Determinants of vitamin D levels in children, adolescents, and young adults with juvenile idiopathic arthritis

Nutritional Aspects of Juvenile Idiopathic Arthritis: An A to Z for Dietitians

Juvenile idiopathic arthritis (JIA) represents a chronic, autoimmune, rheumatic musculoskeletal disease with a diagnosis before 16 years of age. Chronic arthritis is a common manifestation in all JIA subtypes. The nature of JIA, in combination to its therapy often results in the development of nutrition-, gastrointestinal (GI)- or metabolic-related issues. The most-common therapy-related nutritional issues involve methotrexate (MTX) and glucocorticosteroids (GCC) adverse events. MTX is a folic acid antagonist, thus supplementation with folic acid in required for improving GI side effects and correcting low serum levels. On the other hand, long-term GCC administration is often associated with hyperglycemia, insulin resistance and growth delay. This relationship is further aggravated when more joints are affected and greater doses of GCC are being administered. Apart from stature, body mass index z-scores are also suboptimal in JIA. Other signs of malnutrition include decreased phase angle and muscle mass, especially among patients with polyarthritis JIA. Evidence also points to the existence of an inverse relationship between disease activity and overweight/obesity. Specific dietary patterns, including the anti-inflammatory diet, might confer improvements in selected JIA outcomes, but the level of available research is yet insufficient to draw safe conclusions. The majority of patients exhibit suboptimal vitamin D status; hence, supplementation is recommended. Collectively, the evidence indicates that, due to the age of onset and the complexity of the disease, along with its pharmacotherapy, children with JIA are prone to the development of several nutritional problems, warranting expert monitoring. Vitamin deficiencies, oral and GI-problems limiting dietary intake, faltering growth, overweight and obesity, physical inactivity, or impaired bone health are among the many nutritional issues in JIA requiring dietitian support.

Bone Mineral Density and Serum 25OHD in Children and Adolescents With Juvenile Idiopathic Arthritis

Low bone mass is one of the complications of juvenile idiopathic arthritis (JIA). However, a study focusing on the low bone mass in children and adolescents with JIA in Southeast Asian countries is limited. This study aimed to evaluate the bone mineral density (BMD) of Thai patients with JIA and identify factors correlated with BMD. A cross-sectional study was conducted at a tertiary-care center. The BMD of the lumbar spines (BMDLS) and the total body (BMDTB) were measured by dual-energy X-ray absorptiometry. Thirty-eight patients were enrolled between July 2015 and January 2016. No patient had low BMDLS, and only 2 (5.3%) had low BMDTB. Serum 25-hydroxyvitamin D (25OHD) levels were significantly positively correlated with the BMDTB Z-score (coefficient: 0.047; 95% confidence interval = 0.011-0.082; P = .012). Our study demonstrated a very low prevalence of low bone mass. Optimization of the serum 25OHD level should be encouraged.

Vitamin D, oral health, and disease characteristics in juvenile idiopathic arthritis: a multicenter cross-sectional study

Background

Vitamin D deficiency has been associated with autoimmune diseases and oral health. Knowledge about the association between vitamin D status and oral conditions in JIA is limited. We aimed to investigate vitamin D status in a cohort of Norwegian children and adolescents with JIA and possible associations between serum vitamin D levels, clinical indicators of oral health, and JIA disease characteristics.

Methods

This multi-center, cross-sectional study, included individuals with JIA aged 4–16 years from three geographically spread regions in Norway. Demographic data, age at disease onset, disease duration, JIA category, disease status, medication, and vitamin D intake were registered. One blood sample per individual was analyzed for 25(OH) vitamin D, and the level of insufficiency was defined as < 50 nmol/L. A clinical oral examination was performed applying commonly used indices in epidemiological studies of dental caries, dental erosion, enamel defects, gingival bleeding, and oral hygiene. Serum vitamin D was used as exposure variable in multivariable regression analyses to estimate the associations between insufficient vitamin D level, JIA disease status, and oral conditions, with adjustments for age, sex, geographical region, BMI, seasonal blood sampling, and parental education.

