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Background: High body mass index (BMI) is a risk factor for vitamin D deficiency. The rise in serum 25-hydroxyvitamin D [25(OH)D] concentrations following cholecalciferol supplementation is suboptimal, owing to adipose tissue sequestration and/or volumetric dilution. Calcifediol is a proven potent oral alternative for vitamin D supplementation, but whether BMI adversely affects its efficacy in raising 25(OH)D concentrations, is not well known. Material and Methods: Adults with serum concentrations of 25(OH)D < 30 ng/mL were recruited and stratified as normal, overweight, or obese using WHO criteria. Baseline evaluation included 25(OH)D, parathyroid hormone (PTH), and total 1,25-dihydroxyvitamin D [1,25(OH)2D] based on BMI category (n = 883). A subset of participants was supplemented with 50 µg calcifediol (n = 193) and assessed for the rise in serum concentrations of 25(OH)D at 3- and 6-months following supplementation. Results: Participants were stratified as obese (11.2%), overweight (32.1%), or normal weight (56.7%). There were no significant baseline differences in serum concentrations of 25(OH)D among the groups (13.1 ± 6.4 vs 12.8 ± 6.8 vs 11.6 ± 6.6 ng/mL, p = 0.62). Similarly, PTH or 1,25(OH)2D concentrations were not different among the groups. On follow-up, 25(OH)D concentrations increased in all three groups at 3 and 6 months from baseline. The increase in 25(OH)D was 74.4 ng/mL (IQR 35.3–115.3) in obese, followed by overweight 62.2 ng/mL (18.1–98.7) and normal weight groups 47.1 ng/mL (17.5–89.7) at 3 months. 1,25(OH)2D also increased in all groups, without any significant intergroup differences (p > 0.05). Conclusion: BMI does not impede the rise in 25(OH)D concentrations following supplementation with calcifediol in young adults with vitamin D deficiency.

Background:Early secondary hyperparathyroidism (SHPT) diagnosis and treatment are crucial to delay the progression of SHPT and related complications, in particular, cardiovascular events and bone fractures. Extended-release calcifediol (ERC) has been developed for the treatment of SHPT in patients with stage 3/4 chronic kidney disease (CKD) and vitamin D insufficiency (VDI). Summary:This review compares baseline characteristics and treatment responses of SHPT patients receiving ERC in phase 3 studies with those treated with ERC in a real-world study. Mean ± standard deviation baseline parathyroid hormone (PTH) levels were 147 ± 56 pg/mL and 148 ± 64 pg/mL in the phase 3 ERC cohorts, and 181 ± 98 pg/mL in the real-world study. Other baseline laboratory parameters were consistent between the clinical and real-world studies. ERC treatment increased 25-hydroxyvitamin D (25(OH)D) and significantly reduced PTH levels, regardless of baseline CKD stage, in all studies. In the pooled phase 3 per-protocol populations, 74% of the ERC cohort were uptitrated to 60 μg/day after 12 weeks at 30 μg/day, 97% attained 25(OH)D levels ≥30 ng/mL, and 40% achieved ≥30% PTH reduction. Despite a much lower rate of uptitration in the real-world study, 70% of patients achieved 25(OH)D levels ≥30 ng/mL, and 40% had a ≥30% reduction in PTH. Key Messages:These data establish a “continuum” of clinical and real-world evidence of ERC effectiveness for treating SHPT, irrespective of CKD stage, baseline PTH levels, and ERC dose. This evidence supports early treatment initiation with ERC, following diagnosis of SHPT, VDI, and stage 3 CKD, to delay SHPT progression.

Vitamin D plays a critical role in many physiological functions, including calcium metabolism and musculoskeletal health. This commentary aims to explore the intricate relationships among skin complexion, race, and 25-hydroxyvitamin D (25[OH]D) levels, focusing on challenges the Endocrine Society encountered during clinical practice guideline development. Given that increased melanin content reduces 25(OH)D production in the skin in response to UV light, the guideline development panel addressed the potential role for 25(OH)D screening in individuals with dark skin complexion. The panel discovered that no randomized clinical trials have directly assessed vitamin D related patient-important outcomes based on participants' skin pigmentation, although race and ethnicity often served as presumed proxies for skin pigmentation in the literature. In their deliberations, guideline panel members and selected Endocrine Society leaders underscored the critical need to distinguish between skin pigmentation as a biological variable and race and ethnicity as socially determined constructs. This differentiation is vital to maximize scientific rigor and, thus, the validity of resulting recommendations. Lessons learned from the guideline development process emphasize the necessity of clarity when incorporating race and ethnicity into clinical guidelines. Such clarity is an essential step toward improving health outcomes and ensuring equitable healthcare practices.

