Maternal allergy as a potential source of variability of exhaled nitric oxide in children non-sensitized to common domestic allergens.

The goal of the study is to evaluate the importance of maternal atopy as a potential biological source of variability of exhaled FeNO values in healthy children who were non-asthmatic and non-sensitized to common domestic allergens. The study sample consisted of 61 seven-year old children. Fractional exhaled nitric oxide (FeNO) has been measured by NObreath (Bedfont portable device). Children with reported maternal atopy had significantly higher mean FeNO values (geometric mean =10.7 ppb; 95%CI: 6.7-17.1 ppb) than those who denied it (geometric mean =5.2 ppb 95%CI: 3.9-6.9 ppb) (p=0.010). Neither the correlation between FeNO values and gender, respiratory and eczema symptoms, nor ETS exposure in the prenatal and postnatal period or body mass of children were significant. We also found no significant association of FeNO values with the amount of common domestic allergens measured in the households. The results of the ROC analysis suggested 11 ppb as the cut-off point for FeNO to distinguish groups of healthy children with and without maternal atopy. In conclusion, our study provided some evidence suggesting that maternal atopy may affect FeNO level in children independently of asthma and sensitization status to common domestic allergens. The data should be considered in the interpretation of FeNO levels in clinical practice and setting up FeNO screening criteria for identification of eosinophilic airway inflammation.

Wheezing and asthma may be enhanced by broad spectrum antibiotics used in early childhood. Concept and results of a pharmacoepidemiology study.

UNLABELLED: One of the mechanisms supposed to explain the increasing prevalence of asthma, among children in particular, is the use of antibiotics because they may modify natural microbial exposure and development of the immune system in early childhood. The aim of this study is to investigate the association between the use of various classes of antibiotics (penicillin, cephalosporin and macrolide derivatives) in early childhood and the medical diagnosis of asthma or wheezing reported by mothers over the follow-up after adjustment for potential confounders and respiratory infections. In a population-based sample of 5-year-olds, a part of the ongoing birth cohort study, the standardized interviews on health outcomes, potential confounders (child's gender, maternal atopy, parity, prenatal and postnatal environmental tobacco smoke) and the use of antibiotics were gathered from mothers of 310 children. While the overall use of antibiotics during the early childhood was insignificantly associated with asthma (adjusted OR = 1.65, 95%CI: 0.93 - 2.93), the risk estimates were significant both for macrolide antibiotics (adjusted OR=2.14, 95%CI: 1.16-3.95) and cephalosporins (OR=1.98, 95%CI: 1.14-3.37). The significant excess in IRR (incident risk ratio) of wheezing episodes was related only to the use of macrolide antibiotics (adjusted IRR=1.91, 95%CI: 1.12-3.27). The use of other classes of antibiotics was found not to be associated with the medical diagnosis of asthma or wheezing episodes recorded in the study period. CONCLUSION: as early childhood use of broad spectrum antibiotics is associated with an increased risk of developing asthma in 5-year-olds, it may be hypothesized that the antibiotic- related suppression of allergic inflammatory responses in the course of treatment may later lead to greater than before atopic immune response in Th2 children or an impairment of Th1 immune responses in early childhood.

Impact of excessive gestational weight gain in non-smoking mothers on body fatness in infancy and early childhood. Prospective prebirth cohort study in Cracow.