Results

Among the 223 participants with JIA, 97.3% were Caucasians, 59.2% were girls, and median age was 12.6 years. Median disease duration was 4.6 years, and 44.4% had oligoarticular JIA. Mean serum vitamin D level was 61.4 nmol/L and 29.6% had insufficient levels. Vitamin D levels did not differ between sexes, but between regions, iso-BMI categories, age groups, and seasons for blood sampling. Insufficient vitamin D levels were associated with dentin caries (adjusted OR 2.89, 95% CI 1.43–5.86) and gingival bleeding (adjusted OR 2.36, 95% CI 1.10–5.01). No associations were found with active JIA disease or more severe disease characteristics.

Conclusion

In our study, nearly 30% had vitamin D insufficiency, with a particularly high prevalence among adolescents. Vitamin D insufficiency was associated with dentin caries and gingival bleeding, but not with JIA disease activity. These results point to the need for a multidisciplinary approach in the follow-up of children with JIA, including an increased focus on vitamin D status and oral health.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02349-1.

Prevalence of Vitamin D Deficiency in Patients Treated for Juvenile Idiopathic Arthritis and Potential Role of Methotrexate: A Preliminary Study

Background: Vitamin D deficiency is reported in rheumatological diseases in adults. The aim was to evaluate the prevalence of vitamin D deficiency in children with juvenile idiopathic arthritis (JIA) and to investigate potential correlations between vitamin D status and clinical factors, laboratory traits, and medical treatment, including methotrexate (MTX) and glucocorticoids (GCs). Methods: In 189 patients aged 3−17.7 years, with JIA in the stable stage of the disease, anthropometry, clinical status, serum 25-hydroxyvitamin D [25(OH)D], calcium (Ca), phosphate (PO4), total alkaline phosphatase (ALP), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) were assessed. Results: Median 25(OH)D level was 15.00 ng/mL, interquartile range (IQR) 12.00 ng/mL. Vitamin D deficiency was found in 67.2% and was independent of sex, disease manifestation, and CRP, ESR, ALP, or PO4 levels. Higher doses of MTX corresponded with lower 25(OH)D levels using both univariate and multivariate models (p < 0.05). No such trend was found for GCs treatment. Serum Ca was lower in patients treated with GCs (p = 0.004), MTX (p = 0.03), and combined GCs/MTX (p = 0.034). Conclusions: JIA patients are vitamin D depleted independently of disease activity or inflammatory markers. MTX therapy may be an iatrogenic factor leading to inadequate 25(OH)D levels. Vitamin D supplementation should be considered in all children with JIA, particularly those receiving long-term MTX therapy.

Vitamin D Supplementation in Patients with Juvenile Idiopathic Arthritis

Vitamin D has been implicated in the pathogenesis of skeletal disorders and various autoimmune disorders. Vitamin D can be consumed from the diet or synthesized in the skin upon ultraviolet exposure and hydroxylation in the liver and kidneys. In its bioactive form, vitamin D exerts a potent immunomodulatory effect and is important for bone health. Juvenile idiopathic arthritis (JIA) is a collection of inflammatory joint diseases in children that share the manifestation of inflamed synovium, which can result in growth arrest, articular deformity, bone density loss, and disability. To evaluate the potential effect of vitamin D on JIA disease manifestations and outcomes, we review the role of vitamin D in bone metabolism, discuss the mechanism of vitamin D in modulating the innate and adaptive immune systems, evaluate the clinical significance of vitamin D in patients with JIA, and summarize the supplementation studies.

Vitamin D Status Among Children With Juvenile Idiopathic Arthritis: A Multicenter Prospective, Non-randomized, Comparative Study

BACKGROUND

Juvenile idiopathic arthritis (JIA) is a chronic autoimmune disease characterized by destructive and inflammatory damage to the joints. The aim in this study was to compare vitamin D levels between children and adolescents, 1-18 years of age, with juvenile idiopathic arthritis (JIA) and a health control group of peers. We considered effects of endogenous, exogenous, and genetic factors on measured differences in vitamin D levels among children with JIA.

METHODS

Our findings are based on a study sample of 150 patients with various variants of JIA and 277 healthy children. The blood level of vitamin D was assessed by calcidiol level. The following factors were included in our analysis: age and sex; level of insolation in three regions of country (center, south, north); assessment of dietary intake of vitamin D; effect of prophylactic doses of cholecalciferol; a relationship between the TaqI, FokI, and BsmI polymorphisms of the VDR gene and serum 25(OH)D concentration.

