Correlation between maternal and umbilical cord 25-hydroxy-vitamin D levels over a range of values. A prospective observational study from the United Arab Emirates.

Worldwide vitamin D insufficiency is remarkably prevalent in both children and adults, including pregnant women. The total amount of the vitamin is best measured by 25-hydroxy-vitamin D (25(OH)D), which is a measurement of total serum cholecalciferol 25(OH)D3 and ergocalciferol 25(OH)D2. There is a known correlation between maternal and umbilical cord blood (UCB) 25(OH)D; however, whether specific maternal demographics or comorbidities influence the correlation remains uncertain. This prospective observational study was designed to study if maternal 25(OH)D levels, maternal age and BMI, amount of supplementation, mode of delivery, diabetes, hypertension/preeclampsia, or sunlight exposure had an impact on the correlation. Women were enrolled in the study at admission to the labor ward. If they agreed to participate, venous blood was directly collected and analyzed for 25(OH)D. The UCB was sampled after delivery from the unclamped cord and immediately analyzed for 25(OH)D. ANOVA, Fisher's exact test, Pearson's correlation, and test of the differences between correlations using Fisher's z-transformation with Bonferroni correction were used accordingly. Of the 298 women enrolled, blood from both the mother and umbilical cord was analyzed successfully for 25(OH)D in 235 cases. The crude correlation between maternal and UCB 25(OH)D was very strong over all values of 25(OH)D (r = 0.905, R2 = 0.821, p <0,001) and remained strong independently of maternal demographics or co-morbidities (r ≥ 0.803, R2 ≥ 0.644, p <0.001). For women who delivered by caesarean section in second stage the correlation was strong (r ≥ 0.633, R2 ≥ 0.4, p <0.037). Test of differences between correlations showed significant stronger correlation in women with unknown 25(OH)D3 supplementation compared to women receiving 10.000 IU/week (p = 0.02) and 20.000IU/week (p = 0.01) and that the correlation was significantly stronger for women with a BMI of 25-29.9 compared to women with a BMI of <24.9 (p = 0.004) and 30-34.9 (p = 0.002). 213 (91%) women had lower 25(OH)D compared to the neonate, with a mean difference of -13.7nmol/L (SD = 15.6). In summary, the correlation between maternal and UCB 25(OH)D is very strong throughout low to high maternal levels of 25(OH)D with lower levels in maternal blood. Typical maternal demographics and comorbidities did not affect the transition.

Vitamin D status in active and inactive noninfectious uveitis - data from a reference university hospital in Rio de Janeiro, Brazil.

PURPOSE: This study aimed to investigate the correlation between serum vitamin D levels and disease activity in patients with noninfectious uveitis. METHODS: We conducted a prospective case-control study, assessing 51 patients with noninfectious uveitis, categorized into active (n=22) and inactive (n=29) groups, along with 51 healthy controls. Serum 25-hydroxy vitamin D [25(OH)D] levels were measured. The uveitis group also completed a questionnaire regarding sunlight exposure habits and vitamin D supplementation. RESULTS: Patients with inflammation-related uveitis exhibited low serum 25(OH)D levels in 68% of cases. The median 25(OH)D level in patients with active uveitis was 17.8 ng/mL (interquartile range [IQR], 15-21 ng/mL), significantly lower compared to the 31.7 ng/mL (IQR, 25-39 ng/mL) in patients with inactive uveitis (p<0.001) and the 27 ng/mL (IQR, 23-31 ng/mL) in the Control Group (p<0.001). Significantly, nearly all patients with uveitis taking vitamin D supplementation were in the Inactive Group (p<0.005). Moreover, reduced sunlight exposure was associated with active uveitis (p<0.003). Furthermore, patients with 25(OH)D levels below 20 ng/mL had ten times higher odds of developing active uveitis (p=0.001). CONCLUSIONS: This study revealed a prevalent 25(OH)D deficiency among patients with noninfectious uveitis and suggested a link between low 25(OH)D levels and disease activity. To prevent future episodes of intraocular inflammation, vitamin D supplementation and controlled sunlight exposure could be viable options.

Prevalence of vitamin D insufficiency in early pregnancies- a Singapore study.

