[Asthma prevalence and risk factors in adolescents 13 to 14 years of age in Cuiabá, Mato Grosso State, Brazil]

Correlation of digital flow peak with spirometry in children with and without asthma

INTRODUCTION

Spirometry and peak expiratory flow measurement (PEF) are combined during functional respiratory assessments. The new digital peak flow meter (DPM) evaluates the forced expiratory volume in the first second (FEV₁) and PEF.

OBJECTIVE

To compare lung function measurements using spirometry and DPM.

METHODS

This cross-sectional analytical study assessed FEV₁ and PEF in children with and without asthma. Statistical analysis was performed to assess the agreement between the measures using the intraclass correlation coefficient (ICC), Bland-Altman, and survival agreement plot.

RESULTS

125 (3-12 y) and 196 (6-18 y) children without and with asthma, respectively, were studied. In children without asthma, the ICC for FEV₁ and PEF were 0.89 and 0.86, respectively, while the corresponding values were 0.87 and 0.79, respectively, in patients with asthma. The Bland-Altman method showed a difference of -0.4 to 0.5 for FEV₁ in patients without asthma, with a tendency to increase as the FEV₁ increased to a certain extent. In patients with asthma, the pattern was similar for FEV₁, and the PEF had a greater dispersion than among those without asthma; however, a good agreement pattern was maintained. In the survival agreement plot, when accepting a tolerance of 0.150 mL for FEV₁, there was an agreement of close to 55% in both groups. Likewise, when accepting a tolerance of 0.5 L/s for PEF, an agreement of close to 60% and 50% was observed in patients without and with asthma, respectively.

CONCLUSION

DPM was effective as a measure of lung function in pediatric patients with and without asthma.

Factors associated with asthma expression in adolescents

Objective:

To evaluate risk factors associated with asthma symptoms in adolescents in the 13- to 14-year age bracket.

Methods:

This was a cross-sectional study involving adolescents enrolled in randomly selected public schools in the city of Belo Horizonte, Brazil, and conducted with the use of the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire and its supplementary module for risk factor assessment. The ISAAC questionnaire was completed by the students themselves, whereas the supplementary questionnaire was completed by their parents or legal guardians. Variables showing p ≤ 0.25 in the univariate analysis were included in the multivariate analysis. Stepwise regression with backward elimination was used for variable selection.

Results:

We evaluated 375 adolescents, 124 (33.1%) of whom had asthma symptoms. The final multivariate analysis model revealed that asthma symptoms were associated with birth weight < 2,500 g (p < 0.001), day care center or nursery attendance (p < 0.002), maternal history of asthma (p < 0.001), contact with animals during the first year of life (p < 0.027), current contact with animals outside the home (dogs, cats, or farm animals; p < 0.005), and more than 20 cigarettes per day smoked by parents or other household members (p < 0.02).

Conclusions:

Exposure to animals in and outside the home is associated with asthma symptoms, as is environmental tobacco smoke exposure. Families, health professionals, and administrators of health care facilities should take that into account in order to prevent asthma and reduce asthma morbidity.

Is childhood wheeze and asthma in Latin America associated with poor hygiene and infection? A systematic review

Introduction

High asthma prevalence in Latin-American cities is thought to be caused by poor hygiene and infections. This contradicts the widely accepted 'hygiene hypothesis' for asthma aetiology.

Methods

Systematic review of observational studies evaluating the association between poor hygiene exposures or infections and asthma/wheeze among Latin-American children aged 4-16 years. MEDLINE, EMBASE, LILACS and CINAHL electronic databases were searched following a predefined strategy to 18 December 2017. We quantified outcomes measured and reported, assessed risk of bias and tabulated the results.

Results

Forty-five studies included: 6 cohort, 30 cross-sectional and 9 case-control studies. 26 cross-sectional studies were school-based surveys (14 of over 3000 children), whereas 5 case-control studies were hospital/health centre-based. Exposures measured and reported varied substantially between studies, and current wheeze was the most common outcome reported. Data showed selective reporting based on statistical significance (P value <0.05): 17/45 studies did not clearly describe the number of exposures measured and 15/45 studies reported on less than 50% of the exposures measured. Most exposures studied did not show an association with wheeze or asthma, except for a generally increased risk associated with acute respiratory infections in early life. Contradictory associations were observed frequently between different studies.

Conclusion

Selective reporting is common in observational studies exploring the association between environmental exposures and risk of wheeze/asthma. This, together with the use of different study outcomes (wheeze/asthma) associated with possibly distinct causal mechanisms, complicates inferences about the role of poor hygiene exposures and childhood infections in explaining asthma prevalence in Latin-American children.

