Vitamin D insufficiency and severe asthma exacerbations in Puerto Rican children

Serum inflammatory factors, vitamin D levels, and asthma severity in children with comorbid asthma and obesity/overweight: a comparative study

Objective

To investigate serum inflammatory factors, vitamin D levels, and asthma severity in children with comorbid asthma and obesity/overweight, compared with those with asthma or obesity/overweight alone.

Methods

This retrospective comparative study included children suffering from asthma alone, asthma combined with obesity/overweight, or obesity/overweight alone at Shanghai Pudong New Area People's Hospital between January 2020 and December 2021.

Results

A total of 168 children (mean age: 4.32 ± 1.64 years; 117 males) were included. Compared with children with asthma alone (n = 56), those with comorbid asthma and obesity/overweight (n = 56) exhibited higher levels of serum levels of interleukin 6 (IL-6) (35.75 ± 24.56 vs. 15.40 ± 19.67), TNF-α (15.44 ± 7.35 vs. 12.16 ± 7.24), and leptin (3.89 ± 3.81 vs. 1.27 ± 2.31), and lower levels of 25-hydroxycholecalciferol (25-(OH) D3) (26.03 ± 10.77 vs. 37.15 ± 13.35), IL-10 (8.69 ± 2.76 vs. 15.32 ± 6.28), and IL-13 (449.40 ± 315.37 vs. 605.27 ± 351.02) (all P < 0.05). Compared with children with obese/overweight alone (n = 56), those with comorbid asthma and obesity/overweight had lower IL-10 (8.69 ± 2.76 vs. 12.29 ± 6.61) and higher IL-6 (35.75 ± 24.56 vs. 20.53 ± 17.07), IL-13 (449.40 ± 315.37 vs. 309.47 ± 257.45), and leptin (3.89 ± 3.81 vs. 2.48 ± 3.52) (all P < 0.05). Children with comorbid asthma and obesity/overweight showed higher Preschool Respiratory Assessment Measure (PRAM) scores (3.14 ± 2.40 vs. 1.93 ± 1.02, P = 0.008) and longer hospital stays (5.96 ± 1.25 vs. 5.29 ± 1.36 days, P = 0.007) compared to those with asthma alone.

Conclusions

Significant differences were observed in IL-6, IL-10, IL-13, 25-(OH) D3 levels, and leptin among children with asthma combined with obesity/overweight and those with asthma or obesity/overweight alone. Children with obesity/overweight alone displayed more severe clinical manifestations and longer hospital stays compared with those with asthma alone.

Persistent cat ownership and asthma in a longitudinal study of Puerto Rican youth

BACKGROUND

Epidemiologic studies have reported conflicting findings for cat or dog exposure and childhood asthma. No study has evaluated whether persistent pet exposure from early life to school age is associated with asthma or allergic sensitization in youth.

OBJECTIVE

To evaluate whether persistent ownership of a cat or a dog throughout childhood is associated with asthma in Puerto Rican youth, a group disproportionately affected with asthma.

METHODS

Prospective study of 384 youth who completed a baseline visit at ages 6 to 14 years and a second visit at ages 9 to 20 years. Persistent cat or dog ownership was defined as ownership of a cat or a dog in early life (during pregnancy or the first year of life) at either study visit (at school age). An allergen-specific IgE result was considered positive if more than or equal to 0.35 IU/mL. Logistic regression was used for the multivariable analysis of asthma and allergic sensitization.

RESULTS

In an analysis adjusting for household income, family history of atopy, persistent overweight or obesity, a persistent unhealthy diet, the time interval between study visits, and other covariates, persistent cat ownership was significantly associated with 68% reduced odds of asthma (95% CI for odds ratio = 0.11-0.92) but not with any allergic sensitization or sensitization to cat allergen. In contrast, persistent dog ownership was not significantly associated with asthma or allergic sensitization.

CONCLUSION

Among school-aged Puerto Rican youth followed for an average of 5 years, persistent cat ownership from early life to school age was inversely associated with asthma.

Nonlinear relationship between vitamin D status on admission and bronchopulmonary dysplasia in preterm infants

BACKGROUND

This research will explore non-linear relationship between vitamin D status on admission and bronchopulmonary dysplasia (BPD) in preterm infants.

METHODS

Data were retrospectively collected on preterm infants ≤32 weeks gestation and ≥28 weeks gestation hospitalized in our hospital between Jan. 2019 and Jul. 2022, which were classified into BPD and non-BPD groups according to BPD diagnostic criteria. Independent influences between the two groups were staged using comparison of differences between groups, univariate analysis, multivariate analysis, smoothed curve fitting, and threshold effect staging.

RESULTS

255 preterm infants were enrolled in this research, including 135 males and 120 females, with a mean gestational age of 30.59 ± 0.86 weeks. Vitamin D status on admission was an independent protective factor for BPD in preterm infants, with a 6% reduction in the probability of BPD for every 1 ng/ml increase in vitamin D status on admission (p = 0.036). There was also a non-linear relationship, with each 1 ng/ml increase in vitamin D status on admission being associated with an 87% reduction in the incidence of BPD when vitamin D status was <12.82 ng/ml (p = 0.010).

CONCLUSION

Vitamin D status on admission and BPD are non-linearly in preterm infants at 28-32 weeks gestation.

IMPACT STATEMENT

Analyzing the relationship between vitamin D status on admission and BPD. A nonlinear relationship and turning point between vitamin D status on admission and BPD was derived by curve fitting and threshold effect. We provide a new reference point for vitamin D supplementation for the prevention of neonatal BPD and to avoid ineffective overmedication.

Associations between vitamin D status and biomarkers linked with inflammation in patients with asthma: a systematic review and meta-analysis of interventional and observational studies

BACKGROUND

Numerous studies indicate an association between vitamin D status and inflammatory biomarkers in patients with asthma, but findings are inconsistent. This review aims to summarize the relationship between serum vitamin D status, assessed by 25-hydroxyvitamin D (25(OH)D) level, and inflammatory biomarkers in children and adults with asthma.

METHODS

A literature search of interventional and observational studies on 25(OH)D up to November 2022 was conducted across six electronic databases. Outcomes of interest included a range of inflammatory biomarkers classified in four categories: T helper 2 (Th2) pro-inflammatory, non-Th2 pro-inflammatory, anti-inflammatory, and non-specific biomarkers. Study characteristics were extracted and risk of bias was evaluated using the American Academy of Nutrition and Dietetics tool. Meta-analysis was conducted on studies with a low risk of bias, while narrative reporting was used to present the direction of associations (positive, no association, or negative) for each biomarker, overall and within the low-risk studies.

RESULTS

We included 71 studies (3 interventional, 68 observational) involving asthma patients. These studies investigated the association between serum 25(OH)D and Th2 pro-inflammatory biomarkers (N = 58), non-Th2 pro-inflammatory biomarkers (N = 18), anti-inflammatory biomarkers (N = 16), and non-specific biomarkers (N = 10). Thirteen (18.3%) studies, 50 (70.4%), and 8 (11.3%) were at high, moderate, and low risk of bias, respectively. In all studies, irrespective of risk of bias, the most frequently reported finding was no significant association, followed by a negative association between 25(OH)D and pro-inflammatory biomarkers and a positive association with anti-inflammatory biomarkers. In low-risk studies, one biomarker could be meta-analysed. The pooled estimate for 25(OH)D and serum IgE showed a negative association (β (95% CI)= - 0.33 (-0.65 to - 0.01); I2 = 88%; N = 4 studies). A negative association between 25(OH)D and blood eosinophils was also observed in the largest of three studies, as well as with cathelicidin (LL-37) in the only study reporting it. For other biomarkers, most low-risk studies revealed no significant association with 25(OH)D.

CONCLUSION

Serum 25(OH)D is negatively associated with serum IgE and possibly with blood eosinophils and LL-37, supporting an in vivo immunomodulatory effect of 25(OH)D. Future research should employ rigorous methodologies and standardized reporting for meta-analysis aggregation to further elucidate these associations.

U-shaped association between 25-hydroxyvitamin D concentration and the prevalence of asthma in the overweight and obese U.S. population

INTRODUCTION

Vitamin D supplementation has shown promise in averting asthma. However, the association between 25(OH)D levels and asthma prevention in various demographic groups remains inconclusive. Here, we explore this relationship in the context of overweight and obese individuals in the United States.

METHODS

We scrutinized cross-sectional data derived from the National Health and Nutrition Examination Survey conducted between 2007 and 2018. This dataset encompasses comprehensive information about asthma patients with a body mass index greater than 25 kg/m2, in addition to data regarding 25(OH)D concentration and other pertinent variables. Among the 3889 participants, 16.2% (631/3889) reported a history of asthma, constituting 1765 (45.4%) males and 2124 (54.6%) females. The median age was 56.0 years, with a standard deviation of 16.0 years. We conducted restricted cubic spline (RCS) regression analysis to assess the correlation between 25(OH)D levels and asthma.

RESULTS

After adjusting for confounders, compared to individuals with lower 25-hydroxyvitamin D concentration (group1 ≤ 46.6 nmol/L), the adjusted odds ratios (OR) for asthma in group2 (46.7-62 nmol/L), group3 (62.1-78.2 nmol/L), and group4 (≥78.3 nmol/L) were 0.68 (95% CI: 0.49-0.94, p < 0.021), 0.65 (95% CI: 0.47-0.88, p < 0.006), and 0.83 (95% CI: 0.61-1.12, p < 0.22), respectively. Restricted cubic spline (RCS) regression analysis revealed a nonlinear U-shaped curve (p = 0.017) with an inflection point at approximately 84.95 nmol/L.

