Bronchial asthma prevalence in childhood
J. C. Miralles-López*, F. Guillén-Grima**, E. Aguinaga-Ontoso***, I. Aguinaga-Ontoso****, F. Sánchez-Gascón*****, J. M. Negro-Álvarez******, M. Fernández-Benítez******* and M. García-García*
*Allergy Section. University General Hospital of Murcia. **Health Sciences Department. Public University of Navarra. ***Department of Social and Sanitary Sciences. University of Murcia. ****Department of Preventive Medicine and Public Health. University of Navarra School of Medicine. *****Pneumology Section. University General Hospital of Murcia. ******Allergy Section. University Hospital "Virgen de la Arrixaca". El Palmar (Murcia). *******Allergy and Clinical Immunology Department. University Clinic of Navarra.
Correspondence:
Dr. Francisco Guillén Grima
Departamento Ciencias de la Salud
Universidad Pública de Navarra
Avda. de Baranain, s/n
31008 Pamplona, Navarra (Spain)
RESUMEN
Antecedentes: actualmente hay un gran interés en realizar comparaciones internacionales en la prevalencia de asma bronquial, debido a las crecientes evidencias sobre un aumento en su prevalencia. Las comparaciones entre los estudios de prevalencia de asma bronquial presentan el problema de las diferentes metodologías empleadas por los autores, así como la falta de una definición clara de qué es lo que se considera asma bronquial.
Métodos: en este artículo hemos tratado de ofrecer una visión global de los diferentes estudios sobre prevalencia del asma en la infancia publicados en todo el mundo.
Conclusiones: en los estudios realizados en Europa cabe destacar las altas cifras encontradas en el Reino Unido muy superiores a las halladas en el resto del Continente Europeo con la excepción de Suiza.
En España las cifras de los estudios de ámbito nacional están por debajo de la tasa de los países de nuestro entorno, aunque en algunos estudios realizados en Huelva y Barcelona se han encontrado cifras algo mayores.
En Oceanía se han encontrado las cifras más altas de todo el mundo, mayores que las de América y muy por encima de las encontradas en África (con la excepción de Sudáfrica).
Aunque existen diferencias geográficas importantes, la prevalencia de asma bronquial está aumentando constantemente en todo el mundo. Por esta razón se deberían realizar esfuerzos para conocer las causas de este aumento así como estandarizar instrumentos para medir la aparición de esta enfermedad.
Palabras clave: Asma bronquial. Niños. Epidemiología. Revisión.
SUMMARY
Background: at the moment there is a considerable interest in the international comparison of the bronchial asthma prevalence, stimulated by the growing evidence of an increment in the frequency. The comparison among studies of bronchial asthma prevalence present the problem of the varied and different methodologies used by the authors, as well as of the lack of a clear definition of what is considered bronchial asthma.
Methods: in this work we try to offer a global vision of the studies published on childhood asthma prevalence in the world.
Conclusions: in the studies carried out at European level, they highlight the high figures found in the British Islands superiors to those referred in the countries from the continent to exception of those observed in Switzerland.
In Spain the figures of the studies carried out at national level are something below the countries of our environment, although there have been higher figures in studies carried out in Barcelona and Huelva.
In Oceannia they are observed from all over the world in general the highest figures, above the American countries and very above the countries of Asia and Africa to exception of South Africa.
Although there are considerable geographical differences in its presentation, bronchial asthma is an illness in constant increase in the entire world. It is for this reason that efforts should be carried out in the search of the causes of this increment, as well as in the standardization of the instruments of measure of the appearance of the illness.
Key words: Bronchial asthma. Children. Epidemiology. Review.
INTRODUCTION
At the moment there is a considerable interest in the international comparison of the prevalence of bronchial asthma, stimulated by the growing evidence of an increment in the frequency [Weitzman et al (1), Anderson et al (2), Peat et al (3), Aberg et al (4), Omran et al (5), Lewis et al (6), Ciprandi et al (7)] and mortality of the illness [Sears (8), Woolcock (9), Evans et al (10), Esdaile et al (11), Pedersen and Weeke (12)].
Although the presence of bronchial hyperreactivity has been used in occasions as asthma definition, the questionnaires of symptoms continue being the angular stone of epidemiologic studies to great scale of childhood asthma [Pearce et al (13)].
The comparison among studies of bronchial asthma prevalence presents the problem of the varied and different methodologies used by the authors, as well as of the lack of a clear definition of what is considered bronchial asthma. In answer to these problems in the last years the International Study of Asthma and Allergies in Childhood (ISAAC) has been developed in different countries [ISAAC Coordinating Committee (14)] that represents a multicenter project for the establishment of the prevalence of atopic illnesses, in different geographical areas, using the same methodology.
