Validation of a questionnaire for epidemiologic studies of wheezing in infants

Associated factors with recurrent wheezing in infants: is there difference between the sexes?

OBJECTIVE

Identify associated factors for recurrent wheezing (RW) in male and female infants.

METHODS

Cross-sectional multicentric study using the standardized questionnaire from the Estudio Internacional sobre Sibilancias en Lactantes (EISL). The questionnaire was applied to parents of 9345 infants aged 12-15 months at the time of immunization/routine visits.

RESULTS

One thousand two hundred and sixty-one (13.5%) males and nine hundred sixty-three (10.3%) females have had RW (≥3 episodes), respectively (p10 colds episodes (OR = 3.46; IC 95% 2.35-5.07), air pollution (OR = 1.33; IC 95% 1.12-1.59), molds at home (OR = 1.23; IC 95% 1.03-1.47), Afro-descendants (OR = 1.42; IC 95% 1.20-1.69), bronchopneumonia (OR = 1.41; IC; 1.11-1.78), severe episodes of wheezing in the first year (OR = 1.56; IC 95% 1.29-1.89), treatment with bronchodilators (OR = 1.60; IC 95% 1.22-2,1) and treatment with oral corticosteroids (OR = 1,23; IC 95% 0.99-1,52). Associated factors for RW for females were passive smoking (OR = 1.24; IC 95% 1.01-1,51), parents diagnosed with asthma (OR = 1.32; IC 95% 1,08-1,62), parents with allergic rhinitis (OR = 1.26; IC 95% 1.04-1.53), daycare attendance (OR = 1.48; IC 95% 1.17-1,88), colds in the first 6 months of life (OR = 2.19; IC 95% 1.69-2.82), personal diagnosis of asthma (OR = 1.84; IC 95% 1.39-2.44), emergency room visits (OR = 1.78; IC 95% 1.44-2.21), nighttime symptoms (OR = 2.89; IC 95% 2.34-3.53) and updated immunization (OR = 0.62; IC 95% 0.41-0.96).

CONCLUSION

There are differences in associated factors for RW between genders. Identification of these differences could be useful to the approach and management of RW between boys and girls.

Asthma predictive index as a useful diagnostic tool in preschool children: a cross-sectional study in Korea

BACKGROUND

It is challenging to diagnose asthma in preschool children. The asthma predictive index (API) has been used to predict asthma and decide whether to initiate treatment in preschool children.

PURPOSE

This study aimed to investigate the association between questionnaire-based current asthma with API, pulmonary function, airway hyperreactivity (AHR), fractional expiratory nitric oxide (FeNO), and atopic sensitization in preschool children.

METHODS

We performed a population-based cross-sectional study in 916 preschool children aged 4-6 years. We defined current asthma as the presence of both physician-diagnosed asthma and at least one wheezing episode within the previous 12 months using a modified International Study of Asthma and Allergies in Childhood questionnaire. Clinical and laboratory parameters were compared between groups according to the presence of current asthma.

RESULTS

The prevalence of current asthma was 3.9% in the study population. Children with current asthma showed a higher rate of positive bronchodilator response and loose and stringent API scores than children without current asthma. The stringent API was associated with current asthma with 72.2% sensitivity and 82.0% specificity. The diagnostic accuracy of the stringent API for current asthma was 0.771. However, no intergroup differences in spirometry results, methacholine provocation test results, FeNO level, or atopic sensitization rate were observed.

CONCLUSION

The questionnaire-based diagnosis of current asthma is associated with API, but not with spirometry, AHR, FeNO, or atopic sensitization in preschool children.

Prevalence of recurrent wheezing during the first year of life in Setúbal district, Portugal

BACKGROUND

Recurrent wheezing during the first year of life is a major cause of respiratory morbidity worldwide, yet there are no studies on its prevalence in Portugal.

OBJECTIVE

Determine the prevalence and severity of recurrent wheezing, treatments employed and other related aspects, in infants during their first year of life in Setúbal, Portugal.

METHODS

This is a cross-sectional study of a random sample of infants aged 12-15 months living in Setúbal district. It uses a validated questionnaire answered by parents/caregivers at local healthcare facilities where infants attend for growth/development monitoring and/or vaccine administration.

RESULTS

Among the 202 infants surveyed, 44.6% (95% CI 37.7-51.4) had at least one episode of wheezing; and 18.3% (95% CI 12.9-23.6) had recurrent wheezing. There was significant morbidity associated to recurrent wheezing in terms of severe episodes (17.3%-95% CI 12-22.5), visits to the emergency department (26.2%-95% CI 20.1-32.2) and hospital admissions (5.4%-95% CI 2.2-8.5); 10.4% (95% CI 6.1-14.6) used inhaled corticosteroids and 7.9% (95% CI 4.1-11.6) used a leukotriene receptor antagonist.

CONCLUSIONS

The prevalence of recurrent wheezing in infants during the first year of life is high and is associated with significant morbidity, presenting as a relevant public health problem. An important proportion of infants' progress with a more severe condition, resulting in high use of health resources (visits to emergency department and hospitalisations). The prevalence of recurrent wheezing in this district of Portugal stays between those related in other European and Latin American Centres, suggesting that maybe some of the well-known risk factors are shared with affluent countries.

Changes in the prevalence and severity of recurrent wheezing in infants: The results of two surveys administered 7 years apart

OBJECTIVE

To identify changes in the prevalence and severity of recurrent wheezing (RW) in infants using data obtained from two surveys administered seven years apart.

METHODS

A cross-sectional, international, population-based study in infants aged 12-15 months was conducted. Data were obtained from two surveys (S1 and S2, in 2005 and 2012, respectively) using the same methodology in three large Latin American cities: Curitiba (Brazil), São Paulo (Brazil), and Santiago (Chile).

RESULTS

A decrease in the overall prevalence of RW was identified between S1 (23.3%) and S2 (20.4%), p = 0.004, but it was mainly driven by the reduction observed in São Paulo; in Curitiba and Santiago, this change was not significant. The mean prevalence of the following RW severity indicators remained high and stable: severe wheezing episodes (56.9% in S1 and 54.2% in S2, p = 0.32) and emergency department (ED) visits for wheezing (S1 = 68.1%, S2 70.9%, p = 0.21). A significant increase in admissions for wheezing (21.1% to 26.7%, p = 0.004) was observed. In Curitiba and São Paulo, there were significant increases in the prevalence of physician-diagnosed asthma and in the use of inhaled corticosteroids and oral antileukotrienes.