Gestational weight gain (GWG) is important for health policy as it may be associated with overweight epidemics in childhood and adolescence. The purpose of the study was to perform the risk assessment of joint effects of the excessive GWG and the pregravid maternal BMI on overweight in infancy and childhood. The observations were collected in the ongoing prospective birth cohort study of 482 non-smoking mothers and their newborns in Cracow inner city area. At 5 years of age the subsample of 312 infants were reexamined in order to assess their nutritional status. Body fatness was assessed by means of the weight/length ratio (WLR) in neonates and weight/height ratio (WHR) in 5-year-olds since they showed the strongest correlation with subcutaneous fat mass of young children. In the statistical analysis the binary regression models were applied to identify predictors of overweight. The excessive GWG (>18 kg) increased more than twofold the adjusted relative risk (RR) of neonatal fatness (R=2.7; 95% CI 2.0-3.7) and was also a significant independent risk factor for postnatal body fatness at 5 years of age (RR=2.0; 95% CI: 1.3-3.3). The results confirmed earlier findings that pregravid overweight increased not only the relative risk of neonatal fatness (RR=2.9; 95% CI: 2.2-3.9) but also overweight in early childhood (RR=2.7; 95% CI: 1.7-4.4). The conclusion is that excessive GWG may be a risk factor for overweight in early childhood and should be a focus of public health policy.

Cohort study on low physical activity level and recurrent acute respiratory infections in schoolchildren.

The purpose of the study was to explain childhood respiratory infections in terms of life-style factors like being overweight or physically inactive. In the course of the cohort study we gathered data on respiratory health of 1028 preadolescent children in Krakow. Recurrent acute respiratory infections (RARI) in children have been defined as frequent spells (10 or more infections) over the two-year follow-up. In scoring the physical activity level, the data on regularly exercising sport and the number of hours spent daily TV watching or doing homework have been used. Excessive weight was based on the BMI index. In the total sample, the RR estimates of RARI adjusted to BMI and other potential confounders were consistently higher in children with low physical exercise (RR = 2.96; 95% CI: 1.78-4.93) or with moderate exercise (RR = 1.87; 95% CI: 1.33-2.65). Than among the highly active group. In the subgroups of allergic and non-allergic or overweight and not-overweight children the adjusted RR estimates were consistent with those found in the total sample. We concluded that physical exercise in preadolescent children may lessen the risk of acute respiratory infections and that the low physical activity is an independent predictor of increased risk of RARI besides excessive weight and other potential risk factors.

Transient or persistent asthma-like symptoms and lung growth over 2-year follow-up in pre-adolescent children.

BACKGROUND: The main purpose of this study was to assess the effect of transient and continued asthma-like symptoms on lung function growth in preadolescent children. METHODS: The follow-up respiratory health survey has been conducted on the sample of 1,129 children aged 9 years over 2 years follow-up. The basic health end-points were the occurrence of asthma-like symptoms and slower lung function growth (SLFG), which was defined as the lung function gain over 2 years within the lowest quintile of the distribution of a given spirometric test. RESULTS: Adjusted odds ratios (OR) for SLFG [forced vital capacity (FVC)] were significantly higher only in the children having continued symptoms [OR = 3.39: 95% confidence interval (CI) = 1.39-8.27]. There was a consistent trend of adjusted ORs for SLFG [forced expiratory volume (FEV,) with the category of symptoms, where OR was 2.00 (95% Cl = 1.17-3.42) in children with transient symptoms: while 4.10 (95% Cl = 1.71-9.86) in children who had persistent symptoms. The corresponding ORs for SLFG [maximal mid-expiratory flow (FEF25_75c)] were 2.27 (95% Cl = 1.37-3.76); and 5.43 (95% Cl = 2.38-12.40). DISCUSSION: The association between asthma-like symptoms and lung function gain in preadolescent children confirmed the clinical significance of the symptoms in question. The observed slower lung function gain in preadolescence may have implications for the development of chronic lung disease later in adulthood.

[Validity study on the certification and coding of underlying causes of death for the mortality statistic]. / Trafnosc wyboru przez lekarza wyjsciowej przyczyny zgonu i kodowania danych z kart zgonów.

