The association between vitamin D status and recurrent wheezing

Vitamin D Status in Infants with Two Different Wheezing Phenotypes

OBJECTIVE

To investigate vitamin D levels in patients with recurrent wheeze at early ages of childhood.

METHODS

In the present cross-sectional study, serum 25-hydroxy vitamin D [25 (OH)D], levels which is known as an indicator of vitamin D adequacy, was examined in infants with three or more wheezing attacks.

RESULTS

A total of 186 infants with recurrent wheezing were included in the study along with 118 healthy control peers. The recurrent wheezing study participants were classified into two groups according to Asthma Predictive Index (API) positivity and compared to control subjects regarding their serum vitamin D status. The API negative group had the lowest mean serum 25 (OH)D level (n = 121; 22.71 ± 10.76 ng/ml) followed by API positive group (n = 65; 24.08 ± 9.02 ng/ml) compared to healthy group (26.24 ± 11.88 ng/ml) (p < 0.05). In addition, higher vitamin D deficiency was observed in infants in API negative group (52.1 %; p < 0.01) and API positive group (38.5 %; p < 0.05) than control group (31.4 %).

CONCLUSIONS

Low levels of 25 (OH)D were detected in infants with two different phenotypes of recurrent wheeze. Vitamin D deficiency may play a role in the pathogenesis of infants with recurrent wheezing.

Vitamin D exposure during pregnancy, but not early childhood, is associated with risk of childhood wheezing

The association between vitamin D and wheezing in early childhood is unclear. The primary objective of this study was to evaluate the association between vitamin D exposure, during both pregnancy and childhood, and early childhood wheezing. Secondary objectives were to evaluate the associations between vitamin D exposures and asthma and wheezing severity. We conducted a cohort study of children (0-5 years) recruited from 2008 to 2013 through the TARGet Kids! primary-care research network. Vitamin D exposures included maternal vitamin D supplement use during pregnancy, child vitamin D supplementation and children's 25-hydroxyvitamin D (25(OH)D) concentrations. The outcomes measured were parent-reported childhood wheezing, diagnosed asthma and wheezing severity. Vitamin D supplement and wheezing data were available for 2478 children, and blood samples were available for 1275 children. Adjusted odds ratios (aOR) were estimated using logistic regression adjusted for age, sex, ethnicity, body mass index, birth weight, outdoor play, breastfeeding duration, daycare status, parental smoking and family history of asthma. Vitamin D supplementation during pregnancy was associated with lower odds of childhood wheezing (aOR=0.65; 95% CI: 0.46-0.93). In early childhood, neither 25(OH)D (aOR per 10 nmol/l=1.01; 95% CI: 0.96-1.06) nor vitamin D supplementation (aOR=1.00; 95% CI: 0.81-1.23) was associated with wheezing. No significant associations were observed with diagnosed asthma or wheezing severity. Vitamin D supplementation during pregnancy was associated with reduced odds of wheezing, but child vitamin D supplementation and childhood 25(OH)D were not associated with reduced wheezing. The timing of exposure may be important in understanding the association between vitamin D and childhood wheezing.

Vitamin D as an adjunctive therapy in asthma. Part 2: A review of human studies

Vitamin D deficiency (VDD) is highly prevalent worldwide, with adverse effects on bone health but also potentially other unfavorable consequences. VDD and asthma-incidence/severity share many common risk factors, including winter season, industrialization, poor diet, obesity, dark skin pigmentation, and high latitude. Multiple anatomical areas relevant to asthma contain both the enzyme responsible for producing activated vitamin D and the vitamin D receptor suggesting that activated vitamin D (1,25-dihydroxyvitamin D) may have important local effects at these sites. Emerging evidence suggests that VDD is associated with increased airway hyperresponsiveness, decreased pulmonary function, worse asthma control, and possibly decreased response to standard anti-asthma therapy. However the effect is inconsistent with preliminary evidence from different studies suggesting vitamin D is both beneficial and detrimental to asthma genesis and severity. Current evidence suggests that supplementation with moderate doses of vitamin D may be appropriate for maintenance of bone health in asthmatics, particularly steroid users. However emerging data from an increasing number of randomized, controlled, intervention studies of vitamin D supplementation in pediatric and adult asthma are becoming available and should help determine the importance, if any of vitamin D for asthma pathogenesis. The purpose of this second of a two-part review is to review the current human literature on vitamin D and asthma, discussing the possible consequences of VDD for asthma and the potential for vitamin D repletion as adjunct therapy.

Serum level of vitamin D and trace elements in children with recurrent wheezing: a cross-sectional study

Background

We aimed to show the relationship between recurrence of wheezing and serum levels of vitamin D, zinc, and copper in wheezy children compared with a healthy group.

Methods

In this cross sectional study, seventy-three children with wheezing and seventy-five controls were included without a follow-up period. The clinical characteristics of the children were assessed, the asthma predictive index and temporal pattern of wheeze were determined. The serum levels of vitamin D, zinc, and copper were measured. Pearson correlation analysis was used to evaluate the relationship between homogeneously distributed variables.

