Risk Of Childhood Asthma Research Articles

Pre-Birth Cohort Study of Atopic Dermatitis and Severe Bronchiolitis during Infancy

BACKGROUND Infants hospitalized for bronchiolitis (i.e. severe bronchiolitis) are at increased risk of childhood asthma. There are many known risk factors for severe bronchiolitis, including cardiac and pulmonary diseases. Less is known about the association between atopic diseases and risk of severe bronchiolitis. We sought to further examine risk factors for severe bronchiolitis, focusing on atopic dermatitis (AD). METHODS We conducted a nested cohort study within the Massachusetts General Hospital Obstetric Maternal Study (MOMS), a prospective cohort of pregnant women enrolled during 1998-2006. Children of mothers enrolled in MOMS were included in the analysis if they received care within our health system (n = 5407). Potential risk factors for bronchiolitis and hospitalization data were extracted from the children's electronic health records; we also examined pregnancy and perinatal risk factors collected from the underlying MOMS data. RESULTS During the first year of life, 125 infants (2.3%) had severe bronchiolitis. Eighteen of these patients had AD; 11 (61%) were diagnosed with AD prior to bronchiolitis hospitalization. In unadjusted analyses, AD was associated with severe bronchiolitis (χ(2) 14.6; p < 0.001). In multivariable analyses adjusting for nine known risk factors for severe bronchiolitis, including demographics, birth season, disposition at birth, cardiac disease, maternal parity, and delivery mode, AD was associated with increased odds of severe bronchiolitis (odds ratio 2.72, 95% confidence interval 1.60-4.63). CONCLUSIONS Atopic dermatitis is significantly associated with severe bronchiolitis in infancy. The mechanism of the AD-bronchiolitis association is unclear and merits further study; this research may shed light on the pathogenesis of asthma.

Childhood asthma prevalence and risk factors in three Eastern European countries--the Belarus, Ukraine, Poland Asthma Study (BUPAS): an international prevalence study.

BackgroundThe prevalence of asthma and other allergic diseases among children living in Eastern is not well described. Our objective was to estimate and compare the prevalence of asthma, respiratory symptoms and allergic diseases in children in Belarus, Ukraine, and Poland as well as to identify risk factors for these conditions. We also sought to profile and compare children with asthma between locations.MethodsData were collected as a part of an international, multicenter, cross-sectional study of childhood asthma: The Belarus Ukraine Poland Asthma Study (BUPAS). Subjects were children aged 7–13 years attending primary and secondary schools in the urban and surrounding rural area of Grodno (Belarus), Ternopil (Ukraine) and Silesia Region (Poland). Physician-diagnosed respiratory diseases and symptoms as well as allergic diseases were ascertained using the ISAAC questionnaire completed by the parents.ResultsIn total there were 4019 children from Belarus (rural: 2018, urban: 2001), 4493 from Ukraine (1972; 2521), and 4036 from Poland (2002, 2034). The overall response rate was 76.7 %. Groups were similar in case of gender and age (p > 0.05). Almost all analyzed respiratory and allergic conditions differed significantly between countries including asthma [Poland (rural, urban): 3.5 %, 4.1 %; Ukraine: 1.4 %, 2.1 %; Belarus: 1.4 %, 1.5 %], spastic bronchitis (Poland: 2.7 %, 3.2 %; Ukraine: 7.5 %, 6.5 %; Belarus: 6.4 %, 7.9 %), and chest wheeze in the last year (Poland: 4.8 %, 5.2 %; Ukraine: 11.5 %, 13.0 %; Belarus: 10.7 %, 10.0 %). These differences remained after adjustment for potential confounders. Risk factor associations were generally similar between outcomes. Symptom characteristics of children with asthma between countries were not consistent. The ratio of current wheeze:diagnosis of asthma differed by country: (Rural areas: Belarus: 10.9:1, Ukraine: 17.3:1, Poland: 2.4:1; Urban areas: Belarus: 8.1:1, Ukraine: 7.3:1 Poland: 1.9:1).ConclusionsThe findings show large between-country differences and relatively low prevalence of asthma and allergic diseases in children of Western Belarus and Ukraine. There is evidence for underdiagnosis of asthma in these regions.