A long-held precept is that vitamin D supplementation primarily, if not exclusively, benefits individuals with low circulating 25-hydroxyvitamin D (25[OH]D) concentrations at baseline. However, the most appropriate 25(OH)D threshold to distinguish unacceptably low vs reliably adequate concentrations remains controversial. Such threshold proposals have largely been based on observational studies, which provide less robust evidence compared to randomized clinical trials (RCTs). Since the Endocrine Society's first vitamin D–related guideline was published in 2011, several large vitamin D–related RCTs have been published, and a newly commissioned guideline development panel (GDP) prioritized 4 clinical questions related to the benefits and harms of vitamin D supplementation in generally healthy individuals with 25(OH)D levels below a threshold. The GDP determined that available clinical trial evidence does not permit the establishment of 25(OH)D thresholds that specifically predict meaningful benefit with vitamin D supplementation. The panel noted important limitations in the available evidence, and the panel's overall certainty in the available evidence was very low. Nonetheless, based on the GDP's analyses and judgments, the Endocrine Society no longer endorses its previously proposed definition of vitamin D “sufficiency” (ie, at least 30 ng/mL [75 nmol/L]) or its previously proposed definition of vitamin D “insufficiency” (ie, greater than 20 ng/mL [50 nmol/L] but lower than 30 ng/mL [75 nmol/L]). The Endocrine Society's rationale for such is the subject of this Guideline Communication.

ABSTRACTBackground: Inuit in Canada have experienced dietary changes over recent generations, but how this relates to psychological distress has not been investigated.Objective: To evaluate how nutritional biomarkers are related to psychological distress.Design: A total of 36 communities in northern Canada participated in the International Polar Year Inuit Health Survey (2007–2008). Of 2796 households, 1901 (68%) participated; 1699 Inuit adults gave blood samples for biomarker analysis and answered the Kessler 6-item psychological distress questionnaire (K6). Biomarkers included n-3 fatty acids and 25-hydroxyvitamin D (25(OH)D). The K6 screens for psychological distress over the last 30 days with six items scored on a 4-point scale. A total score of 13 or more indicates serious psychological distress (SPD). Logistic regression models were used to investigate any associations between SPD and biomarkers while controlling for age, gender, marital status, days spent out on the land, feeling of being alone, income and smoking.Results: The 30-day SPD prevalence was 11.2%, with women below 30 years having the highest and men 50 years and more having the lowest SPD prevalence at 16.1% and 2.6%, respectively. SPD was associated with being female, younger age, not being married or with a common-law partner, spending few days out on the land, feelings of being alone, smoking and low income. Low levels of both 25(OH)D and long-chain n-3 FAs were associated with higher odds for SPD in both unadjusted and adjusted logistic regression models.Conclusion: In this cross-sectional analysis, low levels of 25(OH)D and long-chain n-3 FAs were associated with higher odds ratios for SPD, which highlights the potential impact of traditional foods on mental health and wellbeing. Cultural practices are also important for mental health and it may be that the biomarkers serve as proxies for cultural activities related to food collection, sharing and consumption that increase both biomarker levels and psychological well-being.Abbreviations: n-3 FAs: omega-3 fatty acids; PUFAs: polyunsaturated fatty acids; 25(OH)D: 25-hydroxyvitamin D; IPY: International Polar Year; IHS : Inuit Health Survey; RBC: red blood cell; OR: odds ratio; K6: Kessler 6-item screening scale; SPD: serious psychological distress; EPA: eicosapentaenoic acid (20:5 n-3); DHA: docosahexaenoic acid (22:6 n-3); DPA n-3: docosapentaenoic acid (22:5 n-3); n-3 LC-PUFAs: EPA (20:5 n-3) + DHA (22:6 n-3) + DPA (22:5 n-3); BMI: body mass index (kg m–2)

