1. What Is The Role Of Vitamin D Deficiency Among Children With Asthma?
By Grace Boamah

2. Objective and Reference
References
Bener, A., Ehlayel, M. S., Tulic, M. K., & Hamid, Q. (2011). Vitamin D deficiency as a strong predictor of asthma in children. International archives of allergy and immunology, 157(2),
Fares, M. M., Alkhaled, L. H., Mroueh, S. M., & Akl, E. A. (2015). Vitamin D supplementation in children with asthma: a systematic review and meta-analysis. BMC research notes, 8(1), 1.
Hatami, G., Ghasemi, K., Motamed, N., Firoozbakht, S., Movahed, A., & Farrokhi, S. (2014). Relationship between Vitamin D and Childhood Asthma: A Case–Control Study. Iran J Pediatr; Vol, 24(6).
Rajabbik, M. H., Lotfi, T., Alkhaled, L., Fares, M., Fuleihan, G. E. H., Mroueh, S., & Akl, E. A. (2014). Association between low vitamin D levels and the diagnosis of asthma in children: a systematic review of cohort studies. Allergy, Asthma & Clinical Immunology, 10(1), 1.
Objectives
Understand the issues relating to vitamin D deficiency and asthma
Be aware of the role of vitamin D in the body
To decide whether or not vitamin D has some role in the development of asthma in children.

3. Background Ways vitamin D Deficiency Occurs
Inadequate sunlight exposure
Poor access to micronutrients rich food
Disorder that limit its absorption
Possible role of dietary fiber
Dietary sources of vitamin D
Fish
Oils
Egg yolks
Butter.
Fortified foods especially dairy products.
Vitamin D is a group of fat soluble prohormones
Two major forms are vitamin D2 and Vitamin D3
Produced in the skin
Function
Regulates calcium and phosphorus levels in the blood
Promotes bone formation and mineralization
Affects the immune system by promoting immunosuppression activity
Immunoregulatory
Ways vitamin D Deficiency Occurs:
Inadequate sunlight exposure
Poor access to micronutrients rich food
Disorder that limit its absorption
Possible role of dietary fiber
DRI: Age 8 and above 600IU (15mcg)

4. Pathway
In this system, the biologically inactive vitamin d3 is activated. First in the liver to produce 25- hydroxyvitamin d3 and the endocrine gland converts it to the hormones.
Vitamin D is important and there are many pathways for asthma. Its role in immune regulation is important

5. Method Article 1: Quasi Experiment Article 2: Case Control
They selected children based on their dietary information, age, gender, place of residence and household income.
400 children were selected from visited pediatric asthma clinic and primary health care clinics.
Article 2: Case Control
200 asthmatic children and 200 healthy children (control).
All patients were on regular treatment with oral or inhaled corticosteroids based on GINA classification.
Participants present with chronic respiratory diseases and history of consumption of any supplements of vitamin were excluded.
Participants with no allergic history or negative atopic family history were enrolled as the healthy controls group.
Article 3: Randomized Controlled Trial.
Children under age 18 with asthma were the ones that participated in this trial.
Vitamin D supplements were given without any restriction.
Article 4: They used a cohort studies.
Children less than 18 years and free of asthma
Article 1: They used quasi experiment to compares a group that gets a intervention with another group that is similar but did not receive the intervention. A quasi experiment uses a control group or randomized group. It also causes a significant difference in participant’s outcomes as compared to non-participants with similar characteristic. They selected children based on their dietary information, age, gender, place of residence and household income. They selected twenty children who visited pediatric asthma clinic and twenty who visited primary health care clinics. This child selected from primary health care clinics are the control groups. The measurement tools used was medical history, lab tests, skin prick test, chest x-ray and lung function test.
Article 2: Data was obtained from 200 asthmatic children and 200 healthy children (control). All patients were on regular treatment with oral or inhaled corticosteroids based on GINA classification. Other participants present with chronic respiratory diseases and history of consumption of any supplements of vitamin were excluded. Participants with no allergic history or negative atropic family history were enrolled as the healthy controls group. The measuring tool used to measure was the chi-square test (this was used to check the categorical variables between the two groups). The PTH levels was also measured by electro chemiluminescence immunoassay method.
Article 3: The study was a randomized controlled trial. Children ages less than eighteen years with asthma were the ones that participated in this trial. They gave these children vitamin D supplementation without any restriction on the dose. The types of outcome they measured was related to symptoms of asthma like nighttime awakenings, interference with normal activity, and short acting beta2.
Article 4: They used a cohort studies. A cohort study is carried out now and look at the past examine medical outcomes. A cohort study also a longitudinal study used in medicine (cite). It focusses on a group of people who share a common experience during a period. A cohort study analysis the risk factors and follows a group of people who do not have the disease, and then uses the correlations to determine the risk of subject reduction. The disadvantage of a cohort study is the limited control the researches has over the data collection. Participants were children less than eighteen years old and free of asthma.