Vitamin D plays an essential role in bone and mineral metabolism. There is increased interest in understanding prevalence of Vitamin D deficiency in pregnancy as many studies report association of low vitamin D levels with obstetric complications and neonatal sequelae. There is a paucity of studies in Singapore evaluating levels of vitamin D levels during the first trimester of pregnancies. We aim to study the prevalence of vitamin D insufficiency in this population. Our study assessed vitamin D levels in these women. Vitamin D (Plasma 25(OH)D concentration) levels in multiracial women during the first trimester were collected via venepuncture at their booking antenatal visit. They were stratified into sufficient ≥30ng/ml, insufficient ≥20ng/ml and <30ng/ml, moderately deficient ≥10ng/ml and <20ng/ml and severely deficient <10ng/ml. 93 women were included in this study. Only 2.2% of our study population had sufficient vitamin D levels. In women who had insufficient levels, the heavier the weight, the more likely to be vitamin D deficient. Interestingly, we also note that the older the patient, the less likely they are to be deficient. In women with periconceptual multivitamin supplementation, the average vitamin D level for those with supplementation was 2.10ng/ml higher than those without. Majority of patients were recruited from a single study member's patient pool who were mostly Chinese. Prevalence of Vitamin D deficiency in general obstetric patients with higher BMI and darker skinned patients may be even lower in Singapore. The high prevalence of Vitamin D insufficiency in our patients prove that it is a prominent problem in our population. We aim to implement screening of vitamin D levels as part of antenatal investigations in the first trimester and recommend supplementation as required. We also hope to evaluate the association of low vitamin D levels with obstetric or neonatal complications further understanding its implications.

An Adapted Questionnaire Tailored for Assessing the Risk of Vitamin D Deficiency in Children That Is Proving Useful in Guiding Clinical Interventions.

BACKGROUND: The identification of vitamin D (VitD) deficiency in pediatric populations is essential for preventive healthcare. We refined and tested the Evaluation of Deficiency Questionnaire (EVIDENCe-Q) for its utility in detecting VitD insufficiency among children. PATIENTS AND METHODS: We enrolled 201 pediatric patients (aged between 3 and 18 years). Clinical evaluation and serum vitamin D levels were assessed in all subjects. The EVIDENCe-Q was updated to incorporate factors influencing VitD biosynthesis, intake, assimilation, and metabolism, with scores spanning from 0 (optimal) to 36 (poor). RESULTS: We established scores for severe deficiency (<10 mg/dL) at 20, deficiency (<20 mg/dL) at 22, and insufficiency (<30 mg/dL) at 28. A score of 20 or greater was determined as the optimal cut-off for distinguishing VitD deficient from sufficient statuses, as evidenced by ROC curve analysis AUC = 0.7066; SE = 0.0841; sensitivity 100%, 95% CI 0.561-1. The most accurate alignment was seen with VitD insufficiency, defined as 25-OH-D3 < 20 ng/mL. CONCLUSIONS: This study confirms that the EVIDENCe-Q is a valid instrument for assessing the risk of vitamin D deficiency and insufficiency in children. It offers a practical approach for determining the need for clinical intervention and dietary supplementation of VitD in the pediatric population.

Association between vitamin D deficiency and benign paroxysmal positional vertigo (BPPV) incidence and recurrence: a systematic review and meta-analysis.

OBJECTIVES: The objective of this study is to determine the relationship between serum vitamin D level and the risk of developing benign paroxysmal positional vertigo (BPPV) incidence and recurrence in countries in the Northern Hemisphere. DESIGN: Systematic review and meta-analysis. DATA SOURCES: PubMed, Scopus and Web of Science databases were searched for studies published between January 2000 and February 2023. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Participants located in the Northern Hemisphere aged 18 or over with at least one episode of BPPV, serum 25-hydroxyvitamin D levels measured and reported, no comorbidities or history of vitamin D supplementation. DATA EXTRACTION AND SYNTHESIS: Data extraction and synthesis were performed by a single reviewer and checked by a second reviewer. Inclusion and exclusion criteria and risk of bias were assessed by two independent reviewers using the Newcastle Ottawa Tool for Cohort studies and Risk of Bias Assessment Tool for Nonrandomised Studies checklist for case-control studies. Meta-analysis was conducted using random effects models. Standard mean difference with a 95% CI was used to measure the relationship between vitamin D level and BPPV. RESULTS: The 35 articles identified by the literature search reported data of 9843 individuals. 19 studies (7387 individuals) were included in the BPPV incidence meta-analysis while 7 studies (622 individuals) were included in the BPPV recurrence meta-analysis. Lower serum vitamin D levels were found in BPPV incidence compared with controls, but the relationship between vitamin D levels in recurrent BPPV compared with non-recurrent disease remained uncertain. CONCLUSION: Results of this systematic review and meta-analysis demonstrated a negative correlation between serum vitamin D and BPPV incidence, while any relationship between serum vitamin D and BPPV recurrence remained uncertain. Risk of bias analysis revealed evidence of variable quality. There were insufficient data available to evaluate seasonal relationships between serum vitamin D and BPPV. Given the potential for this as a confounding factor, future research should aim to investigate this further. PROSPERO REGISTRATION NUMBER: CRD42021271840.

