Children's Respiratory Health Research Articles

Towards a Better Protection of Children's Respiratory Health against Particulate Matter Pollution in Urban Areas – ROkidAIR Project

Many recent evidences raised awareness for the Particulate Matter (PM) air pollution with fine (PM2.5), submicrometric (PM1) and ultrafine fractions (PM0.1) and its impact in urban areas, pointing out the adverse consequences on the wellbeing of children, particularly on the respiratory health. The health effects of PM can range from nausea and difficulty in breathing, to skin irritation and include birth defects, significant developmental delays in children, and reduced activity of the immune system, leading to a number of acute or chronic diseases. In this context, the rationale of the research aimed the protection of the children's health related to poor air quality in two cities of Romania i.e. Ploiesti and Targoviste by deploying a PM2.5 monitoring system as a component of an intelligent cyberinfrastructure, which is able to provide early warnings and forecasting of PM pollution episodes. A PM2.5 monitoring microstation prototype containing a measurement, a climate-conditioning, and a control/communication modules, was designed and developed in the ROkidAIR project. The measurement subassembly samples from the atmosphere a relevant air volume, with a controlled flow, filters the 2.5μm fraction, reduces the humidity of intake air volume, passes the airflow through the PM2.5 optical transducer and measures the PM2.5 concentration level at predefined time intervals. Based on the prototype, an advanced PM2.5 monitoring network system comprising 8 microstations provide continuous PM2.5 data in view to be pre-processed and adapted as inputs in forecasting algorithms based on artificial intelligence techniques. The resulted cyberinfrastructure provides information to the end-user terminals quantifying and estimating children's exposure to airborne particulate matter for elaborating early warnings when significant pollution episodes occur.

Estimating pediatric asthma prevalence in rural senegal: A cross-sectional survey.

In Senegal, the prevalence of childhood asthma and utilization of appropriate asthma therapies is unknown. We used the International Study of Asthma and Allergies in Childhood (ISAAC) survey instrument to assess childhood respiratory health in rural Senegal. We interviewed the caregivers of children aged 5 through 8 years of age in the four largest Niakhar villages in August 2012. We interviewed 1,103 primary caregivers for 1,513 children, representing 91% of all age-eligible children in the study area. Overall, 206 (14%) children had wheeze at any time in the past, 130 (9%) had wheeze within the past year, and only 41 (3%) reported a clinical diagnosis of asthma. Among children with wheeze within the past year, 81 (62%) had symptoms of severe asthma. Nocturnal cough was reported in 186 (14%) children who denied any history of wheezing illness. Only four (3%) children with wheeze in the past year had ever received bronchodilator therapy. Children with wheeze in the past year were significantly more likely to seek medical care for respiratory symptoms and to be perceived as less healthy than their peers. Children of lower socioeconomic status were significantly more likely to have wheeze. Nearly one in ten children in Niakhar, Senegal had symptoms suggestive of asthma; however, few children have a diagnosis of asthma or use appropriate therapies. This study highlights an opportunity to raise community awareness of asthma in rural Senegal and to increase access to appropriate medical therapies. Pediatr Pulmonol. 2017;52:303-309. © 2016 Wiley Periodicals, Inc.

Potential population relocation and respiratory diseases in children, is there any gaining? Results from a mining community in Chile

Background: In northern Chile, the gold and copper open-pit mining industry involves explosive processes resulting in high concentrations of ambient dust. Children living close to these mines were shown to have higher prevalence of respiratory diseases. Population relocation is being considered as a potential policy measure to reduce the adverse health outcomes. We examined the impact of a relocation measure on respiratory health of children in an affected community. Methods: Data on the prevalence of asthma, allergic rhinoconjunctivitis (rhinoc.) and potential confounders were available from a cross-sectional survey among 288 children (age 6-15 yrs.) living in the community. Proximity of children’s home address to the local gold and copper mine, respectively, was estimated using geographical positioning systems. We used Population Intervention Models to estimate the impact of a hypothetical relocation of 25% of children living closest to the mine (i.e. the first quartile of distance to the mines), those with highest level of estimated exposure. Parameters were estimated using targeted minimum loss-based estimation. Results: The prevalence of asthma and rhinoc. was 24% and 34%, respectively; 44% reported at least one respiratory diseases during last 12 months before the survey. The first quartile of distribution of distance between place of residence and the gold mine was 1.9 km, and 1.6 km for the copper mine. Based on the Population Intervention Models, relocating the population living within the first quartile to either mine resulted in a reduction in the prevalence of rhinoc. of 4.7% (95% confidence interval 1.1;8.8%), and of 3.5% (95% confidence interval −0.1;7.1%) for asthma. Considering either of the outcomes, the resulting reduction was overall 4.2% (0.5;7.9%). Conclusion: Our findings suggest a relocation of the population with highest exposure would result in reduction of prevalence of respiratory disease in children in the affected communities.