In this work we have tried to offer a global vision of the studies published on childhood asthma prevalence in the world.
MATERIAL AND METHODS
The search of information was carried out in the database "The Cochrane Library" 1998 n.º 1, using the keyword of the MeSH < ASTHMA > and in the database Medline (Ebsco V 5.1) embracing the period understood from January of 1989 until January of 1998, using the following search strategies: the first MH "ASTHMA/EP" & (ALL "infant*" OR ALL "child" OR ALL "children" OR ALL "adolescen*") and the second ALL "ISAAC" OR (ALL "allergies" AND ALL "asthma" AND ALL "childhood") NOT (AU "ISAAC*" OR ALL ISAACS*). The bibliography of each one of the articles located by the previous procedure was also consulted to locate the reports and articles published in magazines not included in the consultation databases. Later on the original papers were requested to several libraries and documentation centers.
RESULTS
Studies in Europe
In the table I the studies carried out in Europe can be observed. Lewis et al (6), in Great Britain, studying two cohorts born in 1958 and 1970 to the 16 year-old age (in 1974 and 1986), they find that the current prevalence (last 12 months) of asthma it increased of 3.8% in 1974 to 6.5% in 1986. The authors found increments also in the atopic dermatitis and hay fever prevalence, for what they conclude that the increase in the figures of bronchial asthma is part of a general increase in the prevalence of the atopic illnesses. Other authors in the same geographical environment, such as Strachan et al (17) obtained bigger figures communicating a prevalence of 15% in 1991, while Anderson et al (2) of 12.31% in the same year. Strachan et al (15) refer a cumulative incidence of 24% in 1974 to the 16 years and Luyt et al (16) of 16% in smaller than 5 years in 1990.
In England the figures of current asthma prevalence oscillate from 17% in the 8-9 years in 1991-92 [Powel and Primhak (18)] to 8.5% in the 11 years in 1986 [Cliffor et al (20)]. In Scotland the asthma diagnosed by doctors was increasd 5 times between 1964 and 1994 [Ninan and Russell (21), Omran et al (5)]. Also in Wales [Burr et al (23)] an increment has been observed in the current bronchial asthma prevalence from almost 10% in 1973, to 15% in 1988.
In Ireland, Taylor et al (24) find that the diagnosed asthma presence almost increased 4 times between 1983 and 1993. Memon and Loftus (25) refer a wheezing prevalence in the last twelve months of 16.1%; of the 134 children that suffered wheezing in the last 12 months in this study, 90 had only been diagnosed of asthma, what gives an idea of the underdiagnosis level for this illness.
In Switzerland Sennhauser and Kuhni (27) communicate a current prevalence of 17.5%, much bigger to the opposing ones in France: 7.8% [Le Roux et al (28)], Italy [SIDRIA (29)]: 7.7% or Poland [Zejda et al (34)]: 12.3 and 11%. In Germany the figures of diagnosed asthma oscillate among 1.3% [Schafer et al (31)] and 5,9% [Von Mutius et al (33)]. These authors carried out an interesting work, taking advantage of the German reunification, to investigate the impact of the environmental factors in the development of breathing and allergic illnesses, in populations ethnically similar. A questionnaire was administered to the parents. Their children got a provocation test with cold air and cutaneous tests of allergy. The allergic sensitization was considerably more frequent in the children from Western Germany that in those of East Germany. The current prevalence of asthma diagnosed by a doctor and the presence of bronchial hyperresponsiveness was also bigger in Western Germany. The authors concluded that the western lifestyle is a risk factor for atopia development. In Finland an increment has also been observed in the current bronchial asthma prevalence, from 4% in 1980 [Poysa et al (37)] until 13-20% obtained by Pekkanen et al (35), using the methodology ISAAC, in different cities. In Sweden Aberg et al (4) find a prevalence of 5.7% in 1991 and Nystad et al (40) in Norway communicate an increase almost 3 times of the cumulative incidence between 1981 and 1994. In this same country Dotterud et al (41) refer a current prevalence of 7% in 1992-93.
Studies in Spain
The studies carried out in Spain appear in table II Fernández Benítez et al (43) using the methodology ISAAC in Pamplona, found a wheezing prevalence in the last year of 5.3% in 13-14 year-old children and of 3.3% in 6-7 year-old children. Busquets et al (44) obtained a current prevalence of wheezing of 14%. They carried out an exercise test and they found a descent of the pick-flow bigger than 15% in 11.4% of the children, although only in 27% of those that referred breathing symptoms. Pereira et al (45) obtained a similar prevalence in Huelva.