The study was designed to assess the differences in the quality of certification and coding practices of underlying causes of death, which the mortality statistics is based upon. The mains focus of the study was the problem of proper selection of the underlying cause of death in various diseases. In the analysis the potential impact of medical experience of the physicians and the hospitalization of patients before the death have been taken in consideration. There were 479 death certificates chosen randomly out of all certificates filled in by 240 medical doctors in 1999 in Krakow. For each death certificate the available clinical case histories for deceased persons have been collected in order that a team of medical experts could formulate their independent opinion about the underlying cause of death. From comparisons of the underlying causes of death from the death certificates with those of experts, the indices of agreement have been calculated. The best overall agreement has been found for the neoplasmatic diseases (83.1%) and the lowest for the chest diseases (30.7%). For cardiovascular diseases the overall agreement was 65.5%, however in coronary heart disease it reached 74.0% and in cerebrovascular diseases 78.7%. Generally, the better agreement has been demonstrated if the additional information about the coexistent diseases or direct causes of the death has been mentioned in the death certificates as well. The longer period of hospitalization of subjects before death was related significantly with the higher agreement indices.

[Sensitization to common airborne allergens in school children with bronchial asthma]. / Uczulenie na alergeny wziewne u dzieci szkolnych z astma oskrzelowa.

The main purpose of the paper was to assess the prevalence of atopy in the population of preadolescent children in Krakow on the basis of allergic skin testing to airborne allergens and to look into the relationship between atopy and chronic asthma-like respiratory symptoms. The field study was carried out in 1998 among 311 children being the subgroup of the cohort of 1044 children included in the 3-year follow-up in Krakow. The health assessment accounted for the standardised interviews and skin prick testing to 11 common airborne allergens. In the total, the positive allergic reaction at least to only one allergen was found in 32.5% children, and it was more prevalent in boys than in girls (40.4% vs 28.1%). Allergy only to indoor allergens was present in 9.7% children, allergy only to outdoor allergens in 9.7%, and allergy both to outdoor and indoor allergens was confirmed in 13% persons. Most frequently, allergy was established to house mites: Dermatophagoides pter. (16.2%), Dermatophagoides farinae (12.0%) and to cat dander (11.4%). Asthma-like symptoms occurred in 11.0% of children and asthma diagnosed by physician in 7.8% of the sample under the study. The results of this study proved that the prevalence of asthma was about twice so high in boys than in girls. The risk of asthma-like symptoms and/or asthma diagnosed by physician increased significantly with the number of positive allergic tests to airborne allergens (OR = 1.30; 95% CI: 1.11-1.52) and atopy in mother (OR = 1.84; 95% CI: 1.03-3.37).

[Population based studies on the incidence of chronic respiratory symptoms and lung function in children from Krakow]. / Badania populacyjne nad wystepowaniem przewleklych objawów ze strony ukladu oddechowego i czynnoscia pluc u dzieci w Krakowie.

The epidemiologic study has been carried out in the sample of 1048 schoolchildren at the age of 11 years in order to assess the impact of various chronic respiratory symptoms on lung function. The symptoms included chronic dry cough, chronic phlegm, attacks of cough at nights, breathlessness, wheezing independent from respiratory infections or colds, attacks of wheezing at nights, and attacks of dyspnea with wheezing. Lung function was measured by the following spirometric indices: FEV1/FVC%, FEV1, FEF25-75% and PEFR. Multiple regression analysis showed strong statistical inverse relationship between FEV1/FVC% and FEF25-75% and attacks of wheezing at night and attacks of dyspnea with wheezing or asthma diagnosed by physician. The separate analysis performed in the subsample of children without asthma and asthmatic symptoms (attacks of wheezing at night and attacks of dyspnea with wheezing) found out that only chronic dry cough was related significantly to the lower values of FEV1 and PEFR in the children.

The adverse effect of low levels of ambient air pollutants on lung function growth in preadolescent children.