Efficiency of the Vitamin D Status Diagnosticator amongst Geriatric Patients with COVID-19.

The vitamin D status diagnosticator (VDSD), a 16-item tool, effectively identifies hypovitaminosis D in healthy older adults and can assist in determining the need for blood tests in this population. Assessing vitamin D levels is particularly crucial in the context of COVID-19. This study aimed to evaluate the VDSD's effectiveness in pinpointing hypovitaminosis D in older adults affected by COVID-19. The research involved 102 unsupplemented geriatric inpatients consecutively admitted to the acute geriatric division of Angers University Hospital, France, with an average age of 85.0 ± 5.9 years (47.1% women). The physician-administered VDSD was conducted simultaneously with the measurement of serum 25-hydroxyvitamin D (25(OH)D). Hypovitaminosis D was defined as a serum 25(OH)D concentration of ≤75 nmol/L for vitamin D insufficiency and ≤50 nmol/L for vitamin D deficiency. Results revealed that 87 participants (85.3%) had vitamin D insufficiency and 63 (61.8%) had vitamin D deficiency. The VDSD accurately identified vitamin D deficiency with an area under the curve (AUC) of 0.81 and an odds ratio (OR) of 40. However, its accuracy in identifying vitamin D insufficiency was lower (AUC = 0.57). In conclusion, the 16-item VDSD, a concise questionnaire, effectively identifies vitamin D deficiency in geriatric patients with COVID-19. This tool can be valuable in guiding the decision to administer vitamin D supplementation during the early stages of COVID-19.

Vitamin D Status in the Adult Population of Romania-Results of the European Health Examination Survey.

BACKGROUND: Vitamin D deficiency is recognized as a general health condition globally and is acknowledged as a public health concern in Europe. In Romania, a national program of examination of the status of vitamin D for high-risk groups has demonstrated a vitamin D deficiency prevalence of 39.83%. No national data on the status of vitamin D in the general adult population are available to date. METHODS: We used the framework of the European Health Examination Survey to analyze vitamin D levels in a sample population of adults aged 25-64 years, from 120 family doctors' patients lists, by using a sequential sampling method. Data were weighted to the Romanian population. Vitamin D deficiency was defined as 25(OH)D < 20 ng/mL. RESULTS: In total, 5380 adults aged 25-64 years were included in this study. The overall prevalence of vitamin D deficiency is 24.8%. Predictors of vitamin D deficiency were found to be obesity, female sex, living in rural areas, lower education level, and lower socioeconomic status. CONCLUSIONS: Specific recommendations for vitamin D screening and supplementation should be issued for women by specialist boards. Further studies are needed to identify seasonal variation and to establish a correlation with nutritional surveys.

Vitamin D Supplementation and Recurrence of Benign Paroxysmal Positional Vertigo.

Positional vertigo manifests as a spinning sensation triggered by changes in head position relative to gravity. Benign paroxysmal positional vertigo (BPPV) is an inner ear disorder characterized by recurrent episodes of positional vertigo. The connection between vitamin D insufficiency/deficiency and the onset and recurrence of BPPV is established. This study aims to assess vitamin D as a recurring factor in BPPV and the efficacy of vitamin D supplementation in preventing its recurrence. A comprehensive literature review on the relationship between vitamin D and BPPV recurrence was conducted, searching PubMed, Embase, Web of Science, and article reference lists for studies published from 2020 to 2023. A total of 79 articles were initially identified through the search, with 12 of them being utilized in the study. Recurrence rates for BPPV varied from 13.7% to 23% for studies with follow-up less than 1 year and 13.3% to 65% for studies with follow-up equal to or exceeding 2 years. Risk factors for BPPV recurrence include advanced age, female sex, hypertension, diabetes mellitus, hyperlipidemia, osteoporosis, and vitamin D deficiency. While earlier studies did not establish a link between low vitamin D levels and initial BPPV occurrence, they did associate recurrent episodes with low vitamin D levels. Recent research indicates that vitamin D supplementation in BPPV patients with deficiency or insufficiency decreases both the numbers of relapsing patients and relapses per patient. To validate these findings across diverse populations, further randomized controlled studies with larger cohorts and extended follow-up durations are essential.

