Vitamin D levels have been suggested as a marker of disease severity in asthmatic children. Our aim was to investigate possible associations between the
vitamin D receptor (VDR) FokI, BsmI,
ApaI, and TaqI polymorphisms and
asthma susceptibility and control in children. 127 Greek children with
asthma and 91 healthy controls were genotyped for VDR FokI, BsmI
ApaI, and TaqI polymorphisms using Sequenom MassARRAY
iPLEX platform.
Asthma control was assessed according to the Global Initiative for
Asthma guidelines (GINA) and Childhood
Asthma Control Test (C-ACT) and, for the first time, tested for its possible association with VDR SNPs. Asthmatic children were grouped as "controlled (n=49)", "partially controlled (n=38)," and "uncontrolled (n=40)," according to GINA classification. No association was found between VDR polymorphisms and
asthma prevalence. Asthmatic children with the VDR
ApaI aa genotype had significantly higher C-ACT score compared with asthmatic children carrying the AA/AC VDR
ApaI genotypes (p=0.011). The frequency of VDR
ApaI aa genotype was significantly higher in controlled
asthma group (n=92) than uncontrolled
asthma group (n=35), according to C-ACT (24.5% vs 0.0%, p<0.001) and GINA (32.7% vs 7.5%, p=0.001). Also, VDR
ApaI aa genotype was negatively associated with limitation in daily activities because of
asthma (p=0.004). VDR
ApaI aa genotype was positively associated with well-controlled
asthma according to GINA and C-ACT questionnaire and negatively associated with decreased limitation in daily activities in asthmatic children, further supporting the importance of
Vitamin D pathway in
asthma.