Cow's Milk Exposure and Asthma in a Newborn Cohort: Repeated Ascertainment Indicates Reverse Causation

The effect of cow's milk consumption on childhood asthma has been debated for several years. This study attempts to provide further insight into this association through the use of a longitudinal study design. Newborns from parents with atopic history were recruited from Germany, Austria, and England (n = 696). For five repeated ascertainments, information was collected on cow's milk exposure, incidence of doctor-diagnosed asthma, and confounders. Generalized estimation equations, incorporating different models (concurrent, delayed, combined, and reverse causation), were used to determine this association. No association between cow's milk consumption and childhood asthma was found for the concurrent effects model (OR = 0.81, 95% confidence interval [CI]: 0.55, 1.20). In the delayed effects model, the direction of the association varied with time of follow-up. Thus, we stratified by period, which resulted in a significant protective delayed effect at 36 months (OR = 0.18, 95% CI = 0.06, 0.49). However, reverse causation negated this finding since the presence of asthma in prior months led to a reduction in further exposure to cow's milk (OR = 0.40, 95% CI = 0.16, 0.99). Hence, cow's milk consumption does not protect against childhood asthma. The apparent protection of cow's milk against asthma may result from parents of asthmatic children avoiding cow's milk, rather than actual prophylaxis.     

Infant diet and type 1 diabetes in China

Infant milk and food introduction may be linked to type 1 diabetes risk in high incidence populations. Dietary data through age 12 months was collected for 247 type 1 diabetic cases and 443 controls in China, a low incidence population, to determine if milk and solid food intake differed. Age range at introduction to milk and formulas was similar in cases and controls but solid food introduction more often occurred before age 3 months in cases. Logistic regression analyses showed soy milk formula consumption at 4-6 (OR = 2.0; 95% CI: 1.1-3.4) and 7-12 months of age (OR = 1.5; 95% CI: 1.0-2.1) was associated with a twofold higher risk of type 1 diabetes, while steamed bread consumption (4-6 months, OR = 0.44; 95% CI: 0.28-0.68; 7-12 months, OR = 0.48; 95% CI: 0.34-0.69) and higher SES (4-6 months, OR = 0.55; 95% CI: 0.39-0.78; 7-12 months, OR = 0.57; 95% CI: 0.40-0.83) were negatively associated. Drinking cow's milk at 7-12 months (OR = 0.60; 95% CI: 0.43-0.85) was negatively associated with type 1 diabetes while consuming vegetables at 4-6 months (OR = 1.5; 95% CI: 1.0-2.2) was positively associated. Results suggest that infant milk and solid food intake are associated with type 1 diabetes in China. Prospective studies may determine how these dietary factors impact disease etiology, particularly for at-risk-populations.     

Household environmental tobacco smoke exposure, respiratory symptoms and asthma in non-smoker adults: a multicentric population study from India

BACKGROUND: Exposure to environmental tobacco smoke (ETS) is a risk factor for childhood asthma. Its association with asthma in adults is less clear. METHODS: In a multicentric population study on asthma prevalence in adults, specific enquiries were made into childhood and adulthood exposure to household ETS, and its relationship with asthma diagnosis were analysed. RESULTS: From a total of 73605 respondents, 62109 were studied after excluding current or past smokers. Overall observed prevalence of asthma was 2.0% (men 1.5%,women 2.5%, p < 0.001). Of all asthma patients, history of ETS exposure was available in 48.6 percent. Prevalence of asthma in the ETS exposed subjects was higher compared to non-exposed individuals (2.2% vs 1.9%, p < 0.05). Multiple logistic regression analysis showed a higher risk of having asthma in persons who were exposed to ETS compared to those not exposed (odds ratio [OR] 1.22, 95% CI 1.08-1.38) after adjusting for age, gender, usual residence, exposure to biomass fuels and atopy. Stratification of ETS exposure revealed that exposure during childhood and both during childhood and adulthood were significantly associated with asthma prevalence. Exposure only in adulthood was not a significant risk factor (OR 1.13, 95% CI 0.95-1.33). Persons reporting combined environmental tobacco smoke exposure from parents during childhood and spouse during adulthood had highest risk of having asthma (OR 1.69, 95% CI 1.38-2.07). Environmental tobacco smoke exposure was also significantly associated with prevalence of respiratory symptoms such as wheezing, cough and breathlessness. CONCLUSIONS: Environmental tobacco smoke exposure during childhood is an important risk factor for asthma and respiratory symptoms in non-smoking adults.     