CONCLUSIONS

High levels of 25(OH)D are correlated with a diminished prevalence of asthma among overweight and obese individuals in the United States.

Unveiling the potent effect of vitamin D: harnessing Nrf2/HO-1 signaling pathways as molecular targets to alleviate urban particulate matter-induced asthma inflammation

BACKGROUND

Asthma is the most common allergic disease characterized by an inflammatory response in the airways. Mechanismly, urban particulate matter (PM) is the most widely air pollutant associated with increased asthma morbidity and airway inflammation. Current research found that vitamin D is an essential vitamin with anti-inflammatory, antioxidant and other medical efficacy. Inadequate or deficient vitamin D often leads to the pathogenesis and stability of asthma. NGF exacerbates airway inflammation in asthma by promoting smooth muscle cell proliferation and inducing the Th2 immune response. Activation of the Nrf2/HO-1 signaling pathway can exert a protective effect on the inflammatory response in bronchial asthma. However, the specific mechanism of this pathway in PM-involved asthmatic airway smooth muscle cells remains unclear.

METHODS

Mice were sensitized and challenged with Ovalbumin (OVA) to establish an asthma model. They were then exposed to either PM, vitamin D or a combination of both, and inflammatory responses were observed. Including, acetylcholine stimulation at different concentrations measured airway hyperresponsiveness in mice. Bronchoalveolar lavage fluid (BALF) and serum were collected for TNF-α, IL-1β, IL-6, and Nerve growth factor (NGF) analysis. Additionally, lung tissues underwent histopathological examination to observe alveolar structure and inflammatory cell infiltration. Specific ELISA kits were utilized to determine the levels of the inflammatory factors TNF-α, IL-1β, IL-6, and Nerve growth factor (NGF). Nrf2/HO-1 signaling pathways were examined by western blot analysis. Meanwhile, we constructed a cell system with low HO-1 expression by lentiviral transfection of airway smooth muscle cells. The changes of Nrf2, HO-1, and NGF were observed after the treatment of OVA, PM, and Vit D were given.

RESULTS

The in vivo results showed that vitamin D significantly alleviated pathological changes in lung tissue of PM-exposed mice models. Mechanismly, vitamin D decreased substantial inflammatory cell infiltration in lung tissue, as well as the number of inflammatory cells in BALF. Furthermore, vitamin D reduced the heightened inflammatory factors including of TNF-α, IL-1β, IL-6, and NGF caused by PM exposure, and triggered the activity of nucleus Nrf2 and HO-1 in PM-exposed asthmatic mice. Notably, knockdown HO-1 weakens the Vitamin D- mediated inhibition to pollution toxicity in asthma. Importantly, in vitro experiments on OVA-stimulated mice airway smooth muscle cells, the results showed that OVA and PM, respectively, reduced Nrf2/HO-1 and increased NGF's expression, while vitamin D reversed the process. And in the HO-1 knockdown cell line of Lenti-si-HO-1 ASMCs, OVA and PM reduced Nrf2's expression, while HO-1 and NGF's expression were unchanged.

CONCLUSIONS

The above results demastrate that vitamin D downregulated the inflammatory response and the expression of NGF by regulating the Nrf2/HO-1 signaling pathways in airway smooth muscle cells, thereby showing potent anti-inflammatory activity in asthma.

Association between Vitamin D Levels, Puberty Timing, and Age at Menarche

Pubertal development represents the process of physical maturation where an adolescent reaches sexual maturity and attains reproductive function. The effects of vitamin D are mainly mediated by the vitamin D receptor (VDR), which is expressed in almost all body cells, including the ovary and human pituitary gland and animal hypothalamus. Thus, vitamin D has gained great interest as pathogenic factor of pubertal disorders and fertility. This narrative review aimed to provide a broad overview of the available literature regarding the association between vitamin D levels, puberty timing, and age at menarche. A review of the data on the involvement of micronutrient deficiency, as a modifiable cause of pubertal disorders, is important for the prediction and prevention of deficiencies as well as for fertility protection and should be considered a public health priority. Reported data support that vitamin D is a regulator of neuroendocrine and ovarian physiology and, more in detail, a deficiency of vitamin D is involved in altered pubertal timing. Considering the long-term consequences of early pubertal development and early menarche, the detection of modifiable causes is crucial in preventive strategies. Future studies in humans and with an increased scale are needed to elucidate the vitamin D role in sexual maturation and puberty development.

Low parental numeracy and severe asthma exacerbations in a prospective study of Puerto Rican youth

BACKGROUND

Numeracy is the mathematical knowledge required to understand and act on instructions from health care providers. Whether persistently low parental numeracy is linked to childhood asthma exacerbations is unknown.

OBJECTIVE

To evaluate whether low parental numeracy at 2 time points is associated with asthma exacerbations and worse lung function in Puerto Rican youth.

METHODS

Prospective study of 225 youth with asthma in San Juan (PR) who participated in 2 visits approximately 5.3 years apart, with the first at ages 6 to 14 years and the second at ages 9 to 20 years. Parental numeracy was assessed with a modified version of the Asthma Numeracy Questionnaire (score range = 0-3 points), and persistently low parental numeracy was defined as a score less than or equal to 1 point at both visits. Asthma exacerbation outcomes included more than or equal to 1 emergency department (ED) visit, more than or equal to 1 hospitalization, and more than or equal to 1 severe exacerbation (≥1 ED visit or ≥1 hospitalization) for asthma in the year before the second visit. Spirometry was conducted using an EasyOne spirometer (NDD Medical Technologies, Andover, Massachusetts).

RESULTS

In an analysis adjusting for age, sex, parental education, use of inhaled corticosteroids, and the time between study visits, persistently low parental numeracy was associated with more than or equal to 1 ED visit for asthma (odds ratio [ORs], 2.17; 95% confidence interval [CI], 1.10-4.26), more than or equal to 1 hospitalization for asthma (OR, 3.92; 95% CI, 1.42-10.84), and more than or equal to 1 severe asthma exacerbation (OR, 1.99; 95% CI, 1.01-3.87) in the year before the follow-up visit. Persistently low parental numeracy was not significantly associated with change in lung function measures.

CONCLUSION

Persistently low parental numeracy is associated with asthma exacerbation outcomes in Puerto Rican youth.

The Role of Vitamins in the Pathogenesis of Asthma

Vitamins play a crucial role in the proper functioning of organisms. Disturbances of their levels, seen as deficiency or excess, enhance the development of various diseases, including those of the cardiovascular, immune, or respiratory systems. The present paper aims to summarize the role of vitamins in one of the most common diseases of the respiratory system, asthma. This narrative review describes the influence of vitamins on asthma and its main symptoms such as bronchial hyperreactivity, airway inflammation, oxidative stress, and airway remodeling, as well as the correlation between vitamin intake and levels and the risk of asthma in both pre- and postnatal life.

Vitamin D for the management of asthma

BACKGROUND

Since the previous Cochrane Review on this topic in 2016, debate has continued surrounding a potential role for vitamin D in reducing risk of asthma exacerbation and improving asthma control. We therefore conducted an updated meta-analysis to include data from new trials completed since this date.

OBJECTIVES

To evaluate the effectiveness and safety of administration of vitamin D or its hydroxylated metabolites in reducing the risk of severe asthma exacerbations (defined as those requiring treatment with systemic corticosteroids) and improving asthma symptom control.

SEARCH METHODS

We searched the Cochrane Airways Group Trial Register and reference lists of articles. We contacted the authors of studies in order to identify additional trials. Date of last search: 8 September 2022.

SELECTION CRITERIA

We included double-blind, randomised, placebo-controlled trials of vitamin D in children and adults with asthma evaluating exacerbation risk or asthma symptom control, or both.

DATA COLLECTION AND ANALYSIS

Four review authors independently applied study inclusion criteria, extracted the data, and assessed risk of bias. We obtained missing data from the authors where possible. We reported results with 95% confidence intervals (CIs). The primary outcome was the incidence of severe asthma exacerbations requiring treatment with systemic corticosteroids. Secondary outcomes included the incidence of asthma exacerbations precipitating an emergency department visit or requiring hospital admission, or both, end-study childhood Asthma Control Test (cACT) or Asthma Control Test (ACT) scores, and end-study % predicted forced expiratory volume in one second (FEV1). We performed subgroup analyses to determine whether the effect of vitamin D on risk of asthma exacerbation was modified by baseline vitamin D status, vitamin D dose, frequency of dosing regimen, form of vitamin D given, and age of participants.

