Global variations in prevalence of eczema symptoms in children from ISAAC Phase Three
2009; Elsevier BV; Volume: 124; Issue: 6 Linguagem: Inglês
10.1016/j.jaci.2009.10.009
ISSN1097-6825
AutoresJoseph Odhiambo, Hywel C Williams, Tadd Clayton, Colin F. Robertson, M. Innes Asher,
Tópico(s)Asthma and respiratory diseases
ResumoBackgroundIn 1999, The International Study of Asthma and Allergies in Childhood (ISAAC) Phase One reported the prevalence of eczema symptoms in 715,033 children from 154 centers in 56 countries by using standardized epidemiologic tools.ObjectiveTo update the world map of eczema prevalence after 5 to 10 years (ISAAC Phase Three) and include additional data from over 100 new centers.MethodsCross-sectional surveys using the ISAAC questionnaire on eczema symptoms were completed by adolescents 13 to 14 years old and by parents of children 6 to 7 years old. Current eczema was defined as an itchy flexural rash in the past 12 months and was considered severe eczema if associated with 1 or more nights per week of sleep disturbance.ResultsFor the age group 6 to 7 years, data on 385,853 participants from 143 centers in 60 countries showed that the prevalence of current eczema ranged from 0.9% in India to 22.5% in Ecuador, with new data showing high values in Asia and Latin America. For the age group 13 to 14 years, data on 663,256 participants from 230 centers in 96 countries showed prevalence values ranging from 0.2% in China to 24.6% in Columbia with the highest values in Africa and Latin America. Current eczema was lower for boys than girls (odds ratio, 0.94 and 0.72 at ages 6 to 7 years and 13 to 14 years, respectively).Conclusion:ISAAC Phase Three provides comprehensive global data on the prevalence of eczema symptoms that is essential for public health planning. New data reveal that eczema is a disease of developing as well as developed countries. In 1999, The International Study of Asthma and Allergies in Childhood (ISAAC) Phase One reported the prevalence of eczema symptoms in 715,033 children from 154 centers in 56 countries by using standardized epidemiologic tools. To update the world map of eczema prevalence after 5 to 10 years (ISAAC Phase Three) and include additional data from over 100 new centers. Cross-sectional surveys using the ISAAC questionnaire on eczema symptoms were completed by adolescents 13 to 14 years old and by parents of children 6 to 7 years old. Current eczema was defined as an itchy flexural rash in the past 12 months and was considered severe eczema if associated with 1 or more nights per week of sleep disturbance. For the age group 6 to 7 years, data on 385,853 participants from 143 centers in 60 countries showed that the prevalence of current eczema ranged from 0.9% in India to 22.5% in Ecuador, with new data showing high values in Asia and Latin America. For the age group 13 to 14 years, data on 663,256 participants from 230 centers in 96 countries showed prevalence values ranging from 0.2% in China to 24.6% in Columbia with the highest values in Africa and Latin America. Current eczema was lower for boys than girls (odds ratio, 0.94 and 0.72 at ages 6 to 7 years and 13 to 14 years, respectively). Conclusion:ISAAC Phase Three provides comprehensive global data on the prevalence of eczema symptoms that is essential for public health planning. New data reveal that eczema is a disease of developing as well as developed countries. Estimating the prevalence of eczema is important for several reasons including monitoring disease burden, documenting changing trends, and understanding possible causes by contrasting prevalence within and between countries. Atopic eczema (or atopic dermatitis) is the most common form of eczema in childhood. Atopic eczema manifests as a chronic, relapsing itchy rash that usually starts in early life and, in many children, wanes in severity later in childhood.1Williams H.C. Burney P.G. Hay R.J. Archer C.B. Shipley M.J. Hunter J.J. et al.The U.K. Working Party's Diagnostic Criteria for Atopic Dermatitis, I: derivation of a minimum set of discriminators for atopic dermatitis.Br J Dermatol. 1994; 131: 383-396Crossref PubMed Scopus (843) Google Scholar, 2Williams H.C. Strachan D.P. The natural history of childhood eczema: observations from the British 1958 birth cohort study.Br J Dermatol. 