Environmental risk factors for respiratory infection and wheeze in young children: A multicentre birth cohort study.

INTRODUCTION: Respiratory infections and wheeze have a considerable impact on the health of young children and consume significant healthcare resources. We aimed to evaluate the effect of environmental factors on respiratory infections and symptoms in early childhood. METHODS: Environmental risk factors including: daycare attendance; breastfeeding; siblings; damp within the home; environmental tobacco smoke (ETS); child's bedroom flooring; animal exposure; road traffic density around child's home; and solid fuel pollution within home were assessed in children recruited to the GO-CHILD multicentre prospective birth cohort study. Follow-up information on respiratory infections (bronchiolitis, pneumonia, otitis media and cold or flu), wheeze and cough symptoms, healthcare utilisation and medication prescription was collected by postal questionnaires at 12 and 24 months. Log binomial and ordered logistic regression models were fitted to the data. RESULTS: Follow-up was obtained on 1344 children. Daycare was associated with increased odds of pneumonia (odds ratio [OR] = 2.39, 95% confidence interval [CI]: 1.04-5.49), bronchiolitis (OR = 1.40, 1.02-1.90), otitis media (OR = 1.68, 1.32-2.14) and emergency department attendance for wheeze (RR = 1.81, 1.17-2.80). Breastfeeding beyond 6 months was associated with a reduced odds of bronchiolitis (OR = 0.55, 0.39-0.77) and otitis media (OR = 0.75, 0.59-0.99). Siblings at home was associated with an increased odds of bronchiolitis (OR = 1.65, 1.18-2.32) and risk of reliever inhaler prescription (RR = 1.37, 1.02-1.85). Visible damp was associated with an increased odds of wheeze (OR = 1.85, 1.11-3.19), and risk of reliever inhaler (RR = 1.73, 1.04-2.89) and inhaled corticosteroid prescription (RR = 2.61, 1.03-6.59). ETS exposure was associated with an increased odds of primary care attendance for cough or wheeze (OR = 1.52, 1.11-2.08). Dense traffic around the child's home was associated with an increased odds of bronchiolitis (OR = 1.32, 1.08-2.29). CONCLUSION: Environmental factors likely influence the wide variation in infection frequency and symptoms observed in early childhood. Larger population studies are necessary to further inform and guide public health policy to decrease the burden of respiratory infections and wheeze in young children.

Mannose-binding lectin genotype is associated with respiratory disease in young children: A multicenter cohort study.

BACKGROUND: Mannose-binding lectin (MBL) is an important component of the innate immune system. Polymorphisms in the MBL2 gene and promoter region are directly associated with MBL-deficiency. We sought to determine the association between MBL genotype on the frequency of common childhood respiratory infections, respiratory symptoms, and atopic outcomes in early childhood. METHODS: MBL2 gene variants were analyzed in newborns recruited to the GO-CHILD multicenter prospective cohort study. Follow-up for respiratory infection and atopy diagnoses and symptoms, healthcare utilization, and medication prescription were conducted by postal questionnaires at 12 and 24 months. RESULTS: Genotyping and follow-up were completed in 1004 children. Genotypes associated with MBL-deficiency were associated with an increased risk of bronchiolitis (relative risk [RR] 1.95, 95% confidence interval [CI] 1.33-2.85) and pneumonia (RR 2.46, 95% CI 1.16-5.22). MBL-deficient genotypes were associated with an increased risk of wheeze with shortness of breath episodes (RR 1.22, 95% CI 1.04-1.43), emergency department attendance (RR 1.90 95% CI 1.13-3.19), and hospital admission (RR 2.01, 95% CI 1.04-3.89) for wheeze. MBL-deficient genotypes were associated with a reduced risk of developing atopic dermatitis (RR 0.72, 95% CI 0.53-0.98). CONCLUSION: The positive association between MBL-deficient genotypes and bronchiolitis and pneumonia, as well as a severe wheeze phenotype in some young children, supports the hypothesis that MBL is an important component of innate immunity in the vulnerable period before the maturation of the adaptive immune system. Identification of disease-modifying genotypes may help target preventative strategies in high-risk infants.

Diagnosis of coeliac disease by flow cytometry of intraepithelial lymphocytes: a new 'gold' standard?

Objective: The analysis of intraepithelial lymphocytes (IELs) by flow cytometry of duodenal biopsies-the 'IEL' lymphogram-has been proposed as a diagnostic test for coeliac disease. However, its clinical applicability has been limited due to variability in methods and definitions. This study set out to define useful parameters for the application of the IEL lymphogram to the diagnosis of coeliac disease. Design: Flow cytometry was performed on 117 sets of duodenal biopsies in 107 adult patients with active coeliac disease, long-term coeliac disease on a gluten free diet and a control group. The initial 95 samples were used for hypothesis generation for the subsequent samples comprising 12 patients with coeliac disease and 10 controls. Results: Rather than using single linear cut-offs for CD3 and T-cell receptor γδ (TCRγδ)+ve IELs, a discriminant function was identified as %CD3+ve IELs+2x(%TCRγδ+IELs)>100. This differentiated coeliac disease from control biopsies in the hypothesis generating group. These results were replicated in the validation group and found to be independent of histology in patients on long-term gluten free diet up to 12 years (combined sensitivity, 98.5%; specificity, 97.7%). Conclusions: Flow cytometric analysis of IELs is a highly sensitive and specific adjunct to serology and histological examination for the diagnosis of coeliac disease, even in individuals with coeliac disease following a gluten free diet who exhibit normal duodenal histology.