MAIN RESULTS

We included 20 studies in this review; 15 trials involving a total of 1155 children and five trials involving a total of 1070 adults contributed data to analyses. Participant ages ranged from 1 to 84 years, with two trials providing data specific to participants under five years (n = 69) and eight trials providing data specific to participants aged 5 to 16 (n = 766). Across the trials, 1245 participants were male and 1229 were female, with two studies not reporting sex distribution. Fifteen trials contributed to the primary outcome analysis of exacerbations requiring systemic corticosteroids. The duration of trials ranged from three to 40 months; all but two investigated effects of administering cholecalciferol (vitamin D3). As in the previous Cochrane Review, the majority of participants had mild to moderate asthma, and profound vitamin D deficiency (25-hydroxyvitamin D (25(OH)D) < 25 nmol/L) at baseline was rare. Administration of vitamin D or its hydroxylated metabolites did not reduce or increase the proportion of participants experiencing one or more asthma exacerbations treated with systemic corticosteroids (odds ratio (OR) 1.04, 95% CI 0.81 to 1.34; I2 = 0%; 14 studies, 1778 participants; high-quality evidence). This equates to an absolute risk of 226 per 1000 (95% CI 185 to 273) in the pooled vitamin D group, compared to a baseline risk of 219 participants per 1000 in the pooled placebo group. We also found no effect of vitamin D supplementation on the rate of exacerbations requiring systemic corticosteroids (rate ratio 0.86, 95% CI 0.62 to 1.19; I2 = 60%; 10 studies, 1599 participants; high-quality evidence), or the time to first exacerbation (hazard ratio 0.82, 95% CI 0.59 to 1.15; I2 = 22%; 3 studies, 850 participants; high-quality evidence). Subgroup analysis did not reveal any evidence of effect modification by baseline vitamin D status, vitamin D dose, frequency of dosing regimen, or age. A single trial investigating administration of calcidiol reported a benefit of the intervention for the primary outcome of asthma control. Vitamin D supplementation did not influence any secondary efficacy outcome meta-analysed, which were all based on moderate- or high-quality evidence. We observed no effect on the incidence of serious adverse events (OR 0.89, 95% CI 0.56 to 1.41; I2 = 0%; 12 studies, 1556 participants; high-quality evidence). The effect of vitamin D on fatal asthma exacerbations was not estimable, as no such events occurred in any trial. Six studies reported adverse reactions potentially attributable to vitamin D. These occurred across treatment and control arms and included hypercalciuria, hypervitaminosis D, kidney stones, gastrointestinal symptoms and mild itch. In one trial, we could not ascertain the total number of participants with hypercalciuria from the trial report. We assessed three trials as being at high risk of bias in at least one domain; none of these contributed data to the analysis of the outcomes reported above. Sensitivity analyses that excluded these trials from each outcome to which they contributed did not change the null findings.

AUTHORS' CONCLUSIONS

In contrast to findings of our previous Cochrane Review on this topic, this updated review does not find evidence to support a role for vitamin D supplementation or its hydroxylated metabolites to reduce risk of asthma exacerbations or improve asthma control. Participants with severe asthma and those with baseline 25(OH)D concentrations < 25 nmol/L were poorly represented, so further research is warranted here. A single study investigating effects of calcidiol yielded positive results, so further studies investigating effects of this metabolite are needed.

Human matters in asthma: Considering the microbiome in pulmonary health

Microbial communities form an important symbiotic ecosystem within humans and have direct effects on health and well-being. Numerous exogenous factors including airborne triggers, diet, and drugs impact these established, but fragile communities across the human lifespan. Crosstalk between the mucosal microbiota and the immune system as well as the gut-lung axis have direct correlations to immune bias that may promote chronic diseases like asthma. Asthma initiation and pathogenesis are multifaceted and complex with input from genetic, epigenetic, and environmental components. In this review, we summarize and discuss the role of the airway microbiome in asthma, and how the environment, diet and therapeutics impact this low biomass community of microorganisms. We also focus this review on the pediatric and Black populations as high-risk groups requiring special attention, emphasizing that the whole patient must be considered during treatment. Although new culture-independent techniques have been developed and are more accessible to researchers, the exact contribution the airway microbiome makes in asthma pathogenesis is not well understood. Understanding how the airway microbiome, as a living entity in the respiratory tract, participates in lung immunity during the development and progression of asthma may lead to critical new treatments for asthma, including population-targeted interventions, or even more effective administration of currently available therapeutics.

Vitamin D status and asthma, lung function, and hospitalization among British adults

Background

Vitamin D has been known to be associated with asthma. However, the association between vitamin D status and asthma, lung function as well as hospitalization among adults remains unclear.

Objective

To investigate the role of serum vitamin D in asthma prevalence, lung function, and asthma control in adults.

Methods

Multivariable logistic regression was applied to assess the relationship between serum vitamin D and asthma prevalence, lung function (FEV1, FVC, and FEV1/FVC), current wheeze, and asthma-linked hospitalizations in a cross-sectional study of 435,040 adults aged 37-73 years old from the UK Biobank.

Results

Compared to vitamin D deficiency, the odds of asthma were decreased by 6.4% [adjusted odds ratio (aOR) = 0.936; 95% CI: 0.911-0.962; p < 0.001] and 9.8% (aOR = 0. 0.902; 95% CI: 0.877-0. 0.927; p < 0.001) in individuals with insufficient and optimal vitamin D concentration, respectively, in the fully adjusted model. In total asthmatic patients, serum vitamin D was obviously and positively related with FEV1 (β = 1.328 ml, 95% CI = 0.575-2.080), FVC (β = 2.018 ml, 95% CI = 1.127-2.908), and FEV1/FVC (β = 0.006%, 95% CI = 0.002-0.010). Asthmatic patients whose vitamin D level was in the deficient category had 9.3-19.9% higher odds of current wheeze than insufficient categories (aOR = 0.907; 95% CI: 0.861-0.957; p < 0.001) and optimal categories (aOR = 0.801; 95% CI: 0.759-0.845; p < 0.001), but the relationship between vitamin D and asthma hospitalization was not significant.

Conclusion

Vitamin D deficiency was related to higher odds of asthma and current wheeze, and lower lung function in a large sample size study of British adults. Our results indicate a potential positive impact of serum vitamin D on asthma occurrence and disease control in adults.

A Meta-Analysis on Vitamin D Supplementation and Asthma Treatment

Background

Vitamin D, as an immunomodulator, may be related to the therapeutic effect of asthma patients, but the research in this area is still controversial. The aim of this meta-analysis was to analyze the role of vitamin D supplementation in the treatment of asthma patients.

Materials and Methods

Randomized Controlled Trials (RCTs) of vitamin D supplementation in asthma were searched in PubMed, EMBASE, and the Cochrane library. Primary outcomes were forced expiratory volume in one second (FEV1), asthma exacerbations, Asthma Control Test scores (ACT scores), and fractional exhaled nitric oxide (FENO).

Results

A total of 10 RCTs were included, including 1,349 patients. Vitamin D supplementation didn't affect the ACT scores (SMD = 0.04, 95% CI = -0.13 to 0.21, P = 0.87), FEV1 (SMD = 0.04, 95% CI = -0.35 to 0.43, P < 0.01) and FENO (SMD = -0.01, 95% CI = -0.22 to 0.20, P = 0.27), but reduced the rate of asthma exacerbations (RR = 0.69, 95% CI = 0.41 to 0.88, P < 0.01), especially in subgroups of children (RR = 0.46, 95% CI = 0.30 to 0.70, P = 0.83) and follow up time less than 6 months (RR = 0.45, 95% CI = 0.32 to 0.63, P = 0.95). Additionally, though there was only one study included in the subgroup, it significantly enhanced FEV1 at the last visit for patients whose FEV1 baseline value was less than 70% (SMD = 0.94, 95% CI = 0.47 to 1.41).

Conclusion

Vitamin D supplementation can reduce asthma exacerbations, especially in children, and within 6 months of follow up time. In addition, vitamin D has a positive effect on improving FEV1 of patients whose FEV1 baseline value is less than 70%, but more RCTs are still needed to support this conclusion.

Systematic Review Registration

[https://inplasy.com], identifier [10.37766/inplasy20 22.6.0049].

Calcifediol for Use in Treatment of Respiratory Disease

Calcifediol is the prohormone of the vitamin D endocrine system (VDES). It requires hydroxylation to move to 1,25(OH)2D3 or calcitriol, the active form that exerts its functions by activating the vitamin D receptor (VDR) that is expressed in many organs, including the lungs. Due to its rapid oral absorption and because it does not require first hepatic hydroxylation, it is a good option to replace the prevalent deficiency of vitamin D (25 hydroxyvitamin D; 25OHD), to which patients with respiratory pathologies are no strangers. Correcting 25OHD deficiency can decrease the risk of upper respiratory infections and thus improve asthma and COPD control. The same happens with other respiratory pathologies and, in particular, COVID-19. Calcifediol may be a good option for raising 25OHD serum levels quickly because the profile of inflammatory cytokines exhibited by patients with inflammatory respiratory diseases, such as asthma, COPD or COVID-19, can increase the degradation of the active metabolites of the VDES. The aim of this narrative revision is to report the current evidence on the role of calcifediol in main respiratory diseases. In conclusion, good 25OHD status may have beneficial effects on the clinical course of respiratory diseases, including COVID-19. This hypothesis should be confirmed in large, randomized trials. Otherwise, a rapid correction of 25(OH)D deficiency can be useful for patients with respiratory disease.

Association of vitamin D levels and asthma exacerbations in children and adolescents: Experience from a tertiary care center

The role of vitamin D as an immunosuppressant and anti-inflammatory has been studied previously for different pathologies in different populations globally. Relationships between serum vitamin D levels and its effect on asthma exacerbations in the adolescent asthma population are not well studied in this region. Therefore, this study was conducted to determine the vitamin D status in pediatric and adolescent asthma patients, and its association with asthma exacerbations. A retrospective study was conducted at The Aga Khan University Hospital from 2016 to 2020. Children and adolescents who were diagnosed and admitted with acute asthma exacerbations and who had at least one measurement of 25 hydroxy-vitamin D (25 OHD) were included in the study. Serum vitamin D levels were documented for enrolled patients and their past 2-year data was analyzed for asthma exacerbations, mean length of stay per admission, and admission plus length of stay at High Dependency Unit. 114 patients were included in the study. 41 patients (35.96%) were found to be vitamin D deficient, 38 patients (33.3%) were vitamin D insufficient, and 35 patients (30.7%) were labeled as vitamin D sufficient. The average number of exacerbations per year was significantly high in vitamin D deficient group (2.82±1.11) in comparison with insufficient (2.05±0.92) and sufficient groups (1.37±0.59) (p<0.001). Vitamin D deficiency is related to an increased number of annual asthma exacerbations, length of stay per admission, and admission into High Dependency Unit (HDU).