Risk factors for asthma admissions in children.

Bronchial asthma is related to a high morbidity rate, leading to an increasing frequency of emergency room visits and hospital admissions. The aim of this study was to identify severity risk factors for childhood asthma related to hospitalization. The authors studied 124 children admitted to the hospital for asthma, during a 2-year period, correlating the obtained data with a sample of outpatients with asthma matched by age, gender, and socioeconomic status. A standardized questionnaire and skin-prick tests (SPTs) were performed on all children. The significant and independent risk factors identified for hospital admission were prior asthma hospitalization (OR = 7.63; 95% CI = 1.5-39.6; p = 0.01) and last-year admission (OR = 3.18; 95% CI = 1.1-8.9; p = 0.02), environmental tobacco-smoke exposure (OR = 6.63; 95% CI = 2.5-17.8; p = 0.002), allergen sensitization (OR = 3.86; 95% CI = 1.4-10.7; p = 0.009), family history of maternal asthma (OR = 3.58; 95% CI = 1.3-9.6; p = 0.01), and onset of symptoms before 12 months of age (OR = 2.76; 95% CI = 1.0-7.9; p = 0.06). Attendance at day care or kindergarten (OR = 0.38; 95% CI = 0.2-0.9; p = 0.04) and large family size (OR = 0.25; 95% CI = 0.1-0.8; p = 0.01) could be protective factors. Our results stress the importance of early diagnosis and specialized medical care of childhood asthma, mainly in high-risk children, with emphasis on medication planning and the establishment of preventive measures such as environmental tobacco smoke avoidance and limitation of aeroallergen exposure.     

Childhood agricultural and adult occupational exposures to organic dusts in a population-based case-control study of systemic lupus erythematosus

Organic dust exposure can influence the development and symptoms of immune-related diseases such as atopy and asthma, but has rarely been examined in relation to systemic autoimmunity. The present analyses explore the association of lifetime farm and occupational organic dust exposures with systemic lupus erythematosus (SLE) in recently diagnosed patients (n = 265) compared with controls (n = 355) frequency matched by age, sex and state. Questionnaire data included childhood farm residence, childhood and adult experience with specific crops, and adult work in textiles, hog or poultry processing and paper or furniture manufacture. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated by logistic regression models including age, sex, state, race, education and silica exposure. Overall childhood or adult farm contact and childhood farm residence were not associated with SLE. Farm contact with livestock was inversely associated with SLE (OR = 0.55, 95% CI 0.35, 0.88). This effect was most pronounced among those with childhood farm residence and both childhood and adult livestock exposure (OR = 0.19; 95% CI 0.06, 0.63), but was difficult to separate from adult exposure to grains or corn. Other adult occupational exposures were not associated with SLE risk overall, regardless of childhood farm residence or livestock exposure, although an inverse association was seen among non-smokers (OR = 0.59; 95% CI 0.33, 1.1), particularly for textile work (OR = 0.34; 95% CI 0.19, 0.64). These exploratory findings support the development of studies to specifically investigate the effects of organic dust exposure on SLE risk, with particular attention to exposure assessment and characterization of demographics, smoking and other occupational exposures.     