1998; 139: 834-839Crossref PubMed Scopus (146) Google Scholar Not everyone with atopic eczema is truly atopic in terms of demonstrating a specific IgE response to common allergens, especially in developing countries, where helminth infestations are common.3Flohr C. Weiland S.K. Weinmayr G. Björkstén B. Bråbäck L. Brunekreef B. et al.The role of atopic sensitization in flexural eczema: findings from the International Study of Asthma and Allergies in Childhood Phase Two.J Allergy Clin Immunol. 2008; 121: 141-147Abstract Full Text Full Text PDF PubMed Scopus (100) Google Scholar Yet the term “atopic eczema” or “atopic dermatitis” is still commonly used to define the phenotype of poorly demarcated skin inflammation with surface changes (such as scaling or lichenification), a predilection for the flexures (such as the insides of the elbows and backs of the knees4Williams H.C. Diagnostic criteria for atopic dermatitis: where do we go from here? [letter; comment].Arch Dermatol. 1999; 135: 583-586Crossref PubMed Scopus (37) Google Scholar), and association with a personal or family history of asthma and/or hay fever. Severe eczema in childhood and persistence into adult life are associated with considerable direct costs.5Mancini A.J. Kaulback K. Chamlin S.L. The socioeconomic impact of atopic dermatitis in the United States: a systematic review.Pediatr Dermatol. 2008; 25: 1-6Crossref PubMed Scopus (168) Google Scholar Constant itching, which can lead to sleep deprivation, as well as the stigmata associated with visible skin disease can have a major impact on quality of life for such individuals.6Arnold R.J. Donnelly A. Altieri L. Wong K.S. Sung J. Assessment of outcomes and parental effect on Quality-of-Life endpoints in the management of atopic dermatitis.Manag Care Interface. 2007; 20: 18-23PubMed Google Scholar, 7Carroll C.L. Balkrishnan R. Feldman S.R. Fleischer Jr., A.B. Manuel J.C. The burden of atopic dermatitis: impact on the patient, family, and society.Pediatr Dermatol. 2005; 22: 192-199Crossref PubMed Scopus (376) Google Scholar, 8Lewis-Jones S. Quality of life and childhood atopic dermatitis: the misery of living with childhood eczema.Int J Clin Pract. 2006; 60: 984-992Crossref PubMed Scopus (339) Google Scholar, 9Meltzer L.J. Moore M. Sleep disruptions in parents of children and adolescents with chronic illnesses: prevalence, causes, and consequences.J Pediatr Psychol. 2008; 33: 279-291Crossref PubMed Scopus (102) Google Scholar, 10Misery L. Finlay A.Y. Martin N. Boussetta S. Nguyen C. Myon E. et al.Atopic dermatitis: impact on the quality of life of patients and their partners.Dermatology. 2007; 215: 123-129Crossref PubMed Scopus (105) Google Scholar The International Study of Asthma and Allergies in Childhood (ISAAC) was designed to allow comparisons of the prevalence of symptoms of asthma, rhinitis, and eczema between populations in different countries through use of standardized epidemiologic tools.11Asher M.I. Weiland S.K. ISAAC Steering CommitteeThe International Study of Asthma and Allergies in Childhood (ISAAC).Clin Exp Allergy. 1998; 28: 52-66Crossref PubMed Scopus (262) Google Scholar The prevalence of symptoms of eczema in ISAAC Phase One (1992-1997) estimated in 154 centers in 56 countries (715,033 children) varied widely throughout the world. The 1-year period prevalence of eczema symptoms estimated by ISAAC Phase One previously published in this journal ranged from 0.6% to 20.5% of the population.12Williams H. Robertson C. Stewart A. Aït-Khaled N. Anabwani G. Anderson R. et al.Worldwide variations in the prevalence of symptoms of atopic eczema in the International Study of Asthma and Allergies in Childhood.J Allergy Clin Immunol. 1999; 103: 125-138Abstract Full Text Full Text PDF PubMed Scopus (818) Google Scholar Trends in eczema symptoms over a 5-year to 10-year period in just under half a million adolescents and children who participated in both ISAAC Phase One and Three indicate that the prevalence of eczema is rising, especially in younger children,13Williams H. Stewart A. von Mutius E. Cookson W. Anderson H.R. et al.International Study of Asthma and Allergies in Childhood (ISAAC) Phase One and Three Study GroupsIs eczema really on the increase worldwide?.J Allergy Clin Immunol. 