Early life exposure to farm animals and symptoms of asthma, rhinoconjunctivitis and eczema : an ISAAC Phase Three study

We are grateful to the children and parents who willingly cooperated and participated in ISAAC Phase Three and the coordination and assistance by the school staff is sincerely appreciated. The authors also acknowledge and thank the many funding bodies throughout the world that supported the individual ISAAC centres and collaborators and their meetings. The funders of the study had no role in study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the paper for publication.Background: 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. Objective: To study the association between early life exposure to farm animals and symptoms of asthma, rhinoconjunctivitis and eczema in a worldwide study. Methods: 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. Results: 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. Conclusion: 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.peer-reviewe

Acetaminophen use and risk of asthma, rhinoconjunctivitis and eczema in adolescents : ISAAC Phase Three

Rationale: There is epidemiological evidence that the use of acetaminophen may increase the risk of developing asthma. Objectives: To investigate the risk of asthma and other allergic disorders associated with the current use of acetaminophen in 13- to 14-year-old children in different populations worldwide. Methods: As part of the International Study of Asthma and Allergies in Childhood (ISAAC) Phase Three, 13- to 14-year-old children completed written and video questionnaires obtaining data on current symptoms of asthma, rhinoconjunctivitis, and eczema, and a written environmental questionnaire obtaining data on putative risk factors, including acetaminophen use in the past 12 months. Measurements and Main Results: The primary outcome measure was the odds ratio (OR) of current asthma symptoms associated with acetaminophen use calculated by logistic regression. A total of 322,959 adolescent children from 113 centers in 50 countries participated. In the multivariate analyses the recent use of acetaminophen was associated with an exposure-dependent increased risk of current asthma symptoms (OR, 1.43 [95% confidence interval, 1.33–1.53] and 2.51 [95% confidence interval, 2.33–2.70] for medium and high versus no use, respectively). Acetaminophen use was also associated with an exposure-dependent increased risk of current symptoms of rhinoconjunctivitis and eczema. Conclusions: Acetaminophen use may represent an important risk factor for the development and/or maintenance of asthma, rhinoconjunctivitis, and eczema in adolescent children.peer-reviewe

Time trends, ethnicity and risk factors for eczema in New Zealand children: ISAAC Phase Three.

BACKGROUND: Eczema is a common chronic disease which has significant morbidity and costs for children and their families. Phase One (1993) of the International Study of Asthma and Allergies in Childhood (ISAAC) found a high prevalence of symptoms of eczema in New Zealand. OBJECTIVE: In Phase Three (2001-3) we aimed to answer these three questions: Is the prevalence of eczema changing over time?; Are there ethnic differences in prevalence?; and What are the risk factors for eczema? METHODS: Five New Zealand centres participated in ISAAC Phases One and Three using the same methodology. Questionnaires about ethnicity, symptoms of eczema and environmental factors were completed by parents of 6-7 year olds (children) and self-completed by 13-14 year olds (adolescents). Prevalence and change per year were calculated by centre, ethnicity and gender. Prevalence differences between centres and associations with environmental factors were examined using logistic regression. RESULTS: There was little change in prevalence over time for the children, and a decrease in prevalence for the adolescents. Prevalence was higher among Māori and even higher among Pacific participants than among European children. Positive associations with current eczema symptoms were found for both age groups for truck traffic in the street of residence, and current paracetamol consumption, and for children only, antibiotics or paracetamol in the 1st year of life. Inverse associations were found with residence in New Zealand less than 5 years, consumption of milk, seafood, and eggs, and presence of a dog in the home. CONCLUSION: Eczema remains a significant problem, particularly for young Māori and Pacific New Zealanders in whom less recognition of eczema and poorer access to effective, sustained eczema management may be contributing factors. Reverse causation may explain all the environmental findings apart from truck traffic which is increasing in New Zealand

Worldwide time trends for symptoms of rhinitis and conjunctivitis: Phase III of the International Study of Asthma and Allergies in Childhood

In Phase III of the International Study of Asthma and Allergies in Childhood (ISAAC) time trends in the prevalence of rhinoconjunctivitis symptoms were analysed. Cross-sectional questionnaire surveys with identical protocols and questionnaires were completed a mean of 7 yr apart in two age groups comprising 498,083 children. In the 13- to 14-yr age group 106 centres in 56 countries participated, and in the 6- to 7-yr age group 66 centres in 37 countries participated. A slight worldwide increase in rhinoconjunctivitis prevalence was observed, but the variations were large among the centres and there was no consistent regional pattern. Prevalence increases in the older children exceeding 1% per year were recorded in 13 centres, including 3 of 9 centres in Africa, 2 of 15 in Asia-Pacific, 1 of 8 in India, 3 of 15 in Latin America, 3 of 9 in Eastern Europe and 1 of 34 in Western and Northern Europe. Decreasing rhinoconjunctivititis prevalence of similar magnitude was only seen in four centres. The changes were less pronounced in the 6- to 7-yr-old children and only in one centre did any change exceed 1% per year. The decrease in highest prevalence rates in ISAAC Phase I suggests that the prevalence has peaked in those regions. An increase was recorded in several centres, mostly in low and mid-income countries. The increases were more pronounced in the older age group, suggesting that environmental influences on the development of allergy may not be limited to early childhood