RESULTS

We identified a high frequency of low vitamin D among children with JIA, prevalence of 66%, with the medial level of vitamin D being within the range of "insufficient" vitamin D. We also show that the dietary intake of vitamin D by children with JIA is well below expected norms, and that prophylactic doses of vitamin D supplementation (cholecalciferol) at a dose of 500-1,000 IU/day and 1,500-2,000 IU/day do not meet the vitamin D needs of children with JIA. Of importance, we show that vitamin D levels among children with JIA are not affected by clinical therapies to manage the disease nor by the present of VDR genetic variants.

CONCLUSION

Prophylactic administration of cholecalciferol and season of year play a determining role in the development of vitamin D deficiency and insufficiency.

Evaluation of vitamin D profile in juvenile idiopathic arthritis

OBJECTIVE

To observe the association between serum vitamin D level and disease activity in juvenile idiopathic arthritis (JIA).

METHODS

The observational study was conducted at a tertiary care hospital during 2017-2019. Patients suffered from JIA were recruited through purposive sampling which was stratified by the disease activity based on the Juvenile Arthritis Disease Activity Score 27 (JADAS27) criteria. Serum vitamin D was estimated alongside other laboratory parameters. The numerical and categorical variables were analysed with appropriate statistical tests.

RESULTS

40 subjects were studied where inactive disease was observed in nine subjects (22.5%), five subjects (12.5%) were found to be in low disease activity and moderate disease activity groups each, and twenty-one subjects (52.5%) had high disease activity. Considering the total sample size of the study, the mean (SD) JADAS27 score and serum vitamin D level were observed to be 12.02 (11.31) and 23.10 (5.93) respectively. A negative correlation was found between the JADAS27 score and serum vitamin D (r= -0.67). The corrected Chi-square test had revealed significant association between the status of serum vitamin-D and disease activity groups (=16.28; p < .001).

CONCLUSIONS

In JIA, higher grade of disease activity was found to be significantly associated with lower serum vitamin D.

Higher concentrations of vitamin D in Canadian children with juvenile idiopathic arthritis compared to healthy controls are associated with more frequent use of vitamin D supplements and season of birth

A number of studies have demonstrated that patients with autoimmune disease have lower levels of vitamin D prompting speculation that vitamin D might suppress inflammation and immune responses in children with juvenile idiopathic arthritis (JIA).  The objective of this study was to compare vitamin D levels in children with JIA at disease onset with healthy children. We hypothesized that children and adolescents with JIA have lower vitamin D levels than healthy children and adolescents. Data from a Canadian cohort of children with new-onset JIA (n= 164, data collection 2007-2012) were compared to Canadian Health Measures Survey (CHMS) data (n=4027, data collection 2007-2011). We compared 25-hydroxy vitamin D (25(OH)D) concentrations with measures of inflammation, vitamin D supplement use, milk intake, and season of birth. Mean 25(OH)D level was significantly higher in patients with JIA (79 ± 3.1 nmol/L) than in healthy controls (68 ± 1.8 nmol/L P <.05). Patients with JIA more often used vitamin D containing supplements (50% vs. 7%; P <.05). The prevalence of 25(OH)D deficiency (<30 nmol/L) was 6% for both groups. Children with JIA with 25(OH)D deficiency or insufficiency (<50 nmol/L) had higher C-reactive protein levels. Children with JIA were more often born in the fall and winter compared to healthy children. In contrast to earlier studies, we found vitamin D levels in Canadian children with JIA were higher compared to healthy children and associated with more frequent use of vitamin D supplements. Among children with JIA, low vitamin D levels were associated with indicators of greater inflammation.

Exploring the Evidence for an Immunomodulatory Role of Vitamin D in Juvenile and Adult Rheumatic Disease

Vitamin D is synthesized in the skin following exposure to UVB radiation or is directly absorbed from the diet. Following hydroxylation in the liver and kidneys, vitamin D becomes its bioactive form, 1,25(OH)₂D, which has been described to have potent immunomodulatory capacity. This review will focus on the effect of vitamin D in modulating the dysregulated immune system of autoimmune rheumatic diseases (ARD) patients across age, in particular in arthritis (rheumatoid arthritis and juvenile idiopathic arthritis), and systemic lupus erythematosus (with adult and juvenile onset). As well as delineating the impact of vitamin D on the innate and adaptive immune functions associated with each disease pathology, this review will also summarize and evaluate studies that link vitamin D status with disease prevalence, and supplementation studies that examine the potential benefits of vitamin D on disease outcomes. Exploring this evidence reveals that better designed randomized controlled studies are required to clarify the impact of vitamin D supplementation on ARD outcomes and general health. Considering the accessibility and affordability of vitamin D as a therapeutic option, there is a major unmet need for evidence-based treatment recommendations for the use of vitamin D in this patient population.