2008; 121: 947-954Abstract Full Text Full Text PDF PubMed Scopus (407) Google Scholar suggesting that environmental factors could be playing a key role in determining disease expression. This article describes global prevalence data on eczema symptoms in more than a million adolescents and children from ISAAC Phase Three (1999-2004). ISAAC Phase Three provides new data from Phase One centers and includes more than 100 new centers in more than 40 countries not previously studied, thereby providing recent and comprehensive global data that are essential for public health planning. ISAAC Phase Three used the same protocol, framework for registration of participating centers, and sampling as ISAAC Phase One.12Williams H. Robertson C. Stewart A. Aït-Khaled N. Anabwani G. Anderson R. et al.Worldwide variations in the prevalence of symptoms of atopic eczema in the International Study of Asthma and Allergies in Childhood.J Allergy Clin Immunol. 1999; 103: 125-138Abstract Full Text Full Text PDF PubMed Scopus (818) Google Scholar, 14Ellwood P. Asher M.I. Beasley R. Clayton T.O. Stewart A.W. ISAAC Steering CommitteeThe International Study of Asthma and Allergies in Childhood (ISAAC): Phase Three rationale and methods.Int J Tuberc Lung Dis. 2005; 9: 10-16PubMed Google Scholar Briefly, 2 age groups (6-7 and 13-14 years old) were chosen from a random sample of schools from defined geographical areas. A simple questionnaire with questions related to symptoms of wheezing, rhinoconjunctivitis, and eczema was completed by parents of the children and by the adolescents. Only the eczema data are reported and discussed here; the asthma and rhinoconjunctivitis results are reported separately.15Aït-Khaled N. Pearce N. Anderson H.R. Ellwood P. Montefort S. Shah J. et al.Global map of the prevalence of symptoms of rhinoconjunctivitis in children: the International Study of Asthma and Allergies in Childhood (ISAAC) Phase Three.Allergy. 2009; 64: 123-148Crossref PubMed Scopus (314) Google Scholar, 16Lai C. Beasley R. Crane J. Foliaki S. Shah J. Weiland S. et al.Global variation in the prevalence and severity of asthma symptoms: Phase Three of the International Study of Asthma and Allergies in Childhood (ISAAC).Thorax. 2009; 64: 476-483Crossref PubMed Scopus (730) Google Scholar Questionnaires were translated, if necessary, from English into the local language for both age groups. Translated questionnaires were back-translated into English by an independent person according to ISAAC translation guidelines to confirm that other languages used terms as equivalent as possible to the English version.17Ellwood P. Williams H. Aït-Khaled N. Björkstén B. Robertson C. ISAAC Phase Three study groupTranslation of questions: the International Study of Asthma and Allergies in Childhood (ISAAC) experience.Int J Tuberc Lung Dis. 2009; 13: 1174-1182PubMed Google Scholar The full text of the questions concerning eczema symptoms is included in this article's Fig E1 in the Online Repository at www.jacionline.org. These questions on symptoms of eczema include both sensitive and specific questions that are repeatable and have reasonable content, construct, concurrent, and predictive validity.12Williams H. Robertson C. Stewart A. Aït-Khaled N. Anabwani G. Anderson R. et al.Worldwide variations in the prevalence of symptoms of atopic eczema in the International Study of Asthma and Allergies in Childhood.J Allergy Clin Immunol. 1999; 103: 125-138Abstract Full Text Full Text PDF PubMed Scopus (818) Google Scholar, 18Brenninkmeijer E.E. Schram M.E. Leeflang M.M. Bos J.D. Spuls P.I. Diagnostic criteria for atopic dermatitis: a systematic review.Br J Dermatol. 2008; 158: 754-765Crossref PubMed Scopus (167) Google Scholar, 19ISAAC Steering CommitteeInternational Study of Asthma and Allergies in Childhood manual.Auckland/Münster: ISAAC Steering Committee;. 