Persistent overweight or obesity, lung function, and asthma exacerbations in Puerto Rican youth

BACKGROUND

Whether persistent overweight or obesity affects lung function or asthma morbidity in youth is unclear.

OBJECTIVE

To evaluate overweight or obesity that persists between school age and adolescence and change in lung function and total immunoglobulin (Ig)E and severe asthma exacerbations in Puerto Rican youth.

METHODS

Prospective study of 340 Puerto Rican youth assessed at 2 visits, the first at ages 6 to 14 years and the second at ages 9 to 20 years. Persistent overweight or obesity was defined as a body mass index z-score greater than or equal to 85th percentile at both visits. Outcomes of interest were change in percent predicted (%pred) lung function measures and total IgE between study visits and severe asthma exacerbations in the year before visit 2. Logistic or linear regression was used for multivariable analysis.

RESULTS

In multivariable analysis, persistently overweight or obese subjects had changes in %pred forced expiratory volume in 1 second (FEV1) (β = -5.07%; 95% confidence interval, -1.51% to -8.62%; P < .01) and %pred FEV1 to forced vital capacity (FVC) ratio (β = -2.85%; 95% confidence interval, -0.18% to -5.51%; P = .04) which were lower than those observed in subjects with normal weight at both study visits (control subjects). Compared with control subjects, those who were persistently overweight or obese and those who became overweight or obese at visit 2 had increased odds of more than or equal to 1 severe asthma exacerbation in the year before visit 2. There was no significant association between persistent overweight or obesity and change in %pred FVC or total IgE (P > .20 for both instances).

CONCLUSION

In a prospective study of Puerto Rican youth, persistently overweight or obese subjects had lower changes in FEV1 or FEV1 to FVC ratio and higher odds of severe asthma exacerbations than subjects of normal weight.

Perimenstrual Asthma in Adolescents: A Shared Condition in Pediatric and Gynecological Endocrinology

Asthma is a frequent medical condition in adolescence. The worsening of the most common symptoms perimenstrually is defined as perimenstrual asthma (PMA). The cause of PMA remains unclear, but a role for hormonal milieu is plausible. Data on PMA in adolescents are limited, and its management is not fully established. We aimed to discuss the PMA phenomenon in young females from pathophysiology to preventive strategies, focusing on the relationship with the hormonal pattern. The fluctuation of estrogens at ovulation and before menstruation and the progesterone secretion during the luteal phase and its subsequent withdrawal seem to be the culprits, because the deterioration of asthma is cyclical during the luteal phase and/or during the first days of the menstrual cycle. Conventional asthma therapies are not always effective for PMA. Preventive strategies may include innovative hormonal contraception. Even a possible beneficial effect of other hormonal treatments, including estrogens, progestogens, and androgens, as well as leukotriene receptor antagonists and explorative approach using microbial-directed therapy, is considered. The underlying mechanisms, through which sex-hormone fluctuations influence asthma symptoms, represent a challenge in the clinical management of such a distressing condition. Further studies focused on young females are mandatory to promote adolescent health.

The Role of Comorbidities in Difficult-to-Control Asthma in Adults and Children

Assessment of asthma comorbidities, conditions that adversely affect the pathobiology of asthma or impair its response to therapies, is a fundamental step in the evaluation and management of patients with difficult-to-treat asthma. Identifying and effectively treating asthma comorbidities, such as obesity, obstructive sleep apnea, and chronic sinusitis with nasal polyps, may improve asthma control and reduce exacerbations. In addition, identifying comorbid T2 inflammatory conditions may help guide optimal selection of biologic therapies. Here, we describe common comorbid conditions found in adult and pediatric difficult-to-control asthma, discuss evidence for the association with asthma morbidity and treatment benefit, and provide information on how and when to assess comorbidities.

An Update on Vitamin D Deficiency Status in Malaysia

Vitamin D is essential for maintaining serum calcium levels, ensuring sufficient bone mineralization, immunomodulatory properties, and a protective effect on the cardiovascular system, renal disease, cancer, as well as in pregnancy. Vitamin D deficiency is prevalent worldwide, and it is not related to a country's development index. However, the data on vitamin D deficiencies are primarily taken from out-of-date, small-scale studies on target age groups or specific diseases, rather than from large-scale, population-based surveys. In Malaysia, for the past 16 years, studies were conducted involving adult men and women, pregnant women, postmenopausal women, adolescent, and children especially with specific diseases such as spina bifida, epilepsy, chronic liver disease, and atopic dermatitis. Only a few large surveys were conducted involving children and adolescents. Across the specific target population studied, vitamin D deficiency and insufficiency were seen particularly among females, Indians, and those of Malay ethnicity. This is related to widely known causes of vitamin D deficiency such as skin type (melanin) and sun avoidant lifestyles that include covering clothes, largely practiced by Malay Muslims in Malaysia. Other related causes or the high-risk groups are breastfed infants, the elderly, the obese, those on medications, and those characterized by fat malabsorption and geophysical factors. Vitamin D deficiency can be managed with pharmacological or non-pharmacological approaches, depending on the severity. The objective is to raise serum vitamin D to a normal level, hence, relieving the symptoms and reducing the adverse health outcomes. Despite no clear guidelines in treating vitamin D deficiency in Malaysia, this condition can be prevented with taking adequate vitamin D in food resources, sun exposure, or supplementation. Special attention should be given to high-risk groups including infants, obese patients, and the elderly.

Can vitamin D3 supplementation reduce the time to severe asthma exacerbations in children with asthma?

Vitamin D deficiency in children needs to be treated irrespective of asthma benefits. The VDKA trial showed that vitamin D supplementation in school-age asthmatic children with vitamin D insufficiency did not improve asthma control. https://bit.ly/2UF3j61.

Effect of vitamin D supplementation on total and allergen-specific IgE in children with asthma and low vitamin D levels

BACKGROUND

Observational studies have yielded inconsistent findings for the relation between vitamin D level and total IgE or allergic sensitization.

OBJECTIVE

To determine whether vitamin D supplementation reduces levels of total IgE and IgE to each of 2 common indoor allergens in children with asthma and low vitamin D levels.

METHODS

Total IgE, IgE to Dermatophagoides pteronyssinus, and IgE to Blattella germanica were measured at the randomization and exit visits for 174 participants in the Vitamin D Kids Asthma Study, a multicenter, double-blind, randomized placebo-controlled trial of vitamin D₃ supplementation (4000 IU/d) to prevent severe exacerbations in children with persistent asthma and vitamin D levels less than 30 ng/mL. Multivariable linear regression was used for the analysis of the effect of vitamin D supplementation on change in each IgE measure.

RESULTS

Participants were followed for an average of 316 days. At the exit visit, more subjects in the vitamin D arm achieved a vitamin D level equal to or more than 30 ng/mL compared with those in the placebo arm (87% vs 30%; P < .001). In a multivariable analysis, vitamin D₃ supplementation had no significant effect on change in total IgE, IgE to Dermatophagoides pteronyssinus, or IgE to Blattella germanica between the exit and randomization visits (eg, for log₁₀ total IgE, β = 0.007; 95% CI, -0.061 to 0.074; P = .85).

CONCLUSIONS

Vitamin D supplementation, compared with placebo, has no significant effect on serum levels of total IgE, IgE to dust mite, or IgE to cockroach in children with asthma and low vitamin D levels.

Pediatric Obesity-Related Asthma: The Role of Nutrition and Nutrients in Prevention and Treatment

Childhood obesity rates have dramatically risen in numerous countries worldwide. Obesity is likely a factor in increased asthma risk, which is already one of the most widespread chronic respiratory pathologies. The pathogenic mechanism of asthma risk has still not yet been fully elucidated. Moreover, the role of obesity-related inflammation and pulmonary overreaction to environmental triggers, which ultimately result in asthma-like symptoms, and the importance of dietary characteristics is well recognized. Diet is an important adjustable element in the asthma development. Food-specific composition of the diet, in particular fat, sugar, and low-quality nutrients, is likely to promote the chronic inflammatory state seen in asthmatic patients with obesity. An unbalanced diet or supplementation as a way to control asthma more efficiently has been described. A personalized dietary intervention may improve respiratory symptoms and signs and therapeutic response. In this narrative review, we presented and discussed more recent literature on asthma associated with obesity among children, focusing on the risk of asthma among children with obesity, asthma as a result of obesity focusing on the role of adipose tissue as a mediator of systemic and local airway inflammation implicated in asthma regulation, and the impact of nutrition and nutrients in the development and treatment of asthma. Appropriate early nutritional intervention could possibly be critical in preventing and managing asthma associated with obesity among children.