CONCLUSIONS

The prevalence and severity of RW during the first year of life remained high over time, with remarkably high rates of ED visits, admissions for wheezing and use of asthma medications. This study suggests the need for considering early asthma diagnosis and to establish an appropriate treatment in infants with recurrent and severe asthma-like symptoms.

Recurrent wheeze and its relationship with lung function and airway inflammation in preschool children: a cross-sectional study in South Korea

BACKGROUND

Relationship between recurrent wheeze and airway function and inflammation in preschool children is not fully known.

OBJECTIVE

To investigate the relationship between recurrent wheeze and airway inflammation, lung function, airway hyper-reactivity (AHR) and atopy in preschool children.

DESIGN

Observational study, comparing forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC) and mid-forced expiratory flow (FEF_25%-75%), dose-response slope (DRS), exhaled nitric oxide (eNO) and atopic sensitisation between children with recurrent wheeze and those without.

SETTING

Population-based, cross-sectional study in Seoul and the Gyeonggi province of Korea conducted as a government-funded programme to perform standardised measurement of the prevalence of allergic diseases, and related factors, in preschool children.

PARTICIPANTS

900 children aged 4-6 years. PRIMARY AND SECONDARY OUTCOME MEASURES: eNO, FEV₁/FVC, FEF_25%-75%, DRS, atopic sensitisation and allergic diseases.

METHODS

Children completed the modified International Study of Asthma and Allergies in Childhood questionnaire and underwent eNO assessments, spirometry, methacholine bronchial provocation tests and skin prick tests. Recurrent wheeze was defined as having a lifetime wheeze of more than three episodes, based on the questionnaire. The frequency of hospitalisation and emergency room visits was also obtained by means of the questionnaire. 'Current' wheeze was defined as having symptoms or treatments within the past 12 months.

RESULTS

The prevalence of recurrent wheeze was 13.4%. Children with recurrent wheeze showed a higher prevalence of lifetime or current allergic rhinitis (p=0.01 and p=0.002, respectively) and lifetime atopic dermatitis (p=0.007). Children with recurrent wheeze showed lower FEV₁/FVC (p=0.033) and FEF_25%-75% (p=0.004), and higher eNO levels (p=0.013) than those without recurrent wheeze. However, the DRS, prevalence of atopic sensitisation and serum IgE levels were not significantly different between the two groups.

CONCLUSIONS

Recurrent wheeze in preschool children may be associated with airway inflammation and diminished airway function, but not with AHR or atopy.

[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.

Factors associated with the time to the first wheezing episode in infants: a cross-sectional study from the International Study of Wheezing in Infants (EISL)

Male gender, asthmatic heredity, perinatal tobacco smoke exposure and respiratory infections have been associated with wheeze in the first years of life, among other risk factors. However, information about what factors modify the time to the first episode of wheeze in infants is lacking. The present study analyses which factors are associated with shorter time to the first episode of wheeze in infants. Parents of 11- to 24-month-old children were surveyed when attending their health-care centres for a control visit. They answered a questionnaire including the age in months when a first wheeze episode (if any) had occurred (outcome variable). The study was performed in 14 centres in Latin America (LA) and in 8 centres in Europe (EU) (at least 1,000 infants per centre). Factors known to be associated with wheezing in the cohort were included in a survival analysis (Cox proportional hazards model). Summary hazard ratios adjusted for all risk factors (aHR) were calculated using the meta-analysis approach with random effects. A total of 15,067 infants had experienced wheezing at least once, out of 35,049 surveyed. Male gender in LA (aHR 1.05, 95% confidence interval (CI) 1.00-1.10, P=0.047), parental asthma in LA and EU (aHR 1.05, 95% CI 1.00-1.11, P=0.037), infant eczema in EU (aHR 1.25, 95% CI 1.12-1.39, P<0.001) and having a cold during the first 3 months in LA and EU (aHR 1.97, 95% CI 1.90-2.04, P<0.001), in LA (aHR 1.98, 95% CI 1.90-2.06, P<0.001) and in EU (aHR 1.91, 95% CI 1.75-2.09, P<0.001) were associated with a shorter period of time to the first episode. Breast feeding for at least 3 months was associated with a longer period, only in LA (aHR 0.91, 95% CI 0.86-0.96, P<0.001). Cold symptoms during the first 3 months is the most consistent factor shortening the time to the first episode of wheezing; breast feeding for ⩾3 months delays it only in LA, whereas eczema shortens it only in EU. Avoiding a common cold in the first months of life could be a good strategy to delay the first wheeze episode; however, cohort studies will help to elucidate this association.

Pneumonia and wheezing in the first year: An international perspective

BACKGROUND

The relationship between pneumonia and recurrent wheezing (RW) and the factors associated to pneumonia in wheezing and non-wheezing infants have not been compared between affluent and non-affluent populations.

METHODS

The International Study of Wheezing in Infants (EISL) is a large population-based cross-sectional study carried out in Latin America (LA) and Europe (EU). We used a validated questionnaire for identifying wheeze in the first year of life. The questionnaire also inquired about pneumonia diagnosis, together with other potentially related factors. Associations between both conditions and between potential risk/protective factors for pneumonia were tested by random-effects logit model and adjusting for all factors found previously associated to RW in this cohort.

RESULTS

Pneumonia and RW were strongly associated to each other in LA and EU (aOR 5.42; 95%CI: 4.87-6.04 and aOR 13.99; 95%CI: 9.61-20.36, respectively). Infant eczema was the most consistent risk factor of pneumonia in both continents, in the whole population and also among wheezers and non-wheezers (aOR ranging from 1.30; 95%CI: 1.11-1.52 to 2.65; 95%CI: 1.68-4.18); while breast feeding for at least 3 months was the most consistent protective factor (aOR ranging from 0.60; 95%CI: 0.51-0.71 to 0.76; 95%CI: 0.69-0.84). Factors associated to pneumonia were similar between continents among wheezers, but differed considerably among non-wheezers.

CONCLUSION

Pneumonia and RW are associated conditions sharing many risk/protective factors in EU and LA among wheezing infants, but not among non-wheezing infants. The association between pneumonia and RW could be due to shared pathophysiology or by diagnostic confusion between the two conditions.