6. Measurement Tools Medical history Measured the symptoms of asthma
Lab tests
Skin prick test
Chest x-ray
Lung function test.
Measured the symptoms of asthma
Nighttime awakenings
Frequency of upper respiratory infections
Interference with normal activity
Short acting beta2.
Chi-square test
Measure PTH level

7. Results Article 1 Article 2:
Asthmatics children were more likely to have a wheatish skin complexion
Asthmatics had a significantly lower concentration of serum vitamin d, phosphorus and magnesium.
Asthmatics had significantly elevated serum IgE compared to control group.
Exposure to sun and skin pigmentation might be the reasons for low level of vitamin d in asthmatic children.
Article 2:
A high concentration of IgE in asthmatic patient having vitamin D deficiency
A decrease in the concentration of serum in vitamin D in the asthmatic patients
Serum calcium level was found to be decreased significantly in asthmatic patients
No found a concentration difference between the serum level of PTH in asthmatic children and the control group.
vitamin d deficiency is associated with incidence of asthma in children
not sure if this is Bener
Bener is an epidemiological study to collect information and to see if there is an association or correlation.

8. Results Cont. Article 3 Article 4
No correlation between the benefit and harmful effect of vitamin D supplementation
Report that there is improvement in asthma symptoms in the vitamin D supplementation.
Article 4
An association between lower vitamin D levels and incidence of asthma
Imply that vitamin D supplementation may be effective in preventing asthma.
No association with vitamin D2 or vitamin D3 level in asthmatic children.
3. If this is Fares then this is a systematic review and meta- analysis that showed that the body of evidence about the role of vitamin D is of very low quality. Only 4 studies with a total of 149 children qualified to be evaluated.
Conclude that the evidence is of low quality and need to run large size RCTs
4. If this is Rajabbik then it is a systematic review of cohort studies.
It looks at all the citations and looked for cohort studies and only found 3. But the quality of the 3 was not good and had major shortcomings.

9. Authors Conclusions
There is a relationship between vitamin D deficiency and asthma.
Limited factors in the life asthmatic children
Dietary intake
Child’s exposure to sunlight
Serum levels
There is a lower vitamin D level in children who had severe asthma.
Supplementing during pregnancy or lactation period
Prolonged breastfeeding without supplementation have long effect on the immune function
and asthma is still under research. They haven’t yet found the true correlation between those two. But some of the article mentioned that there is a relationship between vitamin D deficiency and asthma. This is due to limited factors in the life asthmatic children such as dietary intake, child’s exposure to sunlight, and serum levels. Also, they found that there is a lower vitamin D level in children who had severe asthma. One of the article suggested that supplementing during pregnancy or lactation period with vitamin D might be safe for the children. This is because a prolonged breastfeeding without vitamin d supplementation can have long effect on the immune function

10. Critique Relatively new research
Research being put in place to detect the correlation between asthma and vitamin D in children.
Early in figuring out the role of Vitamin D in the development of asthma
Need a large scale of randomized control trial
Vitamin D should be supplement if D3 level is low
Not enough evidence to say give it to all asthmatic children
Third article was talking about supplementation
How they could be effective and not effective.
More research needs to be done
Not enough information on how the result were achieved
Limitation
Only 4 studies with a total of 149 children qualified to be evaluated
Includes proper assessment of the exposure
Assessing vitamin D status
Environmental factors
In your critique I would say that it is early in figuring out the role of D in the development of asthma.  There is need for a large scale RCT to decide if vitamin D supplementation should be a treatment for asthma.  Vitamin D should be supplemented if the D3 level is low but probably not enough evidence to say give it to all asthmatic children.
Some limitations that was mentioned in one of the article was for the studies to address the methodological limitation of the available evidence. This includes proper assessment of the exposure, by assessing vitamin D status by multiple measurements throughout the study period and accounting for seasonal variation and other environmental factors
Conclude that the evidence is of low quality and need to run large size