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Determinants of atopic sensitization in Turkish school children: effects of pre- and post-natal events and maternal atopy.

Emergence of new environmental risk factors, and/or loss of protective factors of a traditional lifestyle may explain the increase, or variations in prevalence of allergic diseases. The aim of this study was to delineate the prevalence and spectrum of, and to reveal the causal and/or protective factors for atopic sensitization among a heterogenous cohort of Turkish children, for the first time in our country. The study design adhered to International Study of Asthma and Allergies in Childhood (ISAAC) phase II protocol. A self‐administered parental questionnaire about demographic characteristics and detailed risk factors, and skin‐prick test with 13 allergens were employed in a clustered random sample of 8–11‐yr‐old Turkish school children. Atopy was defined as the presence of at least one positive skin reaction to any allergen tested. The association between a total of 78 risk factors and different aspects of atopy were analyzed in 1144 children with multivariate logistic regression analysis. The overall prevalence of atopy was 20.6%. Most common sensitizations were to grass pollens, Dermatophagoides pteronyssinus and Blatella germanica. Day care attendance, high paternal education level, male gender and maternal asthma were significant risk factors for atopy. Breastfeeding more than 6 months (compared with 0–6 months), maternal smoking during pregnancy and a birth weight under 2500 g were inversely related to (or protective factors for) atopic sensitization. Maternal atopic disease had significant effects on risk factors pattern. In children with a maternal atopy history a low birth weight, day care attendance and maternal smoking during the first year of life independently increased the risk of atopic sensitization. Gender, breastfeeding and paternal education did not show any association with atopy in this group of children. A history of measles and low gestational age were significant protective factors for mite sensitization. This study showed that children of atopic mothers showed a different profile of risk factors associated with atopic sensitization, when compared with other children. Prenatal and early childhood events had important associations with atopic sensitization.

Effect of breastfeeding on asthma, lung function and bronchial hyperreactivity in ISAAC Phase II

The association between breastfeeding and wheezing, lung function and atopy was evaluated in the International Study of Asthma and Allergy in Childhood (ISAAC) Phase II. Cross-sectional studies were performed in 27 centres in 20 countries. Information on disease and exposure factors was collected by parental questionnaires. Data from 54,000 randomly selected school children (aged 8–12 yrs, 31,759 with skin prick testing) and a stratified subsample (n = 4,888) were used for testing the correlation of breastfeeding with bronchial hyperreactivity and lung function. Random effect models for meta-analysis were applied to calculate combined odds ratios (ORs). Any breastfeeding was associated with less wheeze both in affluent (adjusted OR (ORadj) 0.87, 95% confidence interval (CI) 0.78–0.97) and nonaffluent countries (ORadj 0.80, 95% CI 0.68–0.94). Further analyses revealed that this was true only for nonatopic wheeze in nonaffluent countries (ORadj 0.69, 95% CI 0.53–0.90). Breastfeeding was not associated with atopic wheeze and objective measures of allergy in both affluent and nonaffluent countries. In contrast, breastfeeding was associated with higher predicted forced expiratory volume in one second in affluent countries only (mean ratio 1.11, 95% CI 1.02–1.20). Breastfeeding is associated with protection against nonatopic wheeze, which becomes particularly evident in nonaffluent countries. Overall, breastfeeding was not related to any measure of allergy. These findings may explain some of the controversy regarding breastfeeding, since the direction of the association with breastfeeding depends on the predominating wheeze phenotype (e.g. atopic, nonatopic).

Epidemiologic characteristics of rhinitis in Turkish Children: the International Study of Asthma and Allergies in Childhood (ISAAC) phase 2

