Prevalence of respiratory symptoms among 7 and 11 year old schoolchildren and association with asthma

Phenotypes of cough in children: A latent class analysis

INTRODUCTION

Distinguishing phenotypes among children with cough helps understand underlying causes. Using a statistical data-driven approach, we aimed to identify and validate cough phenotypes based on measurable traits, physician diagnoses, and prognosis.

METHODS

We used data from the Swiss Paediatric Airway Cohort and included 531 children aged 5-16 years seen in outpatient clinics since 2017. We included children with any parent-reported cough (i.e. cough without a cold, cough at night, cough more than other children, or cough longer than 4 weeks) without current wheeze. We applied latent class analysis to identify phenotypes using nine symptoms and characteristics and selected the best model using the Akaike information criterion. We assigned children to the most likely phenotype and compared the resulting groups for parental atopy history, comorbidities, spirometry, fractional exhaled nitric oxide (FeNO), skin prick tests and specific IgE, physician diagnoses, and 1-year prognosis.

RESULTS

We identified four cough phenotypes: non-specific cough (26%); non-allergic infectious and night cough with snoring and otitis (4%); chronic allergic dry night cough with snoring (9%); and allergic non-infectious cough with rhino-conjunctivitis (61%). Children with the allergic phenotype often had family or personal history of atopy and asthma diagnosis. FeNO was highest for the allergic phenotype [median 17.9 parts per billion (ppb)] and lowest for the non-allergic infectious phenotype [median 7.0 parts per billion (ppb)]. Positive allergy test results differed across phenotypes (p < .001) and were most common among the allergic (70%) and least common among the non-specific cough (31%) phenotypes. Subsequent wheeze was more common among the allergic than the non-specific phenotype.

CONCLUSION

We identified four clinically relevant cough phenotypes with different prognoses. Although we excluded children with current wheeze, most children with cough belonged to allergy-related phenotypes.

Prevalence of childhood cough in epidemiological studies depends on the question used: findings from two population-based studies

BACKGROUND

Epidemiological studies use different questions to assess recurrent cough in children. In two independent population-based studies, we assessed how prevalence estimates of cough vary depending on the questions parents are asked about their child's cough and how answers to the different questions overlap.

METHODS

We analysed cross-sectional data from two population-based studies on respiratory health: LuftiBus in the School (LUIS), conducted in 2013-2016 among 6- to 17-year-school children in the Canton of Zurich, Switzerland, and the 1998 Leicester Respiratory Cohort (LRC) study, UK where we used data from 6- to 8-year-old children from the 2003 follow-up survey. Both studies used parental questionnaires that included the same three questions on the child's cough, namely cough without a cold, dry cough at night and coughing more than others. We assessed how the prevalence of cough varied depending on the question and how answers to the different questions on cough overlapped. We also assessed how results were influenced by age, sex, presence of wheeze and parental education.

RESULTS

We included 3457 children aged 6-17 years from LUIS and 2100 children aged 6-8 years from LRC. All respiratory outcomes - cough, wheeze and physician-diagnosed asthma - were reported twice as often in the LRC as in LUIS. We found large differences in the prevalence of parent-reported cough between the three cough questions. In LUIS, 880 (25%) parents reported cough without a cold, 394 (11%) dry night cough, and 159 (5%) reported that their child coughed more than other children. In the LRC, these numbers were 1003 (48%), 527 (25%) and 227 (11%). There was only partial overlap of answers, with 89 (3%) answering yes to all questions in LUIS and 168 (8%) in LRC. Prevalence of all types of cough and overlap between the cough questions was higher in children with current wheeze.

CONCLUSION

In both population-based studies prevalence estimates of cough depended strongly on the question used to assess cough with only partial overlap of responses to different questions. Epidemiological studies on cough can only be compared if they used exactly the same questions for cough.

Quality and consistency of clinical practice guidelines on the prevention of food allergy and atopic dermatitis: Systematic review protocol

Background and aims

Allergy prevention strategies have gained significant traction as a means to attenuate the growing burden of allergic diseases over the past decade. As the evidence base for primary prevention of food allergy (FA) and atopic dermatitis (AD) is constantly advancing, clinical practice guideline (CPG) recommendations on interventions for FA and AD prevention vary in quality and consistency among professional organizations. We present a protocol for a systematic review of CPGs on primary prevention of FA and AD.

