Purpose of the Study: To investigate the associations between maternal intake of dietary antioxidants in pregnancy and childhood respiratory and atopic outcomes (including lung function) and to ...explore whether these associations were modified by maternal smoking during pregnancy and common maternal antioxidant gene polymorphisms. Study Population: The study was focused on 8915 mother-child pairs who participated in a population-based birth cohort in Avon, United Kingdom. Methods: Researchers in this study analyzed associations between maternal intake of fruits, vegetables, vitamins C and E, carotene, zinc, and selenium in pregnancy and current doctor-diagnosed asthma, atopy, and lung function in 8915 children at age 7 to 9 years. To explore potential interaction from environmental exposures, results were stratified for maternal smoking history and by maternal antioxidant intake during pregnancy. Results: After controlling for confounders, positive associations were observed between maternal intake of zinc and childhood forced expiratory volume at 1 second and forced vital capacity with evidence of a dose-response relationship. Post hoc analyses of the associations between maternal zinc intake and childhood forced expiratory volume at 1 second and forced vital capacity at 15 years (n = 3669) showed similar findings to those observed at 8 years. In contrast to these findings, there was no evidence that maternal intake of dietary antioxidants is associated with a risk of childhood asthma or atopy. Conclusions: Researchers in this study found that higher maternal intake of zinc during pregnancy may be associated with better lung function in their children.
Purpose of the Study: To assess dose-response relationships between plasma cotinine–determined secondhand smoke (SHS) exposure and asthma outcomes in minority children. Study Population: The study ...included 1172 Latino and African American children with asthma from the mainland and Puerto Rico. Methods: The investigators used subsamples of participants from the Gene-environments and Admixture in Latino Americans Study and the Study of African Americans, Asthma, Genes, and Environments. Both are case-control studies of asthma in which researchers recruited children who were 8 to 21 years old. Logistic regression was used to assess relationships of cotinine levels ≥0.05 ng/mL with asthma exacerbations (defined as asthma-related hospitalizations, emergency department visits, or oral steroid prescription) in the previous year and asthma control. Results: The odds ratio for experiencing asthma exacerbations in the previous year for cotinine levels ≥0.05 ng/mL, compared with <0.05 ng/mL, was 1.40 (95% confidence interval: 1.03–1.89). There was an increase in dose response for asthma control when comparing "very poorly controlled" with "controlled" asthma. When examining the level of asthma control each participant maintained over the past year, the odds ratio for poor asthma control was 1.53 (95% confidence interval: 1.12–2.13). Analyses for dose-response relationships indicated increasing odds of asthma outcomes related with increasing exposure, even at cotinine levels associated with light SHS exposure. Conclusions: Among African American and Latino children, exposure to SHS is associated with higher odds of asthma exacerbations and having poorly controlled asthma. A dose-response relationship exists even at low levels of exposure. There are no safe levels of SHS exposure.
Purpose of the Study: Evidence for the effects of air pollution exposure on lung function growth into adolescence is scarce. Therefore, the purpose of this study was to investigate the associations ...of air pollution exposure from birth with lung function growth from ages 8 to 16 and lung function at age 16. Potential confounders (sex and asthma diagnosis) were also explored. Study Population: The study was performed within the Dutch population-based Prevention and Incidence of Asthma and Mite Allergy birth cohort. From the 3963 pregnant women initially enrolled, 915 children (mean age: 16.3 years) had sufficient longitudinal data for this study. Methods: Both longitudinal (n = 915) and cross-sectional (n = 721) analyses were conducted. Researchers estimated residential concentrations of nitrogen dioxide, "soot," and particulate matter (PMx, where x is the 50% cutoff aerodynamic diameter in μm) with diameters of <2.5 μm (PM2.5), <10 μm (PM10), and 2.5 to 10 μm (PMcoarse) during the preschool, primary school, and secondary school time windows by land use regression models. Associations with (growth in) forced expiratory volume in 1 second (FEV1) and forced vital capacity were analyzed by linear (mixed effects) regression. Results: Greater air pollution exposure was associated with reduced FEV1 growth (eg, adjusted difference: −0.26% 95% confidence interval: −0.49 to −0.03% per interquartile range increase in secondary school PM2.5) and lower FEV1 (adjusted difference: −2.36% 95% confidence interval: −3.76 to −0.94%) but was not adversely associated with forced vital capacity. Associations with FEV1 were stronger in boys than girls and were not modified by asthma status. Conclusions: Greater air pollution exposure may lead to increased airway obstruction but not reduced lung volume in adolescence.