Probiotics Effect on Interleukin-4 (IL-4) and Imunoglobulin E (IgE) Levels on Asthmatic Patients

Introduction: Probiotics may play a role in immune system maturation and may reduce the risk of allergies and asthma in childhood. However, the therapeutic benefits of probiotics in asthma depend on various factors such as strain of probiotics and dosing regimen. Objectives: The aims of this study was to evaluate the effect of probiotic (LactoB®) on Immunoglobulin E (IgE) and Interleukin (IL-4) serum level in childhood Asthma. Methods: Forty children aged 1-5 years with asthma were recruited into a randomized controlled trial. The children were assigned into a probiotic (Lactobacillus acidophilus, Bifidobacterium longun, Streptococcus; Lacto B®) or an equivalent volume of placebo, twice daily orally for 8 weeks. The IgE and IL-4 serum level were determined by ELISA. The differences between groups were analyzed by t-test dependent with confidence interval of 95%. Results: In intervention group, mean of IgE serum levels after the probiotics treatment was significantly lower compared to that of before the treatment (148.18 pg/mg; 283.20 pg/mg; respectively). Mean of IL-4 serum levels after the treatment was significantly lower compared with that of before the treatment (111.03 pg/mg; 142.08 pg/mg respectively). In control group, there were no significant differences between IgE serum levels mean before the administration of placebo and after the intervention (292.39 pg/ml; 286.94 pg/ml respectively). There were no significant differences between IL-4 serum levels mean before and after the treatment (136.76 pg/ml; 139.56 pg/ml).Conclusion: there was an effect of probiotics supplementation on IgE and IL-4 serum levels in childhood asthma.

Probiotics Effect on Interleukin-4 (IL-4) and Imunoglobulin E (IgE) Levels on Asthmatic Patients

Introduction: Probiotics may play a role in immune system maturation and may reduce the risk of allergies and asthma in childhood. However, the therapeutic benefits of probiotics in asthma depend on various factors such as strain of probiotics and dosing regimen. Objectives: The aims of this study was to evaluate the effect of probiotic (LactoB®) on Immunoglobulin E (IgE) and Interleukin (IL-4) serum level in childhood Asthma. Methods: Forty children aged 1-5 years with asthma were recruited into a randomized controlled trial. The children were assigned into a probiotic (Lactobacillus acidophilus, Bifidobacterium longun, Streptococcus; Lacto B®) or an equivalent volume of placebo, twice daily orally for 8 weeks. The IgE and IL-4 serum level were determined by ELISA. The differences between groups were analyzed by t-test dependent with confidence interval of 95%. Results: In intervention group, mean of IgE serum levels after the probiotics treatment was significantly lower compared to that of before the treatment (148.18 pg/mg; 283.20 pg/mg; respectively). Mean of IL-4 serum levels after the treatment was significantly lower compared with that of before the treatment (111.03 pg/mg; 142.08 pg/mg respectively). In control group, there were no significant differences between IgE serum levels mean before the administration of placebo and after the intervention (292.39 pg/ml; 286.94 pg/ml respectively). There were no significant differences between IL-4 serum levels mean before and after the treatment (136.76 pg/ml; 139.56 pg/ml).Conclusion: there was an effect of probiotics supplementation on IgE and IL-4 serum levels in childhood asthma.

Does Early Exposure to Animals Alter Risk of Childhood Asthma?