Effects of DNA methylation in tyrosine receptor kinase genes at birth on childhood respiratory health

Introduction: Tyro3, Axl and Mertk (TAM) receptor kinases are key signaling molecules in immune responses and may affect numerous immune-related health conditions. However the role for TAM in asthma, including epigenetic regulation of TAM, has not been well studied. Increased methylation in the promoter region may silence TAM genes and lead to overstimulation of the immune system. Methods: We aimed to investigate the effects of DNA methylation of multiple CpG loci across regulatory regions of TAM genes at birth on risk of childhood asthma symptoms. DNA methylation at birth was measured from newborn blood spots using the Illumina HumanMethylation450 array on a subset of 251 children from the Children’s Health Study. Asthma symptoms, medication use and other covariates were completed by parents through questionnaire when the children were 6 years old. HM450 data were preprocessed for background correction, normalization and filtering of unwanted probes. General logistic regression models were fit to analyze the association between asthma symptoms and DNA methylation levels adjusting for covariates. FDR was used to adjust for multiple testing. Results: Increased methylation in the AXL gene was consistently associated with higher risk of asthma, wheezing or whistling in the chest, and medication use for asthma. This relationship was mainly driven by the methylation status of the promoter region in an AXL alternative transcript, which was significantly associated with a 40% increase in risk of wheeze. In addition, genetic ancestry modified the associations, with larger associations observed in Hispanic Whites compared to Non-Hispanic Whites or Hispanics of Native American descent. Conclusions: How these differences affect AXL gene expression and further respiratory health are currently unknown but warrant investigation.

Respiratory Health of the Children in the Hebei Spirit Oil Spill

Introduction In December 2007, The oil spill from the Hebei Spirit contaminated the west Coast of South Korea. We evaluated the respiratory effects of oil spill exposure on children who were born in accident site (Taean). Methods Study subjects consisted of 80 children (49 boys, 31 girls) born in Taean and 25 children (10 boys, 15 girls) born in others city. All subjects completed a modified International Study of Asthma and Allergies in Childhood questionnaire. A health examination, pulmonary function test such as FVC and FEV1 administered. Results Mean of Forced Vital Capacity (FVC) were 93.8±0.19%, 98.5±0.15% the children born in Taean and other city, respectively. Mean of Forced Expiratory Volume in one second (FEV1) were 94.4±0.22%, 98.7±0.17% the children born in Taean and other city, respectively. The FVC and FEV1 was lower distribution in children who were born oil spill area than in those who born other city, but not significantly different between the two groups. Conclusions Our study did not show a significant difference between high exposed group(born Taean) and low exposed group. It is still important to have investigated children respiratory health effect long-term. Therefore continuous monitoring of children in Taean is needed.

Cooking and coughing: Estimating the effects of clean fuel for cooking on the respiratory health of children in the Philippines

ABSTRACTHousehold air pollution (HAP) arising from the use of solid fuels for cooking is known to have adverse health effects including acute respiratory infections in children, which remains a major public health concern in developing countries. Hence, various interventions to reduce HAP have been advocated or piloted in many countries. To provide additional evidence on the effectiveness and applicability of the interventions in various settings, we investigate the effects of clean fuel for cooking on the risks of respiratory illness of children below five years old in the Philippines. We apply the propensity score matching method on a subsample of households culled from the 2013 round of the National Demographic and Health Survey to account for the systematic differences in their characteristics that could influence their choices of cooking fuel. We find that the use of electricity, liquefied petroleum gas, natural gas or biogas can lower by 2.4 percentage points the incidence of severe coughing with difficulty in breathing in young children. Our results support worldwide initiatives to promote the household use of clean fuels for cooking and heating to reduce HAP and its undesirable impacts on population health.