Diet among Japanese female university students and asthmatic symptoms, infections, pollen and furry pet allergy

OBJECTIVES: To study associations between diet, respiratory symptoms and allergy among female university students in Japan. METHODS: A standardised questionnaire was distributed to students in Kobe and Kamakura (N=153). Multiple logistic/linear regression was applied, controlling for age, smoking, heredity and diet. RESULTS: Totally 15.7% reported doctor-diagnosed asthma, 3.3% current asthma medication, 56.9% pollen allergy, 15.7% cat allergy, 11.1% dog allergy, 25.0% wheeze, 24.2% daytime and 9.3% nocturnal attacks of breathlessness. Meat consumption was related to wheeze (OR=2.00; 95% CI 1.12-3.60) and respiratory infections (OR=2.10; 95% CI 1.08-4.09). Fish consumption was related to less respiratory infections (OR=0.49; 95% CI 9.28-0.86), seafood to less pollen allergy (OR=0.66; 95% CI 0.44-0.99), and milk consumption to less daytime breathlessness (OR=0.72; 95% CI 0.55-0.95). Fast food consumption was related to wheeze (OR=1.89; 95% CI 1.23-2.91), daytime breathlessness (OR=1.50; 95% CI 1.00-2.28) and pollen allergy (OR=1.69; 95% CI 1.07-2.65). In total, 23.0% used butter, 21.7% margarine, 40.1% olive oil and 55.3% rapeseed oil. Those consuming butter (OR=2.65; 95% CI 1.11-6.32) and rapeseed oil (OR=2.35; 95% CI 1.03-5.38) had more wheeze. Those consuming margarine had more nocturnal breathlessness (OR=4.40; 95% CI 1.42-13.7). An asthma symptom score was related to fast food (p<0.05) and margarine consumption (p<0.01). Factor analysis identified five dietary patterns. A pattern including fast food, juice and soft drinks was related to wheeze and respiratory infections. CONCLUSION: Fish, seafood and milk consumption seems to be beneficial, while butter, margarine, rapeseed oil, fast food and soft drinks could be risk factors for allergy and respiratory health.     

Does antibiotic exposure during infancy lead to development of asthma?: a systematic review and metaanalysis

OBJECTIVES: To determine the association between antibiotic exposure in the first year of life and the development of childhood asthma. DESIGN: Metaanalysis of observational studies retrieved through systematic search of all available electronic data sources. Studies included in the metaanalyses were those with populations exposed to one or more courses of antibiotics during the first year of life, and asthma diagnosis was defined as diagnosis by a physician between the age of 1 to 18 years. SETTING: Retrospective and prospective studies published in the English-language literature from 1966 to present. RESULTS: Eight studies (four prospective and four retrospective) examined the association between exposure to at least one course of antibiotics and development of childhood asthma. The total number of subjects for the analysis comparing exposure to at least one antibiotic to no exposure in the first year of life was 12,082 children and 1,817 asthma cases. In the dose-response analysis, we included data from a total of 27,167 children and 3,392 asthma cases. The pooled odds ratio (OR) for the eight studies was 2.05 (95% confidence interval [CI], 1.41 to 2.99). The association was significantly stronger in the retrospective studies (OR, 2.82; 95% CI, 2.07 to 3.85) than the prospective studies (OR, 1.12; 95% CI, 0.88 to 1.42). Five of the eight studies examined whether the association was related to the number of courses of antibiotics taken in the first year of life. The overall OR for the dose-response analysis was 1.16 (95% CI, 1.05 to 1.28) for each additional course of antibiotics; however, this association was not significantly stronger in the retrospective studies (OR, 1.37; 95% CI, 1.18 to 1.60) relative to the prospective studies (OR, 1.07; 95% CI, 0.95 to 1.20). CONCLUSIONS: Exposure to at least one course of antibiotics in the first year of life appears to be a risk factor for the development of childhood asthma. Because of the limitations of the studies conducted to date, additional large-scale, prospective studies are needed to confirm this potential association.     