Methods

We will systematically review and appraise all CPGs addressing primary prevention of FA and AD and report our findings according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Electronic databases and manual website searches from January 2011 to March 2021 without language or geographical restrictions, and supplemented by author contact, will generate the list of potentially relevant CPGs to screen. Evaluation of the methodological quality, consistency, and global applicability of shortlisted CPGs will be performed by members of the Allergy Prevention Work Group of the World Allergy Organization (WAO) using the Appraisal of Guidelines for Research and Evaluation (AGREE) II and AGREE-REX (Recommendations EXcellence). instruments. Guideline contents, consistency, and quality of the recommendations will be summarised in tabular and narrative formats. We aim to present consolidated recommendations from international guidelines of the highest methodological quality and applicability, as determined by AGREE II and AGREE-REX.

Dissemination

This systematic review will provide a succinct overview of the quality and consistency of recommendations across all existing CPGs for FA and AD prevention, as well as crucial perspectives on applicability of individual recommendations in different geographical contexts. Results from this systematic review will be reported in a peer-reviewed journal. It will also inform a position statement by WAO to provide a practical framework to guide the development of future guidelines for allergy prevention worldwide.

Prospero registration number

CRD42021265689.

A new method for objectively evaluating nocturnal cough in adults

BACKGROUND

For the management of cough diseases in adults, an objective method of evaluating nocturnal cough is required.

METHODS

In Study 1, a cough monitoring system was evaluated using 25 adult volunteers. In Study 2, the cough monitoring system was validated using 20 samples from 10 adult patients with cough diseases obtained overnight. In hospitalized patients, our original cough monitoring system with a microphone and accelerometer was used. At the same time, coughs were recorded using a video camera with digital sound recording. The number of coughs in each 8-h video-audio recording was counted manually by three trained observers. All cough data were printed out, and the basal number of cough events, using both the printed-out data and video-audio recordings, were then calculated by three observers.

RESULTS

In Study 1, the cough monitoring system demonstrated good agreement with the number of coughs counted by examiners (sensitivity 99.2%, specificity 98.9%). In Study 2, there was significant agreement in the counts of natural coughs between our system and the video-audio method (p < 0.0001) and between our system and the basal cough events (p < 0.0001).

CONCLUSIONS

Our method demonstrated excellent agreement with the video-audio recording method in adults and is considered extremely useful for the objective monitoring of overnight cough in adult patients with cough diseases.

Wheeze and cough measurements at night in children with respiratory symptoms

Background

Nocturnal cough and wheeze are important symptoms when diagnosing any respiratory disease in a child, but objective measurements of these symptoms are not performed.

Methods

The aim of our study was to analyze the use of an automated detection system to assess breath sounds objectively in comparison to cough and wheeze questionnaires and to evaluate its feasibility in clinical practice.

Results

Forty-nine recordings of thirty-nine children were processed (asthma n = 13; cystic fibrosis n = 2; pneumonia n = 5; suspicion of habit cough n = 7; prolonged, recurrent or chronic cough n = 13), and cough and asthma scores were compared to the objective nocturnal recordings. Time for audio-validation of recordings took between 2 and 40 min (mean: 14.22 min, (SD): 10.72). Accuracy of the automated measurement was higher for cough than for wheezing sounds. Nocturnal cough readings but not wheeze readings correlated with some of the corresponding scores.

Conclusion

To our knowledge this is the first study using a new device to assess nocturnal cough and obstructive breath sounds objectively in children with a wide variety of respiratory diseases. The assessment proved user friendly. We obtained additional information on nighttime symptoms, which would otherwise have remained obscure. Further studies to assess possible diagnostic and therapeutic benefits of this device are needed.

Otolaryngologic Management of Chronic Cough in School-aged Children: A Review

Importance

The causes of pediatric chronic cough are numerous and span across several medical subspecialties. In addition to the vast array of underlying causes, there are also several different ways to approach and evaluate chronic cough. Given the frequency with which children present to otolaryngology clinics with this problem, a review of common otolaryngologic causes and an algorithm for evaluation and treatment can be beneficial.

Observations

The primary 3 causes of pediatric chronic cough presenting to an otolaryngologist include infectious causes, reflux, and airway hyperreactivity. In these cases and other instances of specific cough, treatment should be directed at the underlying cause-which may include supportive care, antibiotics, antireflux medication, bronchodilators, inhaled steroids, or other intervention. Patients with nonspecific cough should be treated according to pediatric-specific cough algorithms.

Conclusions and Relevance

Appropriate workup and treatment of chronic cough can lead to higher cure rates, shorter cough duration, and improved quality of life for both patients and caregivers. A systematic approach using cough algorithms can help otolaryngologists effectively manage this common yet complex problem.