The importance of toxicity in determining the impact of hazardous air pollutants on the respiratory health of children in Tennessee

Respiratory diseases, exacerbated through point source pollution, are currently among the leading causes of hospitalization of children in the United States. This paper investigates the relationship between the proximity of hazardous air pollutants (HAPs) emitted from Toxic Release Inventory (TRI) facilities and the number of children diagnosed in hospitals with a respiratory disease in Tennessee. The importance of controlling for toxicity of those HAPs is of particular interest. Hospital discharge, socioeconomic, TRI emission, and HAP toxicity data are used to estimate, via Generalized Linear Methods, a logistic regression model describing the relationship between the percent of children living in a zip code area treated for respiratory illness and the average annual emissions over the previous 10 years of HAPs from TRI sites in that area. Controlling for area socioeconomic characteristics, we find that accounting for toxicity is important in uncovering the relationship between HAP emissions and respiratory health of children. A one standard deviation increase in toxicity-weighted emissions per 100 square miles is associated with an increase in the number of children diagnosed with asthma (chronic bronchitis) by about 1205 (260). The evidence suggests that, with a goal to improving children’s respiratory health, monitoring the toxicity of chemicals being emitted is at least as important as simply monitoring total emission levels. This suggests that the EPA should consider making efforts toward establishing toxicity adjusted emission guidelines.

The Breathing for Life Trial: a randomised controlled trial of fractional exhaled nitric oxide (FENO)-based management of asthma during pregnancy and its impact on perinatal outcomes and infant and childhood respiratory health.

BackgroundAsthma exacerbations are common during pregnancy and associated with an increased risk of adverse perinatal outcomes. Adjusting asthma treatment based on airway inflammation rather than symptoms reduces the exacerbation rate by 50 %. The Breathing for Life Trial (BLT) will test whether this approach also improves perinatal outcomes.Methods/designBLT is a multicentre, parallel group, randomised controlled trial of asthma management guided by fractional exhaled nitric oxide (FENO, a marker of eosinophilic airway inflammation) compared to usual care, with prospective infant follow-up. Women with physician-diagnosed asthma, asthma symptoms and/or medication use in the previous 12 months, who are 12–22 weeks gestation, will be eligible for inclusion. Women randomised to the control group will have one clinical assessment of their asthma, including self-management education. Any treatment changes will be made by their general practitioner. Women randomised to the intervention group will have clinical assessments every 3–6 weeks during pregnancy, and asthma treatments will be adjusted every second visit based on an algorithm which uses FENO to adjust inhaled corticosteroid (ICS) dose (increase in dose when FENO >29 parts per billion (ppb), decrease in dose when FENO <19 ppb, and no change when FENO is between 19 and 29 ppb). A long acting beta agonist (LABA) will be added when symptoms remain uncontrolled. Both the control and intervention groups will report on exacerbations at a postpartum phone interview. The primary outcome is adverse perinatal outcome (a composite measure including preterm birth, intrauterine growth restriction, neonatal hospitalisation at birth or perinatal mortality), assessed from hospital records. Secondary outcomes will be each component of the primary outcome, maternal exacerbations requiring medical intervention during pregnancy (both smokers and non-smokers), and hospitalisation and emergency department presentation for wheeze, bronchiolitis or croup in the first 12 months of infancy. Outcome assessment and statistical analysis of the primary outcome will be blinded. To detect a reduction in adverse perinatal outcomes from 35 % to 26 %, 600 pregnant women with asthma per group are required.DiscussionThis trial will provide evidence for the effectiveness of a FENO-based management strategy in improving perinatal outcomes in pregnant women with asthma. If successful, this would improve the management of pregnant women with asthma worldwide.Trial registrationAustralian New Zealand Clinical Trials Registry ACTRN12613000202763.

Potential hazards of air pollutant emissions from unconventional oil and natural gas operations on the respiratory health of children and infants.

