UK Data Service data catalogue record for:

International Study of Asthma and Allergies in Childhood, 1992-2005

Title details

SN: 8131
Title: International Study of Asthma and Allergies in Childhood, 1992-2005
Alternative title: ISAAC
Persistent identifier: 10.5255/UKDA-SN-8131-1
Depositor: Strachan, D., St George's, University of London. Population Health Research Institute
Principal investigator(s): Strachan, D., St George's, University of London. Population Health Research Institute
Asher, I., University of Auckland. Department of Paediatrics, Child and Youth Health
Pearce, N., London School of Hygiene and Tropical Medicine. Department of Medical Statistics
Garcia-Marcos, L., University of Murcia (Spain). Department of Paediatrics
Other acknowledgements: The ISAAC International Data Centre in the Department of Paediatrics, Child and Youth Health, University of Auckland, compiled and analysed the Phase One and Phase Three datasets. Philippa Ellwood, Tadd Clayton and Eamon Ellwood each played distinct and invaluable roles in this process. The ISAAC Phase Two Co-ordinating and Data Centre in the Institute of Epidemiology and Medical Biometry, University of Ulm, compiled and analysed the Phase Two datasets. Gudrun Weinmayr, Andrea Kleiner and Peter Rzehak each played distinct and invaluable roles in this process.


The citation for this study is:

Strachan, D., Asher, I., Pearce, N., Garcia-Marcos, L. (2017). International Study of Asthma and Allergies in Childhood, 1992-2005. [data collection]. UK Data Service. SN: 8131,

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Subject Categories

Health services and medical care - Health
Specific diseases and medical conditions - Health
Youth - Social stratification and groupings


Abstract copyright UK Data Service and data collection copyright owner.

The International Study of Asthma and Allergies in Childhood (ISAAC) was a worldwide epidemiological research programme established in 1991 to investigate asthma, rhinoconjunctivitis and eczema in children, due to considerable concern that these conditions were increasing in many countries, and that the causes of this increase were unknown. ISAAC Phase One was an international multi-centre cross-sectional study involving two age groups of school children, 13-14 year olds (adolescents) and 6-7 year olds (children). Schools were randomly selected from a defined geographical area. Written questionnaires on asthma, rhinitis and eczema symptoms (translated from English) were completed by the adolescents at school, and at home by the parents of the children. An asthma symptoms video questionnaire for the adolescents was optional. ISAAC Phase Two involved more intensive studies in a smaller number of selected centres. Children aged 8-12 years were examined for flexural dermatitis, underwent skin prick tests for atopy, bronchial responsiveness to hypertonic saline, blood sampling and storage for serum IgE and genetic analyses, and additional questionnaires were completed by their parents. ISAAC Phase Three, a repeat of Phase One after at least five years, examined variations in time trends of childhood asthma, rhinoconjunctivitis and eczema around the world, and expanded the world maps of these conditions. Additional questions on risk factors were included in Phase Three. The ISAAC programme grew to involve nearly 2 million children from 306 study centres in 105 countries, before it formally closed in December 2012.

Further information about the study can be found on the ISAAC study website.
Main Topics:
Prevalence and severity of symptoms of asthma, rhinoconjunctivitis and eczema in schoolchildren. Individual risk factors for these conditions. Trends over time in prevalence of these conditions.

Coverage, universe, methodology

Dates of fieldwork: June 1992 - March 2005 - Symptom questions generally refer to the past 12 months.
Country: Multi-nation
Spatial units: Countries
Observation units: Individuals
Kind of data: Numeric data
Individual (micro) level
Universe: Cross-national; National
Almost 2 million children aged 6-7 or 13-14 years from about 300 study centres in over 100 countries took part in either ISAAC Phase One or ISAAC Phase Three (questionnaire surveys). Over 50,000 children aged 8-12 years from 30 study centres in 23 countries took part in ISAAC Phase Two, which involved clinical tests for asthma and allergy as well as data collection by questionnaire.
Time dimensions: Repeated cross-sectional study
Not all centres took part in both Phase One and Phase Three, so information is available on a one-time basis from some centres and a repeated cross-sectional basis from others. Some centres undertook Phase Two in the same study area as Phase One (but in a different age group). Other centres in Phase Two are not represented in either Phase One or Phase Three.
Sampling procedures: One-stage stratified or systematic random sample
In Phase Two, some measurements in some centres were performed only on a stratified sample, with two strata: wheezy children and non-wheezy children.
Method of data collection: Postal survey; Self-completion; Clinical measurements
Self-completion (at school) used for 13-14-year-olds. Postal questionnaire (distributed to parents via schools) used for younger age-groups. Clinical measurements restricted to Phase Two only.
Weighting: Weighting is not applicable to Phases One and Three. In Phase Two, a stratum-weighted analysis is recommended for all purposes although it is strictly necessary only for variables which were ascertained on a stratified sample of wheezy children and non-wheezy children. This recommendation is specified in the documentation.

