2. prevalencia de eczema atopico y sintomas relacionados en niños escolares brasileños de ISAAC...

8/7/2019 2. prevalencia de eczema atopico y sintomas relacionados en nios escolares brasileos de ISAAC fase 3

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J Investig Allergol Clin Immunol 2006; Vol. 16(6): 367-376 2006 Esmon Publicidad

Prevalence of Atopic Eczema in Brazilian Children

Original Art icle

Prevalence of Atopic Eczema andRelated Symptoms in Brazilian

Schoolchildren: Results From theInternational Study of Asthma and

Allergies in Childhood (ISAAC) Phase 3

D Sol, IC Camelo-Nunes, GF Wandalsen, MC Mallozi, Charles K Naspitz, formembers of the Brazilian ISAAC Group*

Division of Allergy, Clinical Immunology, and Rheumatology, Department of Pediatrics, Federal University ofSo Paulo, Brazil

Resumen.Antecedentes: Las comparaciones internacionales sobre la prevalencia del eccema atpico y los sntomasrelacionados son escasas. El protocolo estandarizado del Estudio Internacional del Asma y Alergias en la Infancia(ISAAC) facilita la investigacin de su prevalencia en todo el mundo.Objetivo: Aplicar el cuestionario escrito ISAAC para valorar la prevalencia del eccema atpico y los sntomasrelacionados entre los nios de 6 y 7 aos de edad y los adolescentes de 13 y 14 aos que viven en 20 ciudadesbrasileas.Mtodos: 23.422 nios de 6 y 7 aos de edad y 58.144 adolescentes de 13 y 14, que vivan en dos poblacionesal Norte, ocho del Noreste, una del Medio Oeste, cinco del Sureste y cinco del Sur, respondieron al cuestionarioescrito ISAAC.Resultados:La incidencia de eccema en superficie flexora (erupcin cutnea con picor en puntos caractersticosen los ltimos 12 meses) fue de un 5,3% a un 13% entre los nios, con un porcentaje inferior entre los adolescentes

Abstract.Background: International comparisons of the prevalence of atopic eczema and related symptoms arescarce. The standardized protocol of the International Study of Asthma and Allergies in Childhood (ISAAC)facilitates investigation of prevalence all over the world.Objective: To apply the ISAAC written questionnaire to evaluate the prevalence of atopic eczema and relatedsymptoms among 6-7 year-old children and 13-14 year-old adolescents living in 20 Brazilian cities.Methods: The ISAAC written questionnaire was filled in by 23 422 children aged 6-7 years and 58 144 adoles-

cents aged 13-14 years living in 2 population centers in the north, 8 in the northeast, 1 in the midwest, 5 in thesoutheast, and 5 in the south.Results:The prevalence offlexural eczema (itchy rash ever in characteristic places in the last 12 months) rangedfrom 5.3% to 13.0% for children and was lower among the adolescents (range, 3.4% 7.9%). Among children,the highest rates were observed in population centers in the northeast, mainly along the coast. Among adolescentsthe highest rates were observed in the north and northeast, mainly in Natal, Aracaju, and Vitria da Conquista.The northeastern countryside had higher prevalence rates of severe eczema (kept awake at night by this itchy rashin the last 12 months) in comparison to northeastern coastal centers. There was a significant correlation betweenthe prevalence offlexural eczema and severe eczema for both age groups, separately (6-7 year-olds, = 0.756,P< .004; 13-14 year-olds, = 0.874, P< .0001) or grouped (6-7 plus 13-14 years-olds, = 0.696, P< .0001).Conclusion: The prevalence of eczema and related symptoms is variable in Brazil, where the highest prevalenceis found in the north and northeast; on the other hand, a higher prevalence of severe eczema was observed inBrazilian centers in the south.

Key words: Children. Atopic dermatitis. Atopic eczema. Prevalence. ISAAC. Epidemiology.


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D Sol, et al368

(rango, 3,4% 7,9%). Entre los nios, las tasas ms elevadas se observaron en las poblaciones del Noreste, espe-cialmente en las costeras. Entre los adolescentes, las tasas ms elevadas se observaron en los del Norte y Noreste,especialmente en Natal, Aracaju y Vitria da Conquista. En las zonas rurales del interior del Noreste se detecttasas ms elevadas de eccema grave (imposibilidad de dormir por las noches debido al escozor del eccema en losltimos 12 meses) comparado con las poblaciones costeras del Noreste. Se observ una correlacin importanteentre la incidencia de eccema en superficie flexora y eccema grave para los dos grupos, separadamente (6-7 aos

de edad, = 0,756, P < 0,004; 13-14 aos de edad, = 0,874, P< 0,0001) o agrupados (6-7 aos de edad juntocon los de 13-14 aos de edad, = 0,696, P< 0,0001).Conclusin: La prevalencia de eccema y sntomas relacionados es variable en Brasil, donde es mayor en el Nortey Noreste. Por otro lado, se observ una prevalencia mayor de eccema grave en poblaciones del Sur del pas.