Research on air pollutant emissions associated with unconventional oil and gas (UOG) development has grown significantly in recent years. Empirical investigations have focused on the identification and measurement of oil and gas air pollutants [e.g. volatile organic compounds (VOCs), particulate matter (PM), methane] and the influence of UOG on local and regional ambient air quality (e.g. tropospheric ozone). While more studies to better characterize spatial and temporal trends in exposure among children and newborns near UOG sites are needed, existing research suggests that exposure to air pollutants emitted during lifecycle operations can potentially lead to adverse respiratory outcomes in this population. Children are known to be at a greater risk from exposure to air pollutants, which can impair lung function and neurodevelopment, or exacerbate existing conditions, such as asthma, because the respiratory system is particularly vulnerable during development in-utero, the postnatal period, and early childhood. In this article, we review the literature relevant to respiratory risks of UOG on infants and children. Existing epidemiology studies document the impact of air pollutant exposure on children in other contexts and suggest impacts near UOG. Research is sparse on long-term health risks associated with frequent acute exposures - especially in children - hence our interpretation of these findings may be conservative. Many data gaps remain, but existing data support precautionary measures to protect the health of infants and children.

Quantifying the impact of PM2.5 and associated heavy metals on respiratory health of children near metallurgical facilities.

The aim of this study was to link the concentrations of particulate matter with an aerodynamic diameter below 2.5 μm (PM2.5) and associated heavy metals with occurrence of wheezing and hospitalizations due to wheezing in 111 children who live near metallurgical plants in Targoviste City, Romania. A group of 72 children with high levels of immunoglobulin E (IgE) and eosinophils, as well as frequent wheezing episodes, was geolocated on digital thematic maps. Monitoring campaigns and medical assessments were performed over two consecutive years (2013–2014). The multiannual average concentrations of PM2.5 ranged from 4.6 to 22.5 μg m−3, up to a maximum value of 102 μg m−3. Significant correlations (p < 0.01) were observed between the locations of the children with respiratory issues and the PM2.5 multiannual average (r = 0.985) and PM2.5 maximum (r = 0.813). Fe, Ni, Cd, and Cr were the main marker elements of the emissions from steel production and metal-working facilities in the Targoviste area. The results support the hypothesis that increased PM2.5 levels directly influence wheezing symptom and asthma attacks in the analyzed group. IgE, eosinophils, and wheezing episodes may be considered key indicators with which to evaluate the adverse effects of PM2.5 air pollution on children’s health.

Associations of gestational and early life exposures to ambient air pollution with childhood respiratory diseases in Shanghai, China: A retrospective cohort study

BackgroundAssociations of ambient air pollutants with respiratory health are inconsistent. ObjectivesWe analyzed the associations of gestational and early life exposures to air pollutants with doctor-diagnosed asthma, allergic rhinitis, and pneumonia in children. MethodsWe selected 3358 preschool children who did not alter residences after birth from a cross-sectional study in 2011–2012 in Shanghai, China. Parents reported children's respiratory health history, home environment, and family lifestyle behaviors. We collected daily concentrations of sulphur dioxide (SO2), nitrogen dioxide (NO2), and particulate matter with an aerodynamic diameter ≤10μm (PM10) during the child's total lifetime (2006–2012) for each district where the children lived. We analyzed the associations using logistic regression models. ResultsAfter adjusting for covariates and the other studied pollutants, we found that exposure to NO2 (increment of 20μg/m3) during the first year of life was significantly associated with asthma [odds ratio (OR)=1.77; 95% confidence interval (CI): 1.29–2.43] and allergic rhinitis (OR=1.67; 95% CI: 1.07–2.61). Exposure to NO2 during gestation, the first two and three years, and over total lifetimewas all consistently associated with increased odds of allergic rhinitis. Quartiles of NO2 concentration during different exposure periods showed a slight dose–response relationship with the studied diseases. These diseases had significant associations with pollutant mixtures that included NO2, but had no significant association with exposures to SO2 and PM10 individually or in mixtures. ConclusionsGestational and early life exposures to ambient NO2 are risk factors for childhood respiratory diseases.