ABSTRACTPurpose:25-hydroxyvitamin D (25[OH]D) deficiency is associated with compromised bone mineralisation, fatigue, suppressed immune function and unsatisfactory skeletal muscle recovery. We investigated the risk of 25(OH)D insufficiency or deficiency in endurance athletes compared to sedentary non-athletes living at 64° north.Methods:University student-athletes (TS) and sedentary students (SS) volunteered to participate in this study. TS engaged in regular exercise while SS exercised no more than 20 minutes/week. Metabolic Equivalent of Task (MET) scores for participants were determined. Vitamin D intake was assessed using the National Cancer Institute’s 24-hour food recall (ASA24). Fasting plasma 25(OH)D levels were quantified via enzyme-linked immunosorbent assay.Results:TS reported higher activity levels than SS as assessed with MET-minutes/week and ranking of physical activity levels (p < 0.05). The reported mean daily intake of vitamin D was higher in TS compared to SS (p < 0.05) while 25(OH)D plasma levels were lower in TS than in SS (p < 0.05). In total, 43.8% of the TS were either insufficient (31.3%) or deficient (12.5%) in 25(OH)D, while none of the SS were insufficient and 13.3% were deficient.Conclusion:TS are at increased risk of 25(OH)D insufficiency or deficiency compared to their sedentary counterparts residing at the same latitude, despite higher vitamin D intake.

Etrasimod (APD334) is an investigational, once‐daily, oral, selective sphingosine 1‐phosphate receptor 1,4,5 modulator (S1P1,4,5) in development for treatment of various immune‐mediated inflammatory disorders. The disposition and mass balance of a single 2‐mg [14C]etrasimod dose were evaluated in 8 healthy males. An in vitro study was also conducted to identify etrasimod's oxidative metabolizing enzymes. Peak concentrations of etrasimod and total radioactivity in plasma and whole blood were typically reached 4–7 hours postdose. Etrasimod constituted 49.3% of total radioactivity plasma exposure, with multiple minor/trace metabolites making up the remainder. Etrasimod was slowly cleared mainly via biotransformation, predominantly by oxidative metabolism, with unchanged etrasimod recovered in feces accounting for only 11.2% of the dose and none in urine. The mean apparent terminal half‐lives of etrasimod and total radioactivity in plasma were 37.8 and 89.0 hours, respectively. Mean cumulative recovery of radioactivity in excreta over 336 hours was 86.9% of the dose, mostly in feces. The prevalent metabolites eliminated in feces were M3 (hydroxy‐etrasimod) and M36 (oxy‐etrasimod sulfate), accounting for 22.1% and 18.9% of the dose, respectively. From in vitro reaction phenotyping, the predominant enzymes involved in the oxidation of etrasimod were CYP2C8, CYP2C9, and CYP3A4, with minor contributions from CYP2C19 and CYP2J2.

Few studies have evaluated the association between circulating levels of 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D), and the endocrine disruptor bisphenol A (BPA), with risk of cardiovascular (CV) disease in elderly individuals. This was a cross-sectional study in a subgroup of elderly people from the InCHIANTI Biobank in Italy. We examined the association between circulating serum vitamin D metabolites, 1,25(OH)2D, 25(OH)D, and the endocrine disrupting agent BPA, with an arbitrary CV risk score and the European Society of Cardiology-based 10-year CV risk (SCORE2/SCORE2-OP) using univariate and multiple regression. In 299 individuals, blood samples were tested for serum values of 25(OH)D, 1,25(OH)2D and urinary BPA levels. One hundred eighty individuals (60.2%) were deficient (< 20 ng/ml) in 25(OH)D. Levels of 25(OH)D and 1,25(OH)2D were negatively correlated with CV risk score (p< 0.0001 for both) as well as SCORE2/SCORE2-OP (p< 0.0001 for both) while BPA levels were positively correlated with both CV risk scores (p< 0.0001 for both). In a logistic regression model, male gender (odds ratio; OR: 2.1, 95% CI:1.1–3.8, p= 0.022), obesity (OR:2.8, 95% CI:1.2–6.5, p= 0.016) and BPA levels ≥ 110 ng/dl (OR:20.9, 95% CI:9.4–46.8, p< 0.0001) were associated with deficient levels of 25(OH)D. 1,25(OH)2D levels < 41 ng/dl and 25(OH)D levels < 20 ng/ml were associated with CV risk score ≥ 3 (OR: 4.16, 95% CI: 2.32–7.4, p < 0.0001 and OR: 1.86, 95% CI: 1.02–3.39, p = 0.044) respectively and 1,25(OH)2D levels < 41 ng/dl were associated with SCORE2/SCORE2-OP of ≥ 20% (OR:2.98, 95% CI: 1.7–5.2, p = 0.0001). In this cross-sectional analysis, BPA exposure was associated with significantly reduced levels of vitamin D that in turn were significantly associated with increased CV risk.