Does vitamin D deficiency in asthma affect clinical and functional parameters? A Turkish multicenter study

Background: In recent years, interest in the effects of vitamin D on human health and the immune system has increased. Objective: This study aimed to investigate the relationship of vitamin D with asthma severity, attacks, and clinical and functional parameters in adult patients with asthma who were living in different geographic regions in Turkey. Methods: A total of 384 patients with stable asthma and 87 control subjects were included. A physical examination and a pulmonary function test were performed, and routine blood analyses and vitamin D levels were evaluated. Asthma Control Test was applied. The number of exacerbations in the previous year, asthma therapy, and medication adherence were recorded. Results: In our study, vitamin D levels were below the target values in both patients with asthma (median [minimum-maximum] 16.0 ng/mL [3.5-48 ng/ml]) and control subjects (median [minimum-maximum] 20.0 ng/mL [5.8-58.79 ng/mL]). However, it was lower in the patients with asthma than in the control subjects (p = 0.001). There was a negative relationship between the levels of vitamin D and the severity of asthma (Kendall τ = -0.146; p < 0.001). Furthermore, the patients with severe asthma were received The Global Initiative for Asthma (GINA) step 5 treatment showed significantly lower vitamin D compared with the patients who received GINA step 4 treatment (p = 0.037). Vitamin D levels correlated with forced vital capacity (FVC), forced expiratory volume in the first second of expiration (FEV1), and peak expiratory flow (r, 0.221-0.236; p ≤ 0.001). In addition, a positive relationship was found between Asthma Control Test and vitamin D (r = 0.229; p = 0.001). However, body mass index (BMI), asthma exacerbation, and hospitalization were inversely related to vitamin D (r, 0.198-0.233; p = 0.001). Multivariable regression analysis revealed that FVC (p = 0.002), FEV1 (p = 0.033), and BMI (p = 0.037) were independent determinants associated with vitamin D. Conclusion: This study suggested a high prevalence of vitamin D deficiency in adults with asthma living in different geographic areas in Turkey. Vitamin D deficiency is associated with asthma severity, poor control, and lower lung function.

Testosterone-to-estradiol ratio and lung function in a prospective study of Puerto Rican youth

BACKGROUND

Age- and sex-related differences in asthma may be due to changes in sex hormone levels.

OBJECTIVE

To evaluate whether a change in free testosterone or free testosterone-to-estradiol ratio is associated with changes in lung function and eosinophils in the Puerto Rican youth.

METHODS

We tested for the association between the change in sex hormone levels and change in lung function or change in eosinophils in a prospective study of 317 children (with and without asthma) followed up from ages 6 to 14 years to ages 10 to 20 years (146 females, 171 males) in San Juan, Puerto Rico. Serum levels of testosterone, estradiol, sex hormone-binding globulin, and progesterone were measured at 2 study visits, approximately 4.9 years apart. Using testosterone and sex hormone-binding globulin levels, we derived free testosterone and the free testosterone-to-estradiol ratio. Multivariable linear regression was used for the analysis of change in lung function and eosinophils, conducted separately by sex.

RESULTS

In girls, each quartile increment in the free testosterone-to-estradiol ratio was associated with a 2.03% increment in percent predicted forced expiratory volume in 1 second (FEV₁)/forced vital capacity (FVC) between study visits. In males, each quartile increment in the free testosterone-to-estradiol ratio was associated with a 3.27% increment in percent predicted FEV₁ and a 1.81% increment in percent predicted FEV₁/FVC between study visits. In girls with asthma, an increased free testosterone-to-estradiol ratio was significantly associated with decreased eosinophils between visits (P=0.03).

CONCLUSION

In Puerto Rican youth, increased free testosterone-to-estradiol ratio over time was associated with an increased FEV₁/FVC in both sexes, and with an increased FEV₁ in males.

The role of nutrition in asthma prevention and treatment

Asthma is a chronic respiratory condition characterized by airway inflammation and hyperreactivity. Prevalence has continued to rise in recent decades as Western dietary patterns have become more pervasive. Evidence suggests that diets emphasizing the consumption of plant-based foods might protect against asthma development and improve asthma symptoms through their effects on systemic inflammation, oxidation, and microbial composition. Additionally, increased fruit and vegetable intake, reduced animal product consumption, and weight management might mediate cytokine release, free radical damage, and immune responses involved in the development and course of asthma. The specific aim of this review paper is to examine the current literature on the associations between dietary factors and asthma risk and control in children and adults. Clinical trials examining the mechanism(s) by which dietary factors influence asthma outcomes are necessary to identify the potential use of nutritional therapy in the prevention and management of asthma.

Effect of Vitamin D Supplementation on Improvement of Symptoms in Mild-to-Moderate Asthma Patients with Vitamin D Insufficiency and Deficiency

BACKGROUND

In the current study, we assessed the effect of vitamin D supplementation on improvement of symptoms in mild-to-moderate asthma patients with vitamin D insufficiency and deficiency.

MATERIALS AND METHODS

This randomized, controlled clinical trial included 132 mild-to-moderate asthma patients with vitamin D insufficiency (n=66) and those with vitamin D deficiency (n=66). They were assigned randomly to two groups of cases (with two subgroups) and controls (with two subgroups). In the case subgroups, for patients with vitamin D deficiency, a dose of 50,000 U vitamin D supplementation was administered orally on a weekly basis and for six weeks followed by a maintenance dose of 1000 U daily. For patients with vitamin D insufficiency, a dose of 1000 U vitamin D supplementation was prescribed daily. In control group, we administered placebo. The information including asthma symptoms, parameters measured by spirometer (Forced Vital Capacity-FVC, Forced Expiratory Volume in one second-FEV1) and 25-hydroxyvitamin D [25(OH)D] concentration was collected at baseline and three months later and analyzed using SPSS, Version 20.

RESULTS

Improvement of FEV1/FVC ratios were found in both groups but this improvement in both case subgroups of patients with vitamin D insufficiency and deficiency suggested more appropriate results compared to control group (P-value=0.022). Moreover, the correlation between changes in 25(OH)D level and changes in FEV1 was positive and significant in patients receiving vitamin D supplementation within a three-month follow up (r=0.202, P-value=0.042).

CONCLUSION

According to the results, vitamin D supplementation can be associated with the improvement of asthma symptoms and lung function in mild-to-moderate asthma patients with vitamin D insufficiency and deficiency.

Back to basics: review on vitamin D and respiratory viral infections including COVID-19

IMPORTANCE

As the scientific community is in a marathon in finding out the cure for COVID-19, in this crisis, it is essential for the physicians not to forget about the basics. Due to the pandemic crisis, in many nursing homes and hospitals, there established new policies on decreasing unnecessary medications to minimize cross-contamination. Sometimes these policies are making providers avoid essential drugs such as Vitamins, including Vitamin D. In this paper, we try to emphasize the importance of Vitamin D in COVID-19 and respiratory viral patients.

RELEVANCE

Vitamin D helps in decreasing the 'pro-inflammatory cytokines' in the lungs and acts in immunomodulatory function, and 'also it will increase the anti-inflammatory, antiviral responses of the respiratory epithelial cells during infection.'

CONCLUSION

Due to the highly contagious nature of COVID-19 and the increased morbidity and mortality with no appropriate therapy and vaccine, one must be cautious and do everything to help COVID-19 patients. In hospitals and other health care settings to decrease cross-contamination, holding other non-essential medications is taking place. Discontinuing Vitamins could increase the mortality and morbidity of those affected, especially in deficient/insufficient individuals. Obtaining serum 25 (OH) D levels in all patients with viral respiratory infections, especially COVID-19, could help in the detection and treatment of Vitamin D deficiency and potentially decrease recovery time and improve outcome. Even though evidence suggests that vitamin D has the anti-inflammatory, antiviral properties, randomized double-blinded controlled trials are needed to verify this further, and to understand Vitamin D and COVID-19 better.

ABBREVIATIONS

Vitamin D receptor-VDR; 25(OH)D- 25 hydroxyvitamin D; 1,25 (OH)D-1,25 dihydroxy Vitamin D; 1α,25-dihydroxy Vitamin D-1,25[OH]2 D or calcitriol; IU- International Units; Interferons stimulated genes- ISG; ARI- acute respiratory infection; RSV- respiratory syncytial virus; RTI- Respiratory tract infections; COPD-Chronic obstructive pulmonary disease; BMI-Basal metabolic index; USA-USA.

Maternal Depressive Symptoms, Lung Function, and Severe Asthma Exacerbations in Puerto Rican Children

BACKGROUND

Maternal depression has been linked to health care use for asthma in cross-sectional or short-term follow-up studies of school-aged children.

OBJECTIVE

To examine whether increased or persistent maternal depressive symptoms over approximately 5 years are associated with severe asthma exacerbations or worse lung function in youth.

METHODS

A prospective study of 386 youth living in Puerto Rico, aged 6 to 14 years at a baseline visit and 9 to 20 years at a second visit, was performed. Our exposure of interest was change in persistence of maternal depressive symptoms, assessed at both visits using the Center for Epidemiologic Studies Depression Scale (CESD). Our outcomes of interest were change in percent predicted forced expiratory volume in 1 second (FEV₁) and FEV₁/forced vital capacity (FVC) between the first and second visits in all subjects, and ≥1 severe asthma exacerbation in the year before the second visit in subjects with asthma.

RESULTS

In a multivariable analysis, each 1-point increment in the CESD score was associated with decrements of 0.15% in percent predicted FEV₁ (95% confidence interval [CI] = -0.28% to -0.01%; P = .03) and 0.10% in percent predicted FEV₁/FVC (95% CI = -0.20% to 0.001%; P = .05) between visits, as well as with 1.03 times increased odds of ≥1 severe asthma exacerbation at the second visit (95% CI for odds ratio = 0.99 to 1.06, P = .09). In a multivariable analysis, the presence of maternal depressive symptoms (a CESD score ≥21 points) at the second visit or at both visits was significantly associated with 3.17 to 3.52 times increased odds of ≥1 severe asthma exacerbation in the year before the second visit.

CONCLUSIONS

Increasing or persistent maternal depressive symptoms over approximately 5 years are associated with worse lung function measures and severe asthma exacerbations among Puerto Rican youth, a high-risk population.

