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

Papadopoulou A, Kouis P, Middleton N, Kolokotroni O, Karpathios T, Nicolaidou P, Yiallouros PK - Multidiscip Respir Med (2015)

Bottom Line: 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.No difference was observed between controls, current wheezers and active asthmatics in the genotypic distribution of BsmI and ApaI polymorphic sites.This polymorphism may contribute to asthma susceptibility primarily under conditions of normal vitamin D levels (>20 ng/ml).

View Article: PubMed Central - PubMed

Affiliation: Third Department of Pediatrics, Athens University Medical School, University General Hospital "Attikon", Athens, Greece.

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).

No MeSH data available.


Related in: MedlinePlus

Course of the study: from the 19,849 participants (11–12 years) in Survey 1, a random sample of 3982 adolescents (15–17 years) participated in Survey 2. All (n = 297) subjects from the 3982 sample, who reported wheezing in the last 12 months were invited to participate as cases. A sample of 932 children with no diagnosis of asthma and no wheezing in the past 12 months were invited to participate as controls
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Fig1: Course of the study: from the 19,849 participants (11–12 years) in Survey 1, a random sample of 3982 adolescents (15–17 years) participated in Survey 2. All (n = 297) subjects from the 3982 sample, who reported wheezing in the last 12 months were invited to participate as cases. A sample of 932 children with no diagnosis of asthma and no wheezing in the past 12 months were invited to participate as controls

Mentions: The participants of this study were selected from a cohort of 3982 children who participated in two large school-based health surveys in Cyprus. The first survey in years 2001–2003 involved all children (n = 19,849) attending the 6th form across all primary schools in Cyprus and focused on nutrition and physical fitness. This survey was followed by a second one in year 2007, which recruited 3982 of those participated in the first (20.1 %) and focused on respiratory health (International Study of Asthma and Allergies in Childhood–ISAAC) and risk factors for asthma [46]. In year 2008 when aged 16–18 years and in a case–control design, we invited all those from the 3982 children who on the second survey (ISAAC questionnaire) were current wheezers to participate in this study along with a triplicate number of healthy controls. Current Wheezers were participants who reported wheezing in the past 12 months (Current Wheezers–CUW) and for the purpose of performing a sensitivity analysis, the case definition was further refined to Current Wheezing and Asthma (CUWA), if there was also report of diagnosis of asthma ever. Controls were selected amongst the 3982 adolescents that did not report any wheezing or asthma ever (Never Wheezers Never Asthmatics–NWNA). NWNA were selected using a stratified random sampling approach in order to increase the probability of selection of children at the extremes of BMI change between childhood and adolescence, in line with the scope of another study on the relation of adiposity with asthma. Based on the above selection criteria the group of controls consisted of 671 NWNA and the group of patients of 190 CUW subjects. Among the CUW patients, 69 were categorized as active asthmatic forming the CUWA subgroup (Fig. 1). All participants and their guardians provided informed consent and the study was approved by the National Bioethics Committee of Cyprus.Fig. 1


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

Papadopoulou A, Kouis P, Middleton N, Kolokotroni O, Karpathios T, Nicolaidou P, Yiallouros PK - Multidiscip Respir Med (2015)

Course of the study: from the 19,849 participants (11–12 years) in Survey 1, a random sample of 3982 adolescents (15–17 years) participated in Survey 2. All (n = 297) subjects from the 3982 sample, who reported wheezing in the last 12 months were invited to participate as cases. A sample of 932 children with no diagnosis of asthma and no wheezing in the past 12 months were invited to participate as controls
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4559891&req=5

Fig1: Course of the study: from the 19,849 participants (11–12 years) in Survey 1, a random sample of 3982 adolescents (15–17 years) participated in Survey 2. All (n = 297) subjects from the 3982 sample, who reported wheezing in the last 12 months were invited to participate as cases. A sample of 932 children with no diagnosis of asthma and no wheezing in the past 12 months were invited to participate as controls
Mentions: The participants of this study were selected from a cohort of 3982 children who participated in two large school-based health surveys in Cyprus. The first survey in years 2001–2003 involved all children (n = 19,849) attending the 6th form across all primary schools in Cyprus and focused on nutrition and physical fitness. This survey was followed by a second one in year 2007, which recruited 3982 of those participated in the first (20.1 %) and focused on respiratory health (International Study of Asthma and Allergies in Childhood–ISAAC) and risk factors for asthma [46]. In year 2008 when aged 16–18 years and in a case–control design, we invited all those from the 3982 children who on the second survey (ISAAC questionnaire) were current wheezers to participate in this study along with a triplicate number of healthy controls. Current Wheezers were participants who reported wheezing in the past 12 months (Current Wheezers–CUW) and for the purpose of performing a sensitivity analysis, the case definition was further refined to Current Wheezing and Asthma (CUWA), if there was also report of diagnosis of asthma ever. Controls were selected amongst the 3982 adolescents that did not report any wheezing or asthma ever (Never Wheezers Never Asthmatics–NWNA). NWNA were selected using a stratified random sampling approach in order to increase the probability of selection of children at the extremes of BMI change between childhood and adolescence, in line with the scope of another study on the relation of adiposity with asthma. Based on the above selection criteria the group of controls consisted of 671 NWNA and the group of patients of 190 CUW subjects. Among the CUW patients, 69 were categorized as active asthmatic forming the CUWA subgroup (Fig. 1). All participants and their guardians provided informed consent and the study was approved by the National Bioethics Committee of Cyprus.Fig. 1

Bottom Line: 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.No difference was observed between controls, current wheezers and active asthmatics in the genotypic distribution of BsmI and ApaI polymorphic sites.This polymorphism may contribute to asthma susceptibility primarily under conditions of normal vitamin D levels (>20 ng/ml).

View Article: PubMed Central - PubMed

Affiliation: Third Department of Pediatrics, Athens University Medical School, University General Hospital "Attikon", Athens, Greece.

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).

No MeSH data available.


Related in: MedlinePlus