SUMMARY In this cohort study, the association between early exposure to dogs and farm animals and the risk of asthma was evaluated and included all children born in Sweden. The association was assessed as the odds ratio (OR) for a current diagnosis of asthma at age 6 years for schoolaged children and as the hazard ratio (HR) for incident asthma at ages 1 to 5 years for preschool-aged children. The primary outcome was childhood asthma diagnosis and medication used. Of the 1 011 051 children born during the study period, 376 638 preschool-aged (53 460 [14.2%] exposed to dogs and 1729 [0.5%] exposed to farm animals) and 276 298 school-aged children (22 629 [8.2%] exposed to dogs and 958 [0.3%] exposed to farm animals) were included in the analyses. Of these, 18 799 children (5.0%) in the preschool-aged children’s cohort experienced an asthmatic event before baseline, and 28 511 cases of asthma and 906 071 years at risk were recorded during follow-up (incidence rate, 3.1 cases per 1000 years at risk). In the school-aged children’s cohort, 11 585 children (4.2%) experienced an asthmatic event during the seventh year of life. Dog exposure during the first year of life was associated with a decreased risk of asthma in school-aged children (OR, 0.87; 95% CI, 0.810.93) and in preschool-aged children 3 years or older (HR, 0.90; 95%CI, 0.83-0.99) but not in children younger than 3 years (HR, 1.03; 95% CI, 1.00-1.07). Farm animal exposure was associated with a reduced risk of asthma in both school-aged children and preschool-aged children (OR, 0.48; 95%CI, 0.31-0.76, and HR, 0.69; 95%CI, 0.56-0.84), respectively. The authors conclude that exposure to dogs and farm animals during the first year of life reduce the risk of asthma in children at age 6 years. COMMENTARIES

Path Analysis: The Effect of Biopsychosocial and Environmental Exposure on Child Asthma in Surakarta

Background : Asthma is a non-communicable disease with high morbidity in Indonesia.According to David Barker’s fetal origin hypothesis, biopsychosocial as well as environmental exposure during gestational period affect health outcome in later life. This study aimed to determine the effect of bio-psychosocial and environmental exposure factor on the risk of child asthma in Surakarta. Subjects and M ethods : This was an analytical observational study with case control design.This study was conducted at the Center for Community Pulmonary Health (BBKPM), Surakarta. A total of 105 study subjects were selected by fixed disease sampling, consisting of 35 asthmatic patients and 70 healthy children aged 6-15 year old. The exogenous variables were maternal education, current child stress, indoor cigarette smoke exposure and maternal stress during gestational period, current family income, and current indoor cigarette smoke exposure. The endogenous variables were birth weight and child asthma. The data were collected by a set of questionnaire and analyzed using path analysis model. Result s: Current child stress (b = 3.49; 95% CI = 1.18-5.81; p = 0.003), exposure to indoor cigarette smoke (b = 3.44; 95% CI = 1.07-5.80; p = 0.004), indoor air polution (b = 2.43; 95% CI = 0.60-4.27; p = 0.009), had positive, direct, and statistically significant effects on the risk of child asthma. Birth weight ≥2.500 gram (b = -2.01; 95% CI = -3.95 to -0.07; p = 0.041) had negative, direct, and statistically significant effect on the risk of child asthma. Maternal education had positive and statistically significant effect on family income (b=1.57; 95% CI=0.62 to 2.52; p= 0.001). Family income had negative and statistically significant effect on indoor air pollution (b= -2.48; 95% CI=-3.52 to -1.44; p= 0.001). Maternal stress at gestational period had negative and statistically significant effect on birth weight (b=-1.13; 95% CI= -2.18 to -0.08; p=0.035). Conclusion: In line with David Barker’s fetal origin hypothesis, this study supports that biopsychosocial as well as environmental factors have significant effects on child asthma. Keywords : bio-psychosocial, environmental exposure, asthma, children. Correspondence: Ayunita Dwi Hadianti. Masters Program in Public Health, Sebelas Maret University, Surakarta. Email: ayunitadwihadianti@gmail.com. Mobile: +6282314064445. Journal of Maternal and Child Health (2016), 1(2): 62-72 https://doi.org/10.26911/thejmch.2016.01.02.01

Vitamin D serum levels and risk of asthma in children

Purpose: The role of vitamin D in traditional atopic disorders (i.e., asthma, allergic rhinitis, and atopic dermatitis) is still uncertain. We have analyzed the association between serum 25-hydroxyvitamin D3 (25(OH)-D3) levels and asthma in children. Methods: A total of 133 children were enrolled between April 2008 and December of 2008. Children were divided into 3 groups: the asthma group (n=80), bronchiolitis group (n=50), and normal group (n=35). Serum samples were collected and checked for 25(OH)-D3 levels. From the blood samples, we measured eosinophil counts, total IgE, specific IgE (Dermatophagoides pteronyssinus, Dermatophagoides farinae, milk, egg, cat, dog, cockroach) (Uni-CAP FEIA system). Results: The mean age of the patients was 4.6 years. The mean 25(OH)-D3 levels of the asthma, bronchiolitis, and normal groups were 17.2±8.9, 22.5±9.3, and 27.8±10.2 ng/mL, respectively (P<0.01). There was no association between allergens and vitamin D levels. Mean 25(OH)-D3 levels were lower at acute state of asthma than at stable state. Conclusion: The mean level of 25(OH)-D3 was associated with asthma and acute state of asthma. Further experimental and clinical studies are needed to establish a definite link between vitamin D levels and asthma.