Risk factors for atopic and nonatopic asthma in Puerto Rican children

BACKGROUND

Little is known about the risk factors for atopic and nonatopic asthma among children in Puerto Rico. We aimed to identify modifiable risk factors for atopic and nonatopic asthma in this vulnerable population.

METHODS

Case-control study of children with (n = 305) and without (n = 327) asthma in San Juan (Puerto Rico). Asthma was defined as physician-diagnosed asthma and wheeze in the previous year. Atopic asthma (n = 210) was defined as asthma and greater than or equal to one positive IgE to aero-allergens. Nonatopic asthma (n = 95) was defined as asthma and no positive IgE to the allergens tested. Logistic regression was used for the multivariable analysis of atopic and nonatopic asthma.

RESULTS

In a multivariable analysis, body mass index (BMI) z score, prematurity, parental asthma, lifetime exposure to gun violence, and having a bird in the child's home were associated with increased odds of atopic asthma, while each one-point increment in a dietary score (range: -2 [least healthy diet] to +2 [healthiest diet]) was associated with 37% reduced odds of atopic asthma (95% confidence interval [CI] = 0.48-0.81; P < .01). In a separate multivariable analysis, parental asthma, early-life second-hand smoke (SHS) exposure, and daycare attendance in the first year of life were significantly associated with increased odds of nonatopic asthma, while each one-point increment in the dietary score was associated with 42% reduced odds of nonatopic asthma (95% CI = 0.45-0.76; P < .01).

CONCLUSIONS

We have identified potentially modifiable risk factors for atopic asthma (eg, BMI and gun violence), nonatopic asthma (eg, early-life SHS and daycare attendance), or both (eg, an unhealthy diet) in Puerto Rican children.

Effect of Vitamin D3 Supplementation on Severe Asthma Exacerbations in Children With Asthma and Low Vitamin D Levels: The VDKA Randomized Clinical Trial

IMPORTANCE

Severe asthma exacerbations cause significant morbidity and costs. Whether vitamin D3 supplementation reduces severe childhood asthma exacerbations is unclear.

OBJECTIVE

To determine whether vitamin D3 supplementation improves the time to a severe exacerbation in children with asthma and low vitamin D levels.

DESIGN, SETTING, AND PARTICIPANTS

The Vitamin D to Prevent Severe Asthma Exacerbations (VDKA) Study was a randomized, double-blind, placebo-controlled clinical trial of vitamin D3 supplementation to improve the time to severe exacerbations in high-risk children with asthma aged 6 to 16 years taking low-dose inhaled corticosteroids and with serum 25-hydroxyvitamin D levels less than 30 ng/mL. Participants were recruited from 7 US centers. Enrollment started in February 2016, with a goal of 400 participants; the trial was terminated early (March 2019) due to futility, and follow-up ended in September 2019.

INTERVENTIONS

Participants were randomized to vitamin D3, 4000 IU/d (n = 96), or placebo (n = 96) for 48 weeks and maintained with fluticasone propionate, 176 μg/d (6-11 years old), or 220 μg/d (12-16 years old).

MAIN OUTCOMES AND MEASURES

The primary outcome was the time to a severe asthma exacerbation. Secondary outcomes included the time to a viral-induced severe exacerbation, the proportion of participants in whom the dose of inhaled corticosteroid was reduced halfway through the trial, and the cumulative fluticasone dose during the trial.

RESULTS

Among 192 randomized participants (mean age, 9.8 years; 77 girls [40%]), 180 (93.8%) completed the trial. A total of 36 participants (37.5%) in the vitamin D3 group and 33 (34.4%) in the placebo group had 1 or more severe exacerbations. Compared with placebo, vitamin D3 supplementation did not significantly improve the time to a severe exacerbation: the mean time to exacerbation was 240 days in the vitamin D3 group vs 253 days in the placebo group (mean group difference, -13.1 days [95% CI, -42.6 to 16.4]; adjusted hazard ratio, 1.13 [95% CI, 0.69 to 1.85]; P = .63). Vitamin D3 supplementation, compared with placebo, likewise did not significantly improve the time to a viral-induced severe exacerbation, the proportion of participants whose dose of inhaled corticosteroid was reduced, or the cumulative fluticasone dose during the trial. Serious adverse events were similar in both groups (vitamin D3 group, n = 11; placebo group, n = 9).

CONCLUSIONS AND RELEVANCE

Among children with persistent asthma and low vitamin D levels, vitamin D3 supplementation, compared with placebo, did not significantly improve the time to a severe asthma exacerbation. The findings do not support the use of vitamin D3 supplementation to prevent severe asthma exacerbations in this group of patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02687815.

Sufficient vitamin D status positively modified ventilatory function in asthmatic children following a Mediterranean diet enriched with fatty fish intervention study

Asthma in children is the most prevalent allergic disease worldwide that has become a major public health priority. The objective of this study was to examine the relationship between baseline serum vitamin D status, spirometry, and fractional exhaled nitric oxide levels (FeNO) in 64 Greek children with 'mild asthma' aged 5 to 12 years (51.6% male) in a dietary intervention study. We hypothesized that baseline serum vitamin D levels modify the beneficial response of fatty fish intake on pulmonary function in asthmatic children following a Mediterranean diet. The intervention group consumed 2 fatty fish meals/week (≥150 g cooked filleted fish/meal) as part of the Mediterranean diet for six months, and the control group consumed their usual diet. Baseline serum 25(OH)D was determined using enzyme-linked immunoassay and defined as sufficient levels of 25(OH)D ≥25 ng/mL. Only 36% of children were graded as sufficient in 25(OH)D levels on entry into the study with a higher proportion of girls insufficient than boys (61% vs 39% respectively). Participants with sufficient levels of serum 25(OH)D at baseline, consuming the intervention diet increased FEV₁/FVC by 4.89 units (β = 4.89; 95%CI: 1.19-8.61; p = 0.013) and FEF_25-75% by 12.83 units (β = 12.83; 95%CI: 4.27-21.40; p = 0.006) compared to controls. No significant differences in pulmonary function or FeNO were observed for those with insufficient levels of 25(OH) D in the intervention or control groups. In conclusion, sufficient serum vitamin D levels enhanced ventilatory function in response to a dietary intervention in asthmatic children.

Vitamin D supplementation to prevent acute respiratory infections: individual participant data meta-analysis

BACKGROUND

Randomised controlled trials (RCTs) exploring the potential of vitamin D to prevent acute respiratory infections have yielded mixed results. Individual participant data (IPD) meta-analysis has the potential to identify factors that may explain this heterogeneity.

OBJECTIVES

To assess the overall effect of vitamin D supplementation on the risk of acute respiratory infections (ARIs) and to identify factors modifying this effect.

DATA SOURCES

MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, ClinicalTrials.gov and the International Standard Randomised Controlled Trials Number (ISRCTN) registry.

STUDY SELECTION

Randomised, double-blind, placebo-controlled trials of supplementation with vitamin D₃ or vitamin D₂ of any duration having incidence of acute respiratory infection as a prespecified efficacy outcome were selected.

STUDY APPRAISAL

Study quality was assessed using the Cochrane Collaboration Risk of Bias tool to assess sequence generation, allocation concealment, blinding of participants, personnel and outcome assessors, completeness of outcome data, evidence of selective outcome reporting and other potential threats to validity.

RESULTS

We identified 25 eligible RCTs (a total of 11,321 participants, aged from 0 to 95 years). IPD were obtained for 10,933 out of 11,321 (96.6%) participants. Vitamin D supplementation reduced the risk of ARI among all participants [adjusted odds ratio (aOR) 0.88, 95% confidence interval (CI) 0.81 to 0.96; heterogeneity p < 0.001]. Subgroup analysis revealed that protective effects were seen in individuals receiving daily or weekly vitamin D without additional bolus doses (aOR 0.81, 95% CI 0.72 to 0.91), but not in those receiving one or more bolus doses (aOR 0.97, 95% CI 0.86 to 1.10; p = 0.05). Among those receiving daily or weekly vitamin D, protective effects of vitamin D were stronger in individuals with a baseline 25-hydroxyvitamin D [25(OH)D] concentration of < 25 nmol/l (aOR 0.30, 95% CI 0.17 to 0.53) than in those with a baseline 25(OH)D concentration of ≥ 25 nmol/l (aOR 0.75, 95% CI 0.60 to 0.95; p = 0.006). Vitamin D did not influence the proportion of participants experiencing at least one serious adverse event (aOR 0.98, 95% CI 0.80 to 1.20; p = 0.83). The body of evidence contributing to these analyses was assessed as being of high quality.

LIMITATIONS

Our study had limited power to detect the effects of vitamin D supplementation on the risk of upper versus lower respiratory infection, analysed separately.

CONCLUSIONS

Vitamin D supplementation was safe, and it protected against ARIs overall. Very deficient individuals and those not receiving bolus doses experienced the benefit. Incorporation of additional IPD from ongoing trials in the field has the potential to increase statistical power for analyses of secondary outcomes.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014013953.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Association of 25-hydroxy vitamin D with asthma and its severity in children: a case-control study

Background

Universally, asthma has high prevalence rates and this has led numerous studies done into its causes. Despite extensive study on asthma the association between 25-Hydroxy Vitamin D (25(OH) vit. D) and asthma remains uncertain. In this study, the associations of 25(OH) vit. D levels with asthma and with the severity of asthma were evaluated.

