Epigenetic modifications, including DNA methylation, represent a potential mechanism for environmental impacts on human disease. Maternal smoking in pregnancy remains an important public health problem that impacts child health in a myriad of ways and has potential lifelong consequences. The mechanisms are largely unknown, but epigenetics most likely plays a role. We formed the Pregnancy And Childhood Epigenetics (PACE) consortium and meta-analyzed, across 13 cohorts (n = 6,685), the association between maternal smoking in pregnancy and newborn blood DNA methylation at over 450,000 CpG sites (CpGs) by using the Illumina 450K BeadChip. Over 6,000 CpGs were differentially methylated in relation to maternal smoking at genome-wide statistical significance (false discovery rate, 5%), including 2,965 CpGs corresponding to 2,017 genes not previously related to smoking and methylation in either newborns or adults. Several genes are relevant to diseases that can be caused by maternal smoking (e.g., orofacial clefts and asthma) or adult smoking (e.g., certain cancers). A number of differentially methylated CpGs were associated with gene expression. We observed enrichment in pathways and processes critical to development. In older children (5 cohorts, n = 3,187), 100% of CpGs gave at least nominal levels of significance, far more than expected by chance (p value < 2.2 × 10(-16)). Results were robust to different normalization methods used across studies and cell type adjustment. In this large scale meta-analysis of methylation data, we identified numerous loci involved in response to maternal smoking in pregnancy with persistence into later childhood and provide insights into mechanisms underlying effects of this important exposure.

Few studies have addressed associations between traffic-related air pollution and respiratory disease in young children. The present authors assessed the development of asthmatic/allergic symptoms and respiratory infections during the first 4 yrs of life in a birth cohort study (n5,4,000).Outdoor concentrations of traffic-related air pollutants (nitrogen dioxide PM 2.5 , particles with a 50% cut-off aerodynamic diameter of 2.5 mm and soot) were assigned to birthplace home addresses with a land-use regression model. They were linked by logistic regression to questionnaire data on doctor-diagnosed asthma, bronchitis, influenza and eczema and to selfreported wheeze, dry night-time cough, ear/nose/throat infections and skin rash. Total and specific immunoglobulin (Ig)E to common allergens were measured in a subgroup (n5713).Adjusted odds ratios (95% confidence intervals) per interquartile pollution range were elevated for wheeze (1.2 (1.0-1.4) for soot), doctor-diagnosed asthma (1.3 (1.0-1.7)), ear/nose/throat infections (1.2 (1.0-1.3)) and flu/serious colds (1.2 (1.0-1.4)). No consistent associations were observed for other end-points. Positive associations between air pollution and specific sensitisation to common food allergens (1.6 (1.2-2.2) for soot), but not total IgE, were found in the subgroup with IgE measurements.Traffic-related pollution was associated with respiratory infections and some measures of asthma and allergy during the first 4 yrs of life.

Despite the important contribution of traffic sources to urban air quality, relatively few studies have evaluated the effects of traffic-related air pollution on health, such as its influence on the development of asthma and other childhood respiratory diseases. We examined the relationship between traffic-related air pollution and the development of asthmatic/allergic symptoms and respiratory infections in a birth cohort (n approximately 4,000) study in The Netherlands. A validated model was used to assign outdoor concentrations of traffic-related air pollutants (nitrogen dioxide, particulate matter less than 2.5 micro m in aerodynamic diameter, and "soot") at the home of each subject of the cohort. Questionnaire-derived data on wheezing, dry nighttime cough, ear, nose, and throat infections, skin rash, and physician-diagnosed asthma, bronchitis, influenza, and eczema at 2 years of age were analyzed in relation to air pollutants. Adjusted odds ratios for wheezing, physician-diagnosed asthma, ear/nose/throat infections, and flu/serious colds indicated positive associations with air pollutants, some of which reached borderline statistical significance. No associations were observed for the other health outcomes analyzed. Sensitivity analyses generally supported these results and suggested somewhat stronger associations with traffic, for asthma that was diagnosed before 1 year of age. These findings are subject to confirmation at older ages, when asthma can be more readily diagnosed.