Correction: Pharmacogenomic associations of adverse drug reactions in asthma: systematic review and research prioritization.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Pharmacogenomic associations of adverse drug reactions in asthma: systematic review and research prioritisation.

A systematic review of pharmacogenomic studies capturing adverse drug reactions (ADRs) related to asthma medications was undertaken, and a survey of Pharmacogenomics in Childhood Asthma (PiCA) consortia members was conducted. Studies were eligible if genetic polymorphisms were compared with suspected ADR(s) in a patient with asthma, as either a primary or secondary outcome. Five studies met the inclusion criteria. The ADRs and polymorphisms identified were change in lung function tests (rs1042713), adrenal suppression (rs591118), and decreased bone mineral density (rs6461639) and accretion (rs9896933, rs2074439). Two of these polymorphisms were replicated within the paper, but none had external replication. Priorities from PiCA consortia members (representing 15 institution in eight countries) for future studies were tachycardia (SABA/LABA), adrenal suppression/crisis and growth suppression (corticosteroids), sleep/behaviour disturbances (leukotriene receptor antagonists), and nausea and vomiting (theophylline). Future pharmacogenomic studies in asthma should collect relevant ADR data as well as markers of efficacy.

Childhood asthma exacerbations and the Arg16 ß2-receptor polymorphism: A meta-analysis stratified by treatment.

BACKGROUND: The Gly-to-Arg substitution at the 16 position (rs1042713) in the ß2-adrenoceptor gene (ADRB2) is associated with enhanced downregulation and uncoupling of ß2-receptors. OBJECTIVES: We sought to undertake a meta-analysis to test the hypothesis that there is an interaction between the A allele of rs1042713 (Arg16 amino acid) and long-acting ß-agonist (LABA) exposure for asthma exacerbations in children. METHODS: Children with diagnosed asthma were recruited in 5 populations (BREATHE, Genes-Environments and Admixture in Latino Americans II, PACMAN, the Paediatric Asthma Gene Environment Study, and the Pharmacogenetics of Adrenal Suppression with Inhaled Steroid Study). A history of recent exacerbation and asthma treatment was determined from questionnaire data. DNA was extracted, and the Gly16Arg genotype was determined. RESULTS: Data from 4226 children of white Northern European and Latino origin were analyzed, and the odds ratio for exacerbation increased by 1.52 (95% CI, 1.17-1.99; P = .0021) for each copy of the A allele among the 637 children treated with inhaled corticosteroids (ICSs) plus LABAs but not for treatment with ICSs alone (n = 1758) or ICSs plus leukotriene receptor antagonist (LTRAs; n = 354) or ICSs plus LABAs plus LTRAs (n = 569). CONCLUSIONS: The use of a LABA but not an LTRA as an "add-on controller" is associated with increased risk of asthma exacerbation in children carrying 1 or 2 A alleles at rs1042713. Prospective genotype-stratified clinical trials are now required to explore the potential role of rs1042713 genotyping for personalized asthma therapy in children.

Tailored second-line therapy in asthmatic children with the Arg(16) genotype.

The Arg(16) ß(2) receptor genotype confers increased susceptibility to exacerbations in asthmatic children taking regular LABA (long-acting ß(2) agonists). We therefore evaluated using montelukast as an alternative to salmeterol as tailored second-line asthma controller therapy in children expressing this susceptible genotype. A total of 62 persistent asthmatic children with the homozygous Arg16 genotype were randomized to receive salmeterol (50 µg, b.i.d.) or montelukast (5 or 10 mg, once daily) as an add-on to inhaled fluticasone for 1 year. School absences (the primary outcome) were reduced with montelukast compared with salmeterol {difference in score=-0.40 [95% CI (confidence interval), -0.22 to -0.58]; P=0.005}. Salbutamol use was also reduced with montelukast compared with salmeterol [difference in score=-0.47 (95% CI, -0.16 to -0.79); P<0.0001]. Greater improvements occurred in both symptom and quality of life scores with montelukast against salmeterol, whereas there was no difference in FEV(1) (forced expiratory volume in 1 s). In conclusion, montelukast may be suitable as tailored second-line controller therapy instead of salmeterol in asthmatic children expressing the susceptible Arg(16) genotype, a move towards a personalized medicine approach to management.

The CHI3L1 rs4950928 polymorphism is associated with asthma-related hospital admissions in children and young adults.