Association between children's forced vital capacity and long-term exposure to local ambient temperature in China: A national cross-sectional survey

It is well documented that short-term exposure to extreme ambient temperature is associated with respiratory disorder. However, few studies have assessed the long-term effect of temperature on children's lung function. The present study aimed to investigate the association between long-term exposure to local ambient temperature and children's forced vital capacity (FVC) in China. We analyzed the FVC data of 71,768 children from the 2010 Chinese National Survey on Students' Construction and Health (CHNSCH), and local annual average ambient temperature, relative humidity, air pollutants data from China Meteorological Administration and Ministry of Environment Protection of China. Generalized additive model (GAM) with non-linear function was used to examine the effect of ambient temperature on children's FVC. The results showed that low temperature was significantly associated with decrease of FVC in Chinese children within certain temperature range while adjusting for individual characteristics, socioeconomic conditions, air pollutants and relative humidity. The largest alteration of FVC related to the annual average temperature difference among cities from 20.4°C to 4.5°C was observed, being 242.7ml (95%CI: 220.0, 265.3) decrease in FVC. The similar association was found in both physically active and inactive children, while the largest alteration of FVC related to the temperature difference reached 329.1ml (95%CI: 296.7, 361.6) in physically active children and 290.5ml (95%CI: 255.7, 325.3) in physically inactive ones. Public health policy should be developed for protecting children's respiratory health during growth and development in some areas with cold weather.Key messageWhat is the key question?Few studies have assessed the long-term effect of temperature on children's forced vital capacity (FVC). We analyzed the Chinese national survey data to clarify the association between children's forced vital capacity and long-term exposure to local ambient temperature.What is the bottom line?Our study found that low temperature was significantly associated with decrease of forced vital capacity in children of 30 cities in China. The largest alteration of FVC related to the temperature difference from 20.4°C to 4.5°C was observed, being 242.7ml (95%CI: 220.0, 265.3) decrease in FVC.Why read on?The presented study provide some evidence about long-term effect of temperature on children's respiratory health and public health policy should be developed for protecting children from adverse effects of low temperature on their respiratory health during growth and development in some areas with cold weather.

The first 2-year home environment in relation to the new onset and remission of asthmatic and allergic symptoms in 4246 preschool children

The home environment can influence childhood allergies and respiratory health but there is little information on associations between early life exposure at home and new onset and remission of the asthmatic or allergic symptoms in preschool children. A questionnaire survey was performed in a random cluster sample of 4246 preschool children in Urumqi, China. Information on the home environment (perceptions of odors and indicators of pollution sources) and children's health (wheeze, rhinitis and eczema) was collected for the first 2years of life and the last year (before answering the questionnaire) from one of the parents or another guardian of the child. Associations between the home environment the first 2years of life and new onset and remission of childhood symptoms were analyzed by multiple logistic regression. Home environment factors reported for the first 2years of life were consistently positively associated with new onset of symptoms and negatively associated with remission of symptoms. Visible mold (OR 1.46, 95% CI 1.12–1.90), moldy odor (OR 2.15, 95% CI 1.45–3.18), air dryness (OR 1.31, 95% CI 1.08–1.59), stuffy odor (OR 1.25, 95% CI 1.01–1.54) and parental smoking (OR 1.36, 95% CI 1.13–1.65) were associated with new onset of symptoms. These factors were negatively associated with the remission of symptoms. In conclusion, mold contamination at home (moldy odor/visible mold), poor indoor air quality (stuffy odor, air dryness) and exposure to environmental tobacco smoke (ETS) in the first 2years of life can increase the incidence of asthmatic and allergic symptoms and decrease the remission from these symptoms in preschool children.

Maternal body mass index before pregnancy is associated with increased bronchodilator dispensing in early childhood: A cross-sectional study.

Maternal prepregnancy obesity has been associated with early wheeze and childhood asthma in their offspring. Some of these studies have been in minority, urban, and disadvantaged populations using parental recall and questionnaires. The association of maternal prepregnancy obesity with bronchodilator dispensing to their offspring, in a primarily insured, non-urban, White population in the United States is unknown. We conducted a retrospective cohort study using pharmacy dispensing data from the electronic medical records of a large United States health maintenance organization to examine the relationship between maternal prepregnancy body mass index (BMI) and inhaled bronchodilator dispensing in the offspring to 4 years of age. We included infants ≥37 weeks' gestation with birth weight ≥2.5 kg which yielded 6,194 mother-baby pairs. Maternal prepregnancy BMI was categorized as underweight (<18.5 kg/m(2) ), normal (18.5-24.9 kg/m(2) ), overweight (25-29.9 kg/m(2) ), or obese (≥30 kg/m(2) ). In the entire cohort, 27.6% of the offspring received a bronchodilator dispensing. This ranged from 19.2% in the offspring of underweight mothers to 31.3% of those born to obese mothers. In the fully adjusted model using normal BMI as the referent, children of obese mothers had a 22% higher rate of bronchodilator dispensing (adjusted OR = 1.22; 95%CI 1.05-1.41; P = 0.008). In this insured, non-urban, White population, maternal prepregnancy obesity was associated with bronchodilator dispensing in the offspring in early life. These results extend previous data and reaffirm the potential widespread public health impact that prepregnancy obesity may have on subsequent childhood respiratory health. Pediatr Pulmonol. 2016;51:803-811. © 2016 Wiley Periodicals, Inc.