Methods

This was a case–control study performed in 2015 in the city of Isfahan. In this study 520 children were studied. Children with asthma were classified as cases and children who were referred for reasons other than respiratory problems and asthma were considered as controls. Serum 25 (OH) vit. D levels were then examined and compared between the two groups. Differences among groups were stated to be statistically significant when P-values < 0.05.

Results

There were 260 asthmatic children and 260 controls in the present study. The mean 25 (OH) vit. D levels in the case group was 25.5 ± 16.62 and  16.76 ± 31.40 the control group and this difference was statistically significant (P < 0.05). 25(OH) vit. D levels were found to be 28.05 ± 16.98 in non-severe asthma and 21.41 ± 15.20 in severe asthma. Consequently 25(OH) vit. D level had inverse relationship with asthma severity (P = 0.002).

Conclusions

As the results of this study showed, the lower level of 25(OH) vit. D correlated with the higher severity of asthma manifestations. Therefore, it is recommended that 25(OH) vit. D levels get routinely checked especially in severe asthma cases and if the deficiency presents, appropriate therapeutic measures be used to reduce the asthma severity.

Vitamin D and Immunity in Infants and Children

The last couple of decades have seen an explosion in our interest and understanding of the role of vitamin D in the regulation of immunity. At the molecular level, the hormonal form of vitamin D signals through the nuclear vitamin D receptor (VDR), a ligand-regulated transcription factor. The VDR and vitamin D metabolic enzymes are expressed throughout the innate and adaptive arms of the immune system. The advent of genome-wide approaches to gene expression profiling have led to the identification of numerous VDR-regulated genes implicated in the regulation of innate and adaptive immunity. The molecular data infer that vitamin D signaling should boost innate immunity against pathogens of bacterial or viral origin. Vitamin D signaling also suppresses inflammatory immune responses that underlie autoimmunity and regulate allergic responses. These findings have been bolstered by clinical studies linking vitamin D deficiency to increased rates of infections, autoimmunity, and allergies. Our goals here are to provide an overview of the molecular basis for immune system regulation and to survey the clinical data from pediatric populations, using randomized placebo-controlled trials and meta-analyses where possible, linking vitamin D deficiency to increased rates of infections, autoimmune conditions, and allergies, and addressing the impact of supplementation on these conditions.

Gestational vitamin D deficiency impairs fetal lung development through suppressing type II pneumocyte differentiation

Gestational vitamin D deficiency is associated with pulmonary diseases. This study aimed to investigate the effect of gestational vitamin D deficiency on fetal lung development in mice. Absolute and relative weights of fetal lungs were reduced in vitamin D deficient (VDD) group. Incrassate mesenchyme, measured by septal wall thickness, accompanied by lessened saccular space, was shown in VDD group. Numerous immature type II pneumocytes, as determined by PAS staining, were observed in VDD group. Moreover, increased Ki67-positive cells, a marker of cell proliferation, was detected in VDD group. The additional experiments showed that Sftpa, Sftpb, Sftpc and Sftpd, four surfactant genes, were downregulated and pro-surfactant protein B was reduced in VDD group. FoxA1, FoxA2 and TTF-1, three transcription factors that regulate surfactant genes, and VEGF, a key regulator for pulmonary maturation, were downregulated in VDD group. These results suggest that gestational vitamin D deficiency impairs fetal lung development partially through suppressing type II pneumocyte differentiation.

Annual SO2 exposure, asthma, atopy, and lung function in Puerto Rican children

BACKGROUND

Long-term effects of sulfur dioxide (SO₂ ) exposure on children, a vulnerable population, are largely unknown. Further, how long-term SO₂ affects Puerto Rican children living in the island of Puerto Rico, a group with high asthma prevalence, is unclear. We evaluated the effects of annual average 1-hour daily maximum SO₂ average on asthma, atopy, total immunoglobulin E (IgE), and lung function in Puerto Rican children.

METHODS

A cohort of 678 children (351 with asthma, 327 without asthma) was recruited in Puerto Rico from 2009 to 2010. Annual average 1-hour daily maximum SO₂ exposure was interpolated utilizing publicly available monitoring data. Multivariable logistic and linear regression was used for the analysis of asthma, atopy (defined as an IgE ≥0.35 IU/mL to at least one of five common aero-allergens), total IgE, and lung function measures (forced vital capacity [FVC], forced expiratory volume in 1 second [FEV1], and FEV1/FVC ratio).

RESULTS

Annual SO₂ exposure (per 1 ppb) was significantly associated with asthma (odds ratio [OR] = 1.42; 95% confidence interval [CI] = 1.05-1.91) and atopy (OR = 1.35; 95% CI = 1.02-1.78). Such exposure was also significantly associated with lower FEV1/FVC in all children (β = -1.42; 95% CI = -2.78 to -0.08) and in children with asthma (β = -2.39; 95% CI= -4.31 to -0.46). Annual SO₂ exposure was not significantly associated with total IgE, FEV1, or FVC.

CONCLUSIONS

Among Puerto Rican children in Puerto Rico, long-term SO₂ exposure is linked to asthma and atopy. In these children, long-term SO₂ exposure is also associated with reduced FEV1/FVC, particularly in those with asthma.

Obesity and childhood asthma

PURPOSE OF REVIEW

Asthma is a common chronic disease of the airways characterized by recurrent respiratory symptoms, bronchoreactivity, and airway inflammation. The high toll on quality of life has led to sustained efforts to understand the factors leading to asthma inception and poor disease control. Obesity is another increasingly common pediatric disease, which appears to increase the risk for incident asthma and worsened disease severity. Currently, our understanding of how obesity affects asthma risk and affects its phenotypic characteristics remains incomplete. The current review describes our current understanding of the epidemiology, clinical characteristics, and management considerations of obesity-related asthma in children.

RECENT FINDINGS

The epidemiologic relationship between obesity in children and incident asthma remains confusing despite numerous longitudinal cohort studies, and appears to be influenced by early life exposures, patterns of somatic growth and underlying familial risks of allergic disease. Children with comorbid obesity and asthma demonstrate diverse phenotypic characteristics which are still becoming clear.

SUMMARY

Like any child with asthma, a child with comorbid obesity requires an individualized approach adhering to current best-practice guidelines and an understanding of how obesity and asthma may interact.

Strategies to prevent exacerbations of childhood asthma

PURPOSE OF REVIEW

The goal of this review is to discuss strategies to prevent asthma exacerbations in children, focusing on recent advances in knowledge and understanding.

RECENT FINDINGS

Asthma exacerbations are common, and their prevention is an important goal to avoid detrimental impacts such as loss of disease control and lung function and significant healthcare costs. A number of strategies have been studied as tools for prevention of asthma exacerbations. Daily inhaled corticosteroids (ICSs) are effective for many children with asthma. However, alternative strategies such as intermittent ICS therapy, antileukotrienes, and biologics have been studied as means to lessen corticosteroid exposure. Further, recent studies have examined add-on strategies for children not controlled with ICS alone. Finally, personalizing therapy with targeted approaches has provided significant benefit to those with moderate-severe disease.

SUMMARY

Recent research highlights many potentially effective treatment strategies to prevent asthma exacerbations in children. We have reviewed and summarized the data on treatment approaches to help provide a better understanding of the methods that can be utilized. An individualized approach with careful monitoring is essential to identify the most effective strategies to prevent asthma exacerbations in each child.

Targeting Vitamin D Deficiency to Limit Exacerbations in Respiratory Diseases: Utopia or Strategy With Potential?

Patients with respiratory diseases such as cystic fibrosis, chronic obstructive pulmonary disease, or asthma often experience an acute worsening of respiratory symptoms, termed exacerbations. Although the course of exacerbations is disease specific, they are mostly triggered by a respiratory infection. Exacerbations often require hospitalization and are an important cause of mortality. Treatments of exacerbations aim to minimize the negative impact and to prevent subsequent events. Despite many existing therapy options, many patients do not benefit from therapy and suffer from recurrent events. Vitamin D deficiency is a worldwide problem and is extremely prevalent in these patients. Vitamin D, known for its calcemic effects, also has immunomodulatory and anti-infectious actions and can therefore be a possible agent to treat or prevent exacerbations. This review will focus on vitamin D as a potential candidate to treat or prevent exacerbations in CF, COPD, and asthma.

The Immunomodulatory Role of Vitamin D in Respiratory Diseases

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The growing interest in the new role of vitamin D, particularly as an immunomodulatory factor, has spurred basic research and the development of clinical trials to better understand the influence of supplementation on various diseases. Vitamin D is an important nutrient factor in human health due to its role in calcium metabolism regulation, cellular growth, differentiation and its fundamental discovered activity in immune functions. It has influenced different diseases, particularly inflammatory and autoimmune diseases, through immune response regulation, modulating innate and adaptive immunity.

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The aim of this review was to explore the role of vitamin D in the main respiratory diseases in children such as asthma, chronic rhinosinusitis, cystic fibrosis and recurrent respiratory infections.

Meta-analysis of vitamin D and lung function in patients with asthma

Background

There is growing literature suggesting a link between vitamin D and asthma lung function, but the results from systematic reviews are conflicting. We conducted this meta-analysis to investigate the relation between serum vitamin D and lung function in asthma patients.

Methods

Major databases, including OVID, MEDLINE, Web of Science and PUBMED, were searched until 10th October 2018. All published observational studies related to vitamin D and asthma were extracted. All meta-analyses were performed using Review Manager 5.3.5.