Effect of air temperature on serum 25-hydroxyvitamin D concentrations: A single institutional large-scale study in Korea.

Vitamin D deficiency is a worldwide health issue especially in women. Serum vitamin D concentrations vary depending on the weather. However, the ideal vitamin D supplementation strategy related to weather remains uncertain. We aimed to investigate the relationship between climate factors and serum 25-hydroxy vitamin D [25(OH)D] concentrations. This study included 11,272 women aged 20-79 who visited a health promotion center for annual checkups between January 2013 and December 2015. We reviewed medical records and collected daily meteorological data. We analyzed the association between serum 25(OH)D concentration and climate factors using simple and multiple regression models and then predicted serum 25(OH)D concentration using multiple fractional polynomial models. The median age of the participants was 51 years (20-79 years), and the mean serum 25(OH)D level was 17.4 ± 8.6 ng/mL. The serum 25(OH)D concentration was lower in young women than in older women. The proportions of women with adequate 25(OH)D levels were 14.9% and 47.0% in the age groups 20-29 and 70-79, respectively. The maximum level of predicted log 25(OH)D was found in September, and the minimum was found in January. In multiple regression analysis, age and monthly mean temperature were associated with 25(OH)D concentrations. Serum 25(OH)D level was predicted using the following formula: log (25(OH)D) = 2.144 + 0.009 × age + 0.018 × ((temperature + 12.4)/10)2 (P < 0.001, adjusted R2 = 0.091). Serum 25(OH)D concentrations changed according to air temperature. An adequate strategy for vitamin D supplementation, based on air temperature, is necessary to maintain healthy serum 25(OH)D levels.

Vitamin D deficiency during the coronavirus disease 2019 (COVID-19) pandemic among healthcare workers.

BACKGROUND & AIMS: Vitamin D deficiency is a common nutritional problem worldwide that may have worsened during the coronavirus disease 2019 (COVID-19) pandemic. The present study sought to examine the prevalence and correlates of vitamin D deficiency among healthcare workers three years after the start of the COVID-19 pandemic. METHODS: Participants comprised 2543 staff members from a medical research institute, who completed a questionnaire and donated blood samples in June 2023. 25-hydroxyvitamin D (25[OH]D) levels were measured using an electrochemiluminescence immunoassay. Logistic regression was used to calculate the odds ratio and its 95% confidence interval while adjusting for covariates. RESULTS: The proportions of participants with vitamin D insufficiency (25[OH]D 20-29 ng/mL) and deficiency (25[OH]D < 20 ng/mL) were 44.9% and 45.9%, respectively. In a multivariable-adjusted model, factors associated with a higher prevalence of vitamin D deficiency included younger age, female sex, fewer hours of daytime outdoor physical activity during leisure time (without regular use of sunscreen), lower intake of fatty fish, no use of vitamin D supplements, smoking, and no alcohol consumption. Occupational factors, including shift work, were not independently associated with vitamin D deficiency. CONCLUSIONS: Our results suggest that vitamin D insufficiency and deficiency are highly prevalent among healthcare workers. Health education regarding lifestyle modifications for this occupational group are warranted to improve their vitamin D status in the COVID-19 era.

Post-diagnosis serum 25-hydroxyvitamin D concentrations in women treated for breast cancer participating in a lifestyle trial in Italy.