AbstractObjectiveObesity is often accompanied by insulin resistance (IR) and diabetes. We explored the association between vitamin D levels and IR in non-diabetic obesity.MethodsWe conducted a cross-sectional study based on the data of National Health and Nutrition Examination Survey (NHANES) from 2001 to 2018. Non-diabetic individuals (aged ≥20 years) with obesity (BMI ≥ 30kg/m2) were included in the study. And HOMA-IR ≥ 2.5 was defined as IR. The multivariable linear regression models were constructed to evaluate the associations between levels of 25(OH)D and HOMA-IR. We calculated the odds ratio (OR) and 95% confidential intervals (CIs) for associations between 25(OH)D deficiency and IR in obesity using multivariable logistic regression models.ResultsOverall, a total of 3887 individuals were included in this study. Serum vitamin D level was significant lower in obesity participants with IR than that of non-IRs. The linear regression models showed that vitamin D level was inversely associated with HOMA-IR in obesity after adjusting for covariables (β=-0.15, 95%CI (-0.28, −0.02), p = 0.028). And the multivariable logistic regression models indicated an association between vitamin D deficiency and IR in obesity ((OR= 1.38, 95%CI (1.09-1.73), p = 0.007)). The further stratified regression analyses among different BMI demonstrated that vitamin D deficiency (OR = 1.4, 95%CI (1.05,1.86), p = 0.022) only contributed to developing IR in class I obesity.ConclusionThis study suggested an association of vitamin D levels with IR in obesity. And vitamin D deficiency contributed to IR in class I obesity.

Purpose: While serum 25-hydroxyvitamin D (25[OH]D) deficiency is prevalent in chronic kidney disease (CKD), the effects of 25(OH)D deficiency on cardiovascular mortality and kidney outcomes in patients with early-stage CKD remain incompletely understood. Methods: This multicenter retrospective cohort study included adult patients with stages 1–3 CKD from 19 medical centers across China between January 2000 and May 2021. The primary outcome was cardiovascular mortality. The secondary study outcome included CKD progression (defined as a sustained > 40% eGFR decrease from baseline or progress to end-stage kidney disease), and annual percentage change of eGFR. Results: Of 9229 adults with stages 1–3 CKD, 27.0% and 38.9% had severe (&lt; 10 ng/mL) and moderate (10 to &lt; 20 ng/mL) serum 25(OH)D deficiency, respectively. Compared with patients having 25(OH)D ≥ 20 ng/mL, a significantly higher risk of cardiovascular mortality (hazard ratio [HR] 1.90, 95% CI 1.37–2.63), CKD progression (HR 2.20, 95% CI 1.68–2.88), and a steeper annual decline in eGFR (estimate − 7.87%; 95% CI − 10.24% to − 5.51% per year) was found in those with serum 25(OH)D &lt; 10 ng/mL. Similar results were obtained in subgroups and by sensitivity analyses. Conclusions: 25(OH)D deficiency is associated with increased risks of cardiovascular mortality and CKD progression in patients with early-stage CKD. Studies are needed to determine whether early intervention for 25(OH)D deficiency could improve the prognosis of patients with early-stage CKD.

BackgroundSub-optimal vitamin D status is common worldwide and the condition may be associated with increased risk for various chronic diseases. In particular, low vitamin D status is highly prevalent in indigenous communities in Canada, although limited data are available on the determinants of serum 25-hydroxyvitamin D (25(OH)D) concentrations in this population. The relationship between traditional food consumption and vitamin D status has not been well documented.ObjectiveTo investigate the determinants of serum 25(OH)D status in a First Nations community in Ontario, Canada, with a focus on the role of traditional food consumption and activities.MethodsA cross-sectional analysis was conducted within the Sandy Lake Health and Diabetes Project (2003–2005). A total of 445 participants (>12 years of age) were assessed for serum 25(OH)D status, anthropometric and lifestyle variables, including traditional and non-traditional dietary practices and activities. Diet patterns were identified using factor analysis, and multivariate linear regression analysis was used to analyse the determinants of 25(OH)D concentrations.ResultsMean serum 25(OH)D concentrations were 22.1 nmol/L (16.9, 29.9 nmol/L) in men and 20.5 nmol/L (16.0, 27.3 nmol/L) in women. Multivariate determinants of higher serum 25(OH)D included higher consumption of traditional and healthier market foods, higher wild fish consumption, male gender, spring/summer season of blood collection and more frequent physical activity. Significant negative determinants included hours of TV/day, higher BMI and higher consumption of unhealthy market foods.ConclusionsTraditional food consumption contributed independently to higher 25(OH)D concentrations in a First Nations community with a high prevalence of sub-optimal vitamin D status.