The main purpose of our study was to assess the effect of low concentrations of ambient air pollution on lung function growth in preadolescent children. We accounted for height velocity over the follow-up period and also for other possible confounders such as baseline anthropometric and physiologic characteristics of children. In addition to outdoor air pollution, we considered the possible effects of social class and exposure to indoor pollutants such as gas stove fumes or environmental tobacco smoke. The cohort prospective study was carried out in 1,001 preadolescent children from two areas of Krakow, Poland, that differed in ambient air pollutants. In the city center (higher pollution area), the mean annual level [+/- standard deviation (SD)] of suspended particulate matter was 52.6 +/- 53.98 microg/m(3) and that of SO(2) was 43.87 +/- 32.69 microg/m(3); the corresponding values in the control area were 33.23 +/- 35.99 microg/m(3) and 31.77 +/- 21.93 microg/m(3). Mean lung function growth rate adjusted to height velocity and lung function level at the study entry was significantly lower in boys and girls living in the more polluted areas. Also, the proportion of children with the slower lung function growth (SLFG) was higher in the children from the more polluted area of the city. The analysis completed in the group of children after the exclusion of asthmatic subjects and those with asthmalike symptoms confirmed that, in boys, odds ratios (ORs) for SLFG [forced vital capacity (FVC)] and air pollution after adjustment to baseline FVC, height, and growth rate was significant [OR = 2.15; 95% confidence interval (CI), 1.25-3. 69)]. The analysis also confirmed that for SLFG(FEV(1)) the OR was 1. 90 (CI, 1.12-3.25). The corresponding OR values in girls were insignificant (OR = 1.50; CI, 0.84-2.68 and OR = 1.39; CI, 0.78-2. 44). The association between ambient pollutants and poorer gain of pulmonary volumes in children living in more polluted areas suggests that air pollution in the residence area may be a part of the causal chain of reactions leading to retardation in pulmonary function growth during the preadolescent years.

Exposure misclassification error in studies on prenatal effects of tobacco smoking in pregnancy and the birth weight of children.

Adverse effects of maternal smoking have been mostly identified through epidemiologic investigations that have used questionnaires to assess active and passive smoking. However, unvalidated self-reports of cigarette smoking may bias true estimates of relative risk of smoking-related health outcomes. This report is based on two separate investigations. First, within a molecular epidemiologic study of the relationship between environmental exposures (smoking, air pollution, diet) and developmental impairment, we have compared self-reported tobacco smoke exposure during pregnancy to plasma cotinine measurements in mothers. One hundred and fifty-eight patients from obstetrical wards in Cracow and in Limanowa, Poland were included in the parent study. Biochemically-identified smokers were defined as persons with plasma cotinine levels greater than 25 ng/mL. The data showed that exposure classification based on self-reported smoking status compared with cotinine values was of low sensitivity (52%) but of high specificity (98%). We assessed the effect of this exposure classification error on the association between low birth weight (LBW) and smoking in pregnancy using data from a related epidemiologic study of children's health in Cracow involving 1115 subjects. The odds ratio (OR) estimates for smoking and LBW after adjustment for exposure misclassification error were significantly higher than before adjustment (crude OR = 2.9, corrected OR = 5.1). The estimated attributable fraction (AF(pop)) based on the crude OR amounted to 22%; however, after adjustment it reached 50%. The corresponding values for the attributable fraction in the exposed group (AF(exp)) were 66% and 80%. These results illustrate the value of validating questionnaire responses on smoking during pregnancy against reliable biologic markers.

Effects of air quality on chronic respiratory symptoms adjusted for allergy among preadolescent children.