Rhinitis is a common problem with important comorbidities. In order to search the association between rhinitis, allergic phenotypes and other risk factors in Turkish children, a parental questionnaire about allergic diseases and risk factors, and skin prick test (SPT) with 13 inhalant allergens were performed in a population‐based sample of 2774 children aged 9–11 yr. Bronchoprovocation testing with hypertonic saline (HS)and total IgE analysis were limited to a subsample of 350 children. Rhinitis was defined as a problem with sneezing, rhinorrhea, or nasal congestion when the child did not have a viral respiratory infection. The prevalences of ever rhinitis, current (last 12 months) rhinitis (CR), and ever hay fever were 36.3%, 30.6%, and 8.3%, respectively. SPT positivity rate was 20.4% among children with CR. Current wheezing and flexural dermatitis were significantly associated with CR. CR significantly increased the risk of asthma among both atopic and non‐atopic subjects [odds ratio (OR), 3.98; 95% CI, 1.81–8.76; and OR, 2.79; 95% CI, 1.82–4.26, respectively]. The association between CR and bronchial hyperreactivity (BHR) was not significant. The multiple logistic regression analysis revealed family atopy (OR = 2.25, 95% CI = 1.79–2.83, p < 0.001), current indoor heating with gas stove (OR = 1.78, 95% CI = 1.18–2.64, p = 0.006) and dampness/molds at home during the first year of life (OR = 1.70, 95% CI = 1.25–2.31, p = 0.001) as significant risk factors for CR. Turkish school children showed a high prevalence of rhinitis with a preponderance of non‐atopics. The highly significant association between rhinitis and asthma independent of atopic sensitization emphasize the importance of non‐atopic forms of rhinitis.

Prevalence of asthma symptoms in school children in Ankara, Turkey

The aim of this study was to determine the prevalence of symptoms suggestive of asthma in children aged 7-14 years in Ankara, Turkey. For this purpose, the recently developed ISAAC (International Study for Asthma and Allergies in Childhood) questionnaire supplemented with six additional questions was issued to parents of 3154 primary school children from 12 schools. A separate page with questions regarding risk factors was also added to the questionnaire. The response rate was 88.3%. The cumulative and 12-month prevalence of wheezing were 14.4 and 4.7% respectively. The prevalence of physician-diagnosed asthma was 8.1%. A family history of atopy was found to be the strongest risk factor for having ever had wheezing (odds ratio (OR) = 2.89, 95% confidence interval (CI) = 2.32-3.60), wheezing in the past 12 months (OR = 3.21, CI = 2.21-4.67), and severe attack (OR = 2.41, CI = 1.36-4.25). Passive smoking was a risk only for having ever had wheezing (OR = 1.33, CI = 1.03-1.76). Increasing age was associated with a lower risk of current wheezing (OR = 0.85, CI = 0.81-0.90) and severe attack (OR = 0.77, CI = 0.67-0.88). Gender, socio-economic level and pet ownership did not appear to be risk factors for asthma-related symptoms. This study, the first epidemiological survey in Ankara, Turkey, using the ISAAC protocol, clearly shows that symptoms suggestive of asthma, albeit lower than in most European countries, are quite common and constitute a major health problem in Turkey.

A multi‐centre study of candidate genes for wheeze and allergy: the International Study of Asthma and Allergies in Childhood Phase 2

Background Common polymorphisms have been identified in genes suspected to play a role in asthma. We investigated their associations with wheeze and allergy in a case–control sample from Phase 2 of the International Study of Asthma and Allergies in Childhood.

Prevalence of asthmatic phenotypes and bronchial hyperresponsiveness in Turkish schoolchildren: an International Study of Asthma and Allergies in Childhood (ISAAC) phase 2 study.

BACKGROUND Numerous epidemiologic studies have revealed that bronchial asthma affects populations without regard to frontiers. However, standardized methodological approaches are necessary to compare these populations. OBJECTIVE To investigate objective markers of childhood asthma on an epidemiologic basis and to include Turkish children in international comparisons. METHODS Parental questionnaires were collected and skin prick tests performed on fourth grade primary schoolchildren, aged 8 to 11 years, residing in Ankara, Turkey. Pulmonary function tests and bronchial challenge with hypertonic saline (HS) were conducted in children selected from this cohort with a stratified random sampling according to the presence of current wheezing. RESULTS A total of 3,041 questionnaires were included in the evaluation. Skin prick tests were performed on 2,774 children (97.1%). A total of 347 children from this cohort underwent pulmonary function and bronchial challenge tests. In 18 (5.1%) of the 347 children, bronchial challenge tests could not be successfully completed. The prevalence values were 11.5% for current wheezing, 6.9% for physician-diagnosed asthma, and 7.7% for physician-diagnosed recurrent bronchitis. Population-based weighted prevalence of bronchial hyperresponsiveness (BHR) was 21.8%. Frequency of responses to HS was 38.6% among physician-diagnosed asthma cases and 30.5% among patients with current wheezing. Skin test positivity was present in 38.7% of the children with a diagnosis of asthma or asthmatic bronchitis, 35.0% of current asthmatic patients, and 19.2% of patients with current wheezing. CONCLUSIONS Objective markers, in addition to the questionnaire-based prevalence figures, need to be used in epidemiologic surveys for asthma, especially in countries with inadequate health care facilities or problems with interpretation of the wheeze concept.

