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

Abstract

Background: Polymorphisms 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.
 Methods: We 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.
 Results: The 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.
 Conclusions: The 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).

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

“…Further stratification by sex failed to show differences between patients and controls of the certain gender, as well. 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. However, in asthmatic children, Maalmi et al [2013] showed significant difference in genotype distribution compared to healthy controls suggesting significantly increased risk for BA development in the carriers of B allele and 2.5-folds higher risk for BA in the homozygous carriers of B allele, while Poon et al [2004] showed the association of the b allele with BA and atopy in subjects of French-Canadian origin.…”

“…These results are in accordance with results published by Saadi et al [2009] and Pillai et al [2011]. 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 [ 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]. Furthermore, study by Raby et al [2004] showed that TaqI is significantly associated with IgE levels.…”

Association of vitamin D receptor gene polymorphisms with susceptibility to childhood asthma: A meta‐analysis

“…A total of nine studies were found related VDR polymorphism to childhood asthma after removal of duplicates and those studies did not meet the inclusive criteria. [16][17][18][19][20][21][22][23][24] There were eight studies on ApaI (rs7975232), [16][17][18][19][20][22][23][24] five on BsmI (rs15444 10), 16,17,19,22,24 six on FokI (rs2228570), 16,[18][19][20][21][22] and six involved TapI (rs731236) [16][17][18][19][20]22 separately. The qualities of included studies were estimated according to the Newcastle-Ottawa scale.…”

Vitamin D receptor genetic polymorphisms are associated with oral lichen planus susceptibility in a Chinese Han population

“…And the haplotype analysis involved rs7975232 and rs731236 suggested that the AT haplotype decreased OLP risk (compared with the most common haplotype CT), further confirming that OLP susceptibility was not caused by a single SNP. Many previous epidemiological studies have shown that the incidence of OLP, clinical symptoms and the mutation rate of VDR genes are different in different ethnic populations, so we speculate that this may also be the main reason for the difference between the two studies [26,27]. The sample size for this study was smaller than our study (only 65 patients with oral lichen planus and 100 healthy blood donors), and all of study subjects were Caucasian and Serbian.…”