Study of vitamin D status and vitamin D receptor polymorphisms in a cohort of Italian patients with juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is the most common chronic arthritis of children and adolescents. Autoimmune mechanisms are suspected to have a central role in its development. Vitamin D is an immuno-modulator in a variety of conditions, including autoimmune diseases. Low levels of vitamin D have commonly been found in JIA patients, but the influence of this hormone insufficiency in JIA pathogenesis is still unclear. Vitamin D receptor (VDR) mediates a great majority of vitamin D biological activities; specific polymorphisms of the VDR gene have been associated with different biologic responses to vitamin D. In this study, we analysed clinical characteristics of a cohort of 103 Italian JIA patients. The distribution of VDR polymorphisms in affected patients versus healthy controls was evaluated, as well as if and how these polymorphic variants associate with different disease presentations (active disease vs non-active disease), different JIA subtypes, serum levels of 25-hydroxy-vitamin D and parathyroid hormone (PTH), and lumbar spine Z-score values (osteopenia vs normal bone mineral density). A great majority of our JIA patients (84.5%) showed a suboptimal vitamin D status, in many cases (84.1%) not solved by vitamin D supplementation. Vitamin D status resulted to be independent of VDR genotypes. ApaI genotypes showed a highly significant different distribution between JIA patients and unaffected controls, with both the TT genotype and the T allele significantly more frequent in patient group.

Adjunctive vitamin D for the treatment of active juvenile idiopathic arthritis: An open-label, prospective, randomized controlled trial

Vitamin D has an important immunomodulatory effect, but no trial has examined the effect of boosting serum levels of 25-hydroxyvitamin D (25OHD) in individuals with juvenile idiopathic arthritis (JIA). The aim of the present study was to assess whether vitamin D supplementation reduced disease activity and adjusted/maintained bone mass in patients with active JIA. A 24-week randomized trial was undertaken at Children's Hospital of Chongqing Medical University. Treatment-naive patients with JIA were randomly assigned (1:1) to one of two groups: Standard treatment with high dose oral cholecalciferol [2,000 IU per day; experimental group (EG)] or without supplementation [control group (CG)]. The primary outcomes were the 27-joint Juvenile Arthritis Disease Activity Score (JADAS-27 score), the Z-score for bone mineral density (BMD), and serum levels of 25OHD. A per-protocol analysis set approach was used. The Mann-Whitney U test was the main tool used for data analysis. A total of 42 participants were assigned randomly to the EG (n=20) or the CG (n=22); of these, 36 (n=18 and n=18, respectively) were included in per-protocol analysis. After 24 weeks, the mean level of 25OHD in the EG was higher than that in the CG (P<0.05). At the end of the intervention, there were no clear differences between the two groups in terms of BMD or JADAS-27 score (both P>0.05). Cholecalciferol supplementation (2000 IU/day) for 24 weeks raised serum levels of 25OHD in JIA patients but did not reduce disease activity or improve BMD (registration no. ChiCTR-INR-16009235; Date of Registration: 2016-10-12).

Vitamin D deficiency is associated with higher disease activity and the risk for uveitis in juvenile idiopathic arthritis - data from a German inception cohort

Objective

The objective was to evaluate the 25(OH) vitamin D (25(OH)D) status of patients with juvenile idiopathic arthritis (JIA) and determine whether the 25(OH)D level is associated with disease activity and the course of JIA.

Methods

Patients ≤ 16 years of age with recently diagnosed JIA (< 12 months) were enrolled in the inception cohort of patients with newly diagnosed JIA (ICON), an ongoing prospective observational, controlled multicenter study started in 2010. Clinical and laboratory parameters were ascertained quarterly during the first year and half-yearly thereafter.