An Epidemiological Study of Asthma Prevalence and Related Factors Among Young Adults

Asthma and related factors were assessed by mailed questionnaires among 2041 young adult participants in a smoking prevention project in California in 1993. Hispanics had lower prevalence of physician-reported asthma when compared to blacks and whites. Blacks were significantly more likely to be hospitalized or visit emergency rooms because of asthma or wheezing. After adjusting for sex, race, and educational level, family history of asthma was strongly associated with subjects' asthma (odds ratio = 3.1, 95% CI: 2.4-4.3 for physician-reported asthma; OR = 3.3, 95% CI: 2.4-4.5 for current asthma). Exposure to parental smoking (both parents smoked more than half a pack of cigarettes a day) during childhood (reported when participants were in grade 7) was significantly associated with physician-reported asthma (OR = 2.9, 95% CI: 1.6-5.6) and current asthma (OR = 3.3, 95% CI: 1.7-6.4). The study also found that self-reported mold growth at home was significantly associated with asthma (OR = 2.0, 95% CI: 1.2-3.2). After adjusting for cigarette smoking and demographic variables, use of crack cocaine was marginally significantly associated with current asthma (OR = 2.3, 95% CI: 1.0-5.2), but not with physician-reported asthma (OR = 1.5, 95% CI: 0.7-3.3).     

Effects of maternal smoking during pregnancy and environmental tobacco smoke on asthma and wheezing in children

The effects of maternal smoking during pregnancy and childhood environmental tobacco smoke (ETS) exposure on asthma and wheezing were investigated in 5,762 school-aged children residing in 12 Southern California communities. Responses to a self- administered questionnaire completed by parents of 4th, 7th, and 10th grade students were used to ascertain children with wheezing or physician-diagnosed asthma. Lifetime household exposures to tobacco smoke were assessed using responses about past and current smoking histories of household members and any history of maternal smoking during pregnancy. Logistic regression models were fitted to cross-sectional data to estimate the effects of in utero exposure to maternal smoking and previous and current ETS exposure on the prevalence of wheezing and physician-diagnosed asthma. In utero exposure to maternal smoking without subsequent postnatal ETS exposure was associated with increased prevalence of physician-diagnosed asthma (OR, 1.8; 95% CI, 1.1 to 2.9), asthma with current symptoms (OR, 2.3; 95% CI, 1.3 to 4.0), asthma requiring medication use in the previous 12 mo (OR, 2.1; 95% CI, 1.2 to 3.6), lifetime history of wheezing (OR, 1.8; 95% CI, 1.2 to 2.6), current wheezing with colds (OR, 2.1; 95% CI, 1.3 to 3.4) and without colds (OR, 2.5; 95% CI, 1.4 to 4.4), persistent wheezing (OR, 3.1; 95% CI, 1.6 to 6.1), wheezing with exercise (OR, 2.4; 95% CI; 1.3 to 4.3), attacks of wheezing causing shortness of breath (OR, 2.4; 95% CI, 1.3 to 4.4) or awakening at night in the previous 12 mo (OR, 3.2; 95% CI, 1.7 to 5.8), and wheezing requiring medication (OR, 2.1; 95% CI, 1.2 to 3.7) or emergency room visits during the previous year (OR, 3.4; 95% CI, 1.4 to 7.8). In contrast, current and previous ETS exposure was not associated with asthma prevalence, but was consistently associated with subcategories of wheezing. Current ETS exposure was associated with lifetime wheezing (OR, 1.3; 95% CI, 1.1 to 1.5), current wheezing with colds (OR, 1.6; 95% CI, 1.3 to 2.0) and without colds (OR, 1.5; 95% CI, 1.1 to 1.9), wheezing with exercise (OR, 1.7; 95% CI, 1.3 to 2.2), attacks of wheezing causing shortness of breath (OR, 1.6; 95% CI, 1.2 to 2.1) or awakening at night (OR, 1.5; 95% CI, 1.1 to 2.0), and wheezing requiring medication (OR, 1.4; 95% CI, 1.1 to 1.8) or emergency room visits within the previous year (OR, 1.9; 95% CI, 1.2 to 3.0). The effects of current ETS exposure on subcategories of wheezing were most pronounced among children exposed to two or more smokers and remained significant after adjusting for maternal smoking during pregnancy. We conclude that maternal smoking during pregnancy increases the occurrence of physician-diagnosed asthma and wheezing during childhood. In contrast, current ETS exposure is associated with wheezing, but not physician-diagnosed asthma. Taken together, our findings support the hypothesis that ETS operates as a cofactor with other insults such as intercurrent infections as a trigger of wheezing attacks, rather than as a factor that induces asthma, whereas in utero exposure acts to increase physician-diagnosed asthma     

