[Show abstract][Hide abstract] ABSTRACT: Background: Several studies have suggested an association between the increasing prevalence of allergic diseases and dietary factors. Objective: To prospectively explore the association between changes in body mass index (BMI) and symptoms of asthma, rhinitis, rhinoconjunctivitis, and atopic dermatitis to find out whether an increase in BMI increases the risk of developing atopic diseases in adolescence. Methods: Comprehensive questionnaires and anthropometric measurements were applied in a random subsample of the International Study of Asthma and Allergies in Childhood phase II (1995-1996, 9 to 11 years of age) in Germany. Of these participants, 1,794 could be followed up in 2002 to 2003 in the Study on Occupational Allergy Risks (16 to 18 years of age). The associations between changes of BMI from baseline to follow-up and incident and persistent respiratory diseases and atopic dermatitis were assessed. Results: In logistic regression analyses, weight change in either direction was not statistically significantly associated with the incidence or persistence of any of the diseases of interest except for rhinitis. An increase in BMI was linked to an increased risk of incident rhinitis (odds ratio 1.9, 95% confidence interval 1.2-2.9). Conclusion: These results indicate a nonsignificant trend between increased body weight and risk of atopic diseases. Aside from limitations owing to a small subgroup of obese participants and questionnaire-based asthma diagnosis, reasons might be related to an interaction between BMI and hormonal influences, age, and duration and severity of overweight. The results underline that BMI does not necessarily play a decisive role in the course of atopic diseases in all populations.
Annals of allergy, asthma & immunology: official publication of the American College of Allergy, Asthma, & Immunology 08/2014; 113(4). DOI:10.1016/j.anai.2014.07.011 · 2.60 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND: Certain foods may increase or decrease the risk of developing asthma, rhinoconjunctivitis and eczema. We explored the impact of the intake of types of food on these diseases in Phase Three of the International Study of Asthma and Allergies in Childhood. METHODS: Written questionnaires on the symptom prevalence of asthma, rhinoconjunctivitis and eczema and types and frequency of food intake over the past 12 months were completed by 13-14-year-old adolescents and by the parents/guardians of 6-7-year-old children. Prevalence ORs were estimated using logistic regression, adjusting for confounders, and using a random (mixed) effects model. RESULTS: For adolescents and children, a potential protective effect on severe asthma was associated with consumption of fruit ≥3 times per week (OR 0.89, 95% CI 0.82 to 0.97; OR 0.86, 95% CI 0.76 to 0.97, respectively). An increased risk of severe asthma in adolescents and children was associated with the consumption of fast food ≥3 times per week (OR 1.39, 95% CI 1.30 to 1.49; OR 1.27, 95% CI 1.13 to 1.42, respectively), as well as an increased risk of severe rhinoconjunctivitis and severe eczema. Similar patterns for both ages were observed for regional analyses, and were consistent with gender and affluence categories and with current symptoms of all three conditions. CONCLUSIONS: If the association between fast foods and the symptom prevalence of asthma, rhinoconjunctivitis and eczema is causal, then the findings have major public health significance owing to the rising consumption of fast foods globally.
[Show abstract][Hide abstract] ABSTRACT: Associations between exposure to cats and dogs and respiratory and allergic outcomes in children have been reported in affluent countries, but little is known about such associations in less-affluent countries.
The International Study of Asthma and Allergies in Childhood, phase 3 was carried out in children aged 6-7 years and adolescents aged 13-14 years across the world. Questions about cats and dogs in the home were included in an additional questionnaire. Using logistic regression, we investigated the association between such exposures and symptoms of asthma, rhinoconjunctivitis, and eczema. Adjustments were made for sex, region of the world, language, gross national income per capita, and 10 other covariates.
Among children (6-7 years of age), cat exposure in the first year of life was associated with current symptoms of asthma, wheeze, rhinoconjunctivitis, and eczema, especially in less-affluent countries. Among adolescents (13-14 years of age), we found a positive association between exposure to cats or dogs and symptom prevalence in more-affluent and less-affluent countries. The global multivariate odds ratios for children with complete covariate data were 1.17 (95% confidence interval = 1.08-1.29) for current symptoms of asthma, 1.13 (1.05-1.23) for rhinoconjunctivitis, and 1.38 (1.26-1.52) for eczema. Smaller odds ratios were found for exposure to only dogs. Exposure to only cats was associated with eczema.
Early-life exposure to cats is a risk factor for symptoms of asthma, rhinoconjunctivitis, and eczema in 6- to 7-year-old children, especially in less-affluent countries. Current exposure to cats and dogs combined, and only to dogs, is a risk factor for symptom reporting by 13- to 14-year-old adolescents worldwide.