Of the 954 enrolled patients, 360 patients with two blood samples taken during the first 2 years after inclusion and with follow up of 3 years were selected. The serum 25(OH)D levels were determined and compared with those of subjects from the general population after matching for age, sex, migration status and the month of blood-drawing.

Results

Nearly half of the patients had a deficient 25(OH)D level (< 20 ng/ml) in the first serum sample and a quarter had a deficient level in both samples. Disease activity and the risk of developing JIA-associated uveitis were inversely correlated with the 25(OH)D level (β = − 0.20, 95% CI − 0.37; 0.03, hazard ratio 0.95, 95% CI 0.91; 0.99, respectively).

Conclusion

In this study, 25(OH)D deficiency was common and associated with higher disease activity and risk of developing JIA-associated uveitis. Further studies are needed to substantiate these results and determine whether correcting 25(OH)D deficiency is beneficial in JIA.

Vitamin D and juvenile idiopathic arthritis

BACKGROUND

Vitamin D has been implicated in the pathogenesis of autoimmune diseases. While the roles of vitamin D in other autoimmune diseases have been investigated, less is known about the role of vitamin D in chronic childhood arthritis.

MAIN BODY

This review summarizes and evaluates evidence relating to 25-hydroxyvitamin D (25(OH)D) and chronic childhood arthritis. A scoping literature review was conducted using Ovid Medline, Ovid Embase, Cumulative Index to Nursing and Allied Health Literature, Web of Science and Scopus. Further, we geo-mapped the results of the studies to identify the patterns of the association between vitamin D and chronic childhood arthritis across the globe. Of 38 studies reporting 25(OH)D concentrations in childhood chronic arthritis, 32 (84.2%) reported that a significant number of children had suboptimal (< 75 nmol/L) status.

CONCLUSION

The data indicate suboptimal vitamin D status in children with chronic arthritis. Further, the association between low vitamin D and increased arthritis activity follow a north-south geographical gradient.

Vitamin D deficiency in childhood: old lessons and current challenges

Hypovitaminosis D in childhood is a re-emerging public health problem in developed countries. New life style habits, current "epidemics" of obesity in children and adolescents worldwide, and other preventable risk factors may play a role in favoring the occurrence of vitamin D deficiency. In addition to skeletal consequences, hypovitaminosis D has been found to be involved in the development of serious health extra-skeletal problems in childhood, including atopy and autoimmunity. The increasing concerns about the global health impact of vitamin D deficiency make further research necessary to fill the gaps of knowledge in this field, and particularly to establish universally accepted "normal" serum 25(OH)D levels in the pediatric population, and to improve strategies for the screening, prevention and treatment of hypovitaminosis D. This review discusses the key points of hypovitaminosis D in childhood in the light of new knowledge, and highlights the limitations of current strategies to control this condition.

Bone histomorphometric changes in children with rheumatic disorders on chronic glucocorticoids

BACKGROUND

Rheumatic diseases are associated with an increased fracture risk. The tissue level characteristics of the bone involvement in children have not been well elucidated. Our objectives were to describe the bone micro-architectural characteristics in children with rheumatic diseases on chronic glucocorticoids, and to determine associations between micro-architectural findings with clinical and radiological variables.

METHODS

Children on chronic glucocorticoids for an underlying rheumatic disease were referred for evaluation of bone fragility given the presence of vertebral compression fractures. A trans-iliac bone biopsy was performed as part of the clinical assessment. Histomorphometric analysis and quantitative backscattered electron imaging (qBSE) of the biopsy samples were undertaken.

RESULTS

Data of 15 children (14.0 ± 3.2 years) with a duration of glucocorticoid exposure of 6.2 ± 4.1 years and average prednisone dose of 14.1 ± 6.2 mg/m²/day were assessed. Histomorphometric analyses demonstrated significant decrease in trabecular thickness (p = 0.01), osteoid thickness (p < 0.01), osteoblast surface (p = 0.02) and increase in trabecular separation (p = 0.04) compared to published age-matched normative data. Severity of the trabecular deficit was correlated to glucocorticoid dose, height and body mass index Z score, but not bone mineral density or measures of disease activity. Using qBSE to measure bone mineralization, the subjects were shown to have a heterogeneous and hypermineralized profile, with higher cumulative glucocorticoid dose being associated with greater mineralization (p < 0.01).