The aim of this study was to assess the respiratory effects of outdoor air pollution after correcting for allergy and indoor air quality. The respiratory health survey targeted 1,129 schoolchildren, 9 yrs of age, attending schools in Krakow located in city areas differing in outdoor air pollution levels. Chronic phlegm as a unique symptom was related neither to allergy nor to indoor variables, but was associated with the outdoor air pollution level (odds ratio (OR): 4.2; 95% confidence interval (CI): 1.1-16.9). The same relationship has been confirmed for the self-reported local sources of industrial air pollution in the area of residence (OR: 4.2; 95% CI: 1.5-11.7). Hay fever appeared to be related to outdoor air pollution level (OR: 1.43; 95% CI: 1.1-2.0) and self-reported heavy traffic (OR: 1.3; 95% CI: 1.0-1.7). In the total sample, wheezing was connected exclusively to allergy and parental atopy, while attacks of dyspnoea with wheezing and asthma diagnosed by physician only were associated with allergy. Since the effect of outdoor pollutants on chronic cough and wheezing (odds ratio: 1.85; 95% confidence interval: 1.03-3.33) was only shown to be significant in the subsample of children without allergy and parental atopy, it may be postulated that either allergy is predisposing to respiratory reactions, or outdoor air pollution is coinvolved in an allergization process of the preadolescent children. Consequently, allergy should be considered as an important confound in epidemiological studies on the respiratory effects of air pollution.

Separate and combined effects of the outdoor and indoor air quality on chronic respiratory symptoms adjusted for allergy among preadolescent children.

The purpose of the study was (a) to assess whether the respiratory effects of outdoor air pollutants may be replicated after correcting for indoor air quality (environmental tobacco smoke, home heating and damp or mold houses), (b) to evaluate whether the extent of the allergic status of children modifies the respiratory health due to air pollution, and (c) to determine whether the higher prevalence of respiratory symptoms in more polluted areas of the city may be explained by excess in allergy. The survey targeted 1,129 school children, nine years of age, attending schools in Cracow, located in the areas with different levels of the outdoor air pollution. Based on the measurements obtained from the air pollution monitoring stations and the information provided by parents on the sources of local emission of air pollutants, four categories of air pollution areas have been defined. Chronic phlegm as a single symptom was unrelated to allergy but associated with the outdoor air pollution score. The prevalence odds ratio (OR) for this symptom between the contrasting areas of outdoor air pollution, i.e. very high pollution versus very low, was 5.85 (95% CI: 1.05-32.6). Except for chronic phlegm, the outdoor air pollution score was associated only with hay fever when adjusted for indoor characteristics and allergy. After adjustment for air pollution and allergy, the presence of molds or dampness in the house was significantly related to hay fever (OR = 2.1, 95% CI: 1.5-3.0), wheezing (OR = 1.6, 95% CI: 1.1-2.5), and difficulty in breathing (OR = 2.0, 95% CI: 1.2-3.3). In terms of attributable fraction (AF(pop)), the effect of outdoor air pollution on the occurrence of allergy in children was significant (AF(pop) = 22.3%). The impact of allergy on the occurrence of respiratory symptoms (two or more respiratory symptoms) was stronger (AF(pop) = 52.1%) than that of the outdoor air pollution level (AF(pop) = 21.6%) or that of molds/dampness at home (AF(pop) = 14.1%).

Predisposition to acute respiratory infections among overweight preadolescent children: an epidemiologic study in Poland.

This cross-sectional field health survey has as its subjects 1129 preadolescent children resident in Krakow. Trained health visitors interviewed the mothers at the children's schools or at the parents' homes in order to gather standardized information regarding the families' social background and the families' and children's respiratory health and episodes of respiratory infections. Predisposition to respiratory infections in children has been defined as frequent spells (3 or more) of acute respiratory infections experienced by a given child over the 12 months preceding the interview. Clinical examination of children consisted of anthropometric measurements and spirometric testing. Anthropometric measurements (weight and height) were used for calculation of the body mass index (kg/m2). A child whose BMI was 20 or higher was defined as overweight (90th percentile). Susceptibility to acute respiratory infections was related significantly to body mass index. The children with BMI > or = 20 experienced twice as high a risk for acute respiratory infections than children with low BMI (OR = 2.02, 95% CI: 1.13-3.59). Out of other potential factors possibly involved in the occurrence of respiratory infections only the presence of chronic respiratory symptoms (OR = 2.43, 95% CI: 1.64-3.59), allergy (OR = 1.89, 95% CI: 1.34-2.66), and Environmental Tobacco Smoke (OR = 1.54; 95% CI: 1.05-2.25) increased the susceptibility of children to acute respiratory infections. Central heating in the household was shown to have a protective effect (OR = 0.65, 95% CI: 0.43-1.00) when compared with children from households where coal or gas was used for home heating.