Gender differences in the relationship between body mass index (BMI) changes and the prevalence and severity of wheezing and asthma in the first year of life

BACKGROUND

Rapid weight gain has been recently associated with asthma at school age, but its influence in respiratory symptoms during infancy is still unknown.

METHODS

Answers from 6541 parents living in six different cities of Brazil to the International Study of Wheezing in Infants (EISL) questionnaire were analysed. Data from reported weight and height at birth and at one year were used to calculate BMI. Rapid body mass index (BMI) gain was defined by the difference in BMI superior to 1.0z and excessive by the difference superior to 2.0z.

RESULTS

Rapid BMI gain was found in 45.8% infants and excessive in 24.4%. Boys showed a significantly higher BMI gain than girls. Girls with rapid BMI gain showed a significantly higher prevalence of hospitalisation for wheezing (8.8% vs. 6.4%; aOR: 1.4, 95%CI: 1.1-1.8), severe wheezing (18.1% vs. 15.0%; aOR: 1.3, 95%CI: 1.0-1.5) and medical diagnosis of asthma (7.5% vs. 5.7%; aOR: 1.3, 95%CI: 1.0-1.7). Girls with excessive BMI gain also had a significantly higher prevalence of hospitalisation for wheezing (9.8% vs. 6.7%; aOR: 1.5, 95%CI: 1.1-2.0) and severe wheezing (18.9% vs. 15.5%; aOR: 1.3, 95%CI: 1.0-1.6). No significant association was found among boys.

CONCLUSIONS

The majority of the evaluated infants showed BMI gain above expected in the first year of life. Although more commonly found in boys, rapid and excessive BMI gain in the first year of life was significantly related to more severe patterns of wheezing in infancy among girls.

Wheeze as an adverse event in pediatric vaccine and drug randomized controlled trials: A systematic review

INTRODUCTION

Wheeze is an important sign indicating a potentially severe adverse event in vaccine and drug trials, particularly in children. However, there are currently no consensus definitions of wheeze or associated respiratory compromise in randomized controlled trials (RCTs).

OBJECTIVE

To identify definitions and severity grading scales of wheeze as an adverse event in vaccine and drug RCTs enrolling children <5 years and to determine their diagnostic performance based on sensitivity, specificity and inter-observer agreement.

METHODS

We performed a systematic review of electronic databases and reference lists with restrictions for trial settings, English language and publication date ≥1970. Wheeze definitions and severity grading were abstracted and ranked by a diagnostic certainty score based on sensitivity, specificity and inter-observer agreement.

RESULTS

Of 1205 articles identified using our broad search terms, we identified 58 eligible trials conducted in 38 countries, mainly in high-income settings. Vaccines made up the majority (90%) of interventions, particularly influenza vaccines (65%). Only 15 trials provided explicit definitions of wheeze. Of 24 studies that described severity, 11 described wheeze severity in the context of an explicit wheeze definition. The remaining 13 studies described wheeze severity where wheeze was defined as part of a respiratory illness or a wheeze equivalent. Wheeze descriptions were elicited from caregiver reports (14%), physical examination by a health worker (45%) or a combination (41%). There were 21/58 studies in which wheeze definitions included combined caregiver report and healthcare worker assessment. The use of these two methods appeared to have the highest combined sensitivity and specificity.

CONCLUSION

Standardized wheeze definitions and severity grading scales for use in pediatric vaccine or drug trials are lacking. Standardized definitions of wheeze are needed for assessment of possible adverse events as new vaccines and drugs are evaluated.

Prevalence, Severity, and Treatment of Recurrent Wheezing During the First Year of Life: A Cross-Sectional Study of 12,405 Latin American Infants

PURPOSE

This study aimed to determine the prevalence and severity of recurrent wheezing (RW) defined as ≥3 episodes of wheezing, risk factors, and treatments prescribed during the first year of life in Latin American infants.

METHODS

In this international, cross-sectional, and community-based study, parents of 12,405 infants from 11 centers in 6 South American countries (Argentina, Brazil, Chile, Colombia, Peru, and Uruguay) completed a questionnaire about wheezing and associated risk/protective factors, asthma medications, and the frequency of and indications for the prescription of antibiotics and paracetamol during the first year of life.

RESULTS

The prevalence of RW was 16.6% (95% CI 16.0-17.3); of the 12,405 infants, 72.7% (95% CI 70.7-74.6) visited the Emergency Department for wheezing, and 29.7% (27.7-31.7) was admitted. Regarding treatment, 49.1% of RW infants received inhaled corticosteroids, 55.7% oral corticosteroids, 26.3% antileukotrienes, 22.9% antibiotics ≥4 times mainly for common colds, wheezing, and pharyngitis, and 57.5% paracetamol ≥4 times. Tobacco smoking during pregnancy, household income per month <1,000 USD, history of parental asthma, male gender, and nursery school attendance were significant risk factors for higher prevalence and severity of RW, whereas breast-feeding for at least 3 months was a significant protective factor. Pneumonia and admissions for pneumonia were significantly higher in infants with RW as compared to the whole sample (3.5-fold and 3.7-fold, respectively).

CONCLUSIONS

RW affects 1.6 out of 10 infants during the first year of life, with a high prevalence of severe episodes, frequent visits to the Emergency Department, and frequent admissions for wheezing. Besides the elevated prescription of asthma medications, there is an excessive use of antibiotics and paracetamol in infants with RW and also in the whole sample, which is mainly related to common colds.

A multinational study to compare prevalence of atopic dermatitis in the first year of life

BACKGROUND

Atopic dermatitis (AD) is common in childhood, with peak prevalence in early childhood. However, international comparisons of prevalence have focused on older children. We analysed differences in prevalence rates of AD and the associations with putative risk and protective factors, among infants in two European and two Central American countries.

METHODS

In 1-yr old infants participating in the International Study of Wheezing in Infants (EISL), prevalence of AD and putative risk and protective factors were assessed by a questionnaire applied to parents. For each risk/protective factor summary, odds ratios with 95% confidence intervals were calculated by means of random effects meta-analysis.