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Background Elevated sputum eosinophil counts predict asthma exacerbations and responsiveness to inhaled corticosteroids but are impractical to measure in primary care. We investigated the relation between blood eosinophil count and prospective annual asthma outcomes for a large UK cohort. Methods This historical cohort study used anonymised medical record data to identify primary care patients with asthma aged 12–80 years with 2 years of continuous records, including 1 year before (baseline) and 1 year after (outcome) their most recent eosinophil count. Negative binomial regression was used to compare outcome exacerbation rates and logistic regression to compare odds of asthma control for patients with blood eosinophil counts of 400 cells per μL or less versus greater than 400 cells per μL, adjusting for age, sex, body-mass index, smoking status, and Charlson comorbidity index. The study is registered at ClinicalTrials.gov, number NCT02140541. Findings Overall, 20 929 (16%) of 130 248 patients had blood eosinophil counts greater than 400 cells per μL. During the outcome year, these patients experienced signifi cantly more severe exacerbations (adjusted rate ratio [RR] 1·42, 95% CI 1·36–1·47) and acute respiratory events (RR 1·28, 1·24–1·33) than those with counts of 400 cells per μL or less. They also had signifi cantly lower odds of achieving overall asthma control (OR 0·74, 95% CI 0·72–0·77), defi ned as limited reliever use and no asthma-related hospital attendance or admission, acute course of oral corticosteroids, or prescription for antibiotics. Exacerbation rates increased progressively with nine ascending categories of blood eosinophil count as compared with a reference category of 200 cells per μL or less. Interpretation Patients with asthma and blood eosinophil counts greater than 400 cells per μL experience more severe exacerbations and have poorer asthma control. Furthermore, a count–response relation exists between blood eosinophil counts and asthma-related outcomes. Blood eosinophil counts could add predictive value to Global Initiative for Asthma control-based risk assessment

Exposure to traffic-related air pollution may cause asthma in children.

Mode and place of delivery affect the gastrointestinal microbiota composition, which subsequently influences the risk of atopic manifestations.

PurposePrior work suggests a threshold of four courses/year of systemic corticosteroid (SCS) therapy is associated with adverse consequences. The objective of this study was to investigate the onset of adverse outcomes beginning at SCS initiation in a broad asthma population.Patients and methodsThis historical matched cohort study utilized anonymized, longitudinal medical record data (1984–2017) of patients (≥18 years) with active asthma. Matched patients with first SCS prescription (SCS arm) and no SCS exposure (non-SCS arm) were followed until first outcome event. Associations between time-varying exposure measures and onset of 17 SCS-associated adverse outcomes were estimated using Cox proportional hazard regression, adjusting for confounders, in separate models.ResultsWe matched 24,117 pairs of patients with median record availability before SCS initiation of 9.9 and 8.7 years and median follow-up 7.4 and 6.4 years in SCS and non-SCS arms, respectively. Compared with patients in the non-SCS arm, patients prescribed SCS had significantly increased risk of osteoporosis/osteoporotic fracture (adjusted hazard ratio 3.11; 95% CI 1.87–5.19), pneumonia (2.68; 2.30–3.11), cardio-/cerebrovascular diseases (1.53; 1.36–1.72), cataract (1.50; 1.31–1.73), sleep apnea (1.40; 1.04–1.86), renal impairment (1.36; 1.26–1.47), depression/anxiety (1.31; 1.21–1.41), type 2 diabetes (1.26; 1.15–1.37), and weight gain (1.14; 1.10–1.18). A dose-response relationship for cumulative SCS exposure with most adverse outcomes began at cumulative exposures of 1.0–<2.5 g and for some outcomes at cumulative exposures of only 0.5–<1 g (vs >0–<0.5 g reference), equivalent to four lifetime SCS courses.ConclusionOur findings suggest urgent need for reappraisal of when patients need specialist care and consideration of nonsteroid therapy.