Role of interleukin-4 genetic polymorphisms and environmental factors in the risk of asthma in children.

Asthma is an allergic disease characterized by hyperresponsiveness and chronic inflammation of the airway. The interleukin-4 (IL-4) gene and its single nucleotide polymorphisms are associated with asthma susceptibility in children. A case-control study was performed to evaluate the relationship between asthma risk and the IL-4 rs2243250 (589 C/T) and rs2070874 (107 T/C), and IL-4 receptor (IL-4R) rs1801275 (576 Q/R) polymorphisms in 317 childhood asthma patients and 351 healthy children as controls. Polymerase chain reaction amplification and sequencing was performed. The effects of interactions between the genes of interest and environmental factors were also analyzed. IL-4 rs2243250 and rs2070874 allele and genotype frequencies did not significantly differ between the asthma and control groups (P > 0.05), but those of IL-4R rs1801275 did (P < 0.05). The RR genotype and R allele of this IL-4R variant were significantly associated with asthma risk, with odds ratios (ORs; and 95% confidence intervals) of 2.97 (2.08-4.25) and 2.99 (2.32-3.85), respectively. Logistic regression analysis showed that the IL-4R 576 Q/R RR genotype demonstrated a positive interaction with environments associated with smoking or pets in its effect on asthma risk, with ORs of 2.18 (P = 0.02) and 2.29 (P = 0.01), respectively. Our results suggest that the IL-4R rs1801275 polymorphism is associated with childhood asthma, and the RR genotype confers a high risk of developing this condition. This variant exhibited positive interactions with environments in which smoking or pets were present in increasing the risk of childhood asthma.

Inducible Nitric Oxide Synthase Promoter Haplotypes and Residential Traffic-Related Air Pollution Jointly Influence Exhaled Nitric Oxide Level in Children.

BackgroundExhaled nitric oxide (FeNO), a biomarker of airway inflammation, predicts asthma risk in children. We previously found that the promoter haplotypes in inducible nitric oxide synthase (NOS2) and exposure to residential traffic independently influence FeNO level. Because NOS2 is inducible by environmental exposures such as traffic-related exposure, we tested the hypothesis that common NOS2 promoter haplotypes modulate the relationship between residential traffic-related exposure and FeNO level in children.MethodsIn a cross-sectional population-based study, subjects (N = 2,457; 7–11 year-old) were Hispanic and non-Hispanic white children who participated in the Southern California Children’s Health Study and had FeNO measurements. For residential traffic, lengths of local roads within circular buffers (50m, 100m and 200m radii around homes) around the subjects’ homes were estimated using geographic information system (GIS) methods. We interrogated the two most common NOS2 promoter haplotypes that were found to affect FeNO level.ResultsThe relationship between local road lengths within 100m and 200m circular buffers and FeNO level varied significantly by one of the NOS2 promoter haplotypes (P-values for interaction between road length and NOS2 promoter haplotype = 0.02 and 0.03, respectively). In children who had ≤250m of local road lengths within 100m buffer around their homes, those with two copies of the haplotype had significantly lower FeNO (adjusted geometric mean = 11.74ppb; 95% confidence intervals (CI): 9.99 to 13.80) than those with no copies (adjusted geometric mean = 15.28ppb; 95% CI: 14.04 to 16.63) with statistically significant trend of lower FeNO level with increasing number of haplotype copy (P-value for trend = 0.002). In contrast, among children who had >250m of local road lengths within 100m buffer, FeNO level did not significantly differ by the haplotype copy-number (P-value for trend = 0.34). Similar interactive effects of this haplotype and local road lengths within 200m buffer on FeNO were also observed.ConclusionsHigher exposure from residential traffic nullifies the protective effect of one common NOS2 promoter haplotype on FeNO level. Regulation of traffic-related pollution may protect children’s respiratory health.

