Prevalence of vitamin D deficiency in healthy Iranian children: A systematic review and meta-analysis

The relationship between physical activity levels and serum vitamin D levels varies among children and adolescents in different age groups

Objective

The objective of the present study was to explore the relationship between physical activity (PA) levels and serum vitamin D levels in children and adolescents of different ages and sexes.

Methods

All the data in this study were collected during two cycles (2011-2014) of the National Health and Nutrition Examination Survey (NHANES). Our study participants were aged ≥3 and < 20 years and had valid data for all variables, including vitamin D intake, serum vitamin D levels, PA volume and intensity levels, amount of time spent outdoors, body mass index (BMI), sex, and race.

Results

A total of 3,312 participants were included in the study; 1,672 were boys (50.4%), and 1,640 were girls (49.6%). A total of 250 (7.5%) children were aged 3-5 years, 1,474 (44.5%) were aged 6-11 years, and 1,588 (47.9%) were aged 12-19 years. Both PA volume and intensity were positively related to serum vitamin D levels in the 6-11-year-old boys and girls (p < 0.05 for both) and in the 12-19-year-old boys. No significant relationship between PA volume or intensity and serum vitamin D levels was detected in the 3-5-year-old group or in the 12-19-year-old girl group. The time spent outdoors and the BMI of the participants had mediating effects on the relationships of PA volume and intensity with serum vitamin D levels in boys and girls aged 6-11 years.

Conclusion

The relationship between PA and vitamin D varies among children and adolescents of different sexes and ages, and the sun exposure level and BMI had mediating effects on the relationship between PA and the serum vitamin D level. The mechanism of the relationship between PA and increased serum vitamin D levels needs further in-depth research.

High-dose oral vitamin D supplementation for prevention of infections in children aged 0 to 59 months: a systematic review and meta-analysis

CONTEXT

Vitamin D plays an important role in immune function, and the deficiency thereof has been associated with several infections, most notably respiratory tract infections. However, data from intervention studies investigating the effect of high-dose vitamin D supplementation on infections have been inconclusive.

OBJECTIVE

The aim of this study was to evaluate the level of evidence regarding the efficacy of vitamin D supplementation above the standard dose (400 IU) in preventing infections in apparently healthy children < 5 years of age.

DATA SOURCES

PubMed, Scopus, Science Direct, Web of Science, Google Scholar, CINAHL, and MEDLINE electronic databases were searched between August 2022 and November 2022. Seven studies met the inclusion criteria.

DATA EXTRACTION

Meta-analyses of outcomes in more than one study were performed using Review Manager software. Heterogeneity was evaluated using the I2 statistic. Randomized controlled trials in which vitamin D was supplemented at > 400 IU compared with placebo, no treatment, or standard dose were included.

DATA ANALYSIS

Seven trials that enrolled a total of 5748 children were included. Odds ratios (ORs) with 95%CIs were calculated using random- and fixed-effects models. There was no significant effect of high-dose vitamin D supplementation on the incidence of upper respiratory tract infection (OR, 0.83; 95%CI, 0.62-1.10). There was a 57% (95%CI, 0.30-0.61), 56% (95%CI, 0.27-0.07), and 59% (95%CI, 0.26-0.65) reduction in the odds of influenza/cold, cough, and fever incidence, respectively, with daily supplementation of vitamin D > 1000 IU. No effect was found on bronchitis, otitis media, diarrhea/gastroenteritis, primary care visits for infections, hospitalizations, or mortality.

CONCLUSION

High-dose vitamin D supplementation provided no benefit in preventing upper respiratory tract infections (moderate certainty of evidence) but reduced the incidence influenza/cold (moderate certainty of evidence), cough, and fever (low certainty of evidence). These findings are based on a limited number of trials and should be interpreted with caution. Further research is needed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42022355206.

Vitamin D deficiency prevention policies in Iran: a retrospective policy analysis

Aim

Iran has a higher prevalence of vitamin D deficiency (VDD) than the global level. This study aimed to assess VDD prevention policies in Iran through a policy analysis of agenda setting using the multiple streams framework (MSF).

Methods

Using Kingdon's MSF model, this qualitative analytical study performed a policy analysis on vitamin D-related policies in Iran. The policy documents were reviewed, and in-depth interviews were conducted with stakeholders (n = 27) using the framework analysis method. To categorize data and extract the related themes, MAXQDA version 10 was used.

Results

According to Kingdon's MSF theory, the problem stream included the high prevalence of VDD among Iranian infants (23.3%), adolescents (76%), and adults (59.1%). The policy stream was identified to focus on preventing programs for non-communicable diseases in the health sector. The political stream indicated that national and international support could provide a political climate for this issue.