Palabras clave: Nios. Dermatitis atpica. Eccema atpico. Prevalencia. ISAAC. Epidemiologa.

Introduction:

Recent epidemiological studies evaluating thefrequency of atopic eczema in several countries haveshown differences in prevalence [1-11].The prevalence

of atopic eczema, as well as of asthma and other allergicdiseases, has been increasing [2-6, 12-14]. However,differences in definitions, patient identification criteria,and methods applied in each study make the comparisonsof the results unreliable.

The development of the International Study of Asthmaand Allergies in Childhood (ISAAC) has allowed a betterunderstanding and comparability of methods aboutepidemiology of atopic eczema [1].

Phase I of the ISAAC study sought to describe themagnitude and geographic distribution of atopic eczema,asthma, and allergic rhinoconjunctivitis in as manycountries of the world as possible by using single-page

written core questionnaires to assess the prevalenceand severity of these diseases [15]. This cross-sectionalquestionnaire survey was conducted on random samplesof schoolchildren aged 6 to 7 years (optional) and 13to 14 years (compulsory) from centers in 56 countriesthroughout the world. At the end of ISAAC phase 1,in 1995, data about prevalence of atopic eczema wasavailable for 256410 children aged 6 to 7 years in 90centers and 458623 children aged 13 to 14 years in 153centers [1].

Results were quite variable, with the differencebetween the highest (20.5%) and the lowest values (0.3%)reaching 60 fold [1, 16]. High prevalence rates of atopic

eczema (over 15%) were observed in urban centers fromAfrica, Australia, and Northern and Western Europe andlow rates (under 5%) in China, Eastern Europe, and centralAsia [1, 16]. In Latin America and Eastern Asia valueswere intermediary [1]. In all centers the prevalences ofatopic eczema were higher among young children (6-7years old), mainly among females [1, 16, 17].

In Brazil, Recife, Salvador, So Paulo, Curitiba, andPorto Alegre were the centers that participated in ISAACphase 1. Considering the 6-7-year-old schoolchildren(SC) the prevalence offlexural eczema (itchy rash ever incharacteristics places in the last 12 months) varied from6.6% (Porto Alegre) to 9.8% (Recife), with a mean value

of 7.3% [1, 16, 17]. In this age group the prevalence ofsevere eczema (kept awake at night by this itchy rash inthe last 12 months) ranged from 0.2% (Recife) to 0.6%(Porto Alegre), with a mean value of 0.5% [1, 16, 17]. Ahigher prevalence of severe atopic eczema was observed in

places with lower prevalence offlexural eczema. Amongthe adolescents (13-14 years old) the prevalence of atopiceczema ranged from 3.7% (So Paulo) to 9.2% (Salvador),with a mean value of 5.3% [1, 16, 17]. The prevalence ofsevere eczema ranged from 0.2% (Salvador) to 0.9% (PortoAlegre), with a mean value of 0.5% [1, 16, 17].

In 2002, ISAAC Phase 3 began, with the main objectiveof examining time trends in the prevalence of asthmaand allergic diseases in centers and countries that haveparticipated in ISAAC Phase 1. Phase 3 was a repetition ofphase 1, after at least 5 years. Centers involved in phase 1were invited to participate in ISAAC phase 3; new centerswere also invited to enter the study [15, 18].

The aim of this study was to evaluate the prevalenceof self reported atopic eczema and related-symptomsamong schoolchildren from 21 Brazilian centers located indifferent areas of the country. The research questions were:1) Would the increased number of participating centers (a3-fold increase), from all regions of Brazil, give us moredetails about the prevalence of atopic eczema and relatedsymptoms in the country? and 2) Could these data tell usmore about the real distribution of the disease in Brazil?

Subjects andMethodsTwenty-one centers from 20 Brazilian cities participated.