CONCLUSIONS

In children with rheumatic diseases presenting with vertebral fractures, there is evidence of abnormal bone matrix mineralization and impairments of bone micro-architecture that correlate to glucocorticoid dose.

Comparison of the Vitamin D Status of Children Younger and Older Than 2 Years in Tehran: Are Supplements Really Necessary?

BACKGROUND

Vitamin D is a vital lipid-soluble vitamin in the body, helping the growth and development of bones. Vitamin D deficiency in children has several adverse effects. The most important preventative factor is determining the deficiency at an early stage and prescribing vitamin D-containing supplements.

OBJECTIVES

To investigate the vitamin D status of children younger and older than 2 years and determine the utility of prescribing vitamin D supplements.

PATIENTS AND METHODS

Three hundred healthy children who attended the pediatric clinic for routine assessments were enrolled in this study. Their parents were asked to complete a questionnaire, which included questions about demographics, nutrition, and supplements. Blood levels of vitamin D, calcium, and phosphorus were then measured.

RESULTS

The final study consisted of 286 children, 140 males and 146 females, with a mean age of 4.46 ± 2.82 yr. Of these, 218 (76.22%) children, with a mean age of 5.09 ± 2.82 yr, had vitamin D deficiency, and 76 children (23.78%), with a mean age of 2.58 ± 1.88 yr, had normal vitamin D levels (P = 0.001). The mean level of vitamin D was 29.71 ± 14.42 ng/mL in 88 (30.8%) patients up to 2 years and 17.11 ± 14.02 ng/mL in 198 (69.2%) patients older than 2 years (P = 0.0001).

CONCLUSIONS

The vitamin D levels of children aged more than 2 years are lower than those of children aged less than 2 years. Thus, prescribing vitamin D-containing supplements in children older than 2 years may be beneficial.

Vitamin D—update for the pediatric rheumatologists

Vitamin D, upon its discovery one century ago, was classified as a vitamin. This classification still greatly affects our perception about its biological role. 1,25(OH)2D (now known as the D hormone) is a pleiotropic steroid hormone that has multiple biologic effects. It is integral to the regulation of calcium homeostasis and bone turnover as well as having anti-proliferative, pro-differentiation, anti-bacterial, immunomodulatory and anti-inflammatory properties within the body in various cells and tissues. Vitamin D (cholecalciferol) should be considered a nutritional substrate that must be ingested or synthesized in sufficient amounts for the further synthesis of the very important regulatory steroid hormone (D hormone), especially in patients with pediatric rheumatic diseases (PRD). Vitamin D insufficiency or deficiency was shown to be pandemic and associated with numerous chronic inflammatory and malignant diseases and even with increased risk of mortality. Several studies have demonstrated that a high percentage of children with pediatric rheumatic diseases (PRD-e.g., JIA, jSLE) have a vitamin D deficiency or insufficiency which might correlate with disease outcome and flares. Glucocorticoids used to treat disease may have a regulatory effect on vitamin D metabolism which can additionally aggravate bone turnover in PRD. An effort to define the optimal serum 25(OH)D concentrations for healthy children and adults was launched in 2010 but as of now there are no guidelines about supplementation in PRD. In this review we have tried to summarize the strong evidence now suggesting that as the knowledge of the optimal approach to diagnosis and treatment PRD has evolved, there is also an emerging need for vitamin D supplementation as an adjunct to regular disease treatment. So in accordance with new vitamin D recommendations, we recommend that a child with rheumatic disease, especially if treated with steroids, needs at least 2-3 time higher doses of vitamin D than the dose recommended for age (approximately 2000 UI/day). Vitamin D supplementation has become an appealing and important adjunct treatment option in PRD.