Symptoms of asthma and associated factors in adolescents from Salvador, Bahia

OBJECTIVE

Identify the factors associated with asthma symptoms in adolescents.

METHODS

Cross-sectional study with the participation of 1,176 students between the ages of 11 and 17 years old, in Salvador, Bahia, Brazil. The asthma symptoms were identified by using the standardized questionnaire from The International Study of Asthma and Allergies in Childhood Program (ISAAC), phase III. The subjects' food intake data were collected by a semiquantitative food frequency questionnaire (FFQ) comprised of 97 food items. All of the information was collected during a single interview. Anthropometric, socioeconomic, and demographic data were collected from the study population. The robust Poisson model was adopted to obtain the raw and adjusted PR (prevalence ratio).

RESULTS

From the total number of adolescents, 57.6% are female and 83.71% of them were between 13 and 17 years old. The prevalence of asthma symptoms was of 7.6%, being higher among males (9.62%). The prevalence of wheezing in the last 12 months was 8.6%. Among the adolescents with rhinitis and eczema, the prevalence of asthma symptoms was of 15.2 and 14.3%, respectively. After an adjusted analysis, the following factors were identified: females PR = 0.64 (95%CI 0.42 - 0.96), rhinitis PR = 3.23 (95%CI 2.17 - 4.83) and the 2nd tertile of the healthy pattern (moderate consumption) PR = 0.61 (95%CI 0.37 - 0.99).

CONCLUSION

Rhinitis and eczema were presented as risk factors for asthma symptoms. The healthy food intake pattern that had been stratified in tertiles, presented the 2nd tertile as a protector for asthma symptoms.

Prevalence and factors associated with asthma in students from Montes Claros, Minas Gerais, Brazil

We investigated the prevalence of asthma and factors related to asthma development in schoolchildren aged 6 to 14, living in central and peripheral areas of the city of Montes Claros, Minas Gerais and who were registered with the Family Health Strategy program. Initially, a standard written questionnaire, based on ISAAC (International Study of Asthma and Allergies in Childhood), was administered to collect personal data, information regarding income, asthma prevalence, allergic rhinitis and eczema (N = 1,131). Secondly, a case-control study was performed by grouping the patients as either asthmatic (A; N = 172) or non-asthmatic (NA; N = 379). Potential factors associated with the occurrence of asthma were evaluated using the complementary questionnaire from ISAAC phase II. Skin tests for immediate hypersensitivity (STIH) and parasitological tests were also performed. The odds ratio, estimated by multivariate analysis, indicated that asthma cases were related to kindergarten attendance, household smoking, family history of asthma, rhinitis and positive STIH. It was concluded that, in the studied population, the prevalence of asthma was related to genetic predisposition, in addition to individual history, social demographics, exposure to pollutants such as tobacco smoke and a positive response to allergy testing.

[Prevalence and clinical characteristics of wheezing in children in the first year of life, living in Cuiabá, Mato Grosso, Brazil]

OBJECTIVE:

To evaluate the prevalence and the clinical characteristics of wheezing in infants aged 12 to 15 months in the city of Cuiabá, Mato Grosso State, Midwest Brazil.

METHODS:

Parents and/or guardians of infants were interviewed and completed a written standardized questionnaire of the Estudio Internacional de Sibilancia en Lactantes (EISL) - phase 3 at primary healthcare clinics at the same day of children vaccination or at home, from August of 2009 to November of 2010.

RESULTS:

1,060 parents and/or guardians completed the questionnaire, and 514 (48.5%) infants were male. Among the studied infants, 294 (27.7%) had at least one episode of wheezing during the first year of life, beggining at 5.8±3.0 months of age, with a predominance of male patients. The prevalence of occasional wheezing (<3 episodes of wheezing) was 15.0% and recurrent wheezing (≥3 episodes) was 12.7%. Among the infants with recurrent wheezing, the use of inhaled β2-agonist, oral corticosteroid, leukotriene receptor antagonist, as well as night symptoms, respiratory distress, and hospitalization due to severe episodes were significantly more frequent. Physician-diagnosed asthma was observed in 28 (9.5%) of the wheezing infants. Among the wheezing infants, 80 (27.7%) were diagnosed with pneumonia, of whom 33 (11.2%) required hospitalization; neverthless, no differences between occasional and recurrent wheezing infants were found.

CONCLUSIONS:

The prevalence of recurrent wheezing and physician-diagnosed asthma in infants were lower compared with those observed in other Brazilian studies. Recurrent wheezing had early onset and high morbity.