[Show abstract][Hide abstract] ABSTRACT: Associations between early life exposure to farm animals and respiratory symptoms and allergy in children have been reported in developed countries, but little is known about such associations in developing countries.
To study the association between early life exposure to farm animals and symptoms of asthma, rhinoconjunctivitis and eczema in a worldwide study.
Phase Three of the International Study of Asthma and Allergies in Childhood (ISAAC) was carried out in 6- to 7-year-old children in urban populations across the world. Questions about early life exposure to farm animals (at least once/week) were included in an additional questionnaire. The association between such exposures and symptoms of asthma, rhinoconjunctivitis and eczema was investigated with logistic regression. Adjustments were made for gender, region of the world, language, gross national income and 10 other subject-specific covariates.
A positive association was found between early exposure to farm animals and the prevalence of symptoms of asthma, rhinoconjunctivitis and eczema, especially in non-affluent countries. In these countries, odds ratios (ORs) for 'current wheeze', 'farm animal exposure in the first year of life' and 'farm animal exposure in pregnancy' were 1.27 [95% confidence interval (CI) 1.12-1.44] and 1.38 (95% CI 1.21-1.58), respectively. The corresponding ORs for affluent countries were 0.96 (95% CI 0.86-1.08) and 0.95 (95% CI 0.84-1.08), respectively.
Exposure to farm animals during pregnancy and in the first year of life was associated with increased symptoms of asthma, rhinoconjunctivitis and eczema in 6- to 7-year-old children living in non-affluent but not in affluent countries.
International Journal of Epidemiology 01/2012; 41(3):753-61. DOI:10.1093/ije/dyr216 · 9.18 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background Many studies report that damp housing conditions are associated with respiratory
symptoms. Less is known about mechanisms and possible effect modifiers. Studies
of dampness in relation to allergic sensitization and eczema are scarce.
Objective We study the influence of damp housing conditions world-wide on symptoms
and objective outcomes.
Methods Cross-sectional studies of 8–12-year-old children in 20 countries used standardized
methodology from Phase Two of the International Study of Asthma and Allergies in
Childhood (ISAAC). Symptoms of asthma, rhinitis and eczema, plus residential exposure
to dampness and moulds, were ascertained by parental questionnaires (n = 46 051). Skin
examination, skin prick tests (n = 26 967) and hypertonic saline bronchial challenge
(n = 5713) were performed. In subsamples stratified by wheeze (n = 1175), dust was sampled
and analysed for house dust mite (HDM) allergens and endotoxin.
Results Current exposure to dampness was more common for wheezy children (pooled
odds ratio 1.58, 95% CI 1.40–1.79) and was associated with greater symptom severity
among wheezers, irrespective of atopy. A significant (P < 0.01) adverse effect of dampness
was also seen for cough and phlegm, rhinitis and reported eczema, but not for examined
eczema, nor bronchial hyperresponsiveness. HDM sensitization was more common in
damp homes (OR 1.16, 1.03–1.32). HDM-allergen levels were higher in damp homes and
were positively associated with HDM-sensitization, but not wheeze.
Conclusion A consistent association of dampness with respiratory and other symptoms
was found in both affluent and non-affluent countries, among both atopic and non-atopic
children. HDM exposure and sensitization may contribute, but the link seems to be related
principally to non-atopic mechanisms.
[Show abstract][Hide abstract] ABSTRACT: Intra-abdominal fat (IAF) is a valuable predictor of cardiovascular morbidity. However, neither reference values nor determinants are known in children.
IAF was assessed as sonographically measured intra-abdominal depth in 1,046 children [median age 7.6 years, interquartile range (IQR) 7.2-7.9; 54% boys] of the URMEL-ICE study.
The intraclass correlation coefficient for intraobserver agreement was 0.93. The median IAF showed a significant gender difference (boys: 54.6 mm, IQR 50.1-59.3, vs. girls: 51.7 mm, IQR 46.3-56.4; p < 0.001). Age- and gender-specific centiles were generated. IAF showed a positive correlation to systolic blood pressure [regression coefficient (β) = 0.24 mm Hg/mm; p < 0.001] and a negative correlation to HDL cholesterol (β = -0.01 mmol/l/mm; p < 0.001). IAF showed a positive association with increased paternal and maternal BMI (β = 0.28 mm/kg/m(2) and 0.27 mm/kg/m(2); p < 0.001), increased weight gain in the first 2 years of life (β = 3.04 mm; p < 0.001), and maternal smoking during pregnancy (β = 2.4 mm; p = 0.001). Increased parental education was negatively associated with IAF (maternal: β = -0.65 mm/degree; p = 0.004, and paternal: β = -0.61 mm/degree; p = 0.002).
