsy have a negative impact on bone health in growing children. Given the fact that vitamin D deficiency is a major public health problem worldwide, clinicians caring for children with chronic diseases should be aware of effects of the medication on the bone metabolism. Yet, vitamin D deficiency due to antiepileptic treatment is an overlooked issue among neurologists. In this review, we briefly describe vitamin D metabolism and the effect of vitamin D in the brain. We also discuss the literature in terms of vitamin D deficiency and antiepileptic treatment in the pediatric population.

Prevalence of vitamin D insufficiency among healthy school-age Cree children

BACKGROUND

First Nations children are at higher risk for vitamin D deficiency and rickets.

OBJECTIVE

To assess the prevalence of vitamin D deficiency and the correlations between fat mass, parathyroid hormone and dietary habits with serum vitamin D level in a random sample of Cree children eight to 14 years of age.

METHODS

Serum 25-hydroxyvitamin D (25[OH]D) levels and additional information regarding anthropometrics and dietary habits were obtained from participants in two Cree communities. Vitamin D deficiency and insufficiency was defined as serum 25(OH)D levels <30 nmol/L and <50 nmol/L, respectively. Proportions to estimate the vitamin D status were weighted to account for the complex sampling design, and Pearson's correlation coefficients were used to estimate the associations of milk and fish intake, parathyroid hormone and fat mass with serum 25(OH)D levels.

RESULTS

Data from 52 healthy Cree children (mean [± SD] age 11.1±2.0 years; 27 boys) were included in the analyses. The median serum 25(OH)D level was 52.4 nmol/L (range 22.1 nmol/L to 102.7 nmol/L). Forty-three percent (95% CI 29% to 58%) and 81% (95% CI 70% to 92%) of Cree children had vitamin D levels <50 nmol/L and <75 nmol/L, respectively. Vitamin D intake was positively associated with serum 25(OH)D levels. Obese children had lower vitamin D levels; however, the difference was nonsignificant.

CONCLUSION

There may be a substantial proportion of Cree children who are vitamin D deficient. Increasing age, lower dietary vitamin D intake and, possibly, higher body mass index were associated with decreased vitamin D levels; however, causality cannot be inferred.

Vitamin D deficiency among children with epilepsy in South Queensland

This study evaluated prevalence and risk factors for vitamin D deficiency among children with epilepsy on long-term antiepileptic drugs treated in South Queensland, Australia. Children with epilepsy seen in a tertiary neurology clinic were contacted requesting bone health blood tests during winter of 2011. Vitamin D deficiency was defined as 25-hydroxy vitamin D levels <20 ng/mL, and insufficiency between 21 and 29 ng/mL. One hundred thirty letters were sent, with 111 (85%) subsequently having blood tests performed. Vitamin D deficiency was identified in 24 (22%) of 111 and an additional 45 (41%) of 111 had vitamin D insufficiency. Multiple logistic regression analysis identified children on >2 antiepileptic drugs or with underlying genetic etiologies were more likely to have vitamin D deficiency. High proportion of children on long-term antiepileptic drugs in Queensland risk vitamin D deficiency and insufficiency despite living in the subtropics. Vitamin D monitoring and supplementation is important in the management of children on long-term antiepileptic drugs requiring tertiary care in Queensland.

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 deficiency: a paediatric orthopaedic perspective

PURPOSE OF REVIEW

At the turn of the last century, rickets (vitamin D deficiency) was one of the most common musculoskeletal diseases of the paediatric population presenting to physicians. Today, the most common referral pathway for these patients ends in a paediatric orthopaedic outpatient clinic. Vitamin D deficiency is a clinical entity that can affect all children and should be looked for in all children with musculoskeletal symptoms.

RECENT FINDINGS

The child at risk of rickets is now white, breastfed, protected from the sun and obese. Vitamin D deficiency can present as atypical muscular pain, pathological fractures or slipped upper femoral epiphysis. Obesity is linked with lower vitamin D levels; however, in the paediatric population, this does not necessarily equal clinical disorder. Vitamin D supplements can be used to reduce the risk of pathological fractures in the cerebral palsy child. It should also form part of the differential diagnosis in the work-up of nonaccidental injuries. Children with a low vitamin D present with a higher incidence of fractures from normal activities. Vitamin D levels need to be assessed before any form of orthopaedic surgery, as it can affect growth, both in the diaphysis of the bone and in the growth plate.

SUMMARY

Vitamin D levels are a key element in the successful practice of paediatric orthopaedics. It is not just the possible cause of disorder presenting to the clinician but also extremely important in ensuring the successful postoperative recovery of the patient.

Long-term monitoring of the ketogenic diet: Do's and Don'ts

The ketogenic diet (KD) is an effective treatment for epilepsy and like other treatments it is not without side effects. The side effects encountered are related to the diet composition and the radical metabolic changes that results from a high fat, low carbohydrate and protein diet. Short-term side effects are well documented. Long-term side effects are not as well documented but since the last "international symposium on dietary therapies for epilepsy and other neurological disorders", there are now more prospective and longitudinal data. Monitoring practices and treatments will be discussed and compared to the International Ketogenic Diet Consensus Statement (IKDCS) from 2008.

Serum 25-hydroxyvitamin D is inversely associated with body mass index in cancer

Background

The association between vitamin D deficiency and obesity in healthy populations and different disease states remains unsettled with studies reporting conflicting findings. Moreover, current dietary recommendations for vitamin D do not take into account a person's body mass index (BMI). We investigated the relationship between serum 25-hydroxy-vitamin D [25(OH)D] and BMI in cancer.

Methods

A consecutive case series of 738 cancer patients. Serum 25(OH)D was measured at presentation to the hospital. The cohort was divided into 4 BMI groups (underweight: <18.5, normal weight: 18.5-24.9, overweight: 25-29.9, and obese: >30.0 kg/m²). Mean 25(OH)D was compared across the 4 BMI groups using ANOVA. Linear regression was used to quantify the relationship between BMI and 25(OH)D.

Results

303 were males and 435 females. Mean age at diagnosis was 55.6 years. The mean BMI was 27.9 kg/m² and mean serum 25(OH)D was 21.9 ng/ml. Most common cancers were lung (134), breast (131), colorectal (97), pancreas (86) and prostate (45). Obese patients had significantly lower serum 25(OH)D levels (17.9 ng/ml) as compared to normal weight (24.6 ng/ml) and overweight (22.8 ng/ml) patients; p < 0.001. After adjusting for age, every 1 kg/m² increase in BMI was significantly associated with 0.42 ng/ml decline in serum 25(OH)D levels.

Conclusions

Obese cancer patients (BMI >= 30 kg/m²) had significantly lower levels of serum 25(OH)D as compared to non-obese patients (BMI <30 kg/m²). BMI should be taken into account when assessing a patient's vitamin D status and more aggressive vitamin D supplementation should be considered in obese cancer patients.