Conclusion

According to our results, a window of opportunity for policymaking on VDD prevention has opened. However, there are some challenges related to the implementation of these policies. These include the dominance of a treatment-based view rather than a prevention-based approach in the health sector, economic problems, and restricted access to health services due to the outbreak of coronavirus disease 2019 (COVID-19). To strengthen and implement VDD prevention policies, the stakeholders need support from high-level policymakers.

Vitamin D deficiency and cardiometabolic risk factors in adolescents: systematic review and meta-analysis

Vitamin D deficiency is associated with an increase in the occurrence of cardiometabolic events, but the evidence of this relationship in adolescence is still limited. Thus, we analyzed the association between vitamin D deficiency and cardiometabolic risk factors in adolescents. Observational studies were searching in PubMed/Medline, Embase, Scopus, Web of Science, Science Direct, Lilacs, and Google Scholar database. Random effects models were used to summarize standardized mean differences for as a summary measure. The certainty of the evidence was verified using the Cochrane recommendations. A total of 7537 studies were identified, of which 32 were included in the systematic review and 24 in the meta-analysis.Vitamin D deficiency was associated with increased systolic pressure (SMD = 0.22; 95%CI = 0.10; 0.34), diastolic pressure (SMD = 0.23; 95%CI = 0.10; 0.35), glycemia (SMD = 0.13; 95%CI = 0.05; 0.12), and insulin (SMD = 0.50; 95%CI = 0.15; 0.84), an increase in the HOMA index (SMD = 0.48; 95%CI = 0.36; 0.60), high triglyceride values (SMD = 0.30; 95%CI = 0.11; 0.49), and reduced HDL concentrations (SMD= -0.25; 95%CI = -0.46; -0.04). No statistically significant association was observed for glycated hemoglobin, LDL cholesterol, and total cholesterol. Most of the studies presented low and moderate risks of bias, respectively. The certainty of the evidence was very low for all the outcomes analyzed. Vitamin D deficiency was associated with increased exposure to the factors linked to the occurrence of cardiometabolic diseases in adolescents. Systematic Review Registration: PROSPERO (record number 42,018,086,298).

Best Practices in Achieving Universal Health Coverage: A Scoping Review

Background: The Universal Health Coverage (UHC) is a very important and effective policy in the health system of countries worldwide. Using the experiences and learning from the best practices of successful countries in the UHC can be very helpful. Therefore, the aim of the present study is to provide a scoping review of successful global interventions and practices in achieving UHC. Methods: This is a scoping review study that has been conducted using the Arkesy and O'Malley framework. To gather information, Embase, PubMed, The Cochrane Library, Scopus, Scientific Information Database, and MagIran were searched using relevant keywords from 2000 to 2019. Studies about different reforms in health systems and case studies, which have examined successful interventions and reforms on the path to UHC, were included. Articles and abstracts presented at conferences and congresses were excluded. Framework Analysis was also used to analyze the data. Results: Out of 4257 articles, 57 finally included in the study. The results showed that of the 40 countries that had successful interventions, most were Asian. The interventions were financial protection (40 interventions that were categorized into 14 items), service coverage (31 interventions categorized into 7 items), population coverage (36 interventions categorized into 9 items), and quality (18 interventions categorized into 7 items), respectively. Also, the positive results of interventions on the way to achieving UHC were financial protection (14 interventions), service coverage (7 interventions), population coverage (9 interventions), and quality (7 interventions), respectively. Conclusion: This study provides a comprehensive and clear view of successful interventions in achieving the UHC. Therefore, with consideration to lessons learned from successful interventions, policymakers can design appropriate interventions for their country.

The Role of Vitamin D Supplementation in Children with Autism Spectrum Disorder: A Narrative Review

Children with autism spectrum disorder (ASD) present with persistent deficits in both social communication and interactions, along with the presence of restricted and repetitive behaviors, resulting in significant impairment in significant areas of functioning. Children with ASD consistently reported significantly lower vitamin D levels than typically developing children. Moreover, vitamin D deficiency was found to be strongly correlated with ASD severity. Theoretically, vitamin D can affect neurodevelopment in children with ASD through its anti-inflammatory properties, stimulating the production of neurotrophins, decreasing the risk of seizures, and regulating glutathione and serotonin levels. A Title/Abstract specific search for publications on Vitamin D supplementation trials up to June 2021 was performed using two databases: PubMed and Cochrane Library. Twelve experimental studies were included in the synthesis of this review. Children with ASD reported a high prevalence of vitamin D deficiency or insufficiency. In general, it was observed that improved vitamin D status significantly reduced the ASD severity, however, this effect was not consistently different between the treatment and control groups. The variations in vitamin D dose protocols and the presence of concurrent interventions might provide an explanation for the variability of results. The age of the child for introducing vitamin D intervention was identified as a possible factor determining the effectiveness of the treatment. Common limitations included a small number of participants and a short duration of follow-ups in the selected studies. Long-term, well-designed randomized controlled trials are warranted to confirm the effect of vitamin D on severity in children with ASD.