IgE level in newborn umbilical cord and its relationship with some maternal factors

BACKGROUND AND OBJECTIVES

Allergic diseases are among major pediatric issues as they are highly prevalent and chronic. Therefore, identification of factors contributing to allergic disease could play a significant role in prevention of these conditions. This study aimed at investigating the IgE level in newborn's umbilical cord blood and its relationship with some maternal factors.

METHODS

A cross-sectional study was conducted in 101 mothers and their newborns in Babol, Iran 2016. The samples were selected using non-probability convenience sampling. Information including newborn sex, gravidity, history of allergy before and during pregnancy (asthma, allergic rhinitis, eczema, hives, food allergy, and drug allergy), family history of allergy among mothers, history of exposure to secondhand smoke and pets, and delivery techniques was recorded. The IgE levels in newborn umbilical cord blood and maternal serum were measured using an IgE kit and ELISA technique.

RESULTS

The newborns included 53 females (52.5%) and 29 mothers had vaginal birth (28.7%). History of exposure to secondhand smoke was found in 15 samples (14.9%), and 18 participants reported exposure to pets (17.8%). The median IgE levels in newborns and their mothers were 0.41 and 98.6, respectively. In general, IgE level in all newborns was within the normal range, but, it was higher than normal in 15 mothers (14.9%). The IgE level was significantly higher in male newborns than that of the female newborns (p = 0.011). There were no significant differences in the IgE levels of mothers and their newborns on the basis of delivery technique and history of exposure to pets (p > 0.05).

CONCLUSION

In this study, the IgE level in all newborns was within the normal range, and sex was found to be an effective factor in IgE levels.

Prevalence and Risk Factors of Asthma and Allergy-Related Diseases among Adolescents (PERFORMANCE) study: rationale and methods

Despite a considerable number of international reports on allergic diseases among children, information about the prevalence and risk factors of asthma and allergy-related diseases among Indian adolescents is relatively sparse. The Prevalence and Risk Factors of Asthma and Allergy-Related Diseases among Adolescents (PERFORMANCE) study has been conceived to study the aetiology of asthma and allergic diseases including rhinoconjunctivitis, atopic eczema and food allergies among adolescents in West Bengal, India, using standardised methods and collaborations. The aims of the study are: 1) to estimate the prevalence and risk factors of asthma and allergic diseases among the adolescents residing in rural, suburban and urban areas of West Bengal; 2) to obtain information about the possible role of lifestyle factors (smoking, diet and physical activity) on the disease prevalence; and 3) to create a network for further investigation on social, environmental and genetic factors affecting the diseases. The PERFORMANCE study comprises two phases. The phase I study will investigate the prevalence and possible contributing factors of asthma and allergic diseases in a defined population. The phase II study will be performed as a follow-up of phase I to assess the incidence of asthma and allergic diseases.

The PERFORMANCE study: investigating the prevalence and risk factors of allergy and asthma among Indian adolescentshttp://ow.ly/jP2v30kmt8u

Burosumab Therapy in Children with X-Linked Hypophosphatemia

BACKGROUND

X-linked hypophosphatemia is characterized by increased secretion of fibroblast growth factor 23 (FGF-23), which leads to hypophosphatemia and consequently rickets, osteomalacia, and skeletal deformities. We investigated burosumab, a monoclonal antibody that targets FGF-23, in patients with X-linked hypophosphatemia.

METHODS

In an open-label, phase 2 trial, we randomly assigned 52 children with X-linked hypophosphatemia, in a 1:1 ratio, to receive subcutaneous burosumab either every 2 weeks or every 4 weeks; the dose was adjusted to achieve a serum phosphorus level at the low end of the normal range. The primary end point was the change from baseline to weeks 40 and 64 in the Thacher rickets severity total score (ranging from 0 to 10, with higher scores indicating greater disease severity). In addition, the Radiographic Global Impression of Change was used to evaluate rachitic changes from baseline to week 40 and to week 64. Additional end points were changes in pharmacodynamic markers, linear growth, physical ability, and patient-reported outcomes and the incidence of adverse events.