OBJECTIVE: To report cross-sectionally serum levels of 25-hydroxyvitamin D [25(OH)D] in women living in Italy within 12 months from breast cancer (BC) diagnosis. METHODS: Baseline data were obtained from 394 women diagnosed with primary BC, enrolled from 2016 to 2019 in a lifestyle trial conducted in Italy. Subjects' characteristics were compared between two 25(OH)D concentrations (hypovitaminosis D<20 and ≥20 ng/mL) with the Chi-squared test or Fisher's exact test for small-expected counts. Using multiple logistic regression-adjusted models, we estimated odds ratios (ORs) of hypovitaminosis D with 95% confidence intervals (CIs) in the total sample and in the unsupplemented subgroup. RESULTS: Hypovitaminosis D was found in 39% of all subjects, 60% in unsupplemented subjects, and 10% in supplemented subjects. Increasing ORs of hypovitaminosis D were found with increasing body mass index, 25-30, >30, and ≥35 versus <25 kg/m2 (ORs: 2.50, 4.64, and 5.81, respectively, in the total cohort and ORs: 2.68, 5.38, and 7.08 in the unsupplemented); living in the most southern Italian region (OR 2.50, 95%CI 1.22-5.13); and with hypertriglyceridemia (OR 2.46; 95%CI 1.16-5.22), chemotherapy history (OR 1.86, 95%CI 1.03-3.38), and inversely with anti-estrogenic therapy (OR 0.43, 95%CI 0.24-0.75) in the total sample. CONCLUSIONS: Hypovitaminosis D in women recently diagnosed with BC and participating in a lifestyle trial in Italy was widespread and highest with obesity, hypertriglyceridemia, and chemotherapy use. Considering that hypovitaminosis D is a risk factor for lower efficacy of bone density treatments and possibly BC mortality, our results suggest the need to promptly address and treat vitamin D deficiency.

Association of vitamin D with HIV infected individuals, TB infected individuals, and HIV-TB co-infected individuals: a systematic review and meta-analysis.

Background: Vitamin D deficiency (VDD) is a worldwide disease. VDD is also associated with an increased risk of HIV-related comorbidities and mortality, and patients have a tendency to develop active tuberculosis compared to those with latent tuberculosis infection. Vitamin D supplementation may modulate HIV replication, improve TB inflammation and reduce progression of HIV-TB co-infection. Methods: We meta-analyzed individual participant data from cohort studies, cross-sectional study, and RCTs of vitamin D in HIV group, TB group, and HIV-TB group. The primary outcomes were differences in vitamin D level and VDD prevalence between three groups, the secondary outcomes were CD4 count, HIV viral load, time to sputum smear conversion, time to culture conversion, relapse, morality, and TB score. Results: For vitamin D levels, the overall mean difference (MD) between HIV group and TB group was -0.21 (95% CI, -20.80-20.38; p = 0.9, I2 = 84%), HIV group and HIV-TB group was 0.87 (95% CI, -11.45-13.20; p = 0.89, I2 = 87%), and TB group and HIV-TB group was 1.17 (95% CI, -5.21-7.55; p = 0.72, I2 = 85%). For vitamin D deficiency prevalence, the overall odds ratio (OR) for HIV group versus TB group was 1.23 (95% CI, 0.46-3.31; p = 0.68; I2 = 70%), HIV group versus HIV-TB group was 1.53 (95% CI, 1.03-2.29; p = 0.04; I2 = 0%), and TB group versus HIV-TB group was 0.85 (95% CI, 0.61-1.20; p = 0.36; I2 = 22%). In HIV-TB group, the overall OR for vitamin D group versus placebo group was 0.78 (95% CI, 0.34-1.67; p = 0.52; I2 = 60%). Conclusion: Our findings indicated that there were no variations in vitamin D levels between three groups. The prevalence of vitamin D deficiency was higher in the HIV-TB group than in the HIV group. Additionally, the administration of vitamin D supplements did not have obvious impact on CD4 count and viral load. Likewise, vitamin D had no effect on time to sputum smear conversion, time to culture conversion, relapse, 12-month morality, and TB score.

Prevalence of Micronutrient Deficiencies in Preoperative Bariatric Patients in a New Zealand Tertiary Centre.