TSLP polymorphisms, allergen exposures, and the risk of atopic disorders in children

BackgroundThymic stromal lymphopoietin (TSLP) polymorphisms influence atopy risk. TSLP might constitute a key interface between the environment and the allergic immune response. However, whether the effects of TSLP polymorphisms on atopic dermatitis (AD) are modified by allergic sensitization is not clear. ObjectiveTo evaluate the joint effect of allergic sensitization and TSLP polymorphisms on AD and to test whether TSLP polymorphisms increase the risk of asthma in children with AD. MethodsA total of 1,520 kindergarten children (375 with AD and 1,145 controls) selected from the Childhood Environment and Allergic Diseases Study cohort in 2010 were enrolled. Information about allergic diseases and environmental exposures was collected by questionnaire. Skin prick tests were performed to measure allergic sensitization. TSLP polymorphisms were genotyped by TaqMan assay. Logistic regressions were conducted to estimate the association among TSLP polymorphisms, allergic sensitization, and AD. For replication, a subsample of the British Isle of Wight birth cohort was used. ResultsThe TSLP rs2289278 CC genotype increased the risk of AD (odds ratio 1.90, 95% confidence interval 1.12–3.22). In children sensitized to certain allergens, a genetic predisposition (rs2289278 genotype CC) significantly increased the risk of AD. These findings were replicated in the British subsample using rs2289276 genotypes TT and TC, which are in linkage disequilibrium with rs2289278. In subjects with AD, the rs2289278 C allele also significantly increased the risk of developing asthma (odds ratio 8.31, 95% confidence interval 1.08–64.13). ConclusionThe association of rs2289278 with AD was stronger in children with allergic sensitization than in children without atopy. TSLP polymorphisms also increased the risk of asthma in children with AD.

An association and meta-analysis study of 4 SNPs from beta-2 adrenergic receptor (ADRB2) gene with risk of asthma in children.

Although various case-control studies have been conducted to investigate the relationship between ADRB2 gene polymorphisms and asthma risk in different population groups, the results have been conflicting and inconclusive. We performed a case-control study to investigate the association of 4 SNPs in the ADRB2 gene with risk of asthma in children, and then conducted a meta-analysis by combining the previous studies. A total of 340 patients and 340 age-matched healthy controls were recruited. All of the subjects were genotyped using the PCR-based invader assay. The case-control study was performed to define the contribution of rs1042713, rs1042714, rs1800888, and rs1042711 to the predisposition of asthma. Additionally, we further conducted a meta-analysis of the study findings together with those of previously reported studies. No significant association was found between the polymorphisms rs1042713, rs1042714, rs1800888, and rs1042711 and asthma in the current case-control study. The meta-analysis confirmed that there was no positive association of these SNPs with asthma in children in Asia, South America, Europe and the overall population. None of the four polymorphisms in ADRB2 gene were associated with a risk of asthma in a current children population.

Prenatal and Post-natal Exposure to Antibiotics and Risk of Asthma in Childhood

J Metsala, A Lundqvist, L Virta, M Kaila, S Virtanen. J Clin Exp Allergy. 2014;45(1):137–145 The purpose of this study was to explore associations between prenatal and postnatal exposure to antibiotics and the risk of childhood asthma. All children born in Finland between 1996 and 2004 and diagnosed with asthma and 1 matched control per case were identified from 4 national health registries (Drug Prescription Register, Special Reimbursement Register, Population Register, and Medical Birth Register), resulting in 6690 case-control pairs. Prenatal exposure to antibiotics was identified by extracting purchasing history of all antibiotics (ATC Code J01—antibiotics for systemic use) by the mother during pregnancy from …

Childhood Asthma Hospital Discharge Medication Fills and Risk of Subsequent Readmission

ML Kenyon, DM Rubin, JJ Zorc, Z Mohamad, JA Faerber, C Feudtner. J Pediatr. 2015;166(5):1121–1127 This study assessed the relationship between prescription fills for asthma medications after pediatric asthma hospital discharge and subsequent hospital readmission. Patients between the ages of 2 and 18 years with claims for inpatient hospitalizations for asthma from January 1, 2006, to September 30, 2007, were included. Patients were excluded if aged <2 years, if they died during their index hospitalization, or were discharged to other care facilities. Retrospective cohort study of Medicaid claims data taken from 12 states from 2005 to 2007. The primary outcome of interest was time …