RESULTS

The mean Thacher rickets severity total score decreased from 1.9 at baseline to 0.8 at week 40 with every-2-week dosing and from 1.7 at baseline to 1.1 at week 40 with every-4-week dosing (P<0.001 for both comparisons); these improvements persisted at week 64. The mean serum phosphorus level increased after the first dose in both groups, and more than half the patients in both groups had levels within the normal range (3.2 to 6.1 mg per deciliter [1.0 to 2.0 mmol per liter]) by week 6. Stable serum phosphorus levels were maintained through week 64 with every-2-week dosing. Renal tubular phosphate reabsorption increased from baseline in both groups, with an overall mean increase of 0.98 mg per deciliter (0.32 mmol per liter). The mean dose of burosumab at week 40 was 0.98 mg per kilogram of body weight with every-2-week dosing and 1.50 mg per kilogram with every-4-week dosing. Across both groups, the mean serum alkaline phosphatase level decreased from 459 U per liter at baseline to 369 U per liter at week 64. The mean standing-height z score increased in both groups, with greater improvement seen at all time points with every-2-week dosing (an increase from baseline of 0.19 at week 64) than with every-4-week dosing (an increase from baseline of 0.12 at week 64). Physical ability improved and pain decreased. Nearly all the adverse events were mild or moderate in severity.

CONCLUSIONS

In children with X-linked hypophosphatemia, treatment with burosumab improved renal tubular phosphate reabsorption, serum phosphorus levels, linear growth, and physical function and reduced pain and the severity of rickets. (Funded by Ultragenyx Pharmaceutical and Kyowa Hakko Kirin; ClinicalTrials.gov number, NCT02163577 ; EudraCT number, 2014-000406-35 ).

Prevalence of cough throughout childhood: A cohort study

Background

Cough in children is a common reason for medical consultations and affects quality of life. There are little population-based data on the epidemiology of recurrent cough in children and how this varies by age and sex, or between children with and without wheeze. We determined the prevalence of cough throughout childhood, comparing several standardised cough questions. We did this for the entire population and separately for girls and boys, and for children with and without wheeze.

Methods

In a population-based prospective cohort from Leicestershire, UK, we assessed prevalence of cough with repeated questionnaires from early childhood to adolescence. We asked whether the child usually coughed more than other children, with or without colds, had night-time cough or cough triggered by various factors (triggers, related to increased breathing effort, allergic or food triggers). We calculated prevalence from age 1 to 18 years using generalised estimating equations for all children, and for children with and without wheeze.

Results

Of 7670 children, 10% (95% CI 10–11%) coughed more than other children, 69% (69–70%) coughed usually with a cold, 34% to 55% age-dependently coughed without colds, and 25% (25–26%) had night-time cough. Prevalence of coughing more than peers, with colds, at night, and triggered by laughter varied little throughout childhood, while cough without colds and cough triggered by exercise, house dust or pollen became more frequent with age. Cough was more common in boys than in girls in the first decade of life, differences got smaller in early teens and reversed after the age of 14 years. All symptoms were more frequent in children with wheeze.

Conclusions

Prevalence of cough in children varies with age, sex and with the questions used to assess it, suggesting that comparisons between studies are only valid for similar questions and age groups.

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.

Parental compliance--an emerging problem in Liverpool community child health surveys 1991-2006

Background

Compliance is a critical issue for parental questionnaires in school based epidemiological surveys and high compliance is difficult to achieve. The objective of this study was to determine trends and factors associated with parental questionnaire compliance during respiratory health surveys of school children in Merseyside between 1991 and 2006.

Methods

Four cross-sectional respiratory health surveys employing a core questionnaire and methodology were conducted in 1991, 1993, 1998 and 2006 among 5-11 year old children in the same 10 schools in Bootle and 5 schools in Wallasey, Merseyside. Parental compliance fell sequentially in consecutive surveys. This analysis aimed to determine the association of questionnaire compliance with variation in response rates to specific questions across surveys, and the demographic profiles for parents of children attending participant schools.

Results

Parental questionnaire compliance was 92% (1872/2035) in 1991, 87.4% (3746/4288) in 1993, 78.1% (1964/2514) in 1998 and 30.3% (1074/3540) in 2006. The trend to lower compliance in later surveys was consistent across all surveyed schools. Townsend score estimations of socio-economic status did not differ between schools with high or low questionnaire compliance and were comparable across the four surveys with only small differences between responders and non-responders to specific core questions. Respiratory symptom questions were mostly well answered with fewer than 15% of non-responders across all surveys. There were significant differences between mean child age, maternal and paternal smoking prevalence, and maternal employment between the four surveys (all p<0.01). Out-migration did not differ between surveys (p=0.256) with three quarters of parents resident for at least 3 years in the survey areas.

Conclusion

Methodological differences or changes in socio-economic status of respondents between surveys were unlikely to explain compliance differences. Changes in maternal employment patterns may have been contributory. This analysis demonstrates a major shift in community parental questionnaire compliance over a 15 year period to 2006. Parental questionnaire compliance must be factored into survey designs and methodologies.