Prevalence of Childhood Sexual Abuse Among Women Using the Childhood Trauma Questionnaire: A Worldwide Meta-Analysis

Childhood sexual abuse (CSA) is a common form of childhood maltreatment. Several studies have shown that CSA adversely affects the physical and mental health. Numerous studies have evaluated the prevalence of CSA among females using various instruments. In this meta-analysis, we estimated the rate of CSA among women using the short form of the Childhood Trauma Questionnaire for the first time. Four databases (PsycINFO, PubMed, Cochrane Library, and Embase) were systematically searched for studies published as of April 2, 2018. Forty-eight articles (53 groups of samples) covering 22,224 individuals, including women, from 16 countries were selected. Using the random-effects model, the pooled overall rate of CSA was 24% (95% confidence interval [21%, 27%]). On subgroup analyses, the rate of female CSA in people with mental illness was higher than that in the general group; this result showed variability among different geographical regions.

The cost-effectiveness analysis of a nationwide vitamin D supplementation program among Iranian adolescents for adulthood cardiovascular diseases prevention

OBJECTIVE

This study aimed to evaluate a national vitamin D supplementation program's cost-effectiveness among Iranian adolescents to prevent cardiovascular diseases (CVDs) in adulthood.

STUDY DESIGN

A cost-effectiveness analytical study.

METHODS

A decision tree model was adopted to evaluate the cost per quality-adjusted life-year (QALY) of monthly intake of nine pearls of 50,000 IU vitamin D for nine months to prevent CVD a one-year horizon compared to no intervention. The analysis was conducted in Iranian adolescents in first or second high school grades of 47 climatically different Iran regions.

RESULTS

Our analytical analysis estimated the 1090$ cost per QALY gained of the monthly intake of 50,000 IU vitamin D for nine months among adolescents over a one-year horizon. Based on the incremental cost-effectiveness ratio (ICER) threshold of 1032-2666, vitamin D supplementation was cost-effective for adolescents to prevent adulthood CVD. It means that vitamin D supplementation costs were substantially less than the costs of CVD treatments compared to the no intervention.

CONCLUSIONS

Based on these findings, the national program of vitamin D supplementation in adolescents would be cost effective to prevent CVD development in adulthood. From an economic perspective, vitamin D supplementation, especially in adolescents with vitamin D deficiency, would be administrated.

Vitamin D Intoxication and Nephrocalcinosis in a Young Breastfed Infant

Numerous studies were performed assessing the benefits and side effects of vitamin D. Vitamin D helps in regulating the calcium and phosphate metabolism leading to a healthy mineral and bone development. Vitamin D intoxication is an uncommon event that leads to hypercalcemia which can be associated with both immediate and late morbidities that can cause severe renal complications. Here, we present a case of a 4-month-old girl with a history of decreased feed and activity due hypercalcemia and high vitamin D level, which led to nephrocalcinosis. The patient received IV fluids, IV diuretics, methylprednisolone, and bisphosphonate in order to normalize the calcium level in blood. With clear verbal and written instructions for the dosage and administration of vitamin D supplements, as well as clear warnings of the potential risks of overdose, vitamin D intoxication could be an easily avoidable condition.

Effect of Summer Sunshine Exposure on Vitamin D Status in Young and Middle Age Poles: Is 30 ng/mL Vitamin D Cut-Off Really Suitable for the Polish Population?

Background: There is no consensus regarding vitamin sufficiency status with either 20 ng/mL or 30 ng/mL sufficiency cut-off. We assessed the effects of summer sunshine exposure on vitamin D status. Participants: We measured vitamin D concentrations, PTH, creatinine, and total calcium in 132 healthy subjects, age 29.36 ± 13.57 years, in spring and autumn. Results: There was an overall increase in vitamin D concentrations from spring to autumn from 18.1 ± 7.39 ng/mL to 24.58 ± 7.72 ng/mL, (p < 0.001), accompanied by a decrease in PTH from 44.4 ± 17.76 pg/mL to 36.6 ± 14.84 pg/mL, (p < 0.001). In spring, only 5.3% of individuals were vitamin D sufficient for a 30 ng/mL cut-off, increasing to 23.2% in autumn (p < 0.001). In contrast, when a 20 ng/mL cut-off was employed, vitamin D sufficiency was found in 34.1% in spring and 66.4% individuals in autumn, respectively, (p < 0.001). In multiple regression analysis, holiday leave was the only significant determinant of vitamin D increase (p < 0.001). Conclusions: Holiday leave is the strongest determinant of an increase in vitamin D. The majority of healthy individuals fail to reach a 30 ng/mL vitamin D cut-off after summer sunshine exposure. This raises the question, whether such a cut-off is indeed suitable for the Polish population.