RESULTS

Data from 9803 infants were analysed. AD prevalence varied from 10.6% (Valencia, Spain) to 28.2% (San Pedro Sula, Honduras). Average AD prevalences were lower in Europe (14.2%) than in Central America (18.2%, p < 0.01). Consistent with older children, presence of siblings decreased (OR 0.82 [0.72-0.94]), whereas family history of asthma (OR 1.32 [1.10-1.59]), rhinitis (OR 1.33 [1.14-1.54]) and atopic dermatitis (OR 2.40 [1.89-3.05]) increased the risk of infantile AD. However, gender, family size, breastfeeding and socio-economic status were not associated with AD prevalence.

CONCLUSIONS

This study shows almost threefold differences in the prevalence of AD in infancy between countries. Risk and protective factors involved in the expression of infantile AD differ from those in older children, possibly suggesting a different pathophysiology. There is a need for additional international epidemiological surveys on AD in young children, the peak prevalence age of this condition.

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.

[Prevalence and severity of wheezing in the first year of life in the city of Santo André, Brazil]

Objective:

To determine the prevalence and the severity of wheezing in the first year of life for infants who live in Santo André, São Paulo, Brazil.

Methods:

Cross sectional study with the administration of the Estudio Internacional de Sibilancias en Lactantes (EISL), which is a standardized and validated written questionnaire applied to parents and/or guardians of infants aged 12-24 months treated at primary health units, vaccination centers, day care centers, or kindergartens. The questionnaire consisted of questions regarding demographic characteristics, presence of wheezing, respiratory infections, and risk factors. Results were analyzed using the SPSS for Windows, 20.0 (SPSS Inc. - Chicago, Il, United States). Logistic regression was applied to verify variables associated to recurrent wheezing.

Results:

Among the 1,028 infants studied, 48.5% had one or more episodes of wheezing during the first 12 months of life (wheezing once), and 23.9% had three or more episodes (recurrent wheezing). Nocturnal symptoms, severe breathing difficulty, and visits to the emergency room were observed in 67.3%, 42.4%, and 60.7% of infants, respectively. Among the studied infants, 19.4% were hospitalized, and 11.0% had a medical diagnosis of asthma in the first year of life. Use of β2-agonists, inhaled corticosteroids, oral corticosteroids, and leukotriene receptor antagonists were observed in 88.8%, 21.0%, 54.9%, and 3.2% of children with wheezing, respectively. Use of oral corticosteroids, perception of breathlessness by parents, diagnosis of asthma, pneumonia, and hospitalization for pneumonia were more frequent among infants with recurrent wheezing (p<0.001).

Conclusions:

In the city of Santo André, approximately half of infants had at least one episode of wheezing in the first year of life, and almost 25% had recurrent wheezing. Wheezing disorders in Santo André have early onset and high morbidity.

Increased maternal BMI is associated with infant wheezing in early life: a prospective cohort study

Rates of obesity are increasing in women of child bearing age with negative impacts on maternal and offspring health. Emerging evidence suggests in utero origins of respiratory health in offspring of obese mothers but mechanisms are unknown. Changes in maternal cortisol levels are one potential factor as cortisol levels are altered in obesity and cortisol is separately implicated in development of offspring wheeze. We aimed to assess whether increased pre-pregnancy maternal body mass index (BMI) was associated with offspring early life wheezing, and whether this was mediated by altered cortisol levels in the mother. In a prospective community-based cohort (Amsterdam Born Children and their Development cohort), women completed questionnaires during pregnancy and at 3-5 months post-delivery regarding self-history of asthma and atopy, and of wheezing of their offspring (n=4860). Pre-pregnancy BMI was recorded and serum total cortisol levels were measured in a subset of women (n=2227) at their first antenatal visit. A total of 20.2% (n=984) women were overweight or obese and 10.3% reported wheezing in their offspring. Maternal BMI was associated with offspring wheezing (1 unit (kg/m2) increase, OR: 1.03; 95% CI: 1.00-1.05), after correction for confounders. Although maternal cortisol levels were lower in overweight mothers and those with a history of asthma, maternal cortisol levels did not mediate the increased offspring wheezing. Pre-pregnancy BMI impacts on baby wheezing, which is not mediated by lower cortisol levels. As the prevalence of obesity in women of child-bearing age is increasing, further studies are needed to investigate modifiable maternal factors to avoid risk of wheezing in young children.

Prevalence and risk factors associated with wheezing in the first year of life

OBJECTIVE

to investigate the prevalence and risk factors associated with wheezing in infants in the first year of life.

METHODS

this was a cross-sectional study, in which a validated questionnaire (Estudio Internacional de Sibilancias en Lactantes--International Study of Wheezing in Infants--EISL) was applied to parents of infants aged between 12 and 15 months treated in 26 of 85 primary health care units in the period between 2006 and 2007. The dependent variable, wheezing, was defined using the following standards: occasional (up to two episodes of wheezing) and recurrent (three or more episodes of wheezing). The independent variables were shown using frequency distribution to compare the groups. Measures of association were based on odds ratio (OR) with a confidence interval of 95% (95% CI), using bivariate analysis, followed by multivariate analysis (adjusted OR [aOR]).

RESULTS

a total of 1,029 (37.7%) infants had wheezing episodes in the first 12 months of life; of these, 16.2% had recurrent wheezing. Risk factors for wheezing were family history of asthma (OR=2.12; 95% CI: 1.76-2.54) and six or more episodes of colds (OR=2.38; 95% CI: 1.91-2.97) and pneumonia (OR=3.02; 95% CI: 2.43-3.76). For recurrent wheezing, risk factors were: familial asthma (aOR=1.73; 95% CI 1.22-2.46); early onset wheezing (aOR=1.83; 95% CI: 1.75-3.75); nocturnal symptoms (aOR=2.56; 95% CI: 1.75-3.75), and more than six colds (aOR=2.07; 95% CI 1.43- .00).

CONCLUSION

the main risk factors associated with wheezing in Fortaleza were respiratory infections and family history of asthma. Knowing the risk factors for this disease should be a priority for public health, in order to develop control and treatment strategies.

Risk factors associated with wheezing in infants

OBJECTIVE

to identify possible risk factors associated with wheezing in infants (12-15 months-old) in the state of Mato Grosso, Brazil.