Schoolchildren were selected as standardized by the ISAACprotocol [15, 18]. The cities, states, regions/areas, in whichISAAC phase 3 were carried out were as follows: Manaus(Amazonas, north); Belm (Par, north); Natal (Rio Grandedo Norte, northeast); Recife (Pernambuco, northeast);Caruaru (Pernambuco, northeast); Macei (Alagoas,northeast); Aracaju (Sergipe, northeast); Feira de Santana(Bahia, northeast); Salvador (Bahia, northeast); Vitria daConquista (Bahia, northeast); Braslia (Distrito Federal,midwest); Belo Horizonte (Minas Gerais, southeast); NovaIguau (Rio de Janeiro, southeast); So Paulo (west andsouth, So Paulo, southeast); Santo Andr (So Paulo, SE);Curitiba (Paran, South [S]); Itaja (Santa Catarina, South[S]); Passo Fundo (Rio Grande do Sul, S), Porto Alegre (Rio


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Prevalence of Atopic Eczema in Brazilian Children 369

Grande do Sul, S) and Santa Maria (Rio Grande do Sul, S)(figure). Some of these centers had their data approved bythe ISAAC International Data Center and were consideredas ISAAC s official centers (Tables 1 and 3).

The ISAAC written questionnaire, previously translatedand validated for use within the Brazilian culture [17, 19,20], was applied to 23 422 children (6-7 year olds) and to58 144 adolescents (13-14 year olds). Subjects were selectedamong those who had attended public and private schoolslocated in the aforementioned cities. Information regardingthe number of schools and students in each area wasobtained from the records of the respective city educationofficials. After definition of the sample, the adolescents (13-14 year olds) and the parents or guardians of the 6-7 yearold children filled in the questionnaire. The data obtainedwere transcribed for a database (Epi-Info) supplied by theISAAC coordinators. In this study we only evaluated theresponses to the eczema core of the questionnaire.

The frequency of affirmative answers to each questionwas analyzed by age group and compared with the 2 test[21].

Those children with a positive response to the questionabout the presence of an itchy rash in the last 12 months(question 2) were considered to have current eczema.The results were expressed as odds ratios (OR) with 95%confidence intervals (CI) forflexural eczema (had this itchyrash in the last 12 months in characteristic places) andsevere eczema (kept awake at night by this itchy rash in thelast 12 months) for each center relative to a reference center(Santo Andr). Brazilian regions with at least 2 centers

Location of Brazilian centers participatingin the International Study of Asthma andAllergies in Childhood.

Curitiba

Porto Alegre

Recife

ManausBelm

MaceiCaruaruCaruaru

Aracaju

SalvadorFeira

Santana

FeiraSantana Vitria Conquista

Belo Horizonte

Santo AndrSo PauloSo Paulo

Braslia

Natal

ItajaPouso Alegre

Santa Maria

Nova Iguau

were grouped and compared. In the northeast we comparedthe prevalence of atopic eczema and related symptomsaccording to the place where the subjects lived: coastal(Natal, Recife, Macei, Aracaju, Salvador) or countryside(Caruaru, Feira de Santana, Vitria da Conquista).

In the states of Pernambuco (PE) and Rio Grande doSul (RS), where the population apparently shares the samegenetic background, we compared the prevalence of atopiceczema and related symptoms according to the area wherethe adolescents lived: urban or rural (PE: rural Caruaru vsurban Recife; RS: rural Santa Maria and Passo Fundo vsurban Porto Alegre)

The relationship between the prevalence of flexuraleczema and severe eczema, for each group separately andboth together, and the relationship between the prevalenceof eczema, flexural eczema and severe eczema and thelatitude of the centers were calculated with the Spearmancorrelation coefficient (). In all tests the level for rejection

of the null hypothesis was 5%.

Results

In children aged 6-7 years, the prevalence of itchy rashin the last 12 months varied from 7.3% to 13.3%; flexuraleczema varied from 5.3% to 13.0%; severe eczema from2.1% to 9.1%; and ever had eczema (physician-diagnosedeczema) from 7.9% to 15.4% (Table 1). The highest ratesofflexural and severe eczema were observed in Natal andAracaju and the lowest in Santo Andr (Table 1).


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D Sol, et al

Region

2

Northeast

Question

North,

Northeast,

Southeast,

South,

FisherTest

North

North

OR(95%%Ci)

4782

19128

15847

15378

Coastal

Countryside,

12691

6437

Itchyrashinthe

last12months

11.1

9.9

8.4

7.3

N>NE>SE>S

9.9

9.8

1.0

1(0.9

11.1

1)

Itchyrasheverin

characteristicplaces

6.0

6.2

4.6

4.5

N,

NE>SE,

S

6.0

6.6

0.9

0(0.8

01.0

2)

Keptawakeatnight

bythisitchyrashin

thelast12months

4.6

6.0

36

4.0

NE>N,

SE,

S

5.5

6.9

0.7

9(0.7

0-0.8

9)

N>S,

ES

S>SE

Everhadeczema

13.6

8.5

11.0

9.7

N>SE>S>NE

8.7

8.0

1.1

0(0.9

91.2

3)

*ISAACindicatesInternationalStudyofAsth

maandAllergiesinChildhood;OR,oddsratio;CI.confidenceinterval;N,north;S,south;E

,east

Table4.