Sonography was a reliable tool to estimate IAF. Factors influencing IAF included rapid infant weight gain, smoking during pregnancy, and parental BMI and education. Since IAF showed an association with cardiovascular risk factors even in prepubertal children, it might become a valuable predictor of cardiovascular vulnerability.
Hormone Research in Paediatrics 02/2011; 75(6):412-22. DOI:10.1159/000324110 · 1.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Centres in Phases I and III of the International Study of Asthma and Allergies in Childhood (ISAAC) programme used the method of consent (passive or active) required by local ethics committees.
Retrospectively, relationships between achieved response rates and method of consent for 13-14 and 6-7-year-olds (adolescents and children, respectively), were examined between phases and between English and non-English language centres.
Information was obtained for 113 of 115 centres for adolescents and 72/72 centres for children. Both age groups: most centres using passive consent achieved high response rates (>80% adolescents and >70% children). English language centres using active consent showed a larger decrease in response rate. Adolescents: seven centres changed from passive consent in Phase I to active consent in Phase III (median decrease of 13%), with five centres showing lower response rates (as low as 34%). Children: no centre changed consent method between phases. Centres using active consent had lower median response rates (lowest response rate 45%).
The requirement for active consent for population school-based questionnaire studies can impact negatively on response rates, particularly English language centres, thus adversely affecting the validity of the data. Ethics committees need to consider this issue carefully.
The International Journal of Tuberculosis and Lung Disease 08/2010; 14(8):1059-65. · 2.32 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Our goal was to quantify the short-term effects of particulate matter with aerodynamic diameter < or = 10 microm (PM10) and nitrogen dioxide (NO2) on respiratory health of asthmatic children from published panel studies, and to investigate the influence of study and population characteristics as effect modifiers.
After a systematic literature review, we extracted quantitative estimates of the association of PM10 and/or NO2 with respiratory symptoms and peak expiratory flow (PEF). Combined effect estimates for an increase of 10 microg/m3 were calculated by random effects meta-analysis for all studies and for different strata defined by study characteristics. The effect of publication bias was investigated with Egger's and Begg's tests and "trim-and-fill" analyses.
We identified 36 studies; 14 were part of the European Pollution Effects on Asthmatic Children in Europe (PEACE) study. Adverse associations of PM10 with asthma symptoms were statistically significant [odds ratio (OR) = 1.028; 95% confidence interval (CI), 1.006-1.051]. There were also associations, although not statistically significant, of PM10 with cough (OR = 1.012; 95% CI, 0.997-1.026) and on PEF (decrease of -0.082 L/min; 95% CI, -0.214 to 0.050). NO2 had statistically significant associations with asthma symptoms in the overall analysis considering all possible lags (OR = 1.031; 95% CI, 1.001-1.062), but not when we evaluated only the 0-1 lag. We found no publication bias, although it appeared when excluding the PEACE studies. When we applied the trim-and-fill method to the data set without the PEACE studies, the results were similar to the overall estimates from all studies. There was an indication for stronger PM10 associations for studies conducted in summer, outside of Europe, with longer lags, and in locations with higher NO2 concentrations.
We found clear evidence of effects of PM10 on the occurrence of asthma symptom episodes, and to a lesser extent on cough and PEF. The results for NO2 are more difficult to interpret because they depend on the lag times examined. There was an indication of effect modification by several study conditions.
Environmental Health Perspectives 04/2010; 118(4):449-57. DOI:10.1289/ehp.0900844 · 7.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: 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.
We compared 1105 wheezing and 3137 non-wheezing children aged 8-12 years from 17 study centres in 13 countries. Genotyping of 55 candidate single nucleotide polymorphisms (SNPs) in 14 genes was performed using the Sequenom System. Logistic regression models were fitted separately for each centre and each SNP. A combined per allele odds ratio and measures of heterogeneity between centres were derived by random effects meta-analysis.
Significant associations with wheeze in the past year were detected in only four genes (IL4R, TLR4, MS4A2, TLR9, P<0.05), with per allele odds ratios generally <1.3. Variants in IL4R and TLR4 were also related to allergen-specific IgE, while polymorphisms in FCER1B (MS4A2) and TLR9 were not. There were also highly significant associations (P<0.001) between SPINK5 variants and visible eczema (but not IgE levels) and between IL13 variants and total IgE. Heterogeneity of effects across centres was rare, despite differences in allele frequencies.