The human microbiome associated with the respiratory tract is diverse, heterogeneous, and dynamic. The diversity and complexity of the microbiome and the interactions between microorganisms, host ...cells, and the host immune system are complex and multifactorial. Furthermore, the lymphatics provide a direct highway, the gut-lung axis, for the gut microbiome to affect outcomes related to respiratory disease and the host immune response. Viral infections in the airways can also alter the presence or absence of bacterial species, which might increase the risks for allergies and asthma. Viruses infect the airway epithelium and interact with the host to promote inflammatory responses that can trigger a wheezing illness. This immune response may alter the host's immune response to microbes and allergens, leading to T2 inflammation. However, exposure to specific bacteria may also tailor the host's response long before the virus has infected the airway. The frequency of viral infections, age at infection, sampling season, geographic location, population differences, and preexisting composition of the microbiota have all been linked to changes in microbiota diversity and stability. This review aims to evaluate the current reported evidence for microbiome interactions and the influences that viral infection may have on respiratory and gut microbiota, affecting respiratory outcomes in children.
Background Detection of either viral or bacterial pathogens is associated with wheezing in children; however, the influence of both bacteria and viruses on illness symptoms has not been described. ...Objective We evaluated bacterial detection during the peak rhinovirus season in children with and without asthma to determine whether an association exists between bacterial infection and the severity of rhinovirus-induced illnesses. Methods Three hundred eight children (166 with asthma and 142 without asthma) aged 4 to 12 years provided 5 consecutive weekly nasal samples during September and scored cold and asthma symptoms daily. Viral diagnostics and quantitative PCR for Streptococcus pneumoniae , Haemophilus influenzae , and Moraxella catarrhalis were performed on all nasal samples. Results Detection rates were 53%, 17%, and 11% for H influenzae , S pneumoniae , and M catarrhalis , respectively, with detection of rhinovirus increasing the risk of detecting bacteria within the same sample (odds ratio OR, 2.0; 95% CI, 1.4-2.7; P < .0001) or the following week (OR, 1.6; 95% CI, 1.1-2.4; P = .02). In the absence of rhinovirus, S pneumoniae was associated with increased cold symptoms (mean, 2.7 95% CI, 2.0-3.5 vs 1.8 95% CI, 1.5-2.2; P = .006) and moderate asthma exacerbations (18% 95% CI, 12% to 27% vs 9.2% 95% CI, 6.7% to 12%; P = .006). In the presence of rhinovirus, S pneumoniae was associated with increased moderate asthma exacerbations (22% 95% CI, 16% to 29% vs 15% 95% CI, 11% to 20%; P = .01). Furthermore, M catarrhalis detected alongside rhinovirus increased the likelihood of experiencing cold symptoms, asthma symptoms, or both compared with isolated detection of rhinovirus (OR, 2.0 95% CI, 1.0-4.1; P = .04). Regardless of rhinovirus status, H influenzae was not associated with respiratory symptoms. Conclusion Rhinovirus infection enhances detection of specific bacterial pathogens in children with and without asthma. Furthermore, these findings suggest that M catarrhalis and S pneumoniae contribute to the severity of respiratory tract illnesses, including asthma exacerbations.
Purpose of Review
Evidence suggests that the microbiome of the skin, gastrointestinal tract, and airway contribute to health and disease. As we learn more about the role that the microbiota plays in ...allergic disease development, we can develop therapeutics to alter this pathway.
Recent Findings
Epidemiologic studies reveal that an association exists between environmental exposures, which alter the microbiota, and developing atopic dermatitis, food allergy, and/or asthma. In fact, samples from the skin, gastrointestinal tract, and respiratory tract reveal distinct microbiotas compared with healthy controls, with microbial changes (dysbiosis) often preceding the development of allergic disease. Mechanistic studies have confirmed that microbes can either promote skin, gut, and airway health by strengthening barrier integrity, or they can alter skin integrity and damage gut and airway epithelium.
Summary
In this review, we will discuss recent studies that reveal the link between the microbiota and immune development, and we will discuss ways to influence these changes.
In a phase 3 trial involving children 1 to 3 years of age with peanut allergy, epicutaneous immunotherapy by means of a peanut patch was superior to placebo in desensitizing children to peanut.
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