1993; Google Scholar The key outcome reported (current symptoms of eczema) is that of respondents who answered positively to the question, “Has your child/Have you had this itchy rash at any time in the past 12 months?” and answered positively to the question, “Has this itchy rash at any time affected any of the following places: the folds of the elbows, behind the knees, in front of the ankles, under the buttocks, or around the neck, ears or eyes?” Current eczema associated with sleep disturbance 1 or more nights per week (question 6) was used as a surrogate of severe eczema. To explore the effects of disease labeling, we also report the results for lifetime “eczema” (question 7) or the appropriate local term. Centers were expected to obtain ethics approval and parental consent according to the requirements of the country, and to fund their own study. Centers were examined for adherence to protocol, and only centers that met ISAAC standards were included in analyses. The same approach to data analysis in ISAAC Phase One12Williams H. Robertson C. Stewart A. Aït-Khaled N. Anabwani G. Anderson R. et al.Worldwide variations in the prevalence of symptoms of atopic eczema in the International Study of Asthma and Allergies in Childhood.J Allergy Clin Immunol. 1999; 103: 125-138Abstract Full Text Full Text PDF PubMed Scopus (818) Google Scholar was used in Phase Three. All data submitted to the ISAAC International Data Center were checked for coding errors, omissions, and inconsistencies and were corrected with the assistance of collaborators. Symptom prevalence values in each center were calculated by dividing the number of positive responses to each question by the number of completed questionnaires. Odds ratios and associated 95% CIs were calculated by using logistic regression. All analyses were carried out with SAS (version 9; SAS Institute Inc, Cary, NC). For the age group 6 to 7 years, data from 421,543 participants in 165 centers (65 countries), and for the age group 13 to 14 years, data for 814,837 participants in 242 centers (98 countries) were submitted to the ISAAC International Data Centre for analyses. Adherence to the ISAAC Protocol was assessed, and centers that had not included the eczema questionnaire or had serious deviations from protocol were excluded from the analyses (22 centers from 17 countries with 35,690 participants for the age group 6-7 years and 12 centers from 8 countries with 151,581 participants for the age group 13-14 years). For the age group 6 to 7 years, there were 385,853 participants from 143 centers in 60 countries, and for the age group 13 to 14 years, there were 663,256 participants from 230 centers in 96 countries. Generally high response rates were achieved (age group 6-7 years, 41% of centers registered response rates of 90% to 100%, 31% of 80% to 89%, 17% of 70% to 79%, and 11% of 60% to 70%; age group 13-14 years, 65% of centers registered response rates of 90% to 100%, 25% of 80% to 89%, and 10% of 70% to 79%). The response rate varied between regions from 77% (North America) to 94% (Africa) in the age group 6 to 7 years, and from 78% (North America) to 94% (Eastern Mediterranean) in the age group 13 to 14 years. Details of the languages used are reported elsewhere.16Lai C. Beasley R. Crane J. Foliaki S. Shah J. Weiland S. et al.Global variation in the prevalence and severity of asthma symptoms: Phase Three of the International Study of Asthma and Allergies in Childhood (ISAAC).Thorax. 2009; 64: 476-483Crossref PubMed Scopus (730) Google Scholar Fig 1, A and B, shows color-coded world maps of the prevalence of current symptoms of eczema for children 6 to 7 and 13 to 14 years old, respectively. This article's Fig E2, A and B, in the Online Repository at www.jacionline.org presents similar maps illustrating the prevalence of symptoms of severe eczema. This article's Tables E1 and E2 in the Online Repository at www.jacionline.org include detailed results at a center level. The prevalence of current eczema symptoms among the age group 6 to 7 years varied from 0.9% (Jodhpur, India) to 22.5% (Quito, Ecuador) (Fig 2, A). For the age group 13 to 14 years, the prevalence varied from 0.2% (Tibet, China) to 24.6% (Barranquilla, Colombia) (Fig 2, B). For symptoms of severe eczema, the prevalence varied from 0.0% (Hong Kong; Davangere, India; Kharkiv, Ukraine) to 4.9% (La Habana, Cuba) for the age group 6 to 7 years and from 0.0% (Ho Chi Minh City, Vietnam; Borivali, India) to 5.8% (Marrakech, Morocco) for the age group 13 to 14 years (see this article's Fig E3, A and B, and Fig E4, A and B, in the Online Repository at www.jacionline.org). For lifetime reported “eczema,” the prevalence varied from 1.2% (Panevezys, Lithuania; Cuernavaca, Mexico) to 38.6% (Linköping, Sweden) for the age group 6 to 7 years and from 0.8% (Ciudad Victoria, Mexico) to 48.3% (Linköping) for the age group 13 to 14 years (see this article's Fig E5, A and B, in the Online Repository at www.jacionline.org).Fig 2Ranked prevalence plots of current symptoms of eczema for the age group 6 to 7 years (A) and 13 to 14 years (B). Each symbol represents a center. Countries are ordered by average prevalence.