METHODS

this was a cross-sectional study performed by applying a standardized written questionnaire from the international study on wheezing in infants (Estudio Internacional de Sibilancia en Lactantes - EISL), phase 3. Parents and/or guardians of infants were interviewed at primary health care clinics or at home from August of 2009 to November of 2010. Factors associated to wheezing were studied using bivariate and multivariate analysis (using the Statistical Package for Social Sciences [SPSS] v.18.0), and expressed as odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

the written questionnaire was answered by 1,060 parents and/or guardians. The risk factors for wheezing were: history of asthma in the family [mother (OR = 1.62; 95% CI = 1.07-2.43); father (OR = 1.98; 95% CI = 1.22-3.23); siblings (OR = 2.13; 95% CI = 1.18-3.87)]; history of previous pneumonia (OR = 10.80; 95% CI = 4.52-25.77); having had more than six upper respiratory tract infections (URTIs) (OR = 2.95; 95% CI = 2.11-4.14); having had first URTI before the third month of life (OR = 1.50; 95% CI = 1.04-2.17); living in a moderately polluted area (OR = 1.59; 95% CI = 1.08-2.33); paracetamol use for URTI (OR = 2.13; 95% CI = 1.54-2.95); and antibiotic use for skin infection (OR = 2.29; 95% CI = 1.18-4.46).

CONCLUSIONS

the study of risk factors for wheezing in the first year of life is important to help physicians identify young children at high risk of developing asthma and to improve public health prevention strategies in order to reduce the morbidity of wheezing in childhood.

Cord serum 25-hydroxyvitamin D and risk of early childhood transient wheezing and atopic dermatitis

BACKGROUND

There is increasing evidence of the effect of maternal vitamin D intake during pregnancy on the risk of asthma and allergic outcomes in offspring. However, studies on the relationship between cord levels of 25-hydroxyvitamin D (25[OH]D) and asthma and allergic diseases are very few.

OBJECTIVE

Our aim was to investigate the associations between cord serum 25(OH)D levels and asthma, wheezing, allergic rhinitis, and atopic dermatitis in the offspring from birth to 5 years.

METHODS

Cord blood samples were collected at birth and analyzed for 25(OH)D levels in 239 newborns from the Etude des Déterminants pré et post natals du développement et de la santé de l'Enfant (EDEN) birth cohort. The children were followed up until age 5 years by using International Study of Asthma and Allergies in Childhood-based symptom questionnaires.

RESULTS

The median cord serum level of 25(OH)D was 17.8 ng/mL (interquartile range, 15.1 ng/mL). By using multivariable-adjusted logistic regression models, a significant inverse association was observed between cord serum 25(OH)D levels and risk of transient early wheezing and early- and late-onset atopic dermatitis, as well as atopic dermatitis, by the ages of 1, 2, 3, and 5 years. We found no association between cord serum 25(OH)D levels and asthma and allergic rhinitis at age 5 years.

CONCLUSIONS

Cord serum 25(OH)D levels were inversely associated with the risk of transient early wheezing and atopic dermatitis by the age of 5 years, but no association was found with asthma and allergic rhinitis.

Pediatric allergy and immunology in Brazil

The subspecialty of pediatric allergy and immunology in Brazil is in its early years and progressing steadily. This review highlights the research developed in the past years aiming to show the characteristics of allergic and immunologic diseases in this vast country. Epidemiologic studies demonstrated the high prevalence of asthma in infants, children, and adolescents. Mortality rates and average annual variation of asthma hospitalization have reduced in all pediatric age groups. Indoor aeroallergen exposure is excessively high and contributes to the high rates of allergy sensitization. Prevalence of food allergy has increased to epidemic levels. Foods (35%), insect stings (30%), and drugs (23%) are the main etiological agents of anaphylaxis in children and adolescents. Molecular diagnosis of primary immunodeficiencies (PID) showed a high incidence of fungal infections including paracoccidioidomycosis in X-linked hyper-IgM syndrome, and the occurrence of BCG adverse reactions or other mycobacterial infections in patients with chronic granulomatous disease. Education in pediatric allergy and immunology is deficient for medical students, but residency programs are effective in training internists and pediatricians for the practice of allergy. The field of PID requires further training. Last, this review is a tribute to Prof. Dr. Charles Naspitz, one of the pioneers of our specialty in Brazil.

Latitude modifies the effect size of factors related to recurrent wheeze in the first year of life

BACKGROUND

Although the association between latitude and asthma prevalence has been studied to a certain extent, its influence on the magnitude of the association of risk/protective factors with recurrent wheeze in infants has never been reported.

METHODS

The adjusted odd ratios (aOR) of various risk/protective factors for recurrent wheeze from 31,920 infants from 19 centres of the "Estudio Internacional de Sibilacias en Lactantes" (EISL) in very different parts of the world were used to build a meta-regression using the strength of the aOR of each factor as dependent variable and centre latitude as explanatory variable. The meta-regression was further adjusted for continent.

RESULTS

There was a positive significant correlation between latitude and the magnitude of the aOR between recurrent wheeze and having cold(s) during the first three months of life (p = 0.004); attending a nursery school (p = 0.011); and having additional siblings (p = 0.003). Furthermore, there was a negative correlation for having been breastfed for at least three months (p = 0.044). Heterogeneity (as measured by I2) of the magnitude of aORs between centres was quite high except for breast feeding: 73.1% for colds; 66.9% for nursery school; 52.6% for additional siblings; and 18.1% for breast feeding. Latitude explained a considerable amount of that heterogeneity: 63.8% for colds; 52.8% for nursery school; 86.6% for additional siblings; and 100% for breast feeding, probably as a consequence of its low heterogeneity.

CONCLUSION

The magnitude in which some risk/protective factors are associated to recurrent wheeze during the first year of life varies significantly with latitude.

[Prevalence of wheezing and associated risk factors among infants in Recife, Pernambuco State, Brazil]

The aim of this study was to verify the prevalence of wheezing in infants (< 1 year of age) in Recife, Pernambuco State, Brazil, and to identify associated risk factors.

SAMPLE AND METHODS

the study was performed according to the protocol of the International Study of Wheezing in Infants (EISL) in children ranging from 12 to 15 months of age. The sample was analyzed for presence or absence of wheezing. A total of 1,071 parents of children ranging from 12 to 15 months of age were interviewed. Prevalence of wheezing in the first year of life was 43%, with no difference between the sexes. Wheezing in the first year of life was associated with pneumonia, family history of asthma, more than nine episodes of upper airway infection, and the first cold before six months of age (p < 0.001). Prevalence of wheezing in the first year of life was high in Recife. Early onset (and high number) of colds, family history of asthma, and pneumonia were associated with wheezing in these children.