Table I Studies of asthma prevalence in Europe | ||||||
| Author | Year | Place | Sample | Age | Current prevalence | Study type |
| Lewis (6) (1996) | 1974 | Great Britain | 11,262 | 16 | 3.8% | Interview parents |
| 1986 | 9,266 | 16 | 6.5% | |||
| Strachan (15) (1996) | 1965 | England, | 5,801 | 7 | 18% (cumulative incidence) | Interview parents |
| 1974 | Scotland, Wales | 5,801 | 16 | 24% (cumulative incidence) | Longitudinal prospective study | |
| Luyt (16) (1995) | 1990 | Great Britain | 1,422 | < 5 | 16% (cumulative incidence) | Interview parents |
| Strachan (17) (1994) | 1991 | Great Britain | 5,472 | 5-17 | 15% | Interview parents |
| Anderson (2) (1994) | 1978 | Great Britain | 4,147 | 7-8 | 9.73% | Interview parents |
| 1991 | 3,070 | 7-8 | 12.31% | |||
| Powell (8) (1995) | 1991-92 | England | 4,539 | 8-9 | 17% | Interview parents |
| Gellert (19) (1990) | 1986-89 | England | 11,148 | 0-15 | 19.5% (cumulative incidence) | Retrospective study of general medicine consults |
| Cliffor (20) (1989) | 1986 | England | 2,503 | 7 | 12.1% | Interview parents |
| 11 | 8.5% | |||||
| Omran (5) (1996) | 1989 | Scotland | 3,403 | 8-13 | 10.2% (medical diagnosis) | Interview parents |
| 1994 | 4,034 | 8-13 | 19.6% (medical diagnosis) | |||
| Austin (21) (1994) | 1992 | Scotland | 1,825 | 12-13 | 19% | Interview parents |
| 25% (cumulative incidence) | ||||||
| Ninan (22) (1992) | 1964 | Scotland | 2,510 | 8-13 | 10.4% (cumulative incidence) | Interview parents |
| 4.1% (medical diagnosis) | ||||||
| 19.8% (cumulative incidence) | ||||||
| 1989 | 3,403 | 8-13 | 10.2% (medical diagnosis) | |||
| Burr (23) (1989) | 1973 | Wales | 818 | 12 | 9.8% | Interview parents |
| 17% (cumulative incidence) | ||||||
| 1988 | 965 | 15.2% | ||||
| 22.3% (cumulative incidence) | ||||||
| Taylor (24) (1996) | 1983-84 | Ireland | 4-19 | 4.4% (medical diagnosis) | Interview parents | |
| 1993 | 2,813 | 11.9% (medical diagnosis) | ||||
| Memon (25) (1993) | 1991-92 | Ireland | 832 | 9 | 16.1% | Interview parents |
| 24.5% (cumulative incidence) | ||||||
| Prata (26) (1994) | 1993 | Azores | 927 | 6-12 | 8% (medical diagnosis) | Interview parents |
| Sennhauser (27) (1995) | 1990 | Switzerland | 4,353 | 7, 12, 15 | 17.5% | Interview parents |
| Le Roux (28) (1995) | 1993 | France | 1,193 | Primary school | 7.8% | Interview parents |
| SIDRIA (29) (1997) | 1994-95 | Italy | 18,737 | 6-7 | 7.7% | Interview parents |
| 24% (cumulative incidence) | ||||||
| 8.7% (medical diagnosis) | ||||||
| Angioni (30) (1989) | 1986 | Italy | 1,691 | 6-10 | 5.1% (cumulative incidence) | Interview parents |
| Schäfer (31) (1996) | 1991 | Germany | 1,470 | 5-7 | 1.3% (medical diagnosis) | Interview parents |
| Wjst (32) (1992) | | Germany | 8,130 | 9-10 | 10.2% (cumulative incidence) | Interview parentes |
| Von Mutius (33) (1994) | 1989-90 | Munich | 5,030 | 9-11 | 17% (cumulative incidence) | Interview parents |
| 5,9% (medical diagnosis) | ||||||
| 1991-92 | Leipzig | 2,623 | 26.8% (cumulative incidence) | |||
| 3.9% (medical diagnosis) | ||||||
| 1992-93 | Poland | 7-9 | Interview parents | |||
| Zejda (34) (1996) | Chorzow | 1,142 | 12.3% | |||