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Higher prevalence values for current symptoms of eczema (≥15%) were found in centers from 5 of 9 world regions including Asia-Pacific (centers in Thailand), Latin America (centers in Colombia, Cuba, Ecuador, Honduras, and Nicaragua), Northern and Eastern Europe (1 center in Sweden), Oceania (centers in Australia, New Zealand, and Niue), and Western Europe (1 center in the United Kingdom). Lower prevalence values (<5%) were found in centers in 6 of 9 regions including Asia-Pacific (centers in Hong Kong, Indonesia, and Vietnam), Eastern Mediterranean (centers in Iran, Malta, Pakistan, Sultanate of Oman, and the Syrian Arab Republic), Indian Subcontinent (centers in India), Latin America (centers in Argentina and Mexico), Northern and Eastern Europe (centers in Albania, Bulgaria, Croatia, Georgia, Hungary, Kyrgyzstan, Lithuania, and Ukraine), and Western Europe (centers in Greece and Spain). Overall, higher prevalence centers were generally more common in Oceania, and lower prevalence centers were generally more common in the Indian Subcontinent, the Eastern Mediterranean region, and Northern and Eastern Europe (see this article's Fig E3, A, in the Online Repository at www.jacionline.org). A broadly similar pattern was found for symptoms of severe eczema with higher prevalence centers more common in Oceania and Latin America, and lower prevalence centers more common in the Indian Subcontinent and Northern and Eastern Europe. For lifetime reported “eczema,” there was less consistency across the world. Although Oceania and the Indian Subcontinent were again the regions which most commonly included high and low prevalence centers, respectively, there was a greater range of prevalence in those regions and in all other regions. Of those with lifetime reported “eczema,” 31% had current eczema symptoms. The proportion of boys studied varied among the centers from 38.2% to 66.1%, and the proportion of girls varied from 33.9% to 61.8%. When the data for all centers were combined, there was no clear pattern observed for the main outcome measures. Boys showed a lower prevalence of current symptoms of “eczema” (7.7% for boys and 8.2% for girls; odds ratio [OR], 0.94; 95% CI, 0.92-0.97; P < .001). In contrast, there was little difference in prevalence between boys and girls for symptoms of severe eczema (1.0% male, 1.1% female; OR, 0.97; 95% CI, 0.91-1.03; P = .319) and a slightly higher prevalence for boys for lifetime reported “eczema” (14.4% males, 14.1% females; OR, 1.02; 95% CI, 1.01-1.04; P = .009; see this article's Fig E6, A-C, in the Online Repository at www.jacionline.org). Higher prevalence values (≥15%) were found in 4 of 9 regions including Africa (centers in Congo, Cote d'Ivoire, Ethiopia, Kenya, Morocco, and République de Guinée), Latin America (centers in Bolivia, Chile, Colombia, Ecuador, Honduras, Nicaragua, and Paraguay), Northern and Eastern Europe (1 center in Finland), and Oceania (centers in Kingdom of Tonga and Niue). Lower prevalence values (<5%) were found in 8 of 9 regions including Africa (1 center in Sudan), Asia-Pacific (centers in China, Hong Kong, Indonesia, Taiwan, Thailand, and Vietnam), Eastern Mediterranean (centers in Egypt, Iran, and the Syrian Arab Republic), Indian Subcontinent (centers in India), Latin America (centers in Brazil and Mexico), North America (1 center in the United States), Northern and Eastern Europe (centers in Albania, Bulgaria, Croatia, Former Yugoslav Republic of Macedonia, Georgia, Hungary, Kyrgyzstan, Latvia, Lithuania, Russia, Serbia and Montenegro, and Ukraine), and Western Europe (centers in Italy, Portugal, and Spain). In general, higher prevalence centers are generally more common in Africa and Oceania, and lower prevalence centers are generally more common in the Indian Subcontinent