Children's respiratory health and oxidative potential of PM2.5: the PIAMA birth cohort study

IntroductionThe oxidative potential (OP) of particulate matter (PM) has been proposed as a health-relevant metric, but currently few epidemiological studies investigated associations of OP with health. Our main aim was...

Effect of diet on the respiratory health of children in rural area of Delhi-NCR

Background: Asthma is one of the most common chronic diseases worldwide. For asthma and allergic disorders, diet has been recently established as a potential risk factor. Thus, a change in dietary habit may be postulated, as one of the unknown factors responsible for the rise in prevalence of asthma among children in rural India. Objectives: To assess the association of diet with asthma in Indian rural population. Materials and Methods: This study was a cross-sectional study of children aged <18 years residing in Khanpur Jupti village, Ghaziabad, Uttar Pradesh, during 2011-2015. A questionnaire-based survey was carried out for respiratory illness-related symptoms. It was developed on the basis of American Thoracic Society (ATS), British Medical Research Council, and the International Study of Asthma and Allergies in childhood questionnaires to detect the presence of symptoms suggestive of asthma. The age and sex, birth order, duration of breastfeeding, educational status, food habits (vegetarian and nonvegetarian), and major chronic chest symptoms (cough, sputum, shortness of breath, and wheezing) were included in the questionnaire-based survey. The diagnosis of asthma was made by the physician examining the children, based on the guidelines of ATS. Results: Of 187 houses which were surveyed, there were a total of 607 children (males n = 339 [55.84%] and females n = 268 [44.16%]). 17.1% (n = 104; males n = 59 [56.73%]) children were diagnosed as asthma. In the evaluation of dietary habits, children diagnosed with asthma had significantly higher consumption of nonvegetarian food (43.27% vs. 28.23; P < 0.05). However, age and gender distribution, educational status, birth order, and duration of breastfeeding did not show a significant difference between children diagnosed with asthma and without asthma. Conclusion: The study concluded that increased risk of asthma was associated with higher consumption of nonvegetarian food. Furthermore, breastfeeding did not have any protective effect on asthma.

Strategic Partnerships for Change in an Environmental Justice Community: The ENRRICH Study.

San Bernardino, California, is home to the San Bernardino Railyard (SBR), a major commerce hub with high associated air-pollution, identified as an environmental justice (EJ) issue by local community and air quality agencies. Alarmingly, one elementary school is located only a few hundred yards from SBR. The school, university researchers, and a local community-based organization (CBO) established a partnership to assess potential adverse health impacts in the children and develop interventions and mitigation plans. Study results comparing target school with a demographically matched school verified community concerns finding significantly poorer respiratory health in children attending school near the railyard. Partners are working with local and state collaboratives, the school board, and funding agencies to address the resulting needs of children through education, mitigation, and prevention in an environment where necessary systems changes involving the railyard are elusive. This paper shares lessons learned in moving toward change when addressing an EJ community's health challenges.

Ambient Ammonia Exposures in an Agricultural Community and Pediatric Asthma Morbidity.