ComparisonofthePrevalenceofEczemaandRelatedSymptomsin13-14Year-OldBrazilianSchoolchildrenAccordingtotheRegionWhereTheyLived

andintheNortheastRegionasCoastalorCountryside.ISAACPhase3

The comparison between centers in thenortheast and southeast showed the prevalenceof severe eczema to be significantly higher in thenortheast (Table 2). The prevalence of physician-diagnosed eczema was higher in the southeast.There were no differences in the prevalence of

itchy rash in the last 12 months and flexural eczema(Table 2).

In the northeast the comparison between coastaland countryside centers showed significantlyhigher values for physician-diagnosed eczema inthe coastal region (Table 2).

Considering Santo Andr as the reference, weobserved a significantly higher risk of developingflexural eczema and severe eczema, among childrenaged 6-7 years old, in Natal, Aracaju, Vitoria daConquista, and Nova Iguau (Table 3).

In the adolescent group the prevalence of itchyrash in the last 12 months varied from 6.3% to

11.8%; flexural eczema varied from 3.4% to 7.9%;severe eczema from 1.5% to 8.8%; and physician-diagnosed eczema from 2.2% to 14.2% (Table 1).Prevalence rates were quite variable and theanalysis of data grouped by region showed valuessignificantly higher in the north and northeast,except for physician-diagnosed eczema, whichachieved the lowest mean rate in the northeastregion (Table 4).

Considering the northeast region, the prevalenceof severe eczema was significantly lower amongadolescents living in coastal centers (Table 4). Peoplewith apparently the same genetic background

but inhabiting different centers in Pernambuco(northeast) and Rio Grande do Sul (south) werecompared (Table 5). In both states the prevalenceofflexural eczema and severe disease were higherin countryside centers (Table 5).

Considering Santo Andr as the reference,we observed the highest risk offlexural eczemain Natal, Aracaju, Vitria da Conquista, and SoPaulo-West; centers with the highest frequency ofsevere disease were Natal, Caruaru, Aracaju, Feirade Santana and Vitria da Conquista (Table 3).

The relationship between the prevalence offlexural eczema and severe eczema was significant

considering each group separately (6-7 year olds:= 0.756, P < .004; 13-14 year olds: = 0.874,P< .0001), as well as considering both age groupstogether.

Among children aged 6-7 years old there wasno significant relationship between the latitude ofthe centers and the prevalence of current eczema(= 0.21; 95% CI, 0.71 to 0.43; P= .512);flexural eczema (= 0.245; 95% CI, 0.73 to0.40; P= 0.442) and severe eczema (= 0.54;95%, CI, 0.84 to 0.07; P= .07).

Among the adolescents, the latitude of thecenters was significantly related to the prevalence ofcurrent eczema (= 0.72, 95% CI, 0.88 to 0.41;

372


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Prevalence of Atopic Eczema in Brazilian Children

North

east

OR

South

OR

OR

Question

Recife

Caruaru

95%CI

PassoFundo(a)

PortoAlegre(b)

SantaMaria(c)

95%CI

95%CI

N=2949

N=3007

N=3057

ab

bc

Itchyrashinthe

last12months

10.1

10.3

0.9

8(0.8

31.1

6)

8.6

7.0

7.7

127(1.0

51.5

3)1.1

2(0.9

21.3

6)

Itchyrasheverin

characteristicplaces

5.0

6.5

0.7

6(0.6

10.9

5)

5.5

5.0

4.8

1.1

0(0.8

81.38)0.9

6(0.7

61.2

1)

Keptawakeatnight

bythisitchyrashin

thelast12months

4.1

6.1

0.6

7(0.5

30.8

5)

4.6

5.0

5.7

0.9

1(0.7

21.15)1.1

4(0.9

11.4

3)

Everhadeczema

12.2

14.1

0.8

5(0.7

30.9

8)

13.4

11.7

10.6

1.1

7(1.0

01.3

6)0.9

7(0.8

31.1

3)

*ISAACindicatesInternationalStudyofAsth

maandAllergiesinChildhood;OR,oddsratio;CI.confidenceinterval.

P

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