and Northern and Eastern Europe (see this article's Fig E3, B, in the Online Repository at www.jacionline.org). A generally similar pattern was found for symptoms of severe eczema, with higher prevalence centers more common in Africa and Oceania, and lower prevalence centers more common in the Indian Subcontinent and Northern and Eastern Europe. For lifetime reported “eczema,” there was again less consistency across the world. Oceania and Africa are the regions where high prevalence centers were most common. However, there was a difference in ranking of regions for low prevalence because North America was the region where low prevalence centers were most common. This contrasts with the ranking for current symptoms of eczema and severe eczema, for which North America showed an intermediate range of prevalence. There was again a greater range of prevalence for lifetime reported “eczema” within all other regions than for symptoms of current eczema and severe eczema. Of those with lifetime reported “eczema,” 26% had current eczema symptoms. The proportion of boys studied varied among the centers from 18.7% to 71.4%, and the proportion of girls varied from 28.6% to 81.3%. When the data for all centers were combined, a clear pattern for lower prevalence among boys emerged for age 13 to 14 years. Male adolescents showed a lower prevalence of current symptoms of eczema (6.2% for boys and 8.3% for girls; OR, 0.72; 95% CI, 0.71-0.74; P < .001). Similar differences in prevalence between boys and girls were found for symptoms of severe eczema (0.9% boys, 1.4% girls; OR, 0.63; 95% CI, 0.61-0.66; P < .001) and lifetime reported “eczema” (11.4% boys, 14.1% girls; OR, 0.78; 95% CI, 0.77-0.79; P < .001; see this article's Fig E6, D-F, in the Online Repository at www.jacionline.org). This is the largest study to date that estimates the prevalence of eczema symptoms in children and adolescents, and it contains over twice as much data and increased global coverage when compared with ISAAC Phase One. For the age group 6 to 7 years, Phase Three includes a further 87 centers from 27 new countries, and for the age group 13 to 14 years, a further 133 centers from 43 new countries. The increased coverage provides valuable new insights into the global variation of symptoms of eczema. As in Phase One, the results show large variations in prevalence of symptoms in both the 6 to 7–year and 13 to 14–year age groups. Additional centers available in Phase Three provide interesting new information. For the age group 6 to 7 years, there was an increase in the number of participating centers in Phase Three for all regions except North America and Oceania, with large increases in the Eastern Mediterranean region, Latin America, Northern and Eastern Europe, and Western Europe. Many of the new centers have a relatively high prevalence of current symptoms of eczema, and this is reflected in the region summary values for Phase One and Phase Three. All regions except Northern and Eastern Europe and Western Europe have higher summary prevalence values in Phase Three than in Phase One. The global summary prevalence value for Phase Three (7.9%) is also higher than the comparable value for Phase One (6.1%).12Williams H. Robertson C. Stewart A. Aït-Khaled N. Anabwani G. Anderson R. et al.Worldwide variations in the prevalence of symptoms of atopic eczema in the International Study of Asthma and Allergies in Childhood.J Allergy Clin Immunol. 1999; 103: 125-138Abstract Full Text Full Text PDF PubMed Scopus (818) Google Scholar For the age group 13 to 14 years, there was an increase in the number of participating centers in Phase Three for all regions except Western Europe, with large increases in Africa, Asia-Pacific, the Eastern Mediterranean region, the Indian Subcontinent, Latin America, and Northern and Eastern Europe. In contrast with the age group 6 to 7 years, many of the new centers have a relatively low prevalence of current symptoms of eczema, and this is reflected in the region summary values for Phase One and Phase Three. Only Asia-Pacific, the Indian Subcontinent, and Latin America have higher summary prevalence values in Phase Three than in Phase One. The global summary prevalence value for Phase Three (7.3%) is also lower than the comparable value for Phase One (8.8%).12Williams H. Robertson C. Stewart A. Aït-Khaled N. Anabwani G. Anderson R. et al.Worldwide variations in the prevalence of symptoms of atopic eczema in the International Study of Asthma and Allergies in Childhood.J Allergy Clin Immunol. 