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Administrative and access information

Date of release:
First edition: 22 February 2017
Copyright: Copyright D. Strachan, I. Asher, N. Pearce and L. Garcia-Marcos
Access conditions: The depositor has specified that registration is not required.
Please note: Attribution 4.0 International (CC BY 4.0)
These data are available to any user for any purpose under the Creative Commons Attribution 4.0 International Licence (CC BY 4.0)
Availability: UK Data Service
Contact: Get in touch


Zip files contain data, documentation and licence details

Title Size (KB)
SPSS (Zip) 50796[MD5Checksum: 2824DDE1F1153049F09C3BB8E65EDA5E]
Stata (Zip) 42886[MD5Checksum: 7A3E2A0B96B6FDB9FDE65253E8F7D2B4]
Tab-delimited (Zip) 46225[MD5Checksum: FFFF04B789439F8D86E28F746EC804D7]


Title File Name Size (KB)
Metadata for the ISAAC Core Questionnaire Data Files (Phases One & Three) 8131_isaac1and3_core_ques_metadata.pdf 344
Metadata for the ISAAC Phase One Centre Questionnaire Data Files 8131_isaac1_centre_info_metadata.pdf 234
ISAAC Phase One Manual 8131_isaac1_manual.pdf 599
Metadata for the ISAAC Phase Two Centre Questionnaire Data File 8131_isaac2_centre_info_metadata.pdf 267
ISAAC Phase Two Centre Report - 10-11 Year Age Group 8131_isaac2_centre_questionnaire.pdf 373
Appendix to the ISAAC Phase Two Codebook 8131_isaac2_codebook_appendix.pdf 526
ISAAC Phase Two Codebook for Analyses 8131_isaac2_codebook_for_analyses.pdf 372
ISAAC Phase Two Coding and Data Transfer Manual 8131_isaac2_coding_manual.pdf 372
ISAAC Phase Two Manual 8131_isaac2_fieldwork_manual.pdf 628
Notes on Input and Analysis of ISAAC Phase Two Data Using Stata 8131_isaac2_stata_input_statement.pdf 225
Metadata for the ISAAC Phase Three Centre Questionnaire Data Files 8131_isaac3_centre_info_metadata.pdf 242
Coding and Data Transfer for the ISAAC Phase Three Environmental Questionnaire 8131_isaac3_envt_coding_manual.pdf 381
Metadata for the ISAAC Environmental Questionnaire Data Files (Phase Three) 8131_isaac3_envt_ques_metadata.pdf 291
ISAAC Phase Three Manual 8131_isaac3_manual.pdf 1973
Study information and citation UKDA_Study_8131_Information.htm 6
READ File read8131.htm 11


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By principal investigator(s):
The following key papers describe the methodology of Phases One, Two and Three of ISAAC:

Asher, M.I., Keil, U., Anderson, H.R., Beasley, R., Crane, J., Martinez, F., Mitchell, E.A., Pearce, N., Sibbald, B., Stewart, A.W., Strachan, D., Weiland, S.K. and Williams, H.C. (1995) 'International study of asthma and allergies in childhood (ISAAC): rationale and methods', European Respiratory Journal, 8, p.483-91.

Weiland, S.K., Björkstén, B., Brunekreef, B., Cookson, W.O., von Mutius, E., Strachan, D.P. and the ISAAC Phase Two Study Group (2004) 'Phase II of the International Study of Asthma and Allergies in Childhood (ISAAC II): rationale and methods', European Respiratory Journal, 24, pp.406-12.

Ellwood, P., Asher, M.I., Beasley, R., Clayton, T.O., Stewart, A.W., and the ISAAC Steering Committee (2005) 'The International Study of Asthma and Allergies in Childhood (ISAAC): Phase Three rationale and methods', International Journal of Tuberculosis and Lung Disease, 9, pp.10-16.

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