Antibiotic exposure in early life and childhood overweight and obesity: A systematic review and meta‐analysis

We conducted a systematic review and meta‐analysis of observational studies investigating the association between antibiotic exposure in infancy and risk of childhood overweight and obesity. Thirteen studies, including a total of 527 504 children, were included in the systematic review and 8 were included in meta‐analyses. Exposure to antibiotics in infancy was associated with an increased odds ratio (OR) of childhood overweight and obesity (OR 1.11, 95% confidence interval [CI] 1.02‐1.20). Whereas exposure to 1 treatment only and exposure between 6 and 24 months were not associated with increased risk of childhood overweight and obesity, exposure to >1 treatment was associated with an OR of 1.24 (95% CI 1.09‐1.43) and exposure within the first 6 months of life was associated with an OR of 1.20 (95% CI 1.04‐1.37). In conclusion, antibiotic exposure in infancy was associated with a slightly increased risk of childhood overweight and obesity, mainly if children were exposed to repeated treatments or treatment within the first 6 months of life. It is unclear whether this association is mediated via direct effects of antibiotics on the gut microbiota.     

Maternal and grandmaternal smoking patterns are associated with early childhood asthma

OBJECTIVE: To investigate the associations of maternal and grandmaternal smoking before, during, and after pregnancy with childhood asthma. DESIGN, SETTING, AND PARTICIPANTS: We conducted a case-control study nested within the Children's Health Study in southern California. The case patients consisted of 338 children with asthma that had been diagnosed in the first 5 years of life, and 570 control subjects were countermatched on in utero exposure to maternal smoking within grade, sex, and community of residence. MEASUREMENTS: Detailed maternal and household smoking histories and other asthma risk factor information was obtained by telephone interview. RESULTS: The participation rates were 72.3% and 82.5%, respectively, for control subjects and case patients. In utero exposure to maternal smoking was associated with increased risk for asthma diagnosed in the first 5 years of life (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.0 to 2.3), and for persistent asthma (OR, 1.5; 95% CI, 1.0 to 2.3). The associations did not differ in children with early transient asthma compared to those with early persistent asthma. Relative to never-smokers, children whose mothers smoked throughout the pregnancy had an elevated risk of asthma in the first 5 years of life (OR, 1.6; 95% CI, 1.0 to 2.6). Children of mothers who quit smoking prior to the pregnancy showed no increased risk (OR, 0.9; 95% CI, 0.5 to 1.5). We were unable to assess the association of smoking cessation during pregnancy because very few mothers were reported to have done so (15%). Asthma risk did not increase in a monotonic pattern with smoking intensity during pregnancy. Postnatal secondhand smoke exposure was not independently associated with asthma. Grandmaternal smoking during the mother's fetal period was associated with increased asthma risk in her grandchildren (OR, 2.1; 95% CI, 1.4 to 3.2). CONCLUSIONS: Maternal and grandmaternal smoking during pregnancy may increase the risk of childhood asthma.     