PIP: Factors predisposing to recurrent acute respiratory infection were investigated in a cross-sectional field study of 1129 schoolchildren 9 years of age from Krakow, Poland. Predisposition to respiratory infections was defined as 3 or more spells in the 12 months preceding the 1995 study. Susceptibility to acute respiratory infections was significantly associated with body mass index. Overweight children (body mass index of 20 or higher) had twice the risk of infection than children with a lower body mass index (odds ratio (OR), 2.02; 95% confidence interval (CI), 1.13-3.59). Other significant risk factors were the presence of chronic respiratory symptoms (OR, 2.43; 95% CI, 1.64-3.59), allergy (OR, 1.89; 95% CI, 1.34-2.66), and environmental tobacco smoke (OR, 1.54; 95% CI, 1.05-2.25). Central heating in the household exerted a protective effect compared to households where coal or gas was used (OR, 0.65; 95% CI, 0.43-1.00). The strong effect of obesity on acute respiratory infection risk was independent from other host and environmental factors. Findings of a strong correlation in these children of body weight with the lung function tests FVC and FEV further support the view that the predictive spirometric formulas for preadolescents should consider weight as an important independent predictor of lung function.

[Occurrence of allergy in school-age children and their parents in relation to atmospheric air pollution. Prospective study in Cracow]. / Wystepowanie alergii u dzieci w wieku szkolnym oraz wsród ich rodziców w powiazaniu z zanieczyszczeniami powietrza atmosferycznego. Badanie prospektywne w Krakowie.

The main purpose of the study was to estimate unknown frequency of allergy in children and in their parents in Krakow and to check the hypothesis that allergy may be related to environmental urban factors. The three-year prospective study was carried out in two areas of the city with contrast air pollution levels and covered 1129 children. The occurrence of allergy in children was based on information from the parents that the disease had been diagnosed by a physician. Data on atopy in parents were supported by the information from parents that atopy-related diseases had been diagnosed by a physician. The prevalence of allergy in boys was much higher than in girls (28.1% vs 17.6%) but the inverse was observed in parents--more frequently it occurred in mothers (17.8%) than in fathers (12.9%). Among parents the prevalence and incidence of atopy was not related to air pollution levels in the place of residence. However, the prevalence odds ratio for allergy in children after accounting for potential confounders (parental atopy, environmental tobacco smoke, social class and household characteristics), was significantly higher among those who lived in streets with higher traffic (OR = 1.37, 95% CI: 1.0-1.9) or in vicinity of local industrial emission sources (OR = 1.70, 95% CI: 1.2-2.4) but it was not related to communal air pollutants (SO2/particulate matter). The similar analysis performed for new cases of allergy in children diagnosed over the three year period confirmed the conclusions gained from the prevalence data.

[Chronic respiratory symptoms and lung function in children related to air pollution in the residential areas]. / Przewlekle objawy ze strony ukladu oddechowego u dzieci oraz ich sprawnosc wentylacyjna pluc a zanieczyszczenia powietrza atmosferycznego w miejscu zamieszkania.

The main purpose of the paper was to answer the question whether the various respiratory symptoms are related to type of air pollution in the residential areas and to which extent the worse lung function in children could have been explained by the air pollutants. Cross-sectional field study has been carried out in 1048 children aged 11 years attending grammar schools in Krakow. The results of the study provided the evidence that the current level of communal air pollutants (SPM and SO2) is not related to an excessive risk of respiratory symptoms in children, provided it is not combined with other sources of air pollution such as heavy traffic or local low point industrial emission. The risk of obstructive ventilation disorders (FEV1/FVC% 85) was significantly higher in children from the residential areas with higher air pollution (RR = 1.71; 95% CI: 1.19-2.47).