| 21.4% (cumulative incidence) | ||||||
| 11% | ||||||
| Mikolow | 480 | 17.1% (cumulative incidence) | ||||
| Pekkanen (35) (1997) | 1994-95 | Finland | 13-14 | Written questionnnaire | ||
| Kuopio | 2,821 | 13% 10% | and video questionnaire children | |||
| Helsinki | 2,771 | 20% 12% | ||||
| Turku y Pori | 2,983 | 15% 12% | ||||
| Lapland | 3,032 | 16% 11% | ||||
| Rimpela (36) (1995) | 1977-79 | Finland | 4,335 | 12, 14, 16, 18 | 1% (medical diagnosis) | Questionnaires sent by mail |
| 1991 | 3,059 | 2.8% (medical diagnosis) | ||||
| Poysa (37) (1991) | 1980 | Finland | 3,649 | Children, adolescents | 4.3% | Interview parents |
| Host (38) (1993) | | Denmark | 851 | 6-17 | 8.8% (cumulative incidence) | Interview parents |
| 4% (medical diagnosis) | ||||||
| Aberg (4) (1995) | 1979 | Sweden | 4,628 | 7, 10, 14 | 2.48% | Interview parents |
| 1991 | 2,481 | 5.71% | ||||
| Braback (39) (1988) | 1985 | Sweden | 9,603 | 7-16 | 4% | Interview parents |
| Nystad (40) (1997) | 1981 | Norway | 1,674 | 6-16 | 3.4% (cumulative incidence) | Interview parents |
| 1994 | 2,188 | 9.3% (cumulative incidence) | ||||
| Dotterud (41) (1995) | 1992-93 | Norway | 424 | 7-12 | 7% | Interview children and |
| 13% (cumulative incidence) | discussion with attendants | |||||
| Riikjärv (42) (1995) | 1992-93 | Estonia | 10-12 | Interview parents | ||
| Tallinn | 753 | 9.4% | ||||
| 3.2% (medical diagnosis) | ||||||
| Tartu | 766 | 5.8% | ||||
| 2.5% (medical diagnosis) | ||||||
Callén et al (46), revising the clinical histories of four health centers of the Guipúzcoa province found a prevalence by means of clinical and functional approaches of 8.84%. On the other hand, they found a bigger prevalence in the two health centers of the coast that in the two of the interior. Egea et al (47) refer a very similar prevalence in Seville by means of a survey of breathing symptoms and a personal interview.
In a sample of municipalities of more than 2,000 inhabitants of the Community of Madrid, Galán and Martínez (48) found a quite inferior prevalence, similar to the one referred by the Center for the Study of the Asthmatic Illness (49) (CESEA) in an epidemic study on asthma prevalence in Spain.
To know the prevalence of the allergic illnesses in pediatric age in Spain, Muñoz and Ríos (50) carried out a survey in the general school population, distributed in complete classes of different school centers distributed by the whole national geography. 20% said to suffer allergic illness, of which 13% was certain and 7% probable. The prevalence of asthmatic diagnosed in the general population was of 6.4%, with some bigger figures in children in the Galician-Cantabrian areas, Center and Canary Islands and in girls in Canary Islands and Andalusia interior-Extremadura. The lowest figures were obtained in the south Mediterranean area.
Meana et al (51) carried out a study in the health center of La Calzada (Gijón). They considered asthmatic children that had at least two bronchospasm episodes in the previous year and they also included children with medical report of asthma controlled with antiasthmatic specific therapy, with these approaches they almost identified 10% of asthmatic children.