1999; 103: 125-138Abstract Full Text Full Text PDF PubMed Scopus (818) Google Scholar Sex differences in eczema symptoms were found in ISAAC Phase One in both age groups.12Williams H. Robertson C. Stewart A. Aït-Khaled N. Anabwani G. Anderson R. et al.Worldwide variations in the prevalence of symptoms of atopic eczema in the International Study of Asthma and Allergies in Childhood.J Allergy Clin Immunol. 1999; 103: 125-138Abstract Full Text Full Text PDF PubMed Scopus (818) Google Scholar In Phase Three, our finding of a decreased risk of eczema in boys was strongest in the age group 13 to 14 years and was consistent regardless of how eczema symptoms were defined (current, ever, or severe). Recent studies showing similar findings of lower prevalence among boys have been reported from Singapore,20Tay Y.K. Kong K.H. Khoo L. Goh C.L. Giam Y.C. The prevalence and descriptive epidemiology of atopic dermatitis in Singapore school children.Br J Dermatol. 2002; 146: 101-106Crossref PubMed Scopus (129) Google Scholar Spain,21Martin Fernandez-Mayoralas D. Martin Caballero J.M. Garcia-Marcos Alvarez L. [Prevalence of atopic dermatitis in schoolchildren from Cartagena (Spain) and relationship with sex and pollution].An Pediatr (Barc). 2004; 60: 555-560PubMed Google Scholar Japan,22Miyake Y. Yura A. Iki M. Cross-sectional study of allergic disorders in relation to familial factors in Japanese adolescents.Acta Paediatr. 2004; 93: 380-385Crossref PubMed Google Scholar Lebanon,23Al-Sahab B. Atoui M. Musharrafieh U. Zaitoun F. Ramadan F. Tamim H. Epidemiology of eczema among Lebanese adolescents.Int J Public Health. 2008; 53: 260-267Crossref PubMed Scopus (11) Google Scholar and Russia.24Hugg T. Ruotsalainen R. Jaakkola M.S. Pushkarev V. Jaakkola J.J. Comparison of allergic diseases, symptoms and respiratory infections between Finnish and Russian school children.Eur J Epidemiol. 2008; 23: 123-133Crossref PubMed Scopus (35) Google Scholar Possible explanations could include different genetic-environmental interactions, which become more prominent as children mature, or possibly misclassification of irritant contact dermatitis or allergic contact dermatitis (eg, from nickel earrings), which could be more common in adolescent girls. For the age group 6 to 7 years, the key feature of the more comprehensive picture of global prevalence provided by ISAAC Phase Three compared with Phase One is the emergence of Latin America as a region of comparatively high prevalence of symptoms. This is particularly evident in Central America and the Northern part of South America, where new centers such as La Habana (Cuba), San Pedro Sula (Honduras), Managua (Nicaragua), Barranquilla (Colombia), and Quito (Ecuador) show prevalence values of more than 15%. A similar, if less pronounced, new area of high prevalence has emerged in Southeast Asia, where new and existing centers in Thailand show high or moderate to high prevalence values. For the age group 13 to 14 years, Latin America again emerges as a region of comparatively high prevalence compared with the corresponding results from Phase One. However, the distribution of new high prevalence centers is somewhat different from the age group 6 to 7 years, with some such as Santa Cruz (Bolivia) and Calama (Chile) occurring further South in the South American continent. A more detailed analysis of time trends in eczema symptoms for those children who participated in both ISAAC Phase One and Phase Three is to be found elsewhere.13Williams H. Stewart A. von Mutius E. Cookson W. Anderson H.R. et al.International Study of Asthma and Allergies in Childhood (ISAAC) Phase One and Three Study GroupsIs eczema really on the increase worldwide?.J Allergy Clin Immunol. 2008; 121: 947-954Abstract Full Text Full Text PDF PubMed Scopus (407) Google Scholar There are few other comparable studies that use a common methodology to examine prevalence of eczema or atopic dermatitis, either within or between countries. The prevalence patterns described in this article are broadly s
Referência(s)