BACKGROUND: Asthma exacerbations are the commonest cause of medical admissions in childhood. These have a significant effect on quality of life and are a major financial burden on worldwide healthcare services. A range of gene-environment interactions may influence the course and severity of asthma in children and their response to medication. The Chitinase 3-like 1 (CHI3L1)-131C>G genotype (rs4950928) is associated with increased asthma susceptibility and severity in adults. OBJECTIVES: To study the interactions of the Chitinase 3-Like-1 functional promoter SNP rs4950928 and its role on asthma exacerbations in a population of children and young adults with asthma. METHODS: A cross-sectional survey was undertaken using medical records and direct interviews of 1,071 children and young adults with asthma, aged 3 to 22 years, from Scotland. Saliva samples were collected for genotyping. Binary logistic regression was used to calculate odds ratios (ORs) and P-values for measures of asthma exacerbations. RESULTS: The minor -131G allele confers protection against asthma-related hospital admissions (OR = 0.62; 95% CI 0.41-0.92; P = .018) in children and young adults with asthma. CONCLUSIONS: Our study shows that rs4950928 is significantly associated with hospital admissions in children and young adults; screening for rs4950928 may predict asthma-related hospital admissions, and through individually defined treatment management plans, potentially reduce health care costs.

Airway and systemic effects of soluble and suspension formulations of nebulized budesonide in asthmatic children.

BACKGROUND: Using cyclodextrin with budesonide enables it to be formulated in a solution for nebulization. OBJECTIVE: To observe the effects of a Captisol-enabled budesonide solution (CBIS), 60 microg twice daily, delivered via a nebulizer (eFlow), compared with a conventional budesonide suspension (Pulmicort Respules), 250 microg twice daily, delivered via another nebulizer (LC Plus), using fraction of exhaled nitric oxide (FE(NO)) and overnight urinary cortisol to creatinine ratio as the primary outcomes for efficacy and systemic bioactivity. METHODS: A randomized, open-label, crossover study was conducted in 12 children with mild-to-moderate persistent asthma (aged 5-12 years). Measurements were performed after a 2-week steroid washout at baseline and at the end of each 2-week randomized treatment. RESULTS: The nebulization time was shorter (95% confidence interval [CI], 0.83-5.63 minutes; P = .03) with CBIS (mean, 1.77 minutes) than with Pulmicort Respules (mean, 5.01 minutes). The reduction in FE(NO) with CBIS from pooled baseline was 2.45-fold (95% CI, 1.87-3.21; P < .001); and with Pulmicort Respules, 3.18-fold (95% CI, 2.26-4.47; P < .001). No statistically significant changes from pooled baseline in lung function and overnight urinary cortisol to creatinine ratio were observed with either treatment. CONCLUSIONS: The nebulization time was shorter with CBIS compared with Pulmicort Respules. Both formulations exhibited similar anti-inflammatory activity in terms of reducing FE(NO), with no detectable difference between them when used in a putative microgram nominal dose ratio of 1:4. Neither formulation produced significant adrenal suppression.

Adrenergic beta(2)-receptor genotype predisposes to exacerbations in steroid-treated asthmatic patients taking frequent albuterol or salmeterol.

BACKGROUND: On-demand inhaled albuterol is commonly prescribed worldwide. We have shown that the Arg16 allele of the adrenergic beta(2)-receptor agonist gene (ADRB2) predisposes to exacerbations in young asthmatic patients taking regular salmeterol. OBJECTIVE: We have now extended our previous population by 636 patients and explored the role of the Arg16 allele on asthma exacerbations in the context of the use of on-demand albuterol and regular salmeterol. METHODS: Arg/Gly status at position 16 of ADRB2 was assessed in 1182 young asthmatic patients (age, 3-22 years) from Scotland. Asthma exacerbations, use of beta-agonists and other medications over the previous 6 months, and lung function were also studied. RESULTS: An increased risk of exacerbations per copy of he Arg16 allele was observed in asthmatic patients, regardless of treatment regimen (odds ratio [OR], 1.30; 95% CI, 1.09-1.55; P = .003). This appears to be largely due to exposure to beta(2)-agonists because the risk of exacerbations observed in patients with the Arg16 allele was only observed in those receiving daily inhaled long- or short-acting beta(2)-agonist treatment (OR, 1.64; 95% CI, 1.22-2.20; P = .001). In contrast, there was no genotypic risk for exacerbations in patients using inhaled beta(2)-agonists less than once a day (OR, 1.08; 95% CI, 0.85-1.36; P = .525). The Arg16 genotype-associated risk for exacerbations was significantly different in those exposed to beta(2)-agonists daily versus those that were not (test for interaction, P = .022). CONCLUSION: The Arg16 genotype of ADRB2 is associated with exacerbations in asthmatic children and young adults exposed daily to beta(2)-agonists, regardless of whether the exposure is to albuterol or long-acting agonists, such as salmeterol.