Mode of delivery and risk of asthma in children 5-14 years old in Tabriz, Iran

Introduction: It has been suggested that a cesarean section increases risk of developing asthma due to lack of exposure to maternal microflora during birth. To investigate the association between the mode of delivery and the risk of asthma in children aged 5-14 years in Tabriz, Iran. Methods: A case-control study was performed on 233 (case = 81, control = 152) children aged 5-14 years referred to outpatient clinics of Tabriz Children’s Hospital and Sheikhorrais Clinic in 2014. Clinical asthma diagnosis was done according to Global Initiative for Asthma Criteria. A questionnaire was administered to obtain a demographic, environmental, and clinical history. Age-sex frequency matching with cases was carried out during sampling for controlling of possible cofounding effects of age and sex for asthma. Results: Of 233 children, 53.6% of them were male (case group = 54.3% and control group = 53.3%). Over half (54.5%), the participants had been delivered by caesarian section. Cases were not significantly more likely to have been delivered by caesarian section as compared to controls [adjusted odds ratio (AOR) = 0.69; 95% confidence interval (CI) = 0.34-1.42]. However, more frequent episodes of common cold [b = 0.094; standard error (SE) (b) = 0.031, P < 0.001], birth order (second born children compared to firstborns) (AOR = 2.54; 95% CI = 1.18-5.46), high maternal education levels: 12 years (AOR = 3.76; 95% CI = 1.10-12.9), collegiate (AOR = 6.12; 95% CI = 1.43-26.20), and intra-family marriage (AOR = 2.89; 95% CI = 1.21-6.89) were associated with childhood asthma. Conclusion: Delivery mode was not associated with risk of developing childhood asthma in our study. Intra-family marriage increased the odds of childhood asthma. Further study on the relationship between maternal education and the odds of asthma is proposed.

Exposure to acid-suppressing drugs during pregnancy and the risk of asthma in childhood: an observational cohort study.

Some research has suggested a potential link between prenatal exposure to proton pump inhibitors (PPIs) or H2 -receptor antagonists (H2 RAs) and the development of childhood asthma. To quantify the relative risk of asthma in children who experienced pre-natal exposure to PPIs and/or H2 RAs, adjusting for potential confounders. In this observational cohort study (NCT01787435), women aged 18-45 years with completed pregnancies between January 1996 and December 2010 were identified from The Health Improvement Network in the United Kingdom, and were linked to infants. Hazard ratios (HRs) were estimated using Cox proportional hazard models. Our analysis identified 2371 prenatally exposed and 7745 unexposed infants. The incidence of asthma (per 1000 person-years) was 19.52 in the unexposed cohort, 23.88 in the PPI cohort and 32.16 in the H2 RA cohort. After adjusting for maternal healthcare utilisation during the year before pregnancy, the HR for asthma in infants whose mothers received prescriptions at any time during pregnancy was 1.12 (95% confidence interval: 0.88-1.44) for PPIs and 1.43 (1.20-1.70) for H2 RAs, when compared with unexposed infants. With further adjustment for maternal comorbidities and other medications, the HR for asthma was 1.03 (0.76-1.40) for PPIs and 1.32 (1.05-1.64) for H2 RAs. Our analysis showed no association between prenatal exposure to PPIs and asthma in childhood after adjusting for confounders. The association found for H2 RAs may be explained largely by underlying environmental or genetic factors, as suggested by reductions in hazard ratio estimates following adjustment for maternal comorbidities.