Asthma and panic in young adults: a 20-year prospective community study

RATIONALE: Psychologic factors are increasingly recognized to influence the onset and course of asthma. Previous cross-sectional community-based studies have provided evidence for a relatively specific association between asthma and panic. OBJECTIVES: To examine concurrent and longitudinal associations between asthma and panic in young adults. MEASUREMENTS AND MAIN RESULTS: Prospective community-based cohort study of young adults (n = 591) followed between ages 19 and 40. Information was derived from six subsequent semistructured diagnostic interviews conducted by professionals. Cross-sectionally (over the whole study period), asthma was more strongly associated with panic disorder (odds ratio [OR] = 4.0; 95% confidence interval [CI], 1.7, 9.3) than with any panic, which included panic disorder and panic attacks (OR = 2.1; 95% CI, 1.1, 4.5). Longitudinally, after adjusting for potentially confounding variables, active asthma predicted subsequent panic disorder (OR = 4.5; 95% CI, 1.1, 20.1), and the presence of panic disorder predicted subsequent asthma activity (OR = 6.3; 95% CI, 2.8, 14.0). Asthma predicted any panic (OR = 2.7; 95% CI, 1.1, 7.1), whereas any panic did not predict subsequent asthma activity. Associations were stronger in smokers than in nonsmokers, and stronger in women than in men. Smoking, early-childhood anxiety, and a family history of allergy were important confounders of the asthma-panic association. CONCLUSIONS: This is the first long-term follow-up study on asthma and panic. It showed dose-response-type relationships between panic and asthma, and bidirectional longitudinal associations between the two conditions. It provided evidence for familial factors and smoking as possible shared etiologic explanations.     

Asthma and asthma-related symptoms in 16 789 Chinese children in relation to pet keeping and parental atopy.

BACKGROUND: The relationship between exposure to animals and allergic respiratory diseases in childhood is controversial, and there is little information about how exposure to pets affects the respiratory health of Chinese children, who have lower rates of asthma. OBJECTIVE: To study the association between exposure to pets and doctor-diagnosed asthma and asthma-related symptoms in Chinese children. We also investigated whether genetic propensity as a result of parental atopy modifies these relations. METHODS: A cross-sectional study of 16 789 children was conducted at 24 randomly selected kindergartens and 12 elementary schools in Liaoning province, China. Information on respiratory health and exposure to indoor allergens was obtained by a standard questionnaire from the American Thoracic Society. RESULTS: In children, exposure to animals was associated with a diagnosis of asthma (adjusted odds ratio [OR], 1.49; 95% confidence interval [CI], 1.30-1.70), wheezing (adjusted OR, 1.37; 95% CI, 1.18-1.60), persistent cough (adjusted OR, 1.71; 95% CI, 1.52-1.91), and persistent phlegm (adjusted OR, 2.26; 95% CI, 1.94-2.64). Parental atopy increased the risk of a diagnosis of asthma (adjusted OR, 3.12; 95% CI, 2.61-3.73) and asthma-related symptoms. There was an interaction between parental atopy and pet exposure in persistent cough and persistent phlegm, but not in doctor-diagnosed asthma. CONCLUSIONS: Pet keeping and parental atopy increased the risk of asthma and allergic respiratory diseases in children. Parental atopy modified the effect of pet exposure in persistent cough and persistent phlegm but not in doctor-diagnosed asthma.     

Effects of glutathione S-transferase M1, maternal smoking during pregnancy,and environmental tobacco smoke on asthma and wheezing in children

The rise in childhood asthma prevalence suggests a role for environmental factors in the etiology of this evolving epidemic; however, genetics also influence the occurrence of asthma. Glutathione S-transferase (GST) M1 may play a role in asthma and wheezing occurrence among those exposed to tobacco smoke, as it functions in pathways involved in asthma pathogenesis such as xenobiotic metabolism and antioxidant defenses. Effects of GSTM1 genotype, maternal smoking during pregnancy, and childhood environmental tobacco smoke (ETS) exposure on asthma and wheezing were investigated in 2,950 children enrolled in 4th, 7th, and 10th grade classrooms in 12 Southern California communities. The effects of in utero exposure to maternal smoking on asthma and wheezing occurrence were largely restricted to children with GSTM1 null genotype. Among GSTM1 null children, in utero exposure was associated with increased prevalence of early onset asthma (odds ratio [OR] 1.6, 95% confidence interval [CI] 1.0-2.5), asthma with current symptoms (OR 1.7, 95% CI 1.1-2.8), persistent asthma (OR 1.6, 95% CI 1.1-2.4), lifetime history of wheezing (OR 1.8, 95% CI 1.3-2.5), wheezing with exercise (OR 2.1, 95% CI 1.3-3.3), wheezing requiring medication (OR 2.2, 95% CI 1.4-3.4), and emergency room visits in the past year (OR 3.7, 95% CI 1.9-7.3). Among children with GSTM1 (+) genotype, in utero exposure was not associated with asthma or wheezing. Our findings indicate that there are important long-term effects of in utero exposure in a genetically susceptible group of children.     