Vitamin D levels in juvenile idiopathic arthritis from an equatorial region

We aimed to describe the serum levels of 25-hydroxyvitamin D (25OHD) in juvenile idiopathic arthritis (JIA) patients living in a low-latitude (3°43'S) region. Fifty JIA patients, 31 (62 %) female, seen between May 2012 and April 2013 in the northeast of Brazil had clinical data and serum collected for determination of 25OHD and parathyroid hormone (PTH) using a chemiluminescent ELISA; 20 age- and sex-matched controls were used for comparison. Mean age was 13.4 ± 4 years. Twenty-five (50 %), 15 (30 %), 4 (8 %), 4 (8 %), and 2 (4 %) patients were of the polyarticular, oligoarticular, systemic, enthesitis-related, and undifferentiated categories, respectively. Mean 25OHD was 31.6 ± 10 and 30.4 ± 5.7 ng/mL in patients and controls (P > 0.05), respectively; PTH was normal in JIA and controls; 25OHD was similar regardless of JIA category, disease activity, or severity measured by JADAS-27, CHAQ, or presence of joint deformities. Twenty-six (52 %), 20 (40 %), and 4 (8 %) patients were considered to have optimal, sufficient, and deficient 25OHD levels, respectively, whereas 11 (52 %) and 10 (48 %) controls had optimal and sufficient 25OHD. Ethnicity, body mass index, seasonal variation, and use of steroids did not influence 25OHD levels. This is the first study on 25OHD levels in JIA patients living in a low-latitude region, showing the lowest prevalence of vitamin D deficiency ever reported. Serum 25OHD was similar in JIA and controls and did not vary regardless of JIA category or severity.

Determinants of vitamin d levels in children and adolescents with down syndrome

Background. Poor studies have evaluated 25-hydroxycholecalciferol (25(OH)D) levels in Down syndrome (DS). Objective. To assess in DS subjects serum 25(OH)D value, to identify risk factors for vitamin D deficiency, and to evaluate whether a normal 25(OH)D value can be restored with a 400 I.U. daily supplement of cholecalciferol in respect to controls. Methods. We have longitudinally evaluated 31 DS patients (aged 4.5-18.9 years old) and 99 age- and sex-matched healthy controls. In these subjects, we analysed calcium, phosphate, parathyroid hormone (PTH), 25(OH)D concentrations, and calcium and 25(OH)D dietary intakes, and we quantified outdoor exposure. After 12.3 months (range 8.1-14.7 months) of 25(OH)D supplementation, we reevaluated these subjects. Results. DS subjects showed reduced 25(OH)D levels compared to controls (P < 0.0001), in particular DS subjects with obesity (P < 0.05) and autoimmune diseases history (P < 0.005). PTH levels were significantly higher in DS subjects than controls (P < 0.0001). After cholecalciferol supplementation, 25(OH)D levels were significantly ameliorated (P < 0.05), even if reduced compared to controls (P < 0.0001), in particular in DS subjects with obesity (P < 0.05) and autoimmune diseases (P < 0.001). Conclusions. Hypovitaminosis D is very frequent in DS subjects, in particular in presence of obesity and autoimmune diseases. In these subjects, there could be a need for higher cholecalciferol supplementation.

Determinants of Vitamin D Levels in Italian Children and Adolescents: A Longitudinal Evaluation of Cholecalciferol Supplementation versus the Improvement of Factors Influencing 25(OH)D Status

Objective. This paper aims to assess 25(OH)D levels in Italian children and adolescents identifying risk factors for 25(OH)D deficiency and to evaluate whether a normal 25(OH)D value can be restored in 25(OH)D-deficient patients. Methods. We evaluated 25(OH)D levels in 679 Italian children and adolescents (≤10, 11-20, 21-30, and >30 ng/mL were defined as severe deficiency, deficiency, insufficiency, and sufficiency, resp.). Of these, 365 25(OH)D-deficient were followed up for 1 year; 205 were treated with cholecalciferol (Arm A: 400 I.U.) and 160 by improving the environmental variables influencing 25(OH)D levels (Arm B). Results. At cross-sectional evaluation, 11.3% showed sufficiency, 30.0% insufficiency, and 58.7% 25(OH)D deficiency. Mean 25(OH)D was 19.08 ± 8.44 ng/mL. At the enrollment time (T 0), no difference was found between Arms A and B with respect to distribution and 25(OH)D levels. At end time (T 1) 26.0% (29.7% in Arm A versus 20.6% in Arm B) showed sufficiency, 38.4% (42.0% versus 34.4%) insufficiency, and 35.6% (28.3% versus 45.0%) 25(OH)D deficiency. Mean 25(OH)D level was 23.71 ± 6.83 ng/mL. Conclusions. Neither changes of lifestyle nor 400 I.U. cholecalciferol supplementation alone appears to be sufficient to restore adequate 25(OH)D levels.