Prevalence and determinants of vitamin D deficiency in Iranian children and adolescents: the CASPIAN-V study

Purpose

To examine the prevalence and determinants of vitamin D deficiency in Iranian children and adolescents.

Methods

We used data from a national school-based surveillance program conducted among 7-18-year-old children and adolescents living in rural and urban areas in 30 provinces of Iran. Data on student's lifestyle, health behaviors, and health status was obtained through a validated questionnaire. Serum 25-hydroxy vitamin D (25-OH-D) level was measured by chemiluminescent immunoassay. Vitamin D deficiency was defined as serum 25-OH-D concentrations < 30 ng/ml. Determinants of vitamin D deficiency were identified using logistic regression analysis.

Results

Data of 2,596 participants were available for this study. Prevalence of vitamin D deficiency was 71.1 % (95 % Confidence interval (CI): 69.3-72.8 %), without significant difference between boys and girls (72.0 % vs. 70.1 %, respectively, p = 0.29). In the multivariate regression model, in both genders, those who reported having sun exposure for at least 30 min/day and those taking vitamin D supplementation had lower odds for vitamin D deficiency (all p values < 0.05). In boys, obesity increased the odds of vitamin D deficiency (adjusted OR, 95 % CI: 1.57, 1.08-2.27). The association of vitamin D deficiency with other demographic characteristics and food items was not statistically significant.

Conclusions

This large population-based study revealed a high frequency of hypovitaminosis D in Iranian children and adolescents. Sun exposure for at least 30 min/day and taking vitamin D supplementation may reduce the risk of vitamin D deficiency.

The association of serum levels of zinc and vitamin D with wasting among Iranian pre-school children

PURPOSE

Wasting is a main indicator of Child's undernutrition that is associated with several non-communicable diseases and child mortality. This is the first population-based study which evaluated the association of serum zinc and vitamin D levels with wasting in a Middle East region. We also reported the prevalence of vitamin D and zinc deficiencies among Iranian pre-school children aged 6 years.

METHODS

This was a multicenter cross-sectional study that included 425 children aged between 5 and 7 years (on average 6 years) with BMI-for-age Z-scores of < - 1 SD resident in urban and rural areas of Iran in the spring of 2012 as part of the National Integrated Micronutrient Survey 2 (NIMS-2). Anthropometric measurements and blood sampling were obtained. The prevalence of vitamin D and zinc deficiencies together with the correlations of these variables with the increase of BMI-for-age Z-scores were evaluated.

RESULTS

The prevalence of vitamin D and zinc deficiencies was 18.8% and 12.7%, respectively. In addition, 31.1% of children were wasted. Children in the second tertile of 25(OH)D levels were less likely to have wasting compared with those in the first tertile in both crude and adjusted models (OR 0.47, 95% CI 0.27-0.83). A significant inverse association was found between serum levels of zinc and wasting (OR 0.57, 95% CI 0.34-0.96); such that after adjusting for confounders, children in the highest tertile of serum zinc had 47% less odds of wasting compared with those in the first tertile (OR 0.53, 95% CI 0.31-0.91).

CONCLUSION

The prevalence of vitamin D and zinc deficiencies among Iranian pre-school children aged 6 years was 18.8 and 12.7%, respectively. Serum levels of vitamin D and zinc were inversely associated with wasting either before or after controlling for confounders.

LEVEL OF EVIDENCE

Level III, case-control analytic studies.

Association of Vitamin D Concentrations with subjective health complaints in children and adolescents: the CASPIAN-V study

BACKGROUND

Vitamin D deficiency (VDD) is recognized as a global pandemic. Identification, any association between VDD and subjective health complaints (SHC), can be helpful to realize critical mechanisms and improve psychological and somatic symptoms. Given few studies published on this issue and the importance of its clarification, the main objective of this study was to examine the association between VDD and the SHC in children and adolescents.