Despite the biological plausibility of IgE-related mechanisms in asthma, very few of the tested candidates showed evidence of association with both wheeze and increased IgE levels. We were unable to confirm associations of the positional candidates DPP10 and PHF11 with wheeze, although our study had ample power to detect the expected associations of IL13 variants with IgE and SPINK5 variants with eczema.
[Show abstract][Hide abstract] ABSTRACT: To explore the consequences of translating the International Study of Asthma and Allergies in Childhood (ISAAC) English core questionnaires on asthma, rhinitis and eczema symptoms into other languages.
ISAAC Phase III developed 49 language translations for adolescents and 42 for children following standardised guidelines, which included back-translating the questionnaires into English to check their accuracy and meaning. Language deviations were categorised and analysed with regard to influences on the reported symptom prevalence.
Category 1 deviations for one or more questions were found in seven translations (14%) for adolescents and in three translations (7%) for children. Data for these questions were excluded from the worldwide analyses. Category 2 deviations were identified in the publications, and Category 3 deviations were ignored.
Translations of questionnaires should follow a consistent protocol in global epidemiological research. Cultural norms need to be considered when evaluating back-translations into English, as disease labels are not available in every language, nor are they understood in the same way. Deviations from literal translations of English should be permitted if the intent of the original meaning is retained. A web-based tool of medical terminology would be useful for international research requiring the use of translations.
The International Journal of Tuberculosis and Lung Disease 10/2009; 13(9):1174-82. · 2.32 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To investigate the effect of ambient particulate matter on variation in childhood prevalence of asthma, rhinoconjunctivitis and eczema.
Prevalences of asthma, rhinoconjunctivitis and eczema obtained in Phase One of the International Study of Asthma and Allergies in Childhood (ISAAC) were matched with city-level estimates of residential PM(10) obtained from a World Bank model. Associations were investigated using binomial regression adjusting for GNP per capita and for clustering within country. For countries with more than one centre, a two stage meta-analysis was carried out. The results were compared with a meta-analysis of published multi-centre studies.
Annual concentrations of PM(10) at city level were obtained for 105 ISAAC centres in 51 countries. After controlling for GNP per capita, there was a weak negative association between PM(10) and various outcomes. For severe wheeze in 13-14-year-olds, the OR for a 10 microg/m(3) increase in PM(10) was 0.92 (95% CI 0.84 to 1.00). In 24 countries with more than one centre, most summary estimates for within-country associations were weakly positive. For severe wheeze in 13-14-year-olds, the summary OR for a 10 microg/m(3) increase in PM(10) was 1.01 (0.92 to 1.10). This result was close to a summary OR of 0.99 (0.91 to 1.06) obtained from published multi-centre studies.
Modelled estimates of particulate matter at city level are imprecise and incomplete estimates of personal exposure to ambient air pollutants. Nevertheless, our results together with those of previous multi-centre studies, suggest that urban background PM(10) has little or no association with the prevalence of childhood asthma, rhinoconjunctivitis or eczema either within or between countries.
Occupational and environmental medicine 10/2009; 67(5):293-300. DOI:10.1136/oem.2009.048785 · 3.27 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We investigated long-term changes in weight and skinfold thicknesses in German schoolchildren. In 2006, anthropometric measures were collected after a standardized protocol among 1079 children within the Ulm Research on Metabolism, Exercise and Lifestyle in children (URMEL-ICE) study. Data were compared with historical data (1975-1976). In URMEL-ICE, prevalence of overweight (IOTF criteria) was 16.5% (boys) and 17.3% (girls) and of obesity 3.5 and 3.6%, respectively. Compared with historical data the number of children above the 90th percentile(1975/76) increased statistically significantly for weight (approximately 150% both sexes), for subscapular (boys 288%, girls 206%) and triceps skinfold thickness (boys 460%, girls 413%). Statistically significant increases above the 50th percentile(1975/76) were found: weight 36 and 26%, subscapular 43 and 60% and triceps skinfold thickness 63 and 69% for boys and girls, respectively. Body fat among 6- to 9-year-old children increased dramatically within 30 years. Moreover, our data suggest substantial changes in body composition among normal-weight children towards an increased body fat mass.
