Atopic sensitization and the international variation of asthma symptom prevalence in children.

RATIONALE Atopic sensitization has long been known to be related to asthma in children, but its role in determining asthma prevalence remains to be elucidated further. OBJECTIVES To investigate the role of atopic sensitization in the large international variation in the prevalence of childhood asthma. METHODS Cross-sectional studies of random samples of 8- to 12-year-old children (n = 1,000 per center) were performed according to the standardized methodology of Phase Two of the International Study of Asthma and Allergy in Childhood (ISAAC). Thirty study centers in 22 countries worldwide participated and reflect a wide range of living conditions, from rural Africa to urban Europe. Data were collected by parental questionnaires (n = 54,439), skin prick tests (n = 31,759), and measurements of allergen-specific IgE levels in serum (n = 8,951). Economic development was assessed by gross national income per capita (GNI). MEASUREMENTS AND MAIN RESULTS The prevalence of current wheeze (i.e., during the past year) ranged from 0.8% in Pichincha (Ecuador) to 25.6% in Uruguaiana (Brazil). The fraction of current wheeze attributable to atopic sensitization ranged from 0% in Ankara (Turkey) to 93.8% in Guangzhou (China). There were no correlations between prevalence rates of current wheeze and atopic sensitization, and only weak correlations of both with GNI. However, the fractions and prevalence rates of wheeze attributable to skin test reactivity correlated strongly with GNI (Spearman rank-order coefficient rho = 0.50, P = 0.006, and rho = 0.74, P < 0.0001, respectively). In addition, the strength of the association between current wheeze and skin test reactivity, assessed by odds ratios, increased with GNI (rho = 0.47, P = 0.01). CONCLUSIONS The link between atopic sensitization and asthma symptoms in children differs strongly between populations and increases with economic development.

[1]  M. Ege,et al.  The asthma epidemic. , 2006, The New England journal of medicine.

[2]  D. Strachan,et al.  Effect of albendazole treatments on the prevalence of atopy in children living in communities endemic for geohelminth parasites: a cluster-randomised trial , 2006, The Lancet.

[3]  E. von Mutius,et al.  The many faces of the hygiene hypothesis. , 2006, The Journal of allergy and clinical immunology.

[4]  B. Brunekreef,et al.  Allergic diseases and atopic sensitization in children related to farming and anthroposophic lifestyle – the PARSIFAL study , 2006, Allergy.

[5]  J. Douwes,et al.  Environmental determinants associated with the development of asthma in childhood. , 2006, The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease.

[6]  R. Rona,et al.  Prevalence of asthma, atopy and bronchial hyperresponsiveness and their interrelation in a semi-rural area of Chile. , 2005, The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease.

[7]  P. Burney,et al.  Effect of body mass on exercise-induced bronchospasm and atopy in African children. , 2005, The Journal of allergy and clinical immunology.

[8]  K. Julge,et al.  Intestinal microbiota and immunoglobulin E responses in 5‐year‐old Estonian children , 2005, Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology.

[9]  J. Castro‐Rodriguez,et al.  A different pattern of risk factors for atopic and non‐atopic wheezing in 9–12‐year‐old children , 2005, Pediatric allergy and immunology : official publication of the European Society of Pediatric Allergy and Immunology.

[10]  S. Weiss.  Obesity: insight into the origins of asthma , 2005, Nature Immunology.

[11]  K. Julge,et al.  Atopic sensitization and atopic dermatitis in Estonian and Swedish infants , 2005, Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology.

[12]  D. Jarvis,et al.  Geographic variations in the effect of atopy on asthma in the European Community Respiratory Health Study. , 2004, The Journal of allergy and clinical immunology.

[13]  A. Custovic,et al.  Environmental allergen exposure, sensitisation and asthma: from whole populations to individuals at risk , 2004, Thorax.

[14]  D. Strachan,et al.  Phase II of the International Study of Asthma and Allergies in Childhood (ISAAC II): rationale and methods , 2004, European Respiratory Journal.

[15]  E. Mutius.  Influences in allergy: epidemiology and the environment. , 2004 .

[16]  B. Björkstén.  Effects of intestinal microflora and the environment on the development of asthma and allergy , 2004, Springer Seminars in Immunopathology.

[17]  C. Saçkesen,et al.  Prevalence of asthmatic phenotypes and bronchial hyperresponsiveness in Turkish schoolchildren: an International Study of Asthma and Allergies in Childhood (ISAAC) phase 2 study. , 2003, Annals of allergy, asthma & immunology : official publication of the American College of Allergy, Asthma, & Immunology.