Snoring, mouth-breathing, and apnea trajectories in a population-based cohort followed from infancy to 81 months: a cluster analysis

OBJECTIVE

The objective of this study was to characterize phenotypes of sleep disordered breathing (SDB) in early childhood that clinicians may find useful while monitoring symptom progression and associated SDB morbidity.

METHODS

We performed a cluster analysis of SDB's primary symptoms: snoring, mouth-breathing, and apnea. Parents in the Avon Longitudinal Study of Parents and Children (ALSPAC) reported SDB symptoms by questionnaire for their child at 6, 18, 30, 42, 57, 69, and 81 months of age. Participants were those from the original cohort exclusive of children with congental or other medical conditions predisposing growth aberrations or respiratory problems (i.e. cleft palate, heart surgery and associated conditions, genetic syndromes-primarily Down's, cancer or kidney conditions, celiac disease, congenital adrenal hyperplasia), missing SDB measures for ≥ 2 timepoints, or missing birth length plus 2 subsequent height measures.

RESULTS

Five clusters emerged from 10,441 children and were characterized according to patterns of mean severity of SDB symptoms over time. "Normals" (50%) were asymptomatic throughout. The "late snores and mouth-breathing" cluster (20%) remained asymptomatic until 4 years old. The "early snores" (10%) and "early apnea" (10%) clusters had peak symptoms at 6 and 18 months, respectively. In "all SDB after infancy" (10%), symptoms peaked from 30 to 42 months and remained elevated. Exploratory analyses found that "early snores" were significantly shorter than "normals." Associations with tonsillectomies and wheezing frequency supported external validation.

CONCLUSIONS

Cluster analysis has elucidated the dynamic multi-symptom expression of SDB. The utility of cluster analysis will be evaluated in future analyses to predict growth, cognition and behavior outcomes.

The multiple meanings of "wheezing": a questionnaire survey in Portuguese for parents and health professionals

Background

Most epidemiological studies on pediatric asthma rely on the report of "wheezing" in questionnaires. Our aim was to investigate the understanding of this term by parents and health professionals.

Methods

A cross-sectional survey was carried out in hospital and community settings within the south of Portugal. Parents or caregivers self-completed a written questionnaire with information on social characteristics and respiratory history. Multiple choice questions assessed their understanding of "wheezing". Health professionals (physicians, nurses and physiotherapists) were given an adapted version. We used bivariate analysis and multivariate models to study associations between definitions of "wheezing" and participants' characteristics.

Results

Questionnaires from 425 parents and 299 health professionals were included. The term "wheezing" was not recognized by 34% of parents, more frequently those who were younger (OR 0.4 per 10-year increment, 95% CI 0.3-0.7), had lower education (OR 3.3, 95% CI 1.5-7.4), and whose children had no history of respiratory disease (OR 4.6, 95% CI 2.5-8.7) (all ORs adjusted). 31% of parents familiar with "wheezing" either did not identify it as a sound, or did not locate it to the chest, while tactile (40%) and visual (34%) cues to identify "wheezing" were frequently used. Nurses reported using visual stimuli and overall assessments more often than physicians (p < 0.01). The geographical location was independently associated with how parents recognized and described "wheezing".

Conclusions

Different meanings for "wheezing" are recognized in Portuguese language and may be influenced by education, respiratory history and regional terminology. These findings are likely applicable to other non-English languages, and suggest the need for more accurate questionnaires and additional objective measurement instruments to study the epidemiology of wheezing disorders.

Prevalence and severity of wheezing in the first year of life

OBJECTIVE

To determine the prevalence and severity of wheezing in infants, using the standardized protocol devised for the "Estudio Internacional de Sibilancias en Lactantes" (EISL, International Study of Wheezing in Infants), as well as to determine the relationship between such wheezing and physician-diagnosed asthma, in the first year of life.

METHODS

Between March of 2005 and August of 2006, the EISL questionnaire was administered to the parents or legal guardians of infants undergoing routine procedures or immunization at public primary health care clinics in the southern part of the city of São Paulo, Brazil.

RESULTS

Our sample comprised 1,014 infants (mean age = 5.0 ± 3.0 months), 467 (46.0%) of whom had at least one wheezing episode, 270 (26.6%) having three or more such episodes, in their first year of life. The use of inhaled β2 agonists, inhaled corticosteroids, or antileukotrienes, as well as the occurrence of nocturnal symptoms, difficulty breathing, pneumonia, emergency room visits, and hospitalization due to severe wheezing, was significantly more common among those with recurrent wheezing (p < 0.05). Physician-diagnosed asthma was reported for 35 (7.5%) of the 467 wheezing infants and was found to be associated with the use of inhaled corticosteroids, difficulty breathing during the attacks, and six or more wheezing episodes in the first year of life. However, less than 40% of those infants were treated with inhaled corticosteroids or antileukotrienes.

CONCLUSIONS

In this study, the prevalence of wheezing episodes among infants in their first year of life was high and had an early onset. The proportion of infants diagnosed with and treated for asthma was low.

Cord-blood 25-hydroxyvitamin D levels and risk of respiratory infection, wheezing, and asthma

OBJECTIVE

Higher maternal intake of vitamin D during pregnancy is associated with a lower risk of wheezing in offspring. The relationship between cord-blood levels of 25-hydroxyvitamin D (25[OH]D) and childhood wheezing is unknown. We hypothesized that cord-blood levels would be inversely associated with risk of respiratory infection, wheezing, and asthma.

PATIENTS AND METHODS

Cord blood from 922 newborns was tested for 25(OH)D. Parents were asked if their child had a history of respiratory infection at 3 months of age or a history of wheezing at 15 months of age and then annually thereafter. Incident asthma was defined as doctor-diagnosed asthma by the time the child was 5 years old and reported inhaler use or wheezing since the age of 4 years.

RESULTS

The median cord-blood level of 25(OH)D was 44 nmol/L (interquartile range: 29-78). Follow-up was 89% at the age of 5 years. Adjusting for the season of birth, 25(OH)D had an inverse association with risk of respiratory infection by 3 months of age (odds ratio: 1.00 [reference] for ≥75 nmol/L, 1.39 for 25-74 nmol/L, and 2.16 [95% confidence interval: 1.35-3.46] for <25 nmol/L). Likewise, cord-blood 25(OH)D levels were inversely associated with risk of wheezing by 15 months, 3 years, and 5 years of age (all P < .05). Additional adjustment for more than 12 potential confounders did not materially change these results. In contrast, we found no association between 25(OH)D levels and incident asthma by the age of 5 years.