European journal of clinical nutrition 09/2009; 63(12):1440-3. DOI:10.1038/ejcn.2009.86 · 2.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We investigated the prevalence of overweight and obesity in German schoolchildren and analyzed determinants of overweight. In the context of a randomized intervention study, a baseline cross-sectional assessment was carried out in 2006. During a physical examination, height, weight, skin fold thickness, and upper arm and waist circumferences were measured according to a standardized protocol among 1.079 children aged 6-9 years. Overweight and obesity were classified according to the definitions of the International Obesity Task Force. Parents completed a questionnaire on potential determinants of overweight. Logistic regression models were calculated for determinants of overweight and obesity. The prevalence of overweight was 16.5% in boys and 17.3% in girls and of obesity 3.5% and 3.6%, respectively. Migration (29.4 %) was correlated with overweight and obesity. In particular, among boys with migration background, overweight (24.0%) and obesity (6.6%) were highly prevalent. Higher obesity prevalence was associated with maternal smoking during pregnancy, parental overweight, and low parental education. Indicators for physical inactivity such as watching television more than 1 h per weekday, participation in club sports less than once a week, consumption of sweetened drinks (>or=3 times per week), and skipping breakfast before school were associated with childhood obesity. Our results provide further evidence that parental factors such as migration background and education are strongly associated with body mass of the offspring. Physically inactive children with regular consumption of sweetened drinks and no breakfast were prone to be overweight or obese. Changes of these lifestyle factors as targets of interventions are promising to prevent childhood obesity.
European Journal of Pediatrics 07/2009; 168(10):1259-67. DOI:10.1007/s00431-009-1016-y · 1.89 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Questionnaires are widely used in epidemiological studies to measure eczema symptom prevalence, but there are concerns regarding their accuracy if used as a diagnostic tool.
To compare the performance of a validated eczema symptom questionnaire and a standardized skin examination protocol employed in the second phase of the International Study of Asthma and Allergies in Childhood (ISAAC).
A total of 30,358 schoolchildren aged 8-12 years from 18 countries were examined for flexural eczema. Parents also completed an eczema symptom questionnaire. We compared prevalence estimates at the population level based on the questionnaire vs. physical examination. We also compared the skin examination and the ISAAC questionnaire in making a diagnosis of flexural eczema.
The point prevalences for flexural eczema at centre level based on a single examination were lower than the questionnaire-based 12-month period prevalences (mean centre prevalence 3.9% vs. 9.4%). Correlation between prevalences of both outcome measures was high (r = 0.77, P < 0.001). At the individual level, questionnaire-derived symptoms of 'persistent flexural eczema in the past 12 months' missed < 10% of cases of flexural eczema detected on physical examination. However, between 33% and 100% of questionnaire-based symptoms of 'persistent flexural eczema in the past 12 months' were not confirmed on examination.
ISAAC questionnaire-derived symptom prevalences are sufficiently precise for comparisons between populations. Where diagnostic precision at the individual level is important, questionnaires should be validated and potentially modified in those populations beforehand, or a standardized skin examination protocol should be used.
British Journal of Dermatology 05/2009; 161(4):846-53. DOI:10.1111/j.1365-2133.2009.09261.x · 4.28 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Phase Three of the International Study of Asthma and Allergies in Childhood (ISAAC) measured the global prevalence and severity of asthma symptoms in children.
A cross-sectional questionnaire survey of 798 685 children aged 13-14 years from 233 centres in 97 countries, and 388 811 children aged 6-7 years from 144 centres in 61 countries, was conducted between 2000 and 2003 in >90% of the centres.
The prevalence of wheeze in the past 12 months (current wheeze) ranged from 0.8% in Tibet (China) to 32.6% in Wellington (New Zealand) in the 13-14 year olds, and from 2.4% in Jodhpur (India) to 37.6% in Costa Rica in the 6-7 year olds. The prevalence of symptoms of severe asthma, defined as >or=4 attacks of wheeze or >or=1 night per week sleep disturbance from wheeze or wheeze affecting speech in the past 12 months, ranged from 0.1% in Pune (India) to 16% in Costa Rica in the 13-14 year olds and from 0% to 20.3% in the same two centres, respectively, in the 6-7 year olds. Ecological economic analyses revealed a significant trend towards a higher prevalence of current wheeze in centres in higher income countries in both age groups, but this trend was reversed for the prevalence of severe symptoms among current wheezers, especially in the older age group.
Wide variations exist in the symptom prevalence of childhood asthma worldwide. Although asthma symptoms tend to be more prevalent in more affluent countries, they appear to be more severe in less affluent countries.
[Show abstract][Hide abstract] ABSTRACT: 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 (OR(adj)) 0.87, 95% confidence interval (CI) 0.78-0.97) and nonaffluent countries (OR(adj) 0.80, 95% CI 0.68-0.94). Further analyses revealed that this was true only for nonatopic wheeze in nonaffluent countries (OR(adj) 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).
European Respiratory Journal 02/2009; 33(5):993-1002. DOI:10.1183/09031936.00075708 · 7.64 Impact Factor