METHODS

In this national cross-sectional study, 2596 Iranian children and adolescents aged 8-18 years were included. Data on SHC, anthropometric indices, physical activity, and serum levels of vitamin D were collected. Logistic regression models (crude, adjusted) were applied to examine the association between the VDD and the SHC. Statistical analysis was performed using STATA version 11. P-values< 0.05 were considered as statistically significant.

RESULTS

Serum levels of vitamin D in approximately 70% of Iranian children and adolescents were lower than 30 ng/mL. Among the SHC, irritability (40.9%) and feeling anxiety (33.7%) were the most prevalent ones. Multiple complaints in students with the VDD was 2.5 times greater than those with sufficient vitamin D concentrations (p <  0.001). Compared to the reference group, the strongest association was found between vitamin D status and difficulties in getting to sleep (OR: 2.5, 95%CI: 1.18, 3.53, p <  0.001).

CONCLUSION

VDD was observed in the considerable percentage of the study population. There were no significant differences between the two gender groups. In addition, there were significant associations between vitamin D status and most of the somatic and psychological symptoms, particularly for getting to sleep. It seems national interventional programs for vitamin D supplementation or food fortifications can be helpful.

Vitamin D toxicity in a pediatric toxicological referral center; a cross-sectional study from Iran

Background

Vitamin D is an essential element for body health with its supplements generally administered to prevent vitamin D deficiency. Since these supplements are available in domestic settings, vitamin D toxicity may happen in children.

Methods

All children younger than 12 years who presented to the pediatric emergency department of Loghman Hakim Hospital, Tehran, Iran with history of ingestion of more than 1500 IU/day of vitamin D supplements were enrolled. Patients’ demographic data, on-presentation signs and symptoms, laboratory findings, treatments given, and outcome were evaluated.

Result

Fifteen patients presented during the study period. Their mean age was 46.53 ± 10.14 months and 12 (80%) were girls. All of them had unintentionally ingested vitamin D. Mean ingested dose was 406700.7 ± 227400.1 IU. In eight patients (53.3%), 25 hydroxy vitamin D level was more than 100 ng/mL. One patient experienced hypercalcemia while all of them were asymptomatic and discharged without complications. There was no significant difference between patients with and without high levels of 25 OH vitamin D regarding lab tests, toxicity course, and outcome.

Conclusions

It seems that acute vitamin D toxicity is a benign condition in our pediatric population which may be due to high prevalence of vitamin D deficiency in Iran.

Vitamin D Deficiency and Unclear Abdominal Pain in Patients from Low- and Middle-Income Countries

Background: Abdominal pain is one of the commonest symptoms in emergency departments (EDs). Diagnosis demands full attention and critical thinking, since many diseases manifest atypically and the consequences of overlooking the symptoms may be disastrous. Despite intensive diagnostic procedures, some cases remain elusive and unclear abdominal pain (UAP) is not infrequent. Emerging evidence supports the hypothesis that functional pain might be attributed to vitamin D deficiency (VDD). People with darker or covered skin are predisposed to developing VDD. Patients in Switzerland stemming from low- and middle-income countries (LMIC) are such a population. Aim: To identify cases with UAP in LMIC patients and to compare vitamin D status with a control group. Methods: A retrospective single-center case-control study was carried out from 1 January 2013 to 31 August 2016 in all adult patients (more than 16 years old) stemming from LMIC and presenting at the university ED of Bern with abdominal pain. Vitamin D status was retrieved from these cases when available. The control group consisted of patients without abdominal pain or metabolic diseases and was matched (1:1) to the cases for age, gender, body mass index, geographic distribution, and season of vitamin D estimation. Results: A total of 10,308 cases from LMIC were reported to the ED. In total, 223 cases were identified with UAP. The status of vitamin D was available for 27 patients; 27 matched individuals were subsequently retrieved for the control group. Women made up 56.7% of the UAP group and 43.3% of the control group. The most common origin of the LMIC subjects was southern Europe (20.4%), followed by southern Asia (16.7%) and Eastern Europe (13%). Fourteen UAP patients exhibited severe VDD (<25 nmol/L) versus one in the control group (p = 0.001). The difference remained significant if the patients were identified as having VDD (<50 nmol/L) or not (p = 0.024). Comparison of the means indicated that the UAP group had lower vitamin D levels than the control group (41.3 vs. 53.7 nmol/L, respectively), but this difference was marginal (p = 0.060) and not statistically significant. After adjustment for potential confounders, including gender, mean vitamin D levels remained non-significantly different between groups. In the sub-group analysis, vitamin D levels were lower in women than in men (p = 0.037), compared to the respective controls. Conclusion: This study showed for the first time that patients from LMIC who presented to ED with UAP displayed VDD. Validation from larger studies is warranted to evaluate the linkage of VDD with UAP.