CONCLUSIONS

Cord-blood levels of 25(OH)D had inverse associations with risk of respiratory infection and childhood wheezing but no association with incident asthma.

International study of wheezing in infants: risk factors in affluent and non-affluent countries during the first year of life

Risk factors for wheezing during the first year of life (a major cause of respiratory morbidity worldwide) are poorly known in non-affluent countries. We studied and compared risk factors in infants living in affluent and non-affluent areas of the world. A population-based study was carried out in random samples of infants from centres in Latin America (LA) and Europe (EU). Parents answered validated questionnaires referring to the first year of their infant's life during routine health visits. Wheezing was stratified into occasional (1-2 episodes, OW) and recurrent (3 + episodes, RW). Among the 28687 infants included, the most important independent risk factors for OW and RW (both in LA and in EU) were having a cold during the first 3 months of life [OR for RW 3.12 (2.60-3.78) and 3.15 (2.51-3.97); population attributable fraction (PAF) 25.0% and 23.7%]; and attending nursery school [OR for RW 2.50 (2.04-3.08) and 3.09 (2.04-4.67); PAF 7.4% and 20.3%]. Other risk factors were as follows: male gender, smoking during pregnancy, family history of asthma/rhinitis, and infant eczema. Breast feeding for >3 months protected from RW [OR 0.8 (0.71-0.89) in LA and 0.77 (0.63-0.93) in EU]. University studies of mother protected only in LA [OR for OW 0.85 (0.76-0.95) and for RW 0.80 (0.70-0.90)]. Although most risk factors for wheezing are common in LA and EU; their public health impact may be quite different. Avoiding nursery schools and smoking in pregnancy, breastfeeding babies >3 months, and improving mother's education would have a substantial impact in lowering its prevalence worldwide.

Poverty-associated risk factors for wheezing in the first year of life in Honduras and El Salvador

BACKGROUND

Risk factors for wheezing specifically during the first year of life have been studied in well-developed countries, but the information from developing countries is very scarce. There are no such studies focusing on factors derived from poverty. The aim of the present study was to determine if risk factors related to poverty are associated to wheezing during the first year of life in infants from Honduras and El Salvador.

METHODS

A survey, using a validated questionnaire, was carried out in the metropolitan area of San Pedro Sula (Honduras) and in La Libertad (El Salvador) in centres where infants attended for a scheduled vaccination shot or a healthy child visit at 12 months of age. Fieldworkers offered questionnaires to parents and helped the illiterate when necessary. The main outcome variable was wheezing during the first year of life, as reported by parents.

RESULTS

A total of 1047 infants in El Salvador and 780 in Honduras were included in the analysis. The prevalence of wheeze in the first year was higher in El Salvador (41.2%) than in Honduras (27.7%), as was recurrent wheezing defined as three or more episodes (18.4% vs. 11.7%). Wheezing and recurrent wheezing was associated to unpaved floor in the household (summary odds ratios for both countries 1.55, p=0.036 and 1.72, p=0.054 for any wheeze and recurrent wheezing, respectively); dust entering from streets (1.30, p=0.052 and 1.67, p=0.008); living in a heavily polluted area (1.33, p=0.037 and 1.52, p=0.033); and having mould stains on the household walls (1.36, p=0.072 and 1.76, p=0.007). Furthermore, marginal associations were found for additional person at home and use of kerosene as cooking fuel. University studies in the mother (0.34, p=0.046 and 0.32, p=0.022) and a professional occupation in the father (0.34, p=0.046 and 0.26, p=0.047) were associated to a lower risk.

CONCLUSIONS

The prevalence of wheezing and recurrent wheezing is notoriously high in El Salvador and Honduras. In those populations factors related to poverty are associated to a higher prevalence of wheezing and recurrent wheezing, whereas higher maternal education and paternal professional occupation behave as protective factors.

Olive oil during pregnancy is associated with reduced wheezing during the first year of life of the offspring

OBJECTIVE

To test the hypothesis that consuming Mediterranean diet and using olive oil for cooking/dressing salads during pregnancy might be associated with less wheezing during the first year of the offspring's life.

METHODS

A study was conducted in 1,409 infants (mean age, 16.6 +/- 2.5 months) attending healthy infant clinics in Spain. Dietary data of mothers' intake during pregnancy was collected by means of a parental food frequency questionnaire. Demographic information and data on wheezing during the first year of the offspring's life were also recorded. Infants were stratified according to any wheezing (42.2%) during the first year of life.

RESULTS

In the univariate analysis, adherence to a Mediterranean diet and using olive oil for cooking/dressing salads during pregnancy were both significantly associated with less wheezing during the first year of life. However, after multivariate analysis, only olive oil consumption during pregnancy remained associated with less wheezing in the studied period (aOR = 0.57 [95% CI = 0.4-0.9]); whereas male gender (1.8 [1.4-2.3]), day care attendance (2.15 [1.5-3.1]), maternal asthma (2.16 [1.3-3.6]), maternal smoking during pregnancy (1.83 [1.3-2.2]), infant eczema (1.95 [1.3-2.9]), and mould stains on the household walls (1.72 [1.2-2.5]) remained associated with wheezing.

CONCLUSION

Our findings suggest a protective effect (primary prevention) of olive oil use during pregnancy on wheezing during the first year of the offspring's life.

Allergy related disorders among 2-yrs olds in a general population. The PACT Study

Allergic disorders represent a major health problem in most developed countries, but few population-based studies have focused on these disorders in early childhood. The aims of the present study were to investigate the prevalence, gender differences and distribution of allergy related disorders and their association to sensitization among unselected children, 2 yrs of age, in a general population. A population-based study with parental self reported questionnaire data involving allergy related symptoms and results from allergy tests from 4783 two-yr-old children was conducted, and skin prick tests (SPT) of a randomly selected sample comprising 390 children were performed. In the total population the prevalence of reported wheeze was 26%, doctor diagnosed asthma (DDAsthma) 7.0%, atopic dermatitis (AD) 17% and allergic rhinoconjunctivitis (ARC) 3%. Of the 1008 (21%) allergy tested children 59% reported a positive test, but of the randomly selected children only 8% had a positive SPT. Children with AD were most frequently sensitized and children with ARC were most likely to have other allergy related disorders (70%). More boys than girls had an allergy related disorder or a positive allergy test. In conclusion, two in five had an allergy related disorder, but less than 10% had a positive SPT. Having one allergic disorder, especially ARC, increased substantially the risk of having another, and having AD was most strongly associated to a positive allergy test. Moreover, boys were more likely than girls to have an allergy related disorder or a positive SPT indicating a gender difference in the natural history of allergy related disorders.