[18]  T. Nutman,et al.  Allergic symptoms, atopy, and geohelminth infections in a rural area of Ecuador. , 2003, American journal of respiratory and critical care medicine.

[19]  D. Strachan,et al.  Comparative epidemiology of atopic and non-atopic wheeze and diagnosed asthma in a national sample of English adults , 2002, Thorax.

[20]  D. Nowak,et al.  Environmental exposure to endotoxin and its relation to asthma in school-age children. , 2002, The New England journal of medicine.

[21]  E. von Mutius,et al.  Environmental factors influencing the development and progression of pediatric asthma. , 2002, The Journal of allergy and clinical immunology.

[22]  Xiping Xu,et al.  Ascaris lumbricoides infection is associated with increased risk of childhood asthma and atopy in rural China. , 2002, American journal of respiratory and critical care medicine.

[23]  M. Chapman,et al.  Atopy, asthma, and antibodies to Ascaris among rural and urban children in Kenya. , 2002, The Journal of pediatrics.

[24]  F. Martinez,et al.  Development of wheezing disorders and asthma in preschool children. , 2002, Pediatrics.

[25]  K. Julge,et al.  Development of allergy and IgE antibodies during the first five years of life in Estonian children , 2001, Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology.

[26]  A. Woodcock,et al.  Independent effects of intestinal parasite infection and domestic allergen exposure on risk of wheeze in Ethiopia: a nested case-control study , 2001, The Lancet.

[27]  M. Penny,et al.  Respiratory symptoms, asthma, exercise test spirometry, and atopy in schoolchildren from a Lima shanty town , 2001, Thorax.

[28]  D. Strachan,et al.  The relationship of per capita gross national product to the prevalence of symptoms of asthma and other atopic diseases in children (ISAAC). , 2001, International journal of epidemiology.

[29]  D. Solé,et al.  Prevalence of asthma symptoms in Latin America: The international study of asthma and allergies in childhood (ISAAC) , 2000, Pediatric pulmonology.

[30]  B. Lell,et al.  Decreased atopy in children infected with Schistosoma haematobium: a role for parasite-induced interleukin-10 , 2000, The Lancet.

[31]  J. Sunyer,et al.  The association between atopy and asthma in a semirural area of Tanzania (East Africa) , 2000, Allergy.

[32]  T. Platts-Mills,et al.  Different pattern of risk factors for atopic and nonatopic asthma among children – report from the Obstructive Lung Disease in Northern Sweden Study , 1999, Allergy.

[33]  D. Sherrill,et al.  Respiratory syncytial virus in early life and risk of wheeze and allergy by age 13 years , 1999, The Lancet.

[34]  N. Pearce,et al.  How much asthma is really attributable to atopy? , 1999, Thorax.

[35]  S L Normand,et al.  Meta-analysis: formulating, evaluating, combining, and reporting. , 1999, Statistics in medicine.

[36]  Richard Beasley,et al.  Worldwide variation in prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and atopic eczema: ISAAC , 1998, The Lancet.

[37]  S. Lewis,et al.  Prevalence of wheeze and asthma and relation to atopy in urban and rural Ethiopia , 1997, The Lancet.

[38]  N. Lynch,et al.  Clinical improvement of asthma after anthelminthic treatment in a tropical situation. , 1997, American journal of respiratory and critical care medicine.

[39]  A. Knutsson,et al.  The prevalence of atopic sensitization and respiratory symptoms among Estonian schoolchildren. , 1995, Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology.

[40]  D. Strachan,et al.  International Study of Asthma and Allergies in Childhood (ISAAC): rationale and methods. , 1995, The European respiratory journal.

[41]  A. Knutsson,et al.  Atopic sensitization and respiratory symptoms among Polish and Swedish school children , 1994, Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology.

[42]  T. Nicolai,et al.  Prevalence of asthma and atopy in two areas of West and East Germany. , 1994, American journal of respiratory and critical care medicine.

[43]  D. Pfeffermann.  The Role of Sampling Weights when Modeling Survey Data , 1993 .

[44]  G. Pershagen,et al.  Allergic disease and sensitization in Steiner school children. , 2006, The Journal of allergy and clinical immunology.

[45]  L. Chambless,et al.  Maximum likelihood methods for complex sample data: logistic regression and discrete proportional hazards models , 1985 .