PURPOSE: A potential complication of bariatric surgery is development of nutritional deficiencies. Study aims were to assess prevalence of micronutrient deficiencies in preoperative bariatric patients and to examine for ethnic differences. METHODS: Retrospective analysis of 573 patients that underwent bariatric surgery at Counties Manukau District Health Board was carried out. Mean preoperative levels of albumin, calcium, phosphate, folate, vitamin B12, vitamin D, magnesium, haemoglobin, haematocrit, mean cell volume, mean cell haemoglobin, ferritin, iron, and transferrin were calculated. Chi square, fisher exact test, and multiple logistic regression was used to assess for differences in prevalence of micronutrient deficiencies across ethnicities. RESULTS: The most common micronutrient deficiency was vitamin D (30.85%). There were statistically significant differences in vitamin D deficiency across ethnicities (p < 0.0001). Asians had the highest prevalence of vitamin D deficiency (60%), followed by Pacifica (44.57%), and Maori (31.68%). Asians were more likely to have vitamin D deficiency compared to NZ/Other Europeans (OR = 14.93, p < 0.001). Vitamin D deficiency was associated with higher BMI (OR = 1.05, p = 0.008). The second most common deficiency was iron (21.1%). Asians had the highest prevalence of iron deficiency (44%), followed by Maori (27.95%), and Pacifica (19.57%) (p = 0.0064). Compared to NZ/Other Europeans, Asians (OR = 4.26) and Maori (OR = 1.78) were more likely to be iron deficient (p = 0.004). Female gender was associated with iron deficiency (OR = 2.12, p = 0.007). CONCLUSION: Vitamin D and iron are the most common micronutrient deficiencies among preoperative bariatric patients in this cohort and ethnic differences were seen. There may be a role for preoperative supplementation in these at-risk ethnic groups.

Determinants of Vitamin D Status in Healthy Young Adults from Mexico City.

BACKGROUND AND AIMS: Vitamin D deficiency is a global health problem. The determinants of this deficiency have not been evaluated in developing countries such as Mexico. Thus, this study aimed to determine vitamin D intake and sun exposure and its relationship with plasma concentrations of 25-hydroxyvitamin D -25(OH)D- in young adults from Mexico City. METHODS: One hundred fifty five urban adult subjects were enrolled during 2017 and 2018. Sociodemographic, anthropometric, and clinical data, vitamin D intake, and sun exposure habits were collected. Plasma concentrations of 25(OH)D were also determined. RESULTS: The proportion of vitamin D deficiency was significantly higher in women than in men (65.7 vs. 43.4%, p = 0.012). The overall median dietary vitamin D intake was 112 IU/d (less than 20% of the recommended daily intake; RDI). 25-hydroxyvitamin D correlated directly with vitamin D intake, sun exposure score, waist-to-hip ratio, and age; an inverse significant association was found with body fat percentage. A multiple regression analysis was performed; simultaneous and significant (p <0.01) effects of sun exposure score, dietary vitamin D, the season of the year (spring-summer vs. fall-winter), and age were observed on 25(OH)D levels. CONCLUSION: High rates of vitamin D deficiency and insufficiency were observed in young adults from Mexico City. According to the RDI of this vitamin, its consumption, assessed by a 24 h multi-step nutritional questionnaire, was significantly low. A linear multiple regression model identified several predictors of plasma 25(OH)D concentrations. This multiple regression model was statistically validated.

Vitamin D levels in idiopathic inflammatory myopathy patients: a meta-analysis.

PURPOSE: This meta-analysis aimed to explore correlations between vitamin D and idiopathic inflammatory myopathy (IIM). METHODS: A comprehensive database search was conducted on 13 October 2020. Mean differences (MDs) and aggregated risk ratios (RR) with 95% confidence intervals (CIs) were used to determine the correlation between vitamin D deficiency (VDD) and IIM. Statistical analysis was performed with RevMan 5.4 and Stata15, statistical significance was set at p < 0.05. RESULTS: Search revealed five studies with 286 IIM patients and 480 healthy controls. Results with random-effects modeling indicated that serum vitamin D levels were significantly lower in IIM patients than in healthy controls (MD = -13.10 ng/mL; 95% CI: -16.51 to -9.68; p < 0.00001). No differences were found between patients with IIM and other autoimmune diseases on vitamin D levels (MD =-2.65 ng/mL; 95% CI: -11.31-6.01; p = 0.55). In two studies with 185 IIM patients, those with low vitamin D levels exhibited higher creatine kinase levels (MD = 85.20 IU/L; 95% CI: 72.67-97.73; p < 0.00001) than those with normal vitamin D levels. VDD was correlated with an increased risk of IIM (RR = 3.24, 95% CI: 1.81-5.79; p < 0.0001). CONCLUSION: This meta-analysis showed correlations between vitamin D level and IIM. The results indicated, VDD may be a risk factor for IIM, a determinant of immune dysregulation in IIM, or a consequence of IIM. Also, it implied further research to determine whether vitamin D supplementation is beneficial for patients with IIM.

[A survey on the current situation of serum vitamin A and vitamin D levels among children aged 2-<7 years of 20 cities in China].