[Allergy and lung function in school children]. / Wystepowanie alergii i sprawnosc wentylacyjna pluc w populacji dzieci szkolnych.

In order to measure the effect of allergy on the lung function among schoolchildren a cross-sectional study has been performed in 1048 children of 10-11 year age who attended the grammar schools in Krakow. The lung function was assessed by the following spirometric indices: VC, FVC, FEV0.5, FEV0.75, FEV1, FEF25-75%, FEF0.2-1.2, PEFR while the data on allergy diagnosed clinically by physician was obtained by self-administered questionnaires from the parents of children. For those of the children who had the allergic skin test performed a search in medical records has been carried out. The frequency of allergy diagnosed clinically (without skin tests) was higher in boys (22.3%) than in girls (18.4%) and the same differences have been found for allergy confirmed by skin testing (15.7% vs. 9.3%). Except for VC and FVC, all adjusted mean values of spirometric indices were significantly lower in allergic than in non-allergic group of children. Regression coefficient of spirometric indices were related inversely with the presence of allergy. The greatest effects of allergy (without skin tests) have been observed on PEFR (-180 ml), FEF0.2-1.2 (-171 ml), FEF25-75% (-121 ml) and for FEV0.75 (-69 ml) and FEV1 (-68 ml). The smallest differences were found for VC and FVC. The additional series of analysis done in the subgroup of children without attacks of dyspnea with wheezing or wheezing independent from colds or respiratory infections confirmed the results obtained in the total study sample. The prevalence of obstructive syndrome, defined as FEV1/FVC < 80%, was 4.5% in the total sample, however, only 2.9% in non-allergic children, 7.2% in children in whom allergy was diagnosed by physicians and 8.5% among those children among whom allergy was diagnosed by allergic skin tests.

Maternal smoking during pregnancy and postnatal exposure to environmental tobacco smoke as predisposition factors to acute respiratory infections.

This study compared susceptibility to respiratory morbidity in a cohort of 9-year-old children exposed congenitally and postnatally to environmental tobacco smoke (ETS) to susceptibility in a cohort of unexposed children. The epidemiologic study included 1129 children: 594 boys and 535 girls attending the second grade of grammar schools in Kraków, Poland. We found strong evidence that children exposed to ETS in their homes were more susceptible to acute respiratory tract illnesses than unexposed children. A dose-response relationship between degree of exposure [for lower ETS exposure, odds ratio (OR) = 1.32; for higher ETS exposure, OR = 1.74] supports a causal explanation for the association observed. The significant trend of increased risk of respiratory infections due to ETS level in nonatopic children whose mothers did not smoke cigarettes during pregnancy suggests a direct effect of ETS exposure on the child's respiratory health. ETS combined with allergy nearly tripled the risk of acute respiratory tract illness (OR = 3.39; 95% CI, 1.93-5.93), and maternal smoking during pregnancy had a modifying effect on the risk of respiratory illnesses due to ETS after accounting for atopy. The stronger effect of ETS in atopic children and in those whose mothers smoked during pregnancy may be result of biologic interaction of endogenous and environmental factors. The results of this study are of relevance to public health policy, as children with higher risk of respiratory infections may be more susceptible to environmental hazards later in adolescence or in adulthood. Respiratory infections also increase demands for medical interventions in terms of outpatient services and hospital administrations. In addition, respiratory illnesses cause missed school days, and caring for a sick child may lead to absenteeism from work.

[Respiratory system reactions in children with allergies exposed to air pollution at home. Epidemiologic studies in Cracow]. / Reakcje ukladu oddechowego u dzieci alergicznych narazonych na zanieczyszczenia powietrza w miejscu zamieszkania. Badania epidemiologiczne w Krakowie.