Prenatal and postnatal exposure to Bisphenol A and Asthma: a systemic review and meta-analysis

BackgroundBisphenol A (BPA) is a plasticizer with high production and ubiquitous usage in polycarbonate plastics and epoxy resins. The association between prenatal or postnatal exposure to BPA and childhood wheeze/asthma has not been well established. Our study aimed to provide further justification for the current studies.MethodsStudies were searched from PubMed, Web of Science, Scopus and Embase from inception until Sep 15, 2020. Meta-analysis was performed to calculate pooled adjusted odds ratios (aOR). The methodological quality of included studies was assessed by using the Newcastle Ottawa Scale (NOS).ResultsOf 2,814 screened articles, 9 studies with 3,885 participants were included in the final analysis. When all studies were pooled, postnatal exposure to BPA was associated with a higher risk of childhood asthma (aOR =1.43; 95% CI: 1.28–1.59) or childhood wheeze (aOR =1.38; 95% CI: 1.18–1.62). Prenatal exposure to BPA had a small but significant increased risk of childhood asthma (aOR =1.17; 95% CI: 1.01–1.34). An increased risk of childhood wheeze was related to prenatal exposure to BPA at 16 weeks’ gestation (aOR =1.29; 95% CI: 1.07–1.55), but not at 26 weeks’ gestation (aOR =1.07; 95% CI: 0.88–1.29) nor at random-time gestation (aOR =1.02; 95% CI: 0.89–1.16).ConclusionsPrenatal and postnatal exposure to BPA was related to an increased risk of childhood asthma. However, only postnatal and early gestational exposure (at 16 weeks) to BPA could induce the risk of childhood wheeze, but not late gestational exposure (at 26 weeks).     

Breastfeeding and Asthma Among Brazilian Children

We examined the association of breastfeeding and the presence of chronic respiratory symptoms among 5182 Brazilian schoolchildren 7-14 years of age who were participants in the International Study on Asthma and Allergies in Childhood (ISAAC). The prevalence of medically diagnosed asthma and current wheeze were respectively 4.6% (95% confidence interval [CI] 4.0%-5.2%) and 11.9% (95% CI 11.0%-12.8%). Ninety percent of the mothers in our study population had breastfed their child. After adjusting for potential confounding factors, we found that children who had not been breastfed were more likely to have a medical diagnosis of asthma (odds ration [OR] = 1.51, 95% CI 1.00-2.51), experience current wheeze (OR = 1.29, 95% CI 0.96-1.74), and wheeze after exercise (OR = 1.51, 95% CI 1.01-2.27) than children who had been breastfed for more than 6 months. This effect was only present among children with no family history of asthma (OR = 1.54, 95% CI 0.90-2.42 for medical diagnosis of asthma; OR = 1.27, 95% CI 0.93-1.75 for current wheezing; and OR = 1.74, 95% CI 1.12-2.6 for wheeze after exercise). We conclude that the low prevalence of asthma and wheeze observed in our population may be partly related to the high level of breastfeeding.     