The article discusses research which examined the effect of a loading dose of either vitamin D3 or vitamin D2 on serum 25-hydroxycholecalciferol levels. Topics covered include the collection of fasting blood and urine fasting samples from the subjects, the measurement of serum calcium and urinary calcium and creatinine to evaluate the safety of the loading dose and the preference shown for D3 for daily supplementation.

Mental disorders seriously affect people's health and social stability. This Mendelian randomization (MR) study was designed to investigate the causal relationship between circulating vitamin C (VC) or 25-hydroxyvitamin D (25(OH)D) levels and mental disorders. The data used for the MR analysis were derived from the summary genome-wide association studies (GWAS) database for VC and 25(OH)D and from the FinnGen consortium for fourteen mental disorders. Based on the inverse variance weighted (IVW) method, we found a potential causal association between circulating VC and anxiety disorders (IVW: OR=1.139, 95 %CI: 1.0231.269, P= 0.018). However, no causal association was found between VC or 25(OH)D and other mental disorders (P> 0.05). In the reverse MR analysis, individuals with Alzheimer's disease was causally associated with higher concentrations of circulating VC(P= 0.012), while individuals with anxiety disorders had a negative association between the concentrations of 25(OH)D (P= 0.012). However, the current evidence does not support a causal relationship between VC or 25(OH)D and other mental disorders. In addition, there was no causal association between circulating VC and 25(OH)D (P> 0.05). Future studies are needed to confirm these findings and to elucidate the mechanisms of potential causality.

Background: Osteoporosis and osteopenia are more frequent in patients who have received kidney transplants than in healthy individuals. Although osteoporosis and sarcopenia are closely related, only few studies have considered them in the post-transplantation period. We aimed to investigate the relationship between lower bone mineral density and skeletal muscle in kidney transplant recipients. Methods: We included 371 patients in the maintenance phase of kidney transplantation (> 6 months after transplantation) followed-up at our institution from January to December 2019. The primary endpoint was the association between bone mineral density and skeletal muscle mass index. As secondary endpoints, in addition to skeletal muscle mass index, we investigated other factors associated with low bone mineral density, including kidney function and 25-hydroxy vitamin D (25(OH)D) concentration. Considering the possibility that factors affecting bone mineral density differ between men and women, we explored these factors separately for both sexes. Results: Of the 371 participants, 243 (65.4%) were men. The median age and time after transplantation were 52 and 14 years, respectively. Univariate analysis showed that age, female sex, time since transplantation, cystatin C-based estimated glomerular filtration rate (eGFRcysC), 25(OH)D, and skeletal muscle mass index were associated with bone mineral density. Multivariate analysis showed associations of bone mineral density with eGFRcysC, 25(OH)D, and skeletal muscle mass index. Multivariate analysis by sex showed significant associations with eGFRcysC, hemoglobin, and skeletal muscle mass index in men and with age, eGFRcysC, albumin, and skeletal muscle mass index in women. Bone mineral density was not associated with history of dialysis prior to transplantation or time since transplantation. Conclusions: In kidney transplant recipients, an independent association between lower bone mineral density and skeletal muscle mass index was observed in both sexes. Graphical abstract:

Background:Studies show a high prevalence of osteoporosis and fracture risk in kidney transplant candidates and recipients. However, little is known about the prevalence of osteoporosis among transplant recipients and candidates living with HIV.Objective:To determine the prevalence of osteopenia and osteoporosis and investigate the socio-demographic and nutritional factors associated with BMD in HIV-positive transplant candidates and recipients from an HIV-positive donor.Methods:In this cross-sectional study, 20 HIV- positive transplant recipients and 36 transplant candidates on haemodialysis (HD) and awaiting transplantation had BMD and body composition measured by dual-energy X-ray absorptiometry (DEXA). Vitamin D status was measured using serum 25-hydroxyvitamin D [25(OH)D]. Dietary Vitamin D and calcium intake was obtained from a single 24-hour recall.Results:Participants were mainly black African (92.9%), male (55.4%) with a mean age of 43.8 ± 8.3 years. Serum 25(OH)D levels were low for the group as a whole, with a mean of 22.04 ± 12.74 ng/ml. Osteoporosis was more prevalent amongst transplant recipients (20.0%) than transplant candidates (13.9%). Conversely, osteopenia was present amongst transplant candidates (27.8%). T-scores strongly correlated positively, with lean mass and BMD of the spine (r = 0.707, p = 0.007), and moderately, with each side of the total hip BMD (r = 0.455, p = 0.007 and r = 0.420, p = 0.007). There was a significant positive association between dietary calcium and all BMD sites in transplant recipients only.Conclusion:The prevalence of osteoporosis was similar, and in some cases, lower than in transplant recipients elsewhere. Lean mass was positively associated with BMD, and in transplant recipients, dietary calcium intake was positively associated with BMD emphasising the role of diet and exercise in preserving BMD.