The purpose of the paper was to check the hypothesis whether the domestic air quality together with level of outdoor air pollution increases the risk of allergy and whether allergy determines the occurrence of respiratory symptoms. The results of the study have shown that chronic cough was related mainly to allergy, however, chronic phlegm was linked with air quality. Wheezing independent from respiratory infections was associated in the strongest way with allergy (RR = 7.7; 4.7-12.7) and much weaker related to air quality score (RR = 1.3; 1.1-1.5). The occurrence of attacks of breathlessness was confirmed only in allergic children. Allergic rhinitis, similarly to wheezing, was related stronger to allergy (RR = 3.3; 2.5-4.4) than to air quality score (RR = 1; 1.0-1.2). Pulmonary volumes (FVC, FEV1) were not associated with air quality score, but the lower indices of FEV1/FVC and FEF25 - 75% were observed in those who were exposed to poor air quality. The results are in favor of the hypothesis, that air pollutants bring about spasm of smaller airways and it is independent from respiratory symptoms.

[Atmospheric air pollution as a factor potentiating the risk of asthma in school children. Epidemiologic studies in Krakow]. / Zanieczyszczenia powietrza atmosferycznego jako czynnik potegujacy ryzyko zachorowania na astme u dzieci szkolnych. Badania epidemiologiczne w krakowie.

The purpose of this study was to assess the prevalence of asthma in schoolchildren in relation to residency in areas with higher urban air pollution in Krakow. The material consisted of 1129 children aged 9 years among whom health survey based on standardized interviews with parents, together with anthropometry and spirometry has been carried out in 1995. In the asthmatic children allergy diagnosed by doctor was 4 times more prevalent (83.3% vs 20.2%) and asthma or allergy was twofold more prevalent in their biologic parents (42.6% vs 29.3%). The children with asthma resided more frequently in the city areas with the higher air pollution level (62.5% vs 46.2%). Mean spirometric values of FVC, FEV1, FEF25-75% I PEFR did not differ across the groups, however, FEV1/FVC% was significantly higher in nonasthmatic than in asthmatic groups (corresponding values in boys 90.9% vs 88.7%, in girls 92.7% vs 89.8%). After accounting for potential confounders (child's gender, education level of parents, environmental tobacco smoke, cigarette smoking of mothers in pregnancy and household standard) it was estimated from the multiple logistic regression that the separate effect of air pollution category was relatively small (OR = 2.27; 95%, CI = 1.11-3.93) in comparison with that of allergy (20.5; 95% CI = 9.40-44.7), however, combined effect of both risk factors on the occurrence of asthma in children was multiplicative.

[Classification exposure error in studies on tobacco smoke in pregnancy and birth weight of newborns]. / Blad klasyfikacyjny ekspozycji w badaniach wplywu palenia tytoniu przez kobiety w ciazy na mase urodzeniowa noworodka.

The purpose of the paper was to assess the validity of the self-reported tobacco smoke exposure in pregnancy against plasma cotinine measurements. A total of 158 patients from obstetrical wards was included in the cotinine study. Biochemical smokers were defined as persons with serum cotinine levels greater than 25 ng/ml. The data showed that the exposure classification based on self-reported smoking habit status confronted with cotinine values was of low sensitivity (52%) but of high specificity (98%). To assess the effect of this exposure classification error on the association between the low birth weight (LBW) and smoking in pregnancy, the data from the recent survey in Cracow children have been used. It was shown that RR estimates for smoking and LBW after adjustment for misclassification error were substantially higher than that not adjusted (crude RR = 2.9, corrected RR = 5.1). Due to the exposure misclassification error the attributable fraction (AF) of LBW due to mother's smoking was heavily biased as well. Estimated attributable fraction AF(pop) based on crude RR amounted to 22%, however, after adjustment reached 50%. The corresponding values for attributable fraction in exposed group AF(exp) were 66% and 80%.