I nternational

S tudy of

Asthma and

A llergies in

Childhood

ISAAC1998

ISAAC Objectives

1. To describe the prevalence and severity of asthma, rhinitis and eczema in children living in different centres and to make comparisons within and between countries.

2. To obtain baseline measure for assessment of future trends in the prevalence and severity of these diseases.

3. To provide a framework for further aetiologicalresearch into lifestyle, environmental, genetic and medical care factors affecting these diseases.

Tonga

2004

ISAAC1998

The three phases of ISAAC (so far!)

I International survey of the prevalence and severity of asthma, rhinitis, and eczema in childhood

II Studies of aetiologic factors, including skin tests for atopy, lung function and bronchial reactivity, serum IgE levels, physical examination, genetic markers, aeroallergens at home, and clinical management

III Repetition of Phase I after at least 5 years to determine trends in these diseases

Tonga

2004

Design: Multicentre prevalence studies

Identical methods (but translated questions)

Study areas: Largely recruited by personal contacts but differing in lifestyle and environment

Population: 13-14 year old school children (core)

6-7 year olds (strongly recommended)

Sample size: 3,000 children ideally (minimum 1,000)

Study period: July 1992 - December 1995

ISAAC1998

Phase One methods

Tonga

2004

Phase One “core” instruments

• written questionnaires on the prevalence and severity of asthma, rhinitis, and eczema for self-completion in 13 - 14 yr olds (compulsory)

• video questionnaire on the prevalence and severity of asthma for self-completion by 13 - 14 yr olds(recommended)

• written questionnaires on the prevalence and severity of asthma, rhinitis, and eczema for completion by parents of 6 - 7 yr olds (recommended)

ISAAC1998

Tonga

2004

I Asher (chair)R BeasleyJ CraneE MitchellN PearceC Robertson

C Lai

JR Shah

N Aït-KhaledG Anabwani

J Mallol

(F Martinez)

B Björkstén

S Montefort

R Anderson(M Burr)U KeilD StrachanE von MutiusS WeilandH Williams

ISAAC Steering Committee

ISAAC1998

S Foliaki

Study Centres and Participants: Phase I13-14 Year Age Group

Region Centre

n

Participants

n

Participation

%

Africa 7 21,648 91%

Asia-Pacific 20 83,826 94%

Eastern Mediterranean 10 28,468 93%

Latin America 17 52,549 93%

North America 5 12,460 79%

Northern and Eastern Europe 20 60,819 93%

Oceania 10 31,301 93%

Southeast Asia 14 37,171 95%

Western Europe 52 135,559 90%

Global Total: 155 463,801 92%

ISAAC

gm/08/96: stock_2.ppt

Wheeze in last 12 mths

Phase One

ISAA C

1998

13-14 y r age grp

<5%

5 to <10%

10 to <20%

20%

Asthma prevalence in English-speaking countries

0

5

10

15

20

25

30

35

New

Zealand

Australia United

Kingdom

Ireland USA Canada

Wh

ee

zin

g in

pa

st

12

mo

nth

sChildren

Adults

Asthma severity in English-speaking countries

0

2

4

6

8

10

12

New

Zealand

Australia United

Kingdom

Ireland USA Canada

Severe

wh

eeze l

imit

ing

sp

eech

Children

Adults

Key Findings From ISAAC Phase I

• English-speaking countries have the highest asthma prevalence in the world

• There is little variation within the English-speaking countries

• Other countries in Latin America are also high

• There is a Northwest-Southeast gradient within Europe

Key Findings From ISAAC Phase I

• There is an inconsistent correlation of asthma prevalence with affluence (as measured by GNP)

• There are some areas (West/East Germany, Hong Kong/Guangzhou) with major prevalence differences within the same ethnic group

• There is a weak and inconsistent association between asthma prevalence and that of other “atopic” conditions such as rhinitis and eczema

Key Findings From ISAAC Phase I

• Although there are large international differences in prevalence, these do not, in general, correlate strongly with recognised “risk factors” for asthma symptoms

• Negative associations (or no association) with air pollution, smoking, pollens, antibiotics, immunization

• Positive associations with GNP, tuberculosis, trans fatty acids, (lack of) vegetables, paracetamol, indoor humidity

Design: 3A Repeat prevalence studies after 5+ years

3B First prevalence studies in new centres

Study areas: From phase 1 (3A), or volunteers (3B)

Population: 13-14 year old school children

6-7 year olds (strongly recommended)

Sample size: 3,000 children ideally (minimum 1,000)

Study period: 1999 to 2003 (phase 3A)

1998 (“late phase 1”) to 2003 (phase 3B)

ISAAC1998

Phase Three methods

Tonga

2004

Phase Three “core” instruments

• written symptom questionnaires for self-completion in 13 - 14 yr olds (compulsory)

• video questionnaire for self-completion by 13 - 14 yr olds (recommended)

• written symptom questionnaires for completion by parents of 6 - 7 yr olds (recommended)

• written risk factor questionnaires for completion by parents of 6 - 7 yr olds, and self-completion by 13 - 14 year olds (recommended)