Asthma in children and adolescents in Brazil: contribution of the International Study of Asthma and Allergies in Childhood (ISAAC)

Objective:

To assess asthma among Brazilian pediatric population applying the International Study of Asthma and Allergies in Childhood (ISAAC), an internationally standardized and validated protocol.

Data sources:

ISAAC was conceived to maximize the value of epidemiologic studies on asthma and allergic diseases, establishing a standardized method (self-applicable written questionnaire and/or video questionnaire) capable to facilitate the international collaboration. Designed to be carried out in three successive and dependent phases, the ISAAC gathered a casuistic hitherto unimaginable in the world and in Brazil. This review included data gathered from ISAAC official Brazilian centers and others who used this method.

Data synthesis:

At the end of the first phase, it has been documented that the prevalence of asthma among Brazilian schoolchildren was the eighth among all centers participating all over the world. Few centers participated in the second phase and investigated possible etiological factors, especially those suggested by the first phase, and brought forth many conjectures. The third phase, repeated seven years later, assessed the evolutionary trend of asthma and allergic diseases prevalence in centers that participated simultaneously in phases I and III and in other centers not involved in phase I.

Conclusions:

In Brazil, the ISAAC study showed that asthma is a disease of high prevalence and impact in children and adolescents and should be seen as a Public Health problem. Important regional variations, not well understood yet, and several risk factors were found, which makes us wonder: is there only one or many asthmas in Brazil?

Operational definitions of asthma in recent epidemiological studies are inconsistent

OBJECTIVE

The best combination of questions to define asthma in epidemiological asthma studies is not known. We summarized the operational definitions of asthma used in prevalence studies and empirically assess how asthma prevalence estimates vary depending on the definition used.

METHODS

We searched the Thomson Reuters ISI Web of knowledge and included (1) cross-sectional studies (2) on asthma prevalence (3) conducted in the general population and (4) containing an explicit definition of asthma. The search was limited to the 100 most-cited papers or published since January 2010. For each paper, we recorded the asthma definition used and other variables. Then we applied the definitions to the data of the Portuguese National Asthma survey (INAsma) and of the 2005-2006 National Health and Nutrition Examination Survey (NHANES) computing asthma prevalence estimates for the different definitions.

RESULTS

Of 1738 papers retrieved, 117 were included for analysis. Lifetime asthma, diagnosed asthma and current asthma were defined in 8, 12 and 29 different ways, respectively. By applying definitions of current asthma on INAsma and NHANES data, the prevalence ranged between 5.3%-24.4% and 1.1%-17.2%, respectively.

CONCLUSIONS

There is considerable heterogeneity in the definitions of asthma used in epidemiological studies leading to highly variable estimates of asthma prevalence. Studies to inform a standardized operational definition are needed. Meanwhile, we propose a set of questions to be reported when defining asthma in epidemiological studies.

Prevalences of asthma and rhinitis among adolescents in the city of Fortaleza, Brazil: temporal changes

OBJECTIVE

To describe the prevalences of asthma and rhinitis in adolescents (13-14 years of age) in the city of Fortaleza, Brazil, in 2010, comparing the results with those obtained in a prevalence survey conducted in 2006-2007.

METHODS

This was a cross-sectional study involving probabilistic samples of 3,015 and 3,020 adolescents in surveys conducted in 2006-2007 and 2010, respectively. The International Study of Asthma and Allergies in Childhood protocol was used on both occasions.

RESULTS

Comparing the two periods, there were no significant differences regarding cumulative wheezing, active asthma, four or more wheezing attacks within the last year, sleep disturbed by wheezing more than one night per week, and speech-limiting wheezing. The prevalences of exercise-induced wheezing, dry cough at night, and physician-diagnosed asthma were significantly higher in 2010 than in the 2006-2007 period (p < 0.01 for all). The prevalence of physician-diagnosed rhinitis was significantly lower in 2010 (p = 0.01), whereas there were no significant differences between the two periods regarding cumulative rhinitis, current rhinitis, and rhinoconjunctivitis. In both periods, dry cough at night, current rhinitis, and rhinoconjunctivitis were significantly more prevalent in females than in males (p < 0.01 for all). Also in both periods, active asthma, current rhinitis, and rhinoconjunctivitis were more prevalent in private school students than in public school students (p < 0.01 for all).

CONCLUSIONS

Our data show that the prevalences of asthma and rhinitis symptoms remain high among 13- and 14-year-olds in Fortaleza, predominantly among females and private school students.