Vitamin D deficiency and its impact on asthma severity in asthmatic children
Esfandiar et al. Italian Journal of Pediatrics
Vitamin D deficiency and its impact on asthma severity in asthmatic children
Nasrin Esfandiar 3
Fariba Alaei 2
Shahrzad Fallah 1
Delara Babaie 0 4
Niloofar Sedghi 3
0 Allergy and Clinical Immunology Department, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences , Tehran , Iran
1 Department of Emergency Medicine, Faculty of Medicine, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences , Tehran , Iran
2 Department of Pediatrics Cardiology, Faculty of Medicine, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences , Tehran , Iran
3 Pediatric Nephrology Research Center, Faculty of Medicine, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences , Tehran , Iran
4 Allergy and Clinical Immunology Department, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences , Tehran , Iran
Background: Despite obtaining evidences on association between vitamin D and development of lung in fetus, little is known about vitamin D level and its impact on severity of asthma in children. The present study aimed to assess the relationship between the asthma severity and vitamin D deficiency in asthmatic children. Methods: This case-control study was conducted on 106 individuals including asthmatic (n = 53) and healthy children (n = 53) who referred to Mofid hospital in Tehran in 2013. The level of serum vitamin D in both groups was measured by radioimmunoassay method at the reference lab and was categorized as sufficient (> 30 ng/ml), insufficient (20 to 30 ng/ml), or deficient (< 20 ng/ml). The control status of asthma in patients group was classified as controlled, partially controlled, and uncontrolled. Results: In the groups with and without asthma, the prevalence of vitamin D deficiency was 73.6 and 49.1%, and the prevalence of vitamin D insufficiency was 18.9 and 18.9%, while normal vitamin D level was revealed in 7.5 and 32.1%, respectively with a significant difference (p = 0.005). Using the multivariate logistic regression analysis, the presence of asthma was associated with reduced level of vitamin D (OR = 1.068, 95% CI: 1.027-1.110, P = 0.001). In this context, the risk for asthma in the children with vitamin D deficiency was 6.3 times of those with normal vitamin D level. Although the presence of asthma was strongly associated with reduced level of vitamin D in serum, neither severity of asthma nor control status of asthma were associated with vitamin D deficiency. Conclusion: The presence of vitamin D deficiency effectively predict increased risk for childhood asthma; however the severity or control status of this event may not be predicted by confirming vitamin D deficiency.
Asthma; Vitamin D; Children; Risk
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Background
The upward trend of morbidity and high socioeconomic
burden of asthma in children has prompted scientists to
seek both genetic and environmental factors contribute
to this phenomenon. Recently, the relationship between
vitamin D deficiency and pediatrics asthma has been
supported by some clinical studies [1]. Recent studies
introduced a genetic factor, vitamin D receptor gene
polymorphisms, that is responsible for vitamin D deficiency
in children. In this regard, the predictive role of some
polymorphisms such as FokI, ApaI, and TaqI has been
suggested, but not completely understood [2]. Also, in a
developing long time series transcriptome data (DLCGS)
in order to infer the role of in utero changes of vitamin
D responsive genes in both the developing lung and
asthma, some evidences have been obtained the set of
vitamin D related genes to be associated with lung
development [3], but these gene associations have not been clearly
determined in other population-based studies. On the other
hand level of pH in exhaled breath condensate decrease in
asthma exacerbations [4], and vit-D deficiency aggravates
oxidative stress and DNA damage [5]. Clinically, the
association between vitamin D and fetal lung development has
been also revealed in both animal and fetal models. In
animal studies, it has been found that rachitic rat pups born to
vitamin D deficient mothers had reduced lung compliance
and also delayed alveolar development [4, 6, 7]. It has been
also shown vitamin D3 as a main growth factor necessary
for proliferation of alveolar type-II cells and the vitamin D
receptors has been characterized in alveolar epithelial cells
[8]. Additionally, it has been revealed that exposure to
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