Table II Studies of asthma prevalence in Spain | |||||||
| Author | Year | Place | Sample | Age | Current prevalence | Study type | |
| Fernández (43) (1996) | 1993-94 | Pamplona | 8,087 | 6-7 | 3.3% | Interview parents | |
| 13-14 | 5.3% | Interview children | |||||
| Busquets (44) (1996) | | Barcelona | 3,033 | 13-14 | 14% | Interview children and exercise test | |
| 26% (cumulative incidence) | |||||||
| 11.4% (exercise induced asthma) | |||||||
| Pereira (45) (1995) | 1991-92 | Huelva | 9,644 | 11-15 | 13.4% | Interview children and parents | |
| Callén (46) (1995) | | Guipúzcoa | 2,884 | 5-13 | 8.84% | Retrospective study of clinical histories | |
| Egea (47) (1994) | | Sevilla | 698 | 10-11 | 8% | Interview parents | |
| 17% (cumulative incidence) | |||||||
| Galán (48) (1994) | 1992-93 | Madrid | 4,962 | 2-14 | 3.4% (boys 4.3% girls 2.4%) | Phone interview | |
| 10-14 | 4.5% (boys 6.9% girls 1.9%) | ||||||
| CESEA (49) (1994) | | Spain | 955 | 0-10 | 4.8% | Interview parents | |
| Muñoz (50) (1994) | 1991-92 | Spain | 6,966 | 4-17 | 6.4% (medical diagnosis) | Interview parents | |
| Meana (51) (1993) | 1991 | Gijón | 3,611 | 2-14 | 9.6% | Revision of clinical histories | |
| Sanz (52) (1990) | | Valencia | 1,566 | 7-14 | 13.3% (cumulative incidence) | Interview parents | |
| 5% (medical diagnosis) | |||||||
| Otero (53) (1989) | | La Coruña | 1,550 | 4-18 | 10.8% | Interview children and parents | |
Sanz et al (52) in a survey carried out in Valencia, found a current prevalence of asthma of 5%. Finally, Otero et al (53) observed a prevalence of 10.8% in A Coruña.
Studies in America
In table III the studies carried out in America appear. In United States the figures of current prevalence oscillate predominantly between 28.9% obtained by Hu et al (55) in 1994 in a sample of children of black race from Chicago to the 10-11 years and 4.3% communicated by Weitzman et al (1) in 1988, in questionnaires administered to the parents of children of less than 17 year-old age, from a sample of the National Survey of Health. Farber et al (54) refer an increment of the diagnosed asthma of 9% in 1983-85 to 16% in 1992-94. The prevalence among Hispanic children is of 14% [Christiansen et al (57)].
The studies carried out in South America emphasis the high discharges figures obtained in Costa Rica by Soto-Quirós et al (62) in 1988, with a diagnosed asthma prevalence of 23%.
Table IIIStudies of asthma prevalence in America | |||||||
| Author | Year | Place | Sample | Age | Current prevalence | Study type | |
| Farber (54) (1997) | 1983-85 | USA | 3,174 | 5-17 | 9.2% (medical diagnosis) | Interview parents | |
| 1987-88 | 3,146 | 10,9% (medical diagnosis) | |||||
| 1992-94 | 2,975 | 15.9% (medical diagnosis) | |||||
| Hu (55) (1997) | 1994 | USA | 707 | 10-11 | 28.9% | Interview children and | |
| 34.5% (cumulative incidence) | parents | ||||||
| 23.6% (medical diagnosis) | |||||||
| Nelson (56) (1997) | 1992 | USA | 566 | 8-9 | 9.5% (medical diagnosis) | Phone interview | |
| Christiansen (57) (1996) | 1991-94 | USA (hispanics) | 654 | 9-12 | 14.4% | Interview parents | |
| Joseph (58) (1996) | 1993 | USA | 230 | School- | 14.3% | Interview parents and | |
| children | 17.4% (medical diagnosis) | exercise test | |||||
| Weitzman (1) (1992) | 1981 | USA | 15,224 | 0-17 | 3.1% | Analysis of data of the | |
| 1988 | 17,110 | 4.3% | national health survey | ||||
| Crain (59) (1994) | 1991 | USA | 1,285 | 0-17 | 8.6% | Phone interview | |
| (marginal neighborhood) | 14.3% (cumulative incidence) | ||||||
| Dales (60) (1994) | 1988 | Canada | 18,000 | 5-8 | 13% | Interview parents | |
| 4.7% (medical diagnosis) | |||||||
| Baeza (61) (1992) | 1986 | Mexico | 5,625 | 6-12 | 8.7% (medical diagnosis) | Interview parents | |
| Soto-Quirós (62) (1994) | 1988 | Costa Rica | 2,682 | 5-17 | 23% (medical diagnosis) | Interview parents | |
| Schuhl (63) (1989) | | Uruguay | 4,296 | 12 | 7.5% (point prevalence) | Interview children and | |
| 12.4% (cumulative incidence) | parents | ||||||
Studies in Asia
In table IV can be seen the studies carried out in Asia. In Turkey the figures of current prevalence oscillate among 8% obtained by Ones et al (64) in Istanbul following the methodology ISAAC and 5.8% communicated for Toros-Selçuk et al (65) in Edirne.