ABSTRACTBackgroundAttention deficit hyperactivity disorder (ADHD) is one of the common neurodevelopmental diseases that are accompanied with EEG pattern changes and Low levels of 25-hydroxyvitamin D [25(OH)D]. Neurofeedback provides a feedback signal to alleviate brain wave abnormalities and offers an alternative therapy for ADHD. This study aimed to investigate the concomitant effects of Vitamin D3 supplementation and Neurofeedback on children with ADHD.MethodThis study was implemented on children with an established diagnosis of ADHD who received multisession Neurofeedback therapy. The intervention and control groups received 50000 IU vitamin D3 capsules and placebo respectively once a week for 2 months. The background rhythm was measured using quantitative EEG both before and at the end duration of the therapy.ResultsAll of the vitamin D3 treated children showed a significant increase in the 25(OH)D (46 ± 18, 28 ± 10 (ng/ml), p = 0.001) and serum calcium level (9.5 ± 0.5, 9.8 ± 0.3 (mg/dl), p = 0.003) compared to the baseline. There were a statistically significant decrease in the treatment group about theta relative power, theta/beta, and theta/alpha power ratios within two eyes conditions (p = 0.004). All the changes were significant within eye open state in the treatment group (2.4 ± 1.2, 1.7 ± 0.5, p = 0.01). There is a significant relationship between Connors scores and some brain waves improvement (in relative theta (r = 0.998) and theta-to-beta power difference score (r = 0.56) (p < 0.001).ConclusionConcomitant use of vitamin D3 supplementation and neurofeedback, increases the serum level of this vitamin and reveal favorable electrophysiological results in children with ADHD.Trial registration:Iranian Registry of Clinical Trials identifier: IRCT20200922048802N1..

Objective:To determine the correlation between initial serum 25-hydroxyvitamin D (25(OH)D) levels with granulation growth in diabetic foot ulcers (DFUs) after 21 days of treatment.Method:This cohort study involved patients with type 2 diabetes who had a DFU treated at hospital. Blood samples were taken from patients on admission. The chemiluminescent immunoassay technique was used to measure 25(OH)D levels. Granulation tissue growth was analysed by comparing the photographs from the initial treatment to day 21 of treatment.Results:The median value of 25(OH)D levels at initial treatment was 8 ng/ml. The result showed no correlation between 25(OH)D levels and the granulation growth in DFUs (p=0.86).Conclusion:The initial serum 25(OH)D level was not correlated with the growth of granulation tissue in DFUs.

La vitamine D est essentielle pour le maintien de l’homéostasie minérale osseuse. Sa principale forme circulante est la 25(OH) D dont le taux sérique reflète les réserves en vitamine D Des taux de 25(OH) D entre 30 et 80ng/mL sont considérés comme suffisants et <30ng/mL comme indicateur d’insuffisance en vitamine D. Les niveaux bas de vitamine D sont attribués au manque d’exposition solaire (ES), à une faible activité physique et à l’obésité.

BackgroundCanadian First Nation populations have experienced endemic and epidemic tuberculosis (TB) for decades. Vitamin D–mediated induction of the host defence peptide LL-37 is known to enhance control of pathogens such as Mycobacterium tuberculosis.ObjectiveEvaluate associations between serum levels of 25-hydroxy vitamin D (25(OH)D) and LL-37, in adult Dene First Nation participants (N = 34) and assess correlations with single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) and vitamin D binding protein (VDBP).DesignVenous blood was collected from all participants at baseline (winter and summer) and in conjunction with taking vitamin D supplements (1,000 IU/day) (winter and summer). Samples were analysed using ELISA for concentrations of vitamin D and LL-37, and SNPs in the VDR and VDBP regions were genotyped.ResultsCirculating levels of 25(OH)D were not altered by vitamin D supplementation, but LL-37 levels were significantly decreased. VDBP and VDR SNPs did not correlate with serum concentrations of 25(OH)D, but LL-37 levels significantly decreased in individuals with VDBP D432E T/G and T/T, and with VDR SNP Bsm1 T/T genotypes.ConclusionsOur findings suggest that vitamin D supplementation may not be beneficial as an intervention to boost innate immune resistance to M. tuberculosisin the Dene population.