ISAAC1998

Tonga

2004

Study Centres and Participants: Phase III13-14 Year Age Group

Region Phase I

centres

Phase IIIa

centres

Phase IIIb

centres

Africa 10 9 13

Asia-Pacific 35 23 23

Eastern/Northern Europe

17 12 16

Eastern Mediterranean 10 6 11

Latin America 16 15 41

North America 5 2 5

Oceania 10 5 9

Western Europe 51 34 10

Global Total: 155 106 127

ISAAC

gm/08/96: stock_2.ppt

CENTRES REGISTERED FOR ISAAC PHASE THREE

Phase 3A centres

Phase 3B centres

Phase 1 centres not participating in Phase 3

Wheeze in last 12 mths

Phase One

ISAA C

1998

13-14 y r age grp

<5%

5 to <10%

10 to <20%

20%

Phase Three

ISAAC

2005

13-14 Year Age Group

Change in Symptoms of Asthma

>2 SE Decrease

1-2 SE Decrease

1-2 SE Increase

>2 SE Increase

No Change

Country ordered by average prevalence

Country (Prev. %)

Albania ( 3.0)Indonesia ( 3.6)

Georgia ( 4.3)China ( 5.1)

Taiwan ( 6.2)India ( 6.2)

Algeria ( 7.3)Lithuania ( 7.5)

South Korea ( 8.3)Oman ( 8.7)

Estonia ( 8.9)Morocco ( 9.0)

Poland ( 9.0)Mexico ( 9.1)

Italy ( 9.1)Malaysia ( 9.1)

Latvia ( 9.4)Spain ( 9.5)

Ethiopia ( 9.9)Pakistan (10.1)Belgium (10.2)Tunisia (10.2)

Philippines (10.3)Portugal (10.4)

Hong Kong (10.5)Singapore (10.6)

Sweden (11.1)Nigeria (11.8)

Iran (12.2)Thailand (12.2)

Kuwait (12.3)Argentina (12.4)

Chile (12.8)Romania (12.8)

Japan (13.2)Austria (13.4)Kenya (14.8)Malta (15.3)

South Africa (15.8)Germany (15.8)

Finland (16.1)Ukraine (16.9)

Uruguay (18.5)Barbados (19.2)Paraguay (20.2)

Panama (20.3)Brazil (21.3)USA (22.6)Peru (22.8)

Costa Rica (25.5)Rep. of Ireland (27.9)

New Zealand (28.0)United Kingdom (28.5)

Mean Change per year

-3 -2 -1 0 1 2 3

Country ordered by average prevalence

Country (Prev. %)

Albania ( 0.6)Georgia ( 0.8)

Lithuania ( 0.9)Indonesia ( 0.9)

China ( 1.1)India ( 1.2)

Taiwan ( 1.5)Estonia ( 1.8)

Philippines ( 1.8)Ukraine ( 1.9)Mexico ( 1.9)

Chile ( 2.0)Italy ( 2.1)

Pakistan ( 2.2)South Korea ( 2.2)

Singapore ( 2.3)Poland ( 2.4)

Malaysia ( 2.4)Tunisia ( 2.4)

Portugal ( 2.4)Iran ( 2.5)

Algeria ( 2.6)Romania ( 2.7)Morocco ( 2.7)

Spain ( 2.8)Argentina ( 2.9)

Austria ( 3.0)Belgium ( 3.0)Finland ( 3.2)

Sweden ( 3.3)South Africa ( 3.4)Hong Kong ( 3.4)

Brazil ( 3.7)Japan ( 3.7)

Thailand ( 3.8)Malta ( 3.8)

Germany ( 3.9)Paraguay ( 3.9)

Nigeria ( 4.0)Barbados ( 4.0)

Panamá ( 4.3)Peru ( 4.6)

Ethiopia ( 4.6)Uruguay ( 5.2)

Kenya ( 5.3)USA ( 6.1)

Costa Rica ( 6.7)New Zealand ( 7.7)

United Kingdom ( 7.7)Canada ( 7.8)

Australia ( 8.8)

Mean Change per year

-2 -1 0 1 2

Country ordered by average prevalence

Country (Prev. %)

Albania ( 2.6)Ethiopia ( 2.6)

Lithuania ( 2.7)Iran ( 3.1)

Georgia ( 3.5)South Korea ( 3.9)

Estonia ( 4.0)Poland ( 4.1)

India ( 5.2)China ( 5.4)Latvia ( 5.6)

Mexico ( 5.6)Ukraine ( 5.8)Algeria ( 5.9)Finland ( 6.1)Austria ( 6.2)

Romania ( 6.3)Indonesia ( 7.0)Pakistan ( 7.4)

Germany ( 7.5)Belgium ( 8.3)

Argentina ( 9.6)Italy (10.5)

Hong Kong (10.7)Sweden (11.1)

Malaysia (11.5)Spain (11.8)

South Africa (12.1)Thailand (12.3)

Paraguay (12.5)Malta (12.6)Chile (12.8)

Kenya (12.9)Taiwan (13.1)

Portugal (13.2)Brazil (14.6)

Morocco (14.7)Nigeria (15.0)Tunisia (15.6)Kuwait (15.8)

Uruguay (16.7)USA (18.3)

Rep. of Ireland (18.4)Panama (18.7)

Philippines (19.3)Japan (19.4)Oman (20.3)

Costa Rica (20.8)Barbados (20.9)

United Kingdom (23.0)Singapore (23.7)

New Zealand (27.7)Peru (30.5)

Mean Change per year

-2 -1 0 1 2

Key Findings From ISAAC Phase III

• Little change in overall prevalence

• International differences in asthma symptom prevalence have reduced

• Decreases in English-speaking countries

• Increases in some (but not all) regions where prevalence was previously low

• Increases in diagnosed asthma in most regions

• Particular increases in Africa, Latin America and parts of Asia – asthma is no longer an “english speaking”disease