Point of view
Recent perspectives on global epidemiology of asthma in childhood

https://doi.org/10.1016/j.aller.2009.11.002Get rights and content

Abstract

New research in asthma epidemiology in children includes the development of the ISAAC programme, which has shown large variations globally in the prevalence of asthma symptoms. Time trends in the prevalence of asthma symptoms have shown a mixed picture of increases in low prevalence centres, and a plateau or even a decrease in high prevalence centres. A range of environmental factors have been studied and some potentially protective associations have been found, as well as potentially aggravating factors. Atopy has less influence on the prevalence of symptoms of asthma in low and middle income countries. Breast feeding exerts a protective effect only on non-atopic asthma in non-affluent countries. Future research should explore these areas further.

Section snippets

Background

What causes asthma is a pressing question, but the answers remain elusive. Until the mid 1980s most studies of asthma had been undertaken within high income countries whose populations originated from the British Isles, and thus the broader distribution of the prevalence of asthma in the world was largely unknown.1 Studies of the epidemiology of asthma have burgeoned since that time, reflecting worldwide concern that asthma is increasing in prevalence and is an important cause of morbidity not

Global variations in asthma prevalence

Key findings from ISAAC Phase One (1994–1996) included large variations in the worldwide prevalence of symptoms of asthma which were found even among genetically similar populations8, 11 suggesting that environmental factors play an important role.

Further study of the global prevalence and severity of asthma symptoms was undertaken in ISAAC Phase Three, conducted between 2000 and 2003, involving 798,685 adolescents from 233 centres in 97 countries, and 388,811 children from 144 centres in 61

Time trends in asthma prevalence

Most centres who undertook ISAAC Phase One repeated the study after at least five years, reflecting the large worldwide interest in time trends of prevalence. For most centres it was the first opportunity to obtain time trends information. Following reports from English language countries in the 1990s of increases in asthma prevalence from the 1980s, continuing increases in prevalence had been expected. However, ISAAC found that in most high prevalence countries, particularly the English

What environmental factors are important?

The central ISAAC approach has been to study symptoms of disease between populations, which has naturally led to ecological analyses between symptom prevalence values and potential environmental exposures. As Rose states, “the primary determinants of disease are mainly economic and social, and therefore its remedies must also be economic and social”13, and this has been the thrust of the ISAAC approach. If the environment of populations is important in the occurrence of asthma,

The influence of country income and atopy

The ecological economic analysis undertaken in the ISAAC Phase Three global study of asthma prevalence12 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 children with current wheeze, especially in the adolescents. Although asthma symptoms tended to be more prevalent in high income countries, they appeared to be more severe in low and middle

In conclusion

The asthma epidemic experienced by developed nations over the last 30 years is now affecting developing countries as they become more urbanised. Many of the world's most populous developing countries are now showing similar increases in prevalence of asthma to those experienced in many developed countries. The size of the increases in prevalence implies a large impact on the health of populations. Environmental factors are the key to explain the variations and changes in asthma prevalence. Some

Conflict of interest

Innes Asher is the Chairperson of The International Study of Asthma and Allergies in Childhood.

References (40)

  • D.A. Enarson

    Fostering a spirit of critical thinking: the ISAAC story

    Int J Tuberc Lung Dis

    (2005)
  • Ellwood P, Williams H, Aït-Khaled N, Björkstén B, Robertson C, and the ISAAC Phase Three Study Group. Translation of...
  • ISAAC Steering Committee

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

    Eur Respir J

    (1998)
  • P.G. Burney et al.

    The European Community Respiratory Health Survey

    Eur Respir J

    (1994)
  • N. Pearce et al.

    Comparison of asthma prevalence in the ISAAC and the ECRHS. ISAAC Steering Committee and the European Community Respiratory Health Survey. International Study of Asthma and Allergies in Childhood

    Eur Respir J

    (2000)
  • ISAAC Steering Committee

    Worldwide variation in prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and atopic eczema: ISAAC

    Lancet

    (1998)
  • C. Lai 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)
  • G. Rose

    The strategy of preventive medicine

    (1992)
  • A.W. Stewart et al.

    The relationship of per capita gross national product to the prevalence of symptoms of asthma and other atopic diseases in children (ISAAC). [see comments.]

    Int J Epidemiol

    (2001)
  • R.B. Newson et al.

    Paracetamol sales and atopic disease in children and adults: an ecological analysis

    Eur Respir J

    (2000)
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