Levels of IgE in the serum of patients with coronary arterial disease

Because previous studies have shown that mast cells can be activated by IgE-mediated mechanisms to release potent mediators which affect coronary blood flow, we measured serum IgE levels in 156 patients with coronary arterial disease and in 53 healthy controls (27 men, 26 women, mean 54 years). Patients were classified into 3 groups according to well established criteria as having stable angina pectoris (28 men, 15 women, mean 58 years), unstable angina pectoris (37 men, 15 women, mean 57 years), and acute myocardial infarction (52 men, 9 women, mean 58 years). In every subject, serum IgE measurement, eosinophil count, and stool examination for parasites were performed. Every subject was interviewed concerning history of allergy, smoking habits and the other risk factors for coronary arterial disease. In a model including the factors that may affect the serum levels of IgE (namely, age, sex, cigarette smoking, parasites, and family and personal history of allergy), IgE levels were found to be significantly higher in the patients with unstable angina and acute myocardial infarction compared to the patients with stable angina pectoris and controls. These data indicate that IgE may play a role in the pathogenesis of unstable angina pectoris and acute myocardial infarction.

Prevalence of allergic diseases and influencing factors in primary-school children in the Ankara region of Turkey

We have studied the prevalence of atopic disease, by questionnaire, in 3024 primary-school children from three different socioeconomic levels in Ankara. Physical examinations were also performed on these children. The cumulative prevalence of asthma, allergic rhinitis, allergic conjunctivitis, and atopic eczema was 6.9%, 11.7%, 4.6%, and 2.6%, respectively. Allergic rhinitis was more common in children older than 10 years. Most of the symptoms of asthmatic patients began in the first 3 years of life. The cumulative prevalence of allergic diseases was 23.4%. This study has estimated the prevalence of allergic diseases, including asthma, allergic rhinitis, allergic conjunctivitis, and allergic dermatitis, in the Ankara region of Turkey.

Childhood asthma perception in Turkey under real-life environment (CAPTURE) study

Successful management of asthma requires good communication between patients and the healthcare team. The background and expectations of a patient inevitably influence the success of any partnership. A questionnaire‐based survey was performed to obtain data on the perception of the impact of asthma in daily life among children (age‐range 6–14 years) and adolescents (age‐range 15–20 years). A total of 756 patients (384 children, 372 adolescents) were randomly selected from 11 Turkish cities and interviewed face‐to‐face. Of the total study population, 71.3% received regular follow‐up and 75.9% currently took asthma medication. Almost 50% reported that asthma affected their lives significantly. Even though half of the patients had symptoms at least once a week, one‐third were not receiving regular prophylactic treatment. Exercise produced asthma symptoms in 45.5% of children and 27.4% of adolescents. The finding that asthma continues to be a major health problem clearly indicates an urgent need for further management programs in Turkey.

Comparison of four different measures of bronchial responsiveness in asthmatic children

Although several tests are available to assess the presence and severity of bronchial hyperresponsiveness (BHR), there is no agreement on the most appropriate stimulus. The most commonly used stimuli are methacholine, histamine, and exercise. Daily peak expiratory flow (PEF) variation has been reported to correlate with the severity of BHR, and in recent years this has been widely used because of its noninvasiveness and ease of performance. This study was carried out to determine the relationship among these four commonly used measures of bronchial responsiveness in asthmatic children. For this purpose, 12 asthmatic children of varying disease severity were recruited. Subjects underwent three challenges on 3 separate days in 1 week. During the week preceding the challenges (methacholine, histamine, and exercise), patients recorded PEF three times a day. All patients had PC20 less than 8 mg/ml with methacholine and histamine. Patients with PC20 greater than 3.5 mg/ml for both methacholine or histamine had negative exercise challenges. The strongest correlation was between histamine and methacholine (r=0.95). Exercise‐induced bronchospasm had substantial and significant correlation with the other three measures. No significant correlation was observed between PEF variability and histamine or methacholine. The varying degrees of relationships among the four commonly used measures suggests that each method yields information on different but related phenomena. More than one measure may be required to detect the different aspects of asthmatic bronchial responsiveness.