Results

Thirty-two of the seventy-three children (43.8%) had more than three wheezing attacks (recurrent wheezing). The Asthma Predictive Index index was positive in 26 patients (35.6%). When classified to temporal pattern of wheeze, fifty-three of the study group (72.6%) had episodic wheezing and the remainder (27.4%) was classified as multiple-trigger wheezing. We found no overall significant difference between the study and control group in terms of vitamin D and trace elements . The vitamin D and zinc levels were significantly lower and serum copper and copper/zinc ratio was significantly higher in patients with recurrent wheezing (p =0.03, p <0.01, p =0.013, p <0.01, respectively) positive Asthma Predictive Index and multiple-trigger temporal pattern of wheeze compared with patients with non- recurrent wheezing, negative Asthma Predictive Index and episodic temporal pattern of wheeze.

Conclusion

It may be postulated that for the determination of asthma risk in patients with recurrent wheezing, the serum level of vitamin D, copper and zinc can be used as a routine biomarker alongside the Asthma Predictive Index and temporal pattern of wheeze.

Vitamin D and asthma-life after VIDA?

The vitamin D hypothesis postulates that lower vitamin D levels are causally associated with increased asthma risk and asthma severity. Multiple epidemiological studies have shown an inverse relationship between circulating vitamin D levels (in the form of 25-hydroxy vitamin D) and asthma severity and control and lung function. However, in the recently published vitamin D and asthma (VIDA) study, vitamin D supplementation failed to show an improvement in asthma control in adults. This article reviews the current epidemiological and trial evidence for vitamin D and asthma and explores some of the possible alternative explanations for previous findings (including "reverse causation" and the importance of studying children and adults). We also address some of the unique challenges of conducting vitamin D trials and potential ways to address them. Finally, I will argue for further clinical trials of vitamin D in asthma, especially in children, using knowledge gained from the VIDA trial.

Effect of vitamin D supplementation on moderate to severe bronchial asthma

OBJECTIVE

To define the therapeutic role of vitamin D in children with moderate to severe bronchial asthma as an adjunct to standard treatment.

METHODS

Hundred asthmatic children of either sex, attending the respiratory and asthma clinic were enroled in the study. Diagnosis was made on the basis of history and clinical examination. Randomization was done using sealed opaque envelop method. In addition to the treatment as per GINA guidelines, one group received oral vitamin D3 (Cholecalciferol) 60,000 IU per month for 6 mo and the other group received placebo powder in the form of glucose sachet with a double blinded design. Monthly follow up of every patient was done and during every visit change in severity, level of control, Peak expiratory flow rate (PEFR), steroid dosage, number of exacerbations and number of emergency visits were assessed.

RESULTS

Monthly doses of 60,000 IU vitamin D significantly reduced the number of exacerbations as compared to placebo (p = 0.011). PEFR significantly increased in the treatment group (p = 0.000). Monthly doses of vitamin D significantly reduced the requirement of steroids (p = 0.013) and emergency visits (p = 0.015). Control of asthma was achieved earlier in patients who received monthly vitamin D. Vitamin D significantly reduced the level of severity of asthma patients over 6 mo of treatment (p = 0.016).

CONCLUSIONS

Vitamin D has a definite role in the management of moderate to severe persistent bronchial asthma as an adjunct to standard treatment.

Serum 25 hydroxy vitamin D insufficiency associated with bronchial asthma in Lucknow, India

OBJECTIVES

To assess the association between serum 25 hydroxy vitamin D levels and asthma and its control in Indian children.

METHODS

This was a prospective case-control study conducted in tertiary care hospital. Cases of asthma and healthy age-matched controls were included, aged 1-15 y, who had not received any vitamin D supplementation in the last year and had no other co-morbidity, after obtaining written informed parental consent. 25 hydroxy vitamin D insufficiency was taken below level of ≤ 30 ng/mL.

RESULTS

Fifty asthmatics and 25 age-matched controls were recruited from August 2011-July 2012. 25 hydroxy vitamin D insufficiency was associated with occurrence of asthma (OR = 13.5; 95 % CI = 4.25-42.85: p = 0.000). With decreasing level of asthma control there was increasing strength of association with 25 hydroxy vitamin D insufficiency [χ (2) for trend = 24.96 (p = 0.000)].

CONCLUSIONS

25 hydroxy vitamin D insufficiency is associated with bronchial asthma as well as its level of control.

Immunoregulatory mechanisms of vitamin D relevant to respiratory health and asthma

Vitamin D deficiency is prevalent among people with various immune-mediated conditions, including autoimmune diseases and asthma. Serum 25(OH)D levels inversely correlate with asthma severity, glucocorticoid responsiveness/dosage, and markers of pathogenesis, such as airway remodeling, IgE, and eosinophilia. Trials involving supplementation with active vitamin D or a precursor are beginning to emerge with variable results that, in part, reflect differences in study design. This review looks at the mechanisms by which vitamin D may protect against asthma, including increasing glucocorticoid responsiveness, skewing immune cells towards a regulatory phenotype, reducing the incidence of infections, airway remodeling, eosinophilia, and lowering the levels of IgE. Also discussed is the therapeutic potential for vitamin D, which is likely to be applicable to immune-mediated conditions beyond simply asthma.