Association of vitamin D receptor gene polymorphisms and vitamin D levels with asthma and atopy in Cypriot adolescents: a case–control study

Abstract

BackgroundPolymorphisms in the vitamin D receptor (VDR) gene have been studied in immune-related disorders either as independent contributors or in combination with vitamin D concentration. Vitamin D and VDR have been independently linked to asthma susceptibility. We investigated whether VDR variants were associated independently or in relation to vitamin D levels with asthma in Cypriot adolescents.MethodsWe studied 190 current wheezers, 69 of which were categorized as active asthmatics and 671 healthy controls. We determined three VDR genotypes (BsmI, TaqI, ApaI) and measured serum 25(OH)D levels. Logistic regression and stratified analyses by the presence of hypovitaminosis D (≤20 ng/ml) were used to evaluate the association of the VDR variants with asthma.ResultsThe distribution of TaqI genotypes was significantly different between controls and current wheezers (p = 0.030) or active asthmatics (p = 0.014). The tt genotype was over-represented in wheezers (19.2 %) and asthmatics (21.3 %) compared to respective controls (12.9 %). No difference was observed between controls, current wheezers and active asthmatics in the genotypic distribution of BsmI and ApaI polymorphic sites. After stratification by the presence of hypovitaminosis D, a significant association was detected between tt genotype of TaqI polymorphism with wheezing (OR: 1.97, 95 % CI: 1.12, 3.46) and asthma (OR: 2.37, 95CI%: 1.02, 5.52) only in those with normal vitamin D levels (>20 ng/ml) but not in subjects with low vitamin D.ConclusionsThe minor TaqI genotype of VDR is associated with asthma in Cypriot adolescents. This polymorphism may contribute to asthma susceptibility primarily under conditions of normal vitamin D levels (>20 ng/ml).Electronic supplementary materialThe online version of this article (doi:10.1186/s40248-015-0025-0) contains supplementary material, which is available to authorized users.

Vitamin D Receptor Gene Polymorphisms in Serbian Patients With Bronchial Asthma: A Case‐Control Study

“…Pillai et al [2011] approved the association of FokI with the higher night-time asthma morbidity scores, lower baseline spirometric measures and higher IgE levels. Results obtained in our study are in accordance with the studies by Fang et al [2009], Saadi et al [2009], and Papadopoulou et al [2015 that also did not find association of BsmI with BA. Significantly higher prevalence of F allele in healthy subjects could be the result of evolutional adaptation in human population due to the fact that shorter VDR protein (424 amino acids), synthesized in the presence of FF genotype, have higher affinity for 1,25(OH) 2 D 3 binding and higher transcriptional activity compared to the longer protein synthesized in the presence of ff genotype (427 amino acids) [Uitterlinden et al, 2004].…”

“…However, differences in mRNA stability between the alleles were not confirmed in the later studies [Durrin et al, 1999]. However, studies conducted in Cypriot, Tunisian, and Iranian populations, including our study in Serbian population, failed to find any association of ApaI genotypes and alleles with BA [Poon et al, 2004;Nosratabadi et al, 2011;Papadopoulou et al, 2015]. Their role in BA is still not clear and results of association with BA are contradictory.…”

“…No association was found after stratification by sex. [Papadopoulou et al, 2015], while in the families of French Canadian origin T allele of VDR TaqI was associated with asthma and atopy [Poon et al, 2004]. However, some previous studies considering the TaqI polymorphism reported significant association of TaqI geneotypes in the Iranian asthmatic population [Nosratabadi et al, 2011] and association of minor TaqI genotype in Cypriot adolescents Fig.…”

Vitamin D Receptor<b><i> Taq</i></b>I Gene Polymorphism and Dental Caries in Czech Children

“…Thirdly, different genetic backgrounds due to different ethnicity (Asians vs. Caucasians) in the 3 studies could be a cause of heterogeneity of the results. Apart from the ethnic variations, geographical differences and the interaction between VDR gene variants and environmental conditions may also differ between populations [Papadopoulou et al, 2015]. The aim of the third experiment was to assess the VDR Taq I polymorphism in groups according to gingival health status.…”

The Role of Vitamin D in the Immune System as a Pro-survival Molecule

“…228 Despite the obvious sex-dependent differential availability and tissue distribution of vitamin D in the human body, 229 the efficacy of the administered burden of exogenous vitamin D also depends on body mass index, dietary habits, lifestyle, age, nationality, vitamin D 2 availability, VDR, and CYP polymorphisms. 230,231 Nutritional recommendations regarding vitamin D supplementation should take into account these issues. However, vitamin D should be considered in those populations confronting an immune challenge and/or nutritional starvation (eg, in pregnancy, infants, elderly, those with chronic illnesses).…”