Large-scale animal feeding operations compromise regional air quality in the rural US through emission of pollutants, such as ammonia gas. Exposure to airborne pollution from animal feeding operations may cause pediatric asthma exacerbations in surrounding communities. To describe spatial and temporal patterns in ambient ammonia concentrations in an agricultural region, and to investigate associations between short-term fluctuations in ammonia and subsequent changes in respiratory health in children with asthma. For 13 months in the Yakima Valley of Washington State, 14 monitors sampled ammonia in outdoor air for 24-hour periods every 6 days. School-age children with asthma (n = 51) were followed for two health outcomes: biweekly reports of asthma symptoms and quick relief medication usage, and daily measurements of forced expiratory volume in 1 second. We assessed associations between each outcome and ammonia using generalized estimating equations. Twenty-four-hour ammonia concentrations varied from 0.2 to 238.1 μg/m during the study period and displayed a strong correlation with proximity to animal feeding operations. The percentage of forced expiratory volume in 1 second was 3.8% lower (95% confidence interval = 0.2, 7.3) per interquartile increase in 1-day lagged ammonia concentration and 3.0% lower (95% confidence interval = 0.5, 5.8) for 2-day lagged concentration. We observed no associations between self-reported asthma symptoms or medication usage and estimated ammonia exposure. Ammonia concentrations were elevated in this community and strongly predicted by proximity to animal feeding operations. Ammonia's association with acute lung function decrements in children with asthma in the surrounding community may be causal or, alternatively, ammonia may be a marker for other pollutants from animal feeding operations associated with respiratory effects.

Tobacco smoke exposure and multiplexed immunoglobulin E sensitization in children: a population-based study.

Although there is evidence that exposure to tobacco smoke is harmful to children's respiratory health, the effects of tobacco smoke exposure on the regulation of immunoglobulin E (IgE)-mediated immune responses to specific allergens remain unclear. This study aimed to investigate the relationship between objectively assessed tobacco smoke exposure and specific IgE profiles for a broad spectrum of allergens in a population setting. Children aged 5-18 years (N = 1315) were assessed using serum cotinine measurement and microarray-based multiplexed detection of specific IgE against 40 allergens. Serum cotinine levels were positively associated with sensitization to foods (adjusted odds ratio [AOR] = 4.95; 95% CI: 1.59-15.34), cockroaches (AOR = 3.77; 95% CI: 1.49-9.51), and pollen (AOR = 2.84; 95% CI: 1.20-6.73) while the association was borderline significant for animals (AOR = 2.53; 95% CI: 0.92-6.93). No associations were found for sensitization against mites, mold, and latex. When considering the degree of allergic sensitization, serum cotinine levels were positively correlated to the number of sensitization to cockroaches (P = 0.004), pollen (P = 0.006), and foods (P < 0.001), with statistically significant positive dose-response relationships (all P < 0.01). Similar results were observed when summing up specific IgE concentrations for the aforementioned allergen categories. The association between tobacco smoke exposure and IgE sensitization to environmental allergens varies for different allergens among children. This study demonstrates that elevated serum cotinine levels are significantly associated with IgE sensitization to cockroaches, grass pollen, and certain foods, with potential dose-dependent relationships.

Maternal Folic Acid Supplementation During Pregnancy and Early Childhood Asthma.

Asthma is one of the most common chronic childhood diseases. While folic acid supplementation around conception helps prevent neural tube defects, an animal model suggests that it may be a risk factor for respiratory diseases, although epidemiologic studies have had conflicting results. We investigated the timing of folic acid-containing prescription filling during pregnancy and child asthma. In a retrospective cohort study of 104,428 children, born 1996-2005, and their mothers enrolled in Tennessee Medicaid, we investigated the association of filling folic acid-containing prescriptions during pregnancy and childhood asthma at ages 4.5-6 years. We categorized women into exposure groups based on prescription filling centered around the first trimester: no folic acid prescription exposure, exposure in first trimester only, exposure after first trimester, and exposure in first trimester and beyond. We defined asthma using asthma-specific healthcare visits and medication fills. Using logistic regression models, we investigated the relationship adjusting for potential confounders. Overall 15% of children had asthma. Compared with children born to women with no folic acid prescription exposure, children born to women with exposures in the first trimester only or first trimester and later had increased relative odds of asthma (adjusted odds ratios = 1.2, 95% confidence interval = 1.1, 1.3, and 1.2, 95% confidence interval = 1.2, 1.3); no association was seen in children born to women exposed after the first trimester. Timing of folic acid-containing prescription filling during pregnancy was associated with childhood asthma. Our findings contribute to understanding of the role of prenatal nutritional supplements on child respiratory health.