Plusieurs études appuient le rôle de la vitamine D dans la pathogénie du diabète de type 2. L’objectif de notre travail était d’évaluer l’effet de la supplémentation en vitamine D sur l’équilibre glycémique des diabétiques type 2 déficitaires en vitamine D.

Background: Limited knowledge exists regarding the association between dementia incidence and vitamin D insufficiency/deficiency across seasons.Objective: This study aimed to evaluate the impact of seasonal serum vitamin D (25(OH)D) levels on dementia and its subtypes, considering potential modifiers.Methods: We analyzed 193,003 individuals aged 60–73 at baseline (2006–2010) from the UK Biobank cohort, with follow-up until 2018. 25(OH)D were measured at baseline, and incident dementia cases were identified through hospital records, death certificates, and self-reports.Results: Out of 1,874 documented all-cause dementia cases, the median follow-up duration was 8.9 years. Linear and nonlinear associations between 25(OH)D and dementia incidence across seasons were observed. In multivariable-adjusted analysis, 25(OH)D deficiency was associated with a 1.5-fold (95% CIs: 1.2–2.0), 2.2-fold (1.5–3.0), 2.0-fold (1.5–2.7), and 1.7-fold (1.3–2.3) increased incidence of all-cause dementia in spring, summer, autumn, and winter, respectively. Adjusting for seasonal variations, 25(OH)D insufficiency and deficiency were associated with a 1.3-fold (1.1–1.4) and 1.8-fold (1.6–2.2) increased dementia incidence, respectively. This association remained significant across subgroups, including baseline age, gender, and education levels. Furthermore, 25(OH)D deficiency was associated with a 1.4-fold (1.1–1.8) and 1.5-fold (1.1–2.0) higher incidence of Alzheimer’s disease and vascular dementia, respectively. These associations remained significant across all subgroups.Conclusions: 25(OH)D deficiency is associated with an increased incidence of dementia and its subtypes throughout the year.

ABSTRACTBackgroundVitamin D status has been linked to visual memory in adults. We hypothesized a similar association in young adolescents.MethodsParticipants were 9–13 years. The Rey-Osterrieth Complex Figure Task (ROCF), Rey Auditory Verbal Learning Task (RAVLT), Digit Span (Forward, Backward), and verbal fluency task assessed visual and verbal learning/memory, attention/working memory, and executive functioning/language, respectively. An at-home, mail-in blood spot test assessed 25(OH)D levels.ResultsParticipants (N = 56) were 10.7 ± 1.3 years, 61% females, 25(OH)D levels 84.2 ± 25 nmol/L(39.9 - 167.2 nmol/L) and 41% had insufficient vitamin D status (<75 nmol/L). Only measures of visual memory (ROCF-Recall, -%Recall of Copy) were significantly correlated with 25(OH)D, r = .34, p < .01 and r = .33, p < .01, respectively, and 25(OH)D remained a significant independent predictor on multiple regression analyses, which included age and sex.(ROCF-Recall overall model: Adj R2 = .24, p < .001; for 25(OH)D: p = .009; ROCF-%Recall of Copy overall model: Adj R2 = .20 p < .002; for 25(OH)D: p = .01). Individuals with sufficient vitamin D performed significantly better only on these measures (t-tests; ROCF-Recall, p = .016, d = 0.68; ROCF-%Recall of Copy, p = .022, d = 0.64). Despite moderate effect sizes (d = 0.4–0.5) in the Younger Age Group (9–10 years), only in the Older Age Group (11–13 years) was 25(OH)D significantly correlated with ROCF-Recall, r = .64, p = .0001 and ROCF-%Recall of Copy, r = .64, p = .0001, as well as working memory (Digit Span-Backward), Spearman’s r = .46, p = .013. Similarly, those in the Older Age Group with sufficient vitamin D performed significantly better on ROCF-Recall, p = .01, d = 1.07; and ROCF-%Recall of Copy, p = .009, d = 1.08.ConclusionsVitamin D insufficiency was common in young adolescents. Similar to adults, visual memory was better among participants with higher 25(OH)D and those with sufficient levels. This effect was especially pronounced among older participants, suggesting possible time- and/or age-related implications of vitamin D status on cognition.