In Israel Goren and Hellman (70) find an increase in the current prevalence of bronchial asthma of 11% in 1980 to 16% in 1989 in school, although Auerbach et al (71) communicate a figure of 5% in young of 17 years from an urban area to those that underwent a survey, to a physical exam and breathing functional tests during the medical exams of the regional office of recruitment of the armed forces. In China, Zhong et al (72) carried out a study in two areas, urban and rural, of Guangzhou (Canton). They found a diagnosed asthma prevalence of 2.4%. However, in Hong Kong the figures were significantly bigger: 12% [Leung et al (73)] and 16.9% [Lai et al (74)]. In this city the current prevalence of asthma increased to twice as much among 1989 [Lau et al (75)] and 1994-95 [Leung et al (73)]. In Japan Nishima (77) communicates a current asthma prevalence of 4.6% in 1992.
Table IV Studies of asthma prevalence in Asia | |||||||
| Author | Year | Place | Sample | Age | Current prevalence | Study type | |
| Ones (64) (1997) | 1995 | Turkey | 2,216 | 6-12 | 8.2% | Interview parents | |
| 15.1% (cumulative incidence) | |||||||
| 9.8% (medical diagnosis) | |||||||
| Toros (65) (1997) | 1994 | Turkey | 5,412 | 7-12 | 5.8% | Interview parents | |
| 5.6% (medical diagnosis) | |||||||
| Karaman (66) (1997) | 1992-93 | Turkey | 3,512 | 6-13 | 4.9% (cumulative incidence) | Interview parents | |
| Kalyoncu (67) (1994) | 1992 | Turkey | 1,036 | 6-12 | 11.9% | Interview parents | |
| 23.3% (cumulative incidence) | |||||||
| 8.3% (medical diagnosis) | |||||||
| Bener (68) (1994) | 1992-93 | United Arab Emirates | 850 | 6-14 | 13.6% (medical diagnosis) | Interview parents | |
| Bener (69) (1993) | 1986-89 | Saudi Arabia | Interview parents | ||||
| Damman | 918 | 7-12 | 6.54% (cumulative incidence) | ||||
| 3.59% (medical diagnosis) | |||||||
| Riyadh | 1,008 | 7-12 | 11.86% (cumulative incidence) | ||||
| 9.28% (medical diagnosis) | |||||||
| Goren (70) (1997) | 1980 | Israel | 834 | School- | 11.3% | Interview parents | |
| children | 8.4% (medical diagnosis) | ||||||
| 1989 | 802 | 16% | |||||
| 13% (medical diagnosis) | |||||||
| Auerbach (71) (1993) | 1986 | Israel | 37,150 | 17 | 5% | Interview , physical | |
| 7.9% (cumulative incidence) | examination, spirometry | ||||||
| 1990 | 5.9% | ||||||
| 9.6% (cumulative incidence) | |||||||
| Zhong (72) (1990) | 1987-88 | China | 3,067 | 11-17 | 2.4% (medical diagnosis) | Interview children, | |
| 4.1% (bronchial hyperresponsiveness) | Interview parents, bronchial challenge | ||||||
| Leung (73) (1997) | 1994-95 | Hong Kong | 4,665 | 13-14 | 12% | Interview children, video | |
| 20% (cumulative incidence) | questionnaire | ||||||
| 11% (medical diagnosis) | |||||||
| Lai (74) (1997) | | Hong Kong | 189 | 12-18 | 16.9% (medical diagnosis) | Interview children, video | |
| 8.5% (bronchial hyperresponsiveness) | questionnaire, bronchial | ||||||
| challenge | |||||||
| Lau (75) (1995) | 1989 | Hong Kong | 535 | 3-10 | 6% | Interview parents | |
| Kim (76) (1997) | | Korea | 3,219 | 7-19 | 8.2% | Interview children, | |
| 4.6% (bronchial hyperresponsiveness) | bronchial challenge | ||||||
| Nishima (77) (1993) | 1992 | Japan | 45,674 | Schoolchildren | 4.6% | Interview parents | |
Studies in Africa
In tabla V we find the studies carried out in Africa. The figures of current prevalence are very low in the rural areas of Ethiopia: 1% [Yemaneberhan et al (78)], intermediate in Kenya: 10.2% [Esamai and Anabwani (79)] and high in South Africa: 26.8% [Ehrlich et al (80)], in a population predominantly of black race of Cape Town.