The influence of parental educational level on the development of atopic sensitization, wheezing and eczema during the first year of life

Several studies have investigated the association between socioeconomic status and the occurrence of allergies. Nevertheless, the results remain contradictory. The aim of this study was to evaluate the associations between parental education and the occurrence of atopic sensitization, recurrent wheezing and eczema during the first year of life, differentiating between atopic and non-atopic disorders based on specific serum IgE. We conducted an aetiological study in 690 children, based on a prospective birth cohort project in which environmental and health information was gathered using questionnaires. At the age of 1 yr a blood sample was taken for quantification of specific IgE. Adjusted odds ratios and 95% confidence intervals were computed as measures of association between the outcomes and parental education. Parental educational level was positively associated with the occurrence of atopic sensitization (OR: 2.1; 95% CI: 1.0-4.4) and eczema (OR: 1.9; 95% CI: 1.1-3.4), but negatively with the occurrence of recurrent wheezing (OR: 0.4; 95% CI: 0.2-0.8) in the first year of life. Atopic recurrent wheezing was positively associated with the education of the parents, whereas non-atopic recurrent wheezing was negatively associated. When maternal and paternal education were considered separately, only maternal education had a significant influence. Our results suggest that aspects associated with a high maternal educational level may play an important role in the development of atopic disorders.

Maternal obesity in pregnancy and respiratory health in early childhood

Obesity is associated with systemic inflammation, immunological changes, increased risk of respiratory infections and chronic respiratory illness. Maternal obesity in pregnancy increases the risk of pregnancy complications, caesarean sections and adverse birth outcomes, which have in turn been associated with respiratory illness in children. To our knowledge, the possible influence of maternal obesity in pregnancy on respiratory illness in early childhood beyond the newborn period has not been explored. We examined the relationship between a high maternal body mass index (BMI) in pregnancy and lower respiratory tract infections and wheeze up to 18 months of age in the Norwegian Mother and Child Study (MoBa), a population-based cohort study that includes 100,000 pregnant women, conducted at the Norwegian Institute of Public Health. We analysed data from the first 33 192 children, born between 1999 and 2005. In unadjusted analyses maternal obesity in pregnancy was related to both respiratory infections and wheeze in the children. In multivariable analyses, only an effect on wheeze remained. The risk of wheeze increased linearly with maternal BMI in pregnancy, and was 3.3% higher [95% CI 1.2, 5.3] for children with mothers who were obese during pregnancy, than for children of mothers with normal BMI. This effect was not mediated through obesity-related pregnancy complications, low birthweight, preterm birth or caesarean section.

Respiratory noises: how useful are they clinically?

Although clinicians place considerable weight on the identification of the various forms of noisy breathing, there are serious questions regarding both the accuracy (validity) and the reliability (repeatability) of these noises. To avoid diagnostic errors, clinicians need to consider the whole constellation of symptoms and signs, and not focus on the specific "type" of noise. Given the high error rate with "parent-reported wheeze" there is a need to reexamine the extensive literature on the epidemiology of wheeze in infants and young children, because parent-reported wheeze is unconfirmed by a clinician. It is obvious we need more high-quality research evidence to derive better evidence on the clinical utility of these noises, and their natural history.

Prenatal exposure to acetaminophen and respiratory symptoms in the first year of life

BACKGROUND

Prevalence of asthma in developed countries increased between the 1970s and the 1990s. One factor that might contribute to the trends in asthma is the increased use of acetaminophen vs aspirin in children and pregnant women.

OBJECTIVE

To examine relationships between in utero exposure to acetaminophen and incidence of respiratory symptoms in the first year of life.

METHODS

A total of 345 women were recruited in the first trimester of pregnancy and followed up with their children through the first year of life. Use of acetaminophen in pregnancy was determined by questionnaire and related to incidence of respiratory symptoms.

RESULTS

Use of acetaminophen in middle to late but not early pregnancy was significantly related to wheezing (odd ratio, 1.8; 95% confidence interval, 1.1-3.0) and to wheezing that disturbed sleep (odds ratio, 2.1; 95% confidence interval, 1.1-3.8) in the first year of life after control for potential confounders.

CONCLUSION

This study suggests that use of acetaminophen in middle to late but not early pregnancy may be related to respiratory symptoms in the first year of life. Additional follow-up will examine relationships of maternal and early childhood use of acetaminophen with incidence of asthma at ages 3 to 5 years, when asthma diagnosis is more firmly established.

The International Study of Wheezing in Infants: questionnaire validation

BACKGROUND

There are no internationally validated questionnaires to investigate the prevalence of infant wheezing. This study was undertaken to validate a questionnaire for the International Study on the Prevalence of Wheezing in Infants (Estudio Internacional de Sibilancias en Lactantes, EISL).

MATERIAL AND METHODS

Construct and criterion validity were tested for the question 'Has your baby had wheezing or whistling in the chest during his/her first 12 months of life?'. Construct validity (i.e. the ability of parents and doctors to refer to the same symptoms with the same words) was tested in a sample of 50 wheezing and 50 non-wheezy infants 12-15 months of age in each of 10 centres from 6 different Spanish- or Portuguese-speaking countries. Criterion validity (i.e. the ability of parents to correctly detect the symptom in the general population) was evaluated in 2 samples (Santiago, Chile and Cartagena, Spain) of 50 wheezing and 50 non-wheezing infants (according to parents) of the same age, randomly selected from the general population, who were later blindly diagnosed by a paediatric pulmonologist.

RESULTS

Construct validity was very high (kappa test: 0.98-1) in all centres. According to Youden's index, criterion validity was good both in Cartagena (75.5%) and in Santiago (67.0%). Adding questions about asthma medication did not improve diagnosis accuracy.

CONCLUSIONS

The EISL questionnaire significantly distinguished wheezy infants from healthy ones. This questionnaire has a strong validity and can be employed in large international multicentre studies on wheezing during infancy.