impact of vitamin D deficiency on asthma, allergic rhinitis and wheezing in children: an emerging public health problem

Vitamin D deficiency has been declared a public health problem for both adults and children worldwide. Asthma and related allergic diseases are the leading causes of morbidity in children. The objective of this study was to investigate the potential role of Vitamin D deficiency in childhood asthma and other allergic diseases such as allergic rhinitis and wheezing. This cross-sectional study was conducted in Primary Health Care Centers [PHCs], from March 2012 to October 2013. A total of 2350 Qatari children below the age of 16 were selected from PHCs, and 1833 agreed to participate in this study giving a response rate of [78%]. Face-to-face interviews with parents of all the children were based on a questionnaire that included variables such as socio-demographic information, assessment of nondietary covariates, Vitamin D intake, type of feeding, and laboratory investigations. Their health status was assessed by serum Vitamin D [25-hydoxyvitamin D], family history and body mass index. Most of the children who had asthma [38.5%], allergic rhinitis [34.8%] and wheezing [35.7%] were below 5 years. Consanguinity was significantly higher in parents of children with allergic rhinitis [48.6%], followed by those with asthma [46.4%] and wheezing [40.8%] than in healthy children [35.9%] [P < 0.001]. The proportion of severe Vitamin D deficiency was significantly higher in children with wheezing [23.4%], allergic rhinitis [18.5%], and asthma [17%] than in healthy children [10.5%]. Exposure to the sun was significantly less in Vitamin D deficient children with asthma [60.3%], allergic rhinitis [62.5%] and wheezing [64.4%] than in controls [47.1%] [P = 0.008]. It was found that Vitamin D deficiency was a significant correlate for asthma [odds ratio [OR] =2.31; P < 0.001], allergic rhinitis [OR = 1.59; P < 0.001] and wheezing [relative risk = 1.29; P = 0.05]. The study findings revealed a high prevalence of Vitamin D deficiency in children with asthma and allergic diseases. Vitamin D deficiency was a strong correlate for asthma, allergic rhinitis and wheezing

T1 and T2 ADAM33 single nucleotide polymorphisms and the risk of childhood asthma in a Saudi Arabian population: a pilot study

Genetic association studies have demonstrated that over 100 variants in target genes [including ADAM33] are associated with airway remodeling and hyper-responsiveness in different ethnic groups; however, this has never been evaluated in Arabic populations. The objective of this study was to determine whether ADAM33 polymorphisms that are associated with asthma in a population of asthmatic children from Saudi Arabia. A cross-sectional pilot study comparing the polymorphisms of normal subjects and asthmatic patients from Saudi Arabia over a period of 1 year. One hundred and seven Saudi asthmatic children and 87 healthy Saudi children of 3-12 years old were assessed for allelic association of ADAM33 T1 [rs2280091], T2 [rs2280090], ST+4 [rs44707] and S1 [rs3918396] SNPs to asthma. Genotyping was done by real-time PCR, multiplex ARMS and PCR-RFLP. T1 and T2 SNP genotype frequencies in asthmatic children were significantly different compared to controls [P<.05], indicating allelic association with asthma. The T1 A/G and G/G and the T2 A/G and A/A genotypes [P=0.0013 and P=.008, respectively] but not S1 and ST+4, increased the risk of asthma when using the best fit dominant model. Strong linkage disequilibrium between T1 [rs2280091] and T2 [rs2280090] was observed [r2=0.83; D'=0.95; P<.001]. The haplotype G-A-A-C was significantly more frequent in asthmatics, thus supporting the association of T1 G-allele and T2 A-allele with increased predisposition to asthma [P=.007]. T1 A/G and T2 G/A ADAM33 polymorphisms, but not S1 or ST+4, were significantly associated with asthma development in Saudi children, like those reported for white and Hispanic population in the United States

New insights into the pathophysiology of the small airways in asthma

Asthma is a lung disease characterized by inflammation and remodeling of the airways, which leads to airflow obstruction and symptoms of wheeze, chest tightness, cough and dyspnea. It is now widely accepted that airway inflammation and remodeling occur not only in the central airways but also in the small airways and even in the lung parenchyma. Inflammation of the distal lung can be observed even in mild asthmatics with normal or noncompromised lung function. Moreover, the small airways and the lung parenchyma can produce many Th2 cytokines and chemokines involved in initiation and perpetuation of the inflammatory process. In addition, the distal parts of the lung have been recognized as a predominant site of airflow obstruction in asthmatics. In fact, the inflammation at this distal site has been described as more severe when compared to the large airway inflammation, and evidence of remodeling in the lung periphery is emerging. Recognition of asthma as a disease of the entire respiratory tract has an important clinical significance, highlighting the need to also consider the distal lung as a target in any therapeutic strategy for effective treatment of this disease