| Table VStudies of asthma prevalence in Africa | |||||||
| Author | Year | Place | Sample | Age | Current prevalence | Study type | |
| Yemaneberhan (78) | 1996 | Ethiopia | 0-9 | Interview parents | |||
| (1997) | Urban | 9,844 | 2.4% | ||||
| 1.7% (medical diagnosis) | |||||||
| Rural | 3,032 | 1.1% | |||||
| 1.1% (medical diagnosis) | |||||||
| Esamai (79) (1996) | 1995 | Kenya | 3,018 | 13-14 | 10.2% | Written questionnaire and | |
| 21.2% (cumulative incidence) | Video questionnaire | ||||||
| 11.4% (cumulative incidence-video) questionnaire | children | ||||||
| Ehrlich (80) (1995) | 1993 | South Africa | 1,955 | 7-8 | 26.8% | Interview parents | |
| 10.8% (medical diagnosis) | |||||||
| Bennis (81) (1992) | 1986 | Morocco | 1,464 | 10-24 | 6% (cumulative incidence) | Interview children and | |
| 3.4% (medical diagnosis) | physical examination | ||||||
Studies in Oceania
Table VI shows the studies carried out in Oceania. In New Zealand they are obtained in general some quite high figures: 29% [Wilkie et al (82)] in 1993, 34% [Shaw et al (85)] in 1989 among a rural population''s adolescent scholars predominatly maorí, 19.6% [Jones et al (86)] in Dunedin, a population of the east coast. Robson et al (84), using the methodology ISAAC found a higher figures with the video questionnaire, until 38% in Lower-Hut that with the written questionnaire. However Campbell et al (83) refer a prevalence of 9.21% until the 13 year-old age, although in this case the source of obtaining of the data was the medical registration of Golden Bay only Medical Center.
In Australia, Veale et al (87) carried out a study in 1991 and 1992 in four aboriginal communities. The prevalence of current asthma was of 0.5% in children of 8-12 years that it is very low in comparison with that of the non-aboriginal Australians. Peat et al (3) checked that the prevalence of childhood asthma had been increased from 1982 to 1992, in two cities of New Wales of the South: Belmont (humid and coastal) and Wagga Wagga (dry and interior). Robertson et al (89) communicate a prevalence of 23% to the 7 year-old age and of 18% to the 15 years.
| Table VIStudies of asthma prevalence in Oceania | ||||||
| Author | Year | Place | Sample | Age | Current prevalence | Study type |
| Wilkie (78) (1995) | 1993 | New Zealand | Interview parents | |||
| Hornby | 646 | 5-8 | 29% | |||
| 45% (cumulative incidence) | ||||||
| 28% (medical diagnosis) | ||||||
| Christchurch | 1,183 | 6-7 | 27% | |||
| 44% (cumulative incidence) | ||||||
| 28% (medical diagnosis) | ||||||
| Campbell (83) (1993) | 1991 | New Zealand (Golden Bay) | 1,194 | 0-14 | 9.21% | Patients'' registration of medical center |
| Robson (84) (1993) | 1991 | New Zealand | 2,187 | 12-15 | Written questionnaire-Video questionnaire | Written questionnnaire |
| Wellington City | 28% 32% | and video questionnaire | ||||
| Lower Hutt | 27% 38% | children | ||||
| Porirua | 30% 37% | |||||
| Shaw (85) (1990) | 1975 | New Zealand | 26.2% | Interview children | ||
| 1989 | 435 | Adolescents | 34% | |||
| Jones (86) (1987) | 1981-82 | New Zealand | 815 | 9 | 19.6% | Interview parents |
| 27.1% (cumulative incidence) | ||||||
| Veale (87) (1996) | 1990-91 | Australia (aborigines) | 1,252 | 8-12 | 0.5% | Interview children |
| Peat (3) (1994) | Australia | 8-10 | Interview parents | |||
| 1982 | Belmont | 718 | 10.4% | |||
| Wagga-Wagga | 769 | 15.5% | ||||
| 1992 | Belmont | 873 | 27.6% | |||
| Wagga-Wagga | 795 | 23.1% | ||||
| Jenkins (88) (1993) | 1968 | Australia | 8,585 | 7 | 16.2% (cumulative incidence) | Interview parents |
| Robertson (89) (1991) | 1990 | Australia | 3,324 | 7 | 23.1% | Interview parents |
| 2,899 | 12 | 21.7% | ||||
| 2,968 | 15 | 18.6% | ||||
Studies in different countries
In the table VII we find the studies carried out in different countries. Leung and Ho (90) studied the asthma prevalence in three populations of the Southwest of Asia: Hong Kong, Kota Kinabalu in Malaysia and San Bu in China, finding some very low figures in the three populations. To value the frequency of the bronchial asthma in countries with different language and culture, Robertson et al (91) carried out a study in 1991 in Melbourne (Australia), St. Gallen (Switzerland) and La Serena (Chile), in children of 7, 12 and 15 years to those that were administered a questionnaire of breathing symptoms, obtaining some much higher figures in Australia and Chile that in Switzerland.