Objective: To investigate serum vitamin A and vitamin D status in children aged 2-<7 years in 20 cities in China. Methods: A cross-sectional study was conducted. A total of 2 924 healthy children aged 2-<7 years were recruited from September 2018 to September 2019 from 20 cities in China, categorized by age groups of 2-<3 years, 3-<5 years, and 5-<7 years. The demographic and economic characteristics and health-related information of the enrolled children were investigated. Body weight and height were measured by professional staff members. The serum vitamin A and vitamin D levels were detected by high-performance liquid chromatography-tandem mass spectrometry. Chi-square test and Logistic regression were applied to analyze the association between vitamin A and vitamin D deficiency and insufficiency as well as their underlying impact factors. Results: The age of the 2 924 enrolled children was 4.33 (3.42, 5.17) years. There were 1 726 males (59.03%) and 1 198 females (40.97%). The prevalences of vitamin A and vitamin D deficiency in enrolled children were 2.19% (64/2 924) and 3.52% (103/2 924), respectively, and the insufficiency rates were 29.27% (856/2 924) and 22.20% (649/2 924), respectively. Children with both vitamin A and vitamin D deficiencies or insufficiencies were found in 10.50% (307/2 924) of cases. Both vitamin A (χ2=7.91 and 8.06, both P=0.005) and vitamin D (χ2=71.35 and 115.10, both P<0.001) insufficiency rates were higher in children aged 3-<5 and 5-<7 years than those in children aged 2-<3 years. Vitamin A and vitamin D supplementation in the last 3 months was a protective factor for vitamin A and D deficiency and insufficiency, respectively (OR=0.68 and 0.22, 95%CI 0.49-0.95 and 0.13-0.40, both P<0.05). The rates of vitamin A and D insufficiency was higher in children with annual household incomes <60 000 RMB than in those with annual household incomes ≥60 000 RMB (χ2=34.11 and 10.43, both P<0.01). Northwest and Southwest had the highest rates of vitamin A and vitamin D insufficiency in children aged 2-<7 yeas, respectively (χ2=93.22 and 202.54, both P<0.001). Conclusions: Among 20 cities in China, children aged 2-<7 years experience high rates of vitamin A and vitamin D insufficiency, which are affected by age, family economic level, vitamin A and vitamin D supplementation, and regional economic level. The current results suggest that high level of attention should be paid to vitamin A and vitamin D nutritional status of preschool children.

Seasonal Variations in 25-Hydroxyvitamin D Levels among Pediatric Patients Attending the Healthcare Centre.

Vitamin D plays an essential role in maintaining bone density, building the immune system, and regulating cell growth alongside other key biological functions. Limited data are available about the seasonal variation in vitamin D levels in the pediatric population in Saudi Arabia. This study aimed to investigate the seasonal influence on the pediatric circulating levels of 25(OH)D. A total of 1790 pediatric outpatients who visited the University healthcare centre were included in this study. Overall, there was a noticeably high prevalence (69%) of both combined 25(OH)D deficiency and insufficiency. The highest mean serum concentration of 25(OH)D was recorded in summer (29 ng/mL) and autumn (27 ng/mL). The deficient and insufficient categories were predominant, accounting for 33% and 36%, respectively. Comparable patterns were recorded during autumn, winter, and spring. Interestingly, the 25(OH)D level was significantly associated with the four seasons (p = 0.001), with females having a higher prevalence of 25(OH)D deficiency in the spring and summer than males. Furthermore, only in autumn and winter, we found a significant association between gender and 25(OH)D status (p < 0.001 for both). Another association between nationality and the circulating levels 25(OH)D was found during autumn and winter (p < 0.001 and p = 0.01), respectively. In all seasons, age had a negative impact on serum (OH)D levels. However, this relationship was statistically significant (p < 0.05) only in summer, autumn, and winter. Gender was a significant predictor, with 25(OH)D levels in autumn and winter and an odds ratio of 1.67 in autumn and 2 in winter, indicating that being men had a positive influence on circulating 25(OH)D levels. There were highly significant differences in 25(OH)D concentrations among different age categories. The Saudi population experiences low levels of vitamin D, particularly in autumn and winter periods. This study showed that seasonality, age category, nationality, and gender influence vitamin D status, suggesting the need for tailored intervention and monitoring of 25(OH)D status to reach adequate levels of vitamin D. Healthcare practitioners and policymakers may consider the interplay between age, nationality, gender, and seasonal variations when addressing vitamin D status and a targeted supplementation approach for high-risk groups that may develop health issues.