Early growth characteristics and the risk of reduced lung function and asthma: A meta-analysis of 25,000 children

Children born preterm or with a small size for gestational age are at increased risk for childhood asthma. We sought to assess the hypothesis that these associations are explained by reduced airway patency. We used individual participant data of 24,938 children from 24 birth cohorts to examine and meta-analyze the associations of gestational age, size for gestational age, and infant weight gain with childhood lung function and asthma (age range, 3.9-19.1 years). Second, we explored whether these lung function outcomes mediated the associations of early growth characteristics with childhood asthma. Children born with a younger gestational age had a lower FEV1, FEV1/forced vital capacity (FVC) ratio, and forced expiratory volume after exhaling 75% of vital capacity (FEF75), whereas those born with a smaller size for gestational age at birth had a lower FEV1 but higher FEV1/FVC ratio (P < .05). Greater infant weight gain was associated with higher FEV1 but lower FEV1/FVC ratio and FEF75 in childhood (P < .05). All associations were present across the full range and independent of other early-life growth characteristics. Preterm birth, low birth weight, and greater infant weight gain were associated with an increased risk of childhood asthma (pooled odds ratio, 1.34 [95% CI, 1.15-1.57], 1.32 [95% CI, 1.07-1.62], and 1.27 [95% CI, 1.21-1.34], respectively). Mediation analyses suggested that FEV1, FEV1/FVC ratio, and FEF75 might explain 7% (95% CI, 2% to 10%) to 45% (95% CI, 15% to 81%) of the associations between early growth characteristics and asthma. Younger gestational age, smaller size for gestational age, and greater infant weight gain were across the full ranges associated with childhood lung function. These associations explain the risk of childhood asthma to a substantial extent.

Early Exposure to Dogs and Farm Animals and the Risk of Childhood Asthma.

The association between early exposure to animals and childhood asthma is not clear, and previous studies have yielded contradictory results. To determine whether exposure to dogs and farm animals confers a risk of asthma. In a nationwide cohort study, the association between early exposure to dogs and farm animals and the risk of asthma was evaluated and included all children born in Sweden from January 1, 2001, to December 31, 2010 (N = 1,011,051), using registry data on dog and farm registration, asthma medication, diagnosis, and confounders for parents and their children. The association was assessed as the odds ratio (OR) for a current diagnosis of asthma at age 6 years for school-aged children and as the hazard ratio (HR) for incident asthma at ages 1 to 5 years for preschool-aged children. Data were analyzed from January 1, 2007, to September 30, 2012. Living with a dog or farm animal. Childhood asthma diagnosis and medication used. Of the 1,011,051 children born during the study period, 376,638 preschool-aged (53,460 [14.2%] exposed to dogs and 1729 [0.5%] exposed to farm animals) and 276,298 school-aged children (22,629 [8.2%] exposed to dogs and 958 [0.3%] exposed to farm animals) were included in the analyses. Of these, 18,799 children (5.0%) in the preschool-aged children's cohort experienced an asthmatic event before baseline, and 28,511 cases of asthma and 906,071 years at risk were recorded during follow-up (incidence rate, 3.1 cases per 1000 years at risk). In the school-aged children's cohort, 11,585 children (4.2%) experienced an asthmatic event during the seventh year of life. Dog exposure during the first year of life was associated with a decreased risk of asthma in school-aged children (OR, 0.87; 95% CI, 0.81-0.93) and in preschool-aged children 3 years or older (HR, 0.90; 95% CI, 0.83-0.99) but not in children younger than 3 years (HR, 1.03; 95% CI, 1.00-1.07). Results were comparable when analyzing only first-born children. Farm animal exposure was associated with a reduced risk of asthma in both school-aged children and preschool-aged children (OR, 0.48; 95% CI, 0.31-0.76, and HR, 0.69; 95% CI, 0.56-0.84), respectively. In this study, the data support the hypothesis that exposure to dogs and farm animals during the first year of life reduces the risk of asthma in children at age 6 years. This information might be helpful in decision making for families and physicians on the appropriateness and timing of early animal exposure.

Prevalence and severity of asthma among Indian school children aged between 6 and 14 years: associations with parental smoking and traffic pollution