ABSTRACTObjectiveTo investigate the correlation between serum ferritin (SF) and bone turnover markers in type 2 diabetes mellitus (T2DM) patients with non-alcoholic fatty liver disease (NAFLD).MethodsSeven hundred and forty-two people with T2DM were selected. Serum bone turnover markers: osteocalcin (OC), type I procollagen N-terminal peptide (PINP), β-I type collagen carboxy-terminal peptide (β-CTx), and 25-hydroxyvitamin D3 (25-[OH]-D) levels were detected. High SF (HF) was defined as the indicated SF levels above 400 ng/mL in males and more than 150 ng/mL in females. Patients were divided into four groups: T2DM+normal SF (non-HF); T2DM+high SF (HF); T2DM+NAFLD+non-HF; andT2DM+NAFLD+HF. Relationships between SF and bone turnover markers were analyzed.ResultsCompared with the T2DM+non-HF group, β-CTx levels were higher in the T2DM+HFgroup. Compared with the T2DM+NAFLD+non-HF group, β-CTx levels were increased and 25-(OH)-D levels decreased in the T2DM+NAFLD+HF group (all p < 0.05). SF was positively correlated with β-CTx [β = 0.074; 95% CI (0.003, 0.205)] and negatively correlated with 25-(OH)-D [β=-0.108; 95%CI (−0.006, −0.001)]. Compared with the T2DM+non-HF group, an independent positive correlation was found between β-CTx and SF in the T2DM+NAFLD+HF group [OR = 1.002; 95% CI (1.001, 1.004)]. Among males, SF was positively correlatedwith β-CTx [β = 0.114; 95% CI (0.031, 0.266)]. SF was negatively correlated with 25-(OH)-D levels in both male and female patients [β=-0.124; 95% CI (0.007,0.001) and β=-0.168; 95% CI (−0.012, −0.002)]. Among those >50 years of age and postmenopausal females, SF was negatively correlated with 25-(OH)-D levels [β=-0.117; 95% CI (−0.007, −0.001) and β=-0.003; 95% CI (−0.013, −0.003)].ConclusionSF level was positively correlated with β-CTx in T2DM patients with NAFLD, which may promote bone resorption and increase the risk of bone loss.

It has been shown that 25-OH vitamin D not only preserves calcium and bone homeostasis but also has immunomodulatory effects. The purpose of this study was to assess the association between adult patients with recently diagnosed immune thrombocytopenia (ITP) and vitamin D levels. Retrospective technique was employed in this study. The associations between 25(OH)D value and platelet count, as well as the clinical symptoms of ITP upon diagnosis and 25(OH)D value, were our main findings. A total of 60 patients diagnosed and followed up in our clinic were included in the study. Forty-one patients (68.3%) were female and 19 (31.7%) were male. The median age of the patients was 52.5 (19–88). The median vitamin D level of all patients at diagnosis of ITP was 11.5 (3–86). There was no statistically significant difference between the patients divided into three groups according to their vitamin D levels, in terms of laboratory parameters. There was no statistically significant difference in clinical findings according to vitamin D status in ITP patients. There was no statistically significant difference in terms of relapse-free survival in all three groups (p = 0.71). In conclusion, in our study, no correlation was found between laboratory and clinical findings at diagnosis and vitamin D levels in adult ITP patients. Additional investigations, particularly randomized controlled trials, are required to examine the relationship between 25(OH)D and the incidence and severity of ITP.

ABSTRACTBackgroundAssessing vitamin D status, typically evaluated using serum or plasma 25-hydroxy vitamin D [25(OH)D] concentration, is complex because of various influencing factors.MethodsSeasonality significantly affects intra-individual variability in 25(OH)D levels. This variation can be addressed by employing cosinor functions that are tailored to the geographical location of the patient to correct for seasonal effects. In addition to seasonality, genetic factors, such as DBP polymorphism and body composition, particularly adiposity, play crucial roles. Dialysis patients with DBP 2–2 phenotype exhibit higher vitamin D requirements. Genotyping/phenotyping of DBP allows for better tailored vitamin D supplementation. The lipid-soluble nature of vitamin D also interacts with plasma components such as serum triglycerides, which can influence vitamin D measurements. Adiposity, which is negatively correlated with vitamin D concentration, necessitates body mass-based mathematical adjustments for accurate vitamin D assessment in subjects with extreme BMI values.ConclusionsAccordingly, vitamin D replacement therapy must be personalized, taking into account factors such as body size and seasonal variations, to effectively reach the target serum 25(OH)D concentrations.