Results

This quantitative synthesis found that asthma patients with low vitamin D levels had lower forced expiratory volume In 1 s (FEV1) (mean difference (MD) = − 0.1, 95% CI = − 0.11 to − 0.08,p < 0.01;I2 = 49%, p = 0.12) and FEV1% (MD = − 10.02, 95% CI = − 11 to − 9.04, p < 0.01; I2 = 0%, p = 0.82) than those with sufficient vitamin D levels. A positive relation was found between vitamin D and FEV1 (r = 0.12, 95% CI = 0.04 to 0.2, p = 0.003; I2 = 59%,p = 0.01), FEV1% (r = 0.19, 95% CI = 0.13 to 0.26, p < 0.001; I2 = 42%, p = 0.11), forced vital capacity (FVC) (r = 0.17, 95% CI = 0.00 to 0.34, p = 0.05; I2 = 60%, p = 0.04), FEV1/FVC (r = 0.4, 95% CI = 0.3 to 0.51, p < 0.001; I2 = 48%, p = 0.07), and the asthma control test (ACT) (r = 0.33, 95% CI = 0.2 to 0.47, p < 0.001; I2 = 0%, p = 0.7). Subgroup analysis indicated that the positive correlation between vitamin D and lung function remained significant in both children and adults.

Conclusions

Our meta-analysis suggested that serum vitamin D levels may be positively correlated with lung function in asthma patients. Future comprehensive studies are required to confirm these relations and to elucidate potential mechanisms.

Solar radiation, air pollution, and bronchiolitis hospitalizations in Chile: An ecological study

OBJECTIVE

To evaluate trends and geographic distribution of infant bronchiolitis hospitalizations in Chile, a country with large variation in solar radiation (SR) and high rates of urban air pollution.

METHODS

We performed a nationwide ecological study of bronchiolitis hospitalizations from 2001 to 2014. We investigated the associations of regional SR (a proxy of vitamin D status) and regional fine particulate matter (PM2.5) air pollution with bronchiolitis hospitalizations. We also evaluated the role of sociodemographic factors, including regional poverty, education, indigenous population, and rurality rates.

RESULTS

During the study period, 119 479 infants were hospitalized for bronchiolitis in Chile; 59% were boys. The mean bronchiolitis hospitalization rate increased from 29 to 41 per 1000 infants per year (P = .02). There was an inverse correlation between regional SR and incidence of hospital admissions for bronchiolitis (r = -0.52, P = .049), accounting for 27% of these hospitalizations. There was also a significant direct correlation between regional ambient PM2.5 and bronchiolitis hospitalizations (R = 0.68, P = .006), accounting for 42% of the variation in admission rate. High firewood and/or coal residential use for heating, high regional poverty, lower years of education, and high rurality rates were also significantly correlated with bronchiolitis hospitalization rates. None of the environmental or sociodemographic factors evaluated were correlated with regional case fatality rates or length of stay at the hospital.

CONCLUSIONS

This ecological study revealed significant associations between regional SR, air pollution, and sociodemographic factors with infant bronchiolitis hospitalizations in Chile, suggesting that these factors play a major role in the incidence and severity of respiratory infections in early childhood.

Vitamin D for secondary prevention of acute wheeze attacks in preschool and school-age children

INTRODUCTION

Vitamin D is best known for its role in bone health; however, the discovery of the vitamin D receptor and the expression of the gene encoding the vitamin D 1α-hydroxylase (CYP27B1) enzyme in a wide variety of tissues including immune cells and respiratory epithelium has led to the discovery of potential roles for vitamin D in the prevention of acute wheeze.

METHODS

We review here the literature concerning the relationships between circulating 25-hydroxyvitamin D (25(OH)D) concentration and secondary prevention of acute wheeze attacks in preschool and school-age children.

RESULTS

Epidemiological data suggest that vitamin D insufficiency (25(OH)D <75 nmol/L) is highly prevalent in preschool and school-age children with wheeze. Preschool age children with a history of wheeze attacks and circulating 25(OH)D <75 nmol/L are at increased risk and frequency of future acute wheeze. However, no consistent association between low vitamin D status and risk of acute wheeze is reported in school-age children. Seven randomised controlled trials (RCTs) with relatively small sample sizes (30-430) and variable quality showed inconsistent results regarding the effect of oral vitamin D supplementation during childhood on the risk of asthma attacks, asthma symptom control, inhaled corticosteroid requirements, spirometry and unscheduled healthcare attendances for wheeze. A RCT showed that vitamin D supplementation had no effect on the frequency of unplanned healthcare attendances due to acute wheeze in 22 preschool children.

DISCUSSION

An evidence-based recommendation for the use of vitamin D as a preventive therapy for wheeze attacks cannot be made until results of further trials are available. The assessment of circulating 25(OH)D concentration and the optimisation of vitamin D status to prevent acute respiratory tract infections, and to maintain skeletal and general health in preschool and school-age children with acute wheeze is worthwhile in its own right, but whether this will reduce the risk of acute wheeze attacks is unclear.

The Vitamin D Receptor Gene Polymorphisms in Asthmatic Children: A Case-Control Study

Background: The association between vitamin D receptor (VDR) polymorphisms and the risk of asthma remains unclear. This study aimed to investigate the effect of VDR gene polymorphisms and VDR mRNA expression levels on respiratory function, nitric oxide levels in expiratory air, and serum vitamin D levels in children with asthma. Materials and Methods: The study included 80 healthy children (control group) and 100 asthmatic children (asthma group) between the age of 5 and 18 years. The VDR genotypes (ApaI, TaqI, and FokI) and VDR mRNA levels were determined in all groups. Results: There was no statistically significant difference in vitamin D levels between the asthma group and the control group (P > 0.05). A significant association was found between both genotype (CC) of the TaqI polymorphism [odds ratio (OR) = 0.2, 95% confidence interval (CI) (0.07-0.5), P = 0.003] and genotype (CA) of ApaI polymorphisms [OR = 0.2, 95% CI (0.07-0.8), P = 0.02], and asthma risk. In addition, when single-nucleotide polymorphism allelic frequencies between asthma and control groups were compared there is no significant association (P > 0.05). When compared to control group, VDR mRNA expression in asthma group decreased in genotypes CC and CA of ApaI and in genotypes TT and TC of TaqI (P < 0.05). Conclusion: The results provide supporting evidence for an association between TaqI and ApaI polymorphisms and asthma susceptibility.

Transcriptomics of atopy and atopic asthma in white blood cells from children and adolescents

Early allergic sensitisation (atopy) is the first step in the development of allergic diseases such as atopic asthma later in life. Genes and pathways associated with atopy and atopic asthma in children and adolescents have not been well characterised.A transcriptome-wide association study (TWAS) of atopy and atopic asthma in white blood cells (WBCs) or whole blood was conducted in a cohort of 460 Puerto Ricans aged 9-20 years (EVA-PR study) and in a cohort of 250 Swedish adolescents (BAMSE study). Pathway enrichment and network analyses were conducted to further assess top findings, and classification models of atopy and atopic asthma were built using expression levels for the top differentially expressed genes (DEGs).In a meta-analysis of the study cohorts, both previously implicated genes (e.g. IL5RA and IL1RL1) and genes not previously reported in TWASs (novel) were significantly associated with atopy and/or atopic asthma. Top novel genes for atopy included SIGLEC8 (p=8.07×10^-13), SLC29A1 (p=7.07×10^-12) and SMPD3 (p=1.48×10^-11). Expression quantitative trait locus analyses identified multiple asthma-relevant genotype-expression pairs, such as rs2255888/ALOX15 Pathway enrichment analysis uncovered 16 significantly enriched pathways at adjusted p<0.01, including those relevant to T-helper cell type 1 (Th1) and Th2 immune responses. Classification models built using the top DEGs and a few demographic/parental history variables accurately differentiated subjects with atopic asthma from nonatopic control subjects (area under the curve 0.84).We have identified genes and pathways for atopy and atopic asthma in children and adolescents, using transcriptome-wide data from WBCs and whole blood samples.

Health Disparities in the Hospitalized Child

Health care disparities exist along the continuum of care for children admitted to the hospital; they start before admission, impact hospital course, and continue after discharge. During an acute illness, risk of admission, length of stay, hospital costs, communication during family-centered rounds, and risk of readmission have all been shown to vary by socioeconomic status, race, and ethnicity. Understanding factors beyond the acute illness that increase a child's risk of admission, increase hospital course complications, and lower discharge quality is imperative for the new generation of pediatric hospitalists focused on improving health for a population of children. In this article, we describe a framework to conceptualize socioeconomic, racial, and ethnic health disparities for the hospitalized child. Additionally, we offer actions pediatric hospitalists can take to address disparities within their practices.

Influence of Vitamin D and Cotinine on T-Regulatory Cells and Asthma Severity in Children

Asthma is a common chronic respiratory diseases in children. Understanding the immune mechanisms of epigenetic factors may contribute to a better control of asthma. This study seeks to determine the effects of serum vitamin D and urine cotinine on asthma severity and on T regulatory cells (Tregs) and other immune-related factors such as CD3, CD4, CD8, CD19, CD16/56, and anti-CD3 HLA-DR3. The study involved 34 children with asthma. Disease severity was assessed with the Asthma Control Test, spirometry, and the fractional exhaled nitric oxide (FeNO). The control group consisted of 18 healthy children. We found a significantly lower proportion of Tregs in the serum of asthmatic children compared with the control group (p < 0.002). There were no significant differences in the other immunological factors investigated. Nor was there any appreciable association between vitamin D or cotinine and the course of asthma, FeNO, Tregs, and the other immune factors. However, the percentage of Tregs was positively associated with the level of FeNO (p < 0.02). In conclusion, the study shows a role of T regulatory cells in the pathogenesis of asthma in children, but fails to show any influence of serum vitamin D or urine cotinine on disease course.