Objective: Phase three of the International Study of Asthma and Allergy in Children (ISAAC) was carried out at various sites in India. The prevalence of asthma symptoms in school children and the effect of environmental tobacco smoke and traffic pollution on the occurrence of asthma were analysed. Methods: Two groups of school children, aged 6–7 yr and 13–14 yr, participated according to the ISAAC protocol. Schools were randomly selected and responses to the ISAAC questionnaire were recorded. Results: The prevalence of asthma was 5.35% in the 6–7 yr age group and 6.05% in the 13–14 yr age group. The odds ratios (ORs) for the risk of asthma in children with exposure to mild, moderate and heavy traffic pollution compared with minimal traffic pollution were 1.63 (95% CI: 1.43, 1.85), 1.71 (95% CI: 1.49, 1.96) and 1.53 (95% CI: 1.31, 1.78), respectively, in the younger group. Similarly, in the older group, they were 1.19 (95% CI: 1.04, 1.36), 1.51 (95% CI: 1.31, 1.75) and 1.51 (95% CI: 1.29, 1.76). Asthma was associated with maternal smoking [6–7 yr group: OR = 2.72 (2.05, 3.6); 13–14 yr group: OR = 2.14 (1.72, 2.66)] and paternal smoking [6–7 yr group: OR = 1.9 (1.70, 2.11); 13–14 yr group: OR = 1.21 (1.09, 1.34)]. Conclusions: The prevalence of asthma was lower in the 6–7 than the 13–14 yr age group. Environmental tobacco smoke and traffic pollution were the factors most strongly associated with asthma in Indian children.

Modification of additive effect between vitamins and ETS on childhood asthma risk according to GSTP1 polymorphism : a cross -sectional study

BackgroundAsthma is characterized by airway inflammation, and bronchial airways are particularly susceptible to oxidant-induced tissue damage.ObjectiveTo investigate the effect of dietary antioxidant intake and environmental tobacco smoke (ETS) on the risk of childhood asthma according to genotypes susceptible to airway diseases.MethodsThis cross-sectional study included 1124 elementary school children aged 7–12 years old. Asthma symptoms and smoking history were measured using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Intake of vitamin A (including retinol and β-carotene), C, and E was measured by a semi-quantitative food frequency questionnaire (FFQ). GSTP1 polymorphisms were genotyped from peripheral blood samples.ResultsETS was significantly associated with presence of asthma symptoms (adjusted odds ratio [aOR], 2.48; 95 % confidence interval [CI], 1.29–4.76) and diagnosis (aOR, 1.91; 95 % CI, 1.19–3.06). Dietary antioxidant intake was not associated with asthma symptoms, although ETS plus low vitamin A intake showed a significant positive association with asthma diagnosis (aOR, 2.23; 95 % CI, 1.10–4.54). Children with AA at nucleotide 1695 in GSTP1 who had been exposed to ETS and a low vitamin A intake have an increased risk of asthma diagnosis (aOR, 4.44; 95 % CI,1.58–12.52) compared with children who had not been exposed to the two risk factors. However, ETS exposure and low vitamin A intake did not significantly increase odds of asthma diagnosis in children with AG or GG genotypes.ConclusionLow vitamin A intake and ETS exposure may increase oxidative stress and thereby risk for childhood asthma. These relationships may be modified by gene susceptibility alleles of GSTP1.Electronic supplementary materialThe online version of this article (doi:10.1186/s12890-015-0093-0) contains supplementary material, which is available to authorized users.

Periconceptional and Gestational Exposure to Antibiotics and Childhood Asthma.

BackgroundPrevious studies suggest that maternal antibiotics exposure during pregnancy may increase the risk of childhood asthma, but the results were inconsistent. Furthermore, most studies did not examine periconception period as an exposure window. We aim to assess the associations between maternal exposure to specific antibiotics before and during pregnancy and the risk of asthma in early childhood.MethodsData from the Collaborative Perinatal Project were used. Maternal exposure to antibiotics before and during pregnancy was recorded at each prenatal visit. A total of 39,907 singleton children were followed up to 7 years of age. Multilevel multiple logistic regression models were used to control for potential confounders and account for multiple pregnancies per woman.ResultsMaternal use of penicillin or chloramphenicol was associated with an increased risk of asthma in the offspring (adjusted odds ratio = 1.21, 95% confidence interval 1.08–1.36 for penicillin; 1.72 [1.14–2.59] for chloramphenicol). The risk was significantly increased if penicillin or chloramphenicol was used in the 1st trimester (1.09 [1.04–1.13] for penicillin and 1.23 [1.01–1.51] for chloramphenicol).ConclusionMaternal exposure to certain antibiotics is associated with childhood asthma by 7 years of age. Early pregnancy may be a sensitive window.