Table VII Studies of asthma prevalence in different countries | ||||||
| Author | Year | Place | Sample | Age | Current prevalence | Study type |
| Leung (90) (1994) | 1992 | Hong Kong | 1,062 | 13.9 ± 1.8 | 3.7% | Interview children |
| 11.6% (cumulative incidence) | ||||||
| Malaysia | 409 | 15.5 ± 2.1 | 4.9% | |||
| 8.2% (cumulative incidence) | ||||||
| China | 737 | 16.4 ± 1.8 | 1.1% | |||
| 1.9% (cumulative incidence) | ||||||
| Robertson (91) (1993) | 1990 | Australia | 10,901 | 7, 12, 15 | 23.1%, 20.9%, 18.6% | Interview parents |
| Switzerland | 4,464 | 7, 12, 15 | 7.4%, 6%, 4.5% | |||
| Chile | 11,183 | 7, 12, 15 | 26.5%, 21.1%, 17.7% | |||
| Pearce (13) (1993) | 1991 | Australia | 12-15 | Written questionnaire-Video questionnaire | Written questionnnaire | |
| Adelaide | 1,428 | 29% 37% | and video questionnaire | |||
| Sydney | 1,519 | 30% 40% | children | |||
| New Zealand | 1,863 | 28% 36% | ||||
| England | 2,097 | 29% 30% | ||||
| Germany | 1,928 | 20% 27% | ||||
Pearce et al (13) carried out a study pilot of the ISAAC project in Adelaide and Sydney (Australia), Wellington (New Zealand), West Sussex (England) and Bochum (Germany). They were similar prevalence figures in the first four places and smaller in Bochum, being obtained, in general, bigger figures with the video questionnaire that with the written questionnaire.
DISCUSSION
In the studies carried out at European level, they highlight the high figures found in the British Islands, superiors to those referred in the countries from the continent to exception of those observed by Sennhauser and Kuhni (27) in Switzerland.
In France and Italy a similar figures of current prevalence are obtained, around 7% and in Germany they are in lower general with the exception of the figures of Leipzig. In the Scandinavian countries some quite low figures appear in general, except in the work of Pekkanen et al (35) in Finland.
In Spain the highest figures are those contributed by Busquets et al (44) in Barcelona and Pereira et al (45) in Huelva, and the lowest those of Fernández Benítez et al (43) in Pamplona. Assisting to the two studies carried out at national level; the obtained data are something below the countries of our environment.
In the studies of Lewis et al (6) and Strachan et al (15) in Great Britain, Omran et al (5) and Ninan and Russell (22) in Scotland, Burr et al (23) in Wales, Taylor et al (24) in Ireland, Rimpela et al (36) in Finland, Aberg et al (4) in Sweden and Nystad et al (40) in Norway can be proven that the prevalence of the bronchial asthma has left increasing in the last years.
In United States Weitzman et al (1) find a quite low prevalence in a national study based on the National Survey of Health in 1988, although in the later works the obtained figures have been superior highlighting the high percentage obtained by Hu et al (55) in population of black race. Also Soto Quirós et al (62) in Costa Rica finds a high proportion of diagnosed bronchial asthma. In the works of Farber et al (54) and Weitzman et al (1) we can check the increment of the asthma prevalence again in the last years.
The works of Goren and Hellman (70) and Auerbach et al (71) in Israel also illustrate the increment of the asthma prevalence, being their data in schoolchildren something superiors to that of the rest of countries of their environment, except for the figures communicated by Bener et al (68) in Arab Emirates and Kalyoncu et al (67) in Turkey.
It highlights the biggest presentation in the illness in Hong Kong with regard to China, what already agrees with the statement referred of an increment of the illness together to the development of the countries.
This fact is also illustrated in the studies carried out in Africa, where the presentation of the illness is much more frequent in South Africa that in the rest of countries.
In Oceania they are the biggest figures of bronchial asthma prevalence, also in increase in the last years, highlighting however that the asthma is almost nonexistent among aboriginal Australian, according to the data obtained for Veale et al (87).
We can see therefore that, even with considerable geographical differences in their presentation, the bronchial asthma is an illness in constant increase in the entire world. It is for this reason that they should be carried out efforts in the search of the causes of this increment, as well as in the standardization of the measure instruments of the illness, land this in which the ISAAC project constitutes an important advance.
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