Urban environment adherence to the Mediterranean diet and prevalence of asthma symptoms among 10- to 12-year-old children: The Physical Activity, Nutrition, and Allergies in Children Examined in Athens study

Epidemiological studies have revealed several associations between asthma symptoms and environmental and dietary factors, but the potential environment- diet interactions on asthma incidence have rarely been investigated. The aim of this work was to evaluate the interrelationships between urban/rural environment, adherence to a healthy dietary pattern, the Mediterranean diet, and childhood asthma. A cross-sectional survey was performed and 1125 (529 boys), 10- to 12-year-old children were selected from 18 schools located in urban Athens area (n = 700) and from 10 schools located in rural areas of Ilia and Viotia (n = 425), Greece. Children and their parents completed standardized questionnaires, which evaluated, among others, environmental factors and dietary habits. Asthma was defined according to Phase II of the International Study on Allergies and Asthma in Childhood criteria. Adherence to the Mediterranean diet was assessed using the Mediterranean and Diet Quality Index for children and adolescents (KIDMED) score. Living in urban areas was associated with higher odds of ever had asthma symptoms by 1.78 times (95% confidence interval [CI], 1.25-2.54) when compared with rural areas. In contrast, 1-unit increase in the KIDMED score was associated with 16% lower likelihood of having asthma symptoms (95% CI, 0.77-0.91), after adjusting for various confounders. When stratifying the analysis by area of living it was observed that adherence to the Mediterranean diet was associated with lower likelihood of asthma in both urban and rural areas (urban, odds ratio [OR] = 0.81, 95% CI, 0.73-0.91; rural, OR = 0.87, 95% CI, 0.75-1.00). Urban environment seems to increase the likelihood of childhood asthma, whereas adherence to the healthy Mediterranean dietary pattern could mediate the aforementioned association and confers significant protection.     

Relationship of serum antioxidants to asthma prevalence in youth

The relationship of serum vitamin E, beta-carotene, vitamin C, and selenium to asthma was investigated among 7,505 youth (4-16 years old) in the Third National Health and Nutrition Examination Survey. Logistic regression models adjusted for potentially confounding variables, which generally had no effect on the coefficients for the antioxidants. Serum vitamin E had little or no association with asthma. In separate models, a SD increase in beta-carotene (odds ratio [OR], 0.9; 95% confidence interval [CI], 0.7, 1.0), vitamin C (OR, 0.8; 95% CI, 0.7, 0.9), and selenium (OR, 0.9; 95% CI, 0.7, 1.1) was associated with a 10-20% reduction in asthma prevalence. Serum cotinine was used to identify youth with no cigarette smoke exposure and passive exposure (7%): Active smokers were too few to be studied further. The selenium-asthma association was stronger in youth who were smoke exposed (p = 0.075). A SD increase in selenium was associated with a 50% reduction in asthma prevalence (OR, 0.5; 95% CI, 0.2, 1.4) in youth with passive smoke exposure compared with a 10% reduction in youth with no smoke exposure. The findings support an association of antioxidants with prevalent asthma, which for some antioxidants is stronger among children exposed to cigarette smoke.     

Pet exposure and the symptoms of asthma, allergic rhinitis and eczema in 6-7 years old children

Allergic diseases are frequent in children and their prevalence and severity differ in the different regions of the world. The association between pet ownership in childhood and subsequent asthma and sensitization is very controversial.In our survey conducted with standardized method (International Study of Asthma and Allergies in Childhood), 3200 children 6-7 years old were questioned regarding asthma, allergic rhinitis and eczema. The prevalence of Attacks and shortness of breath with wheezing during last 12 months in the children who had exposure to pets in the first year of life was 34.3% 'that was less than children who had not exposure (OR=3.06, 95% confidence interval [CI] 1.14-8.21, P=0.021). Also during the past 12 months the prevalence of night dry coughs, allergic rhinitis symptoms and eczema symptoms in those who had pet exposure in the first year of their life was lower than the children did not have it. However there was no significant difference in some other symptoms of asthma in two groups.Our findings suggest that pet exposure in the first year of life can have a protective effect on asthma, allergic rhinitis and eczema.