Association between paracetamol use in infancy and childhood, and risk of asthma, rhinoconjunctivitis, and eczema in children aged 6-7 years: analysis from Phase Three of the ISAAC programme

Background: Exposure to paracetamol during intrauterine life, childhood, and adult life may increase the risk of developing asthma. We studied 6-7-year-old children from Phase Three of the International Study of Asthma and Allergies in Childhood (ISAAC) programme to investigate the association between paracetamol consumption and asthma. Methods: As part of Phase Three of ISAAC, parents or guardians of children aged 6-7 years completed written questionnaires about symptoms of asthma, rhinoconjunctivitis, and eczema, and several risk factors, including the use of paracetamol for fever in the child's first year of life and the frequency of paracetamol use in the past 12 months. The primary outcome variable was the odds ratio (OR) of asthma symptoms in these children associated with the use of paracetamol for fever in the first year of life, as calculated by logistic regression. Findings: 205 487 children aged 6-7 years from 73 centres in 31 countries were included in the analysis. In the multivariate analyses, use of paracetamol for fever in the first year of life was associated with an increased risk of asthma symptoms when aged 6-7 years (OR 1.46 [95% CI 1.36-1.56]). Current use of paracetamol was associated with a dose-dependent increased risk of asthma symptoms (1.61 [1.46-1.77] and 3.23 [2.91-3.60] for medium and high use vs no use, respectively). Use of paracetamol was similarly associated with the risk of severe asthma symptoms, with population-attributable risks between 22% and 38%. Paracetamol use, both in the first year of life and in children aged 6-7 years, was also associated with an increased risk of symptoms of rhinoconjunctivitis and eczema. Interpretation: Use of paracetamol in the first year of life and in later childhood, is associated with risk of asthma, rhinoconjunctivitis, and eczema at age 6 to 7 years. We suggest that exposure to paracetamol might be a risk factor for the development of asthma in childhood. Funding: The BUPA Foundation, the Health Research Council of New Zealand, the Asthma and Respiratory Foundation of New Zealand, the Hawke's Bay Medical Research Foundation, the Waikato Medical Research Foundation, Glaxo Wellcome New Zealand, the New Zealand Lottery Board, Astra Zeneca New Zealand, and Glaxo Wellcome International Medical Affairs

Has the prevalence and severity of symptoms of asthma changed among children in New Zealand? ISAAC Phase Three.

AIM: To investigate time trends in prevalence of symptoms of asthma by repeating, during 2001-3 (Phase Three), the International Study of Asthma and Allergies in Childhood (ISAAC) Phase One study that was conducted in New Zealand in 1992-3. METHODS: ISAAC Phase Three involved repeating the cross-sectional questionnaire survey of two age groups of school children (6-7 years and 13-14 years, children and adolescents respectively) using the same methodology as Phase One. In New Zealand it was conducted in Auckland, Bay of Plenty, Christchurch, Nelson, and Wellington. RESULTS: After 9 years, reported asthma ever increased from 24.6% to 30.2% in children and from 24.1% to 32.4% in adolescents (p<0.001). Current wheeze (written questionnaire) significantly decreased in children from 23.6% to 22.2% (p=0.002) and in adolescents from 29.7% to 26.7% (p=0.047), and for the video questionnaire from 18.1% to 11.1% (p<0.001). There was a significant reduction in wheezing limiting speech from 5.0% to 3.7% in children, and 7.9% to 6.2% in adolescents. Little regional variation was found. A higher proportion of children with asthma symptoms now report having ever had asthma. CONCLUSIONS: The decrease in prevalence and severity of symptoms of asthma is encouraging, but the reasons for these trends are currently unclear. Increases in asthma labelling are likely to be due to greater awareness of asthma. A trend of decreasing prevalence of asthma symptoms, if maintained, has positive implications for lessened burden of disease among asthmatics and lowered cost of treatment

Birthweight and the risk of atopic diseases:The ISAAC Phase III study

Background: The association between birthweight and asthma, eczema and rhinoconjunctivitis is conflicting. Aims: To examine the association between birthweight and symptoms of asthma, eczema and rhinoconjunctivitis. Methods: Parents or guardians of children aged 6-7 yr completed written questionnaires about symptoms of asthma, rhinoconjunctivitis and eczema, and several risk factors, including birthweight. Results: There were 162,324 children from 60 centres in 26 countries. Low birthweight (&lt;2.5 kg) was associated with an increased risk of symptoms of asthma (current wheeze odds ratio = 1.20; 95% confidence interval = 1.12-1.30). Low birthweight was associated with a lower risk of eczema ever. Low birthweight was not associated with rhinoconjunctivitis. Large babies (birthweight ≥4.5 kg) were not associated with any of these outcomes. Conclusions: This study has confirmed that low birthweight is a risk factor for symptoms of asthma, but not for rhinoconjunctivitis. The findings for eczema are equivocal.</p