Worldwide trends in the prevalence of asthma symptoms: phase III of the International Study of Asthma and Allergies in Childhood (ISAAC)

Abstract

Background: Phase I of the International Study of Asthma and Allergies in Childhood (ISAAC) was designed to allow worldwide comparisons of the prevalence of asthma symptoms. In phase III the phase I survey was repeated in order to assess changes over time. Methods: The phase I survey was repeated after an interval of 5-10 years in 106 centres in 56 countries in children aged 13-14 years (n = 304 679) and in 66 centres in 37 countries in children aged 6-7 years (n = 193 404). Results: The mean symptom prevalence of current wheeze in the last 12 months changed slightly from 13.2% to 13.7% in the 13-14 year age group (mean increase of 0.06% per year) and from 11.1% to 11.6% in the 6-7 year age group (mean increase of 0.13% per year). There was also little change in the mean symptom prevalence of severe asthma or the symptom prevalence measured with the asthma video questionnaire. However, the time trends in asthma symptom prevalence showed different regional patterns. In Western Europe, current wheeze decreased by 0.07% per year in children aged 13-14 years but increased by 0.20% per year in children aged 6-7 years. The corresponding findings per year for the other regions in children aged 13-14 years and 6-7 years, respectively, were: Oceania (20.39% and 20.21%); Latin America (+0.32% and +0.07%); Northern and Eastern Europe (+0.26% and +0.05%); Africa (+0.16% and +0.10%); North America (+0.12% and +0.32%); Eastern Mediterranean (20.10% and +0.79%); Asia-Pacific (+0.07% and 20.06%); and the Indian subcontinent (+0.02% and +0.06%). There was a particularly marked reduction in current asthma symptom prevalence in English language countries (20.51% and 20.09%). Similar patterns were observed for symptoms of severe asthma. However, the percentage of children reported to have had asthma at some time in their lives increased by 0.28% per year in the 13-14 year age group and by 0.18% per year in the 6-7 year age group. Conclusions: These findings indicate that international differences in asthma symptom prevalence have reduced, particularly in the 13-14 year age group, with decreases in prevalence in English speaking countries and Western Europe and increases in prevalence in regions where prevalence was previously low. Although there was little change in the overall prevalence of current wheeze, the percentage of children reported to have had asthma increased significantly, possibly reflecting greater awareness of this condition and/or changes in diagnostic practice. The increases in asthma symptom prevalence in Africa, Latin America and parts of Asia indicate that the global burden of asthma is continuing to rise, but the global prevalence differences are lessening.

Tendência temporal de asma em crianças e adolescentes no Brasil no período de 1998 a 2008

“…The recent literature on time trends in asthma shows the large use of the comparison between stages I and III of ISAAC, 2,5,11,15,16,20 which observed this prevalence in the six-and-seven-year age group, in the 13-and-14-year age group, or in both. However, the majority of these studies were performed in Europe and Asia; only three of these were conducted in Latin America, of which one was in Chile 11 and two in Brazil.…”

“…In the United States, data from the Centers for Disease Control and Prevention pointed to an increase of 4.6% from 1980 to 1996 and a stability in the prevalence of asthma in individuals aged between zero and 17 years, between 1997 and 2007. 1 By analyzing information from all countries that participated in the ISAAC, Pearce et al 15 observed an annual increase in asthma prevalence in adolescents that varied between 0.07% in Africa and 0.93% in Oceania. Only in the Indian subcontinent was there an annual decrease of 0.01%.…”

“…prevalence of asthma in childhood, with a reduction in mortality rates in the same period. 1 A study conducted by Pearce et al, 15 with data from the International Study of Asthma and Allergy in Childhood (ISAAC), showed a reduction in asthma in English-speaking countries and Western Europe. In contrast, there was an increase in the asthma prevalence throughout the years in countries where the prevalence was considered to be low.…”

“…In Latin America, the prevalence of asthma symptoms has increased. 15 Nonetheless, in South America, a systematic review pointed to inconsistencies in the decreasing or increasing pattern of asthma prevalence in studies that use the ISAAC methodology. 3 The Pesquisa Nacional por Amostra de Domicílios (PNAD -National Household Sample Survey), performed by the Instituto Brasileiro de Geografi a e Estatística (IBGE -Brazilian Institute of Geography and Statistics), regularly investigates health aspects of the population.…”

Enfermedades sensibles al clima, Distrito Metropolitano de Quito, un análisis temporal en el periodo 2001-2010

“…Evidencia recolectada alrededor del mundo sugiere que las enfermedades alérgicas y respiratorias como el asma y la rinitis han aumentado en las últimos décadas (Van der Heide, 1994), y que la contaminación del aire podría ser una de las causas para tal incremento (Pearce et al, 2007).…”