Respiratory involvement in inflammatory bowel diseases

Inflammatory bowel diseases (IBD) include ulcerative colitis (UC) and Crohn's disease (CD) and are due to a dysregulation of the antimicrobial defense normally provided by the intestinal mucosa. This inflammatory process may extend outside the bowel to many organs and also to the respiratory tract. The respiratory involvement in IBD may be completely asymptomatic and detected only at lung function assessment, or it may present as bronchial disease or lung parenchymal alterations. Corticosteroids, both systemic and aerosolized, are the mainstay of the therapeutical approach, while antibiotics must be also administered in the case of infectious and suppurative processes, whose sequels sometimes require surgical intervention. The relatively high incidence of bronchopulmonary complications in IBD suggests the need for a careful investigation of these patients in order to detect a possible respiratory involvement, even when they are asymptomatic.

Risk factors of childhood asthma in Sao Jose do Rio Preto, Sao Paulo, Brazil

BACKGROUND

Epidemiological studies have shown increased prevalence of asthma over the last decades and a considerable variation in these rates between different countries, mainly developed. Changes in lifestyle of different populations could explain the increasing prevalence of asthma and its different rates in different communities.

OBJECTIVES

A case-control study was conducted to investigate some risks factors associated to asthma in schoolchildren in São José do Rio Preto, São Paulo, Brazil.

CASUISTIC AND METHODS

A total of 3793 self-administered written questionnaire (WQ) was filled in by parents of 6-7-year-old schoolchildren, applying the International Study of Asthma and Allergies in Childhood (ISAAC) protocol. Additionally, was added a supplementary WQ evaluating risk factors: gender, personal history of rhinitis and atopic eczema, familial history of atopy, older siblings, day care, breastfeeding, and exposure to pets and to cigarette smoking. Children whose parents responded affirmatively to question 'Has your child had wheezing in the past 12 monthsquest;' were identified as having current asthma.

RESULTS

The prevalence of current asthma was 18.3%. In multivariate analysis the following risk factors were associated with asthma: rhinitis (OR = 10.6; 95% CI = 8.27-13.56), atopic eczema (OR = 1.54; 95% CI = 1.00-2.35), father with asthma (OR = 3.49; 95% CI = 1.83-6.67), mother with asthma (OR = 1.84; 95% CI = 1.11-3.05), current exposure to pets (OR = 1.83; 95% CI = 1.45-2.32) and passive tobacco smoking exposure (OR = 1.43; 95% CI = 1.12-1.83).

CONCLUSIONS

Our results show that genetic background, environmental factors and the presence of co-morbidities such as rhinitis and atopic eczema are associated to the genesis of asthma in Brazilian schoolchildren.

A parent-completed respiratory questionnaire for 1-year-old children: repeatability

BACKGROUND AND AIMS

There are few standardised questionnaires for the assessment of respiratory symptoms in preschool children. We have developed and tested the short-term repeatability of a postal questionnaire on respiratory symptoms for 1-year-old children.

METHODS

A newly developed postal questionnaire for the assessment of wheeze and other respiratory symptoms was sent to parents of a population-based random sample of 4300 children aged 12-24 months. After an interval of 3 months, a random sample of 800 respondents received the questionnaire a second time. The responses were compared using Cohen's kappa (kappa) to assess agreement corrected for chance.

RESULTS

The first questionnaire was returned by 3194 (74%) families, the second one by 460/800 (58%). Repeatability was excellent (kappa 0.80-0.96) for questions on household characteristics, environmental exposures and family history, good (kappa 0.61-0.80) for questions on prevalence, severity and treatment of wheeze, and moderate (kappa 0.39-0.66) for chronic cough and upper respiratory symptoms.

CONCLUSIONS

This short postal questionnaire designed for use in population-based studies has excellent repeatability for family and household characteristics and good repeatability for questions on wheeze. Short-term changes in symptom status might be responsible for variable answers on recent chronic cough and upper respiratory symptoms. Overall, the questionnaire is a valuable instrument for community-based research on respiratory symptoms in 1 to 2-year-old children.

Associations between home dampness and presence of molds with asthma and allergic symptoms among young children in the tropics

Existing literature has shown that home dampness increases indoor mold burden and is associated with increased allergic symptoms among young children in temperate environments. There is no report of any studies of similar nature in the tropics where conditions are characterized typically by high temperatures and humidity with rainfall throughout the year. To evaluate if there are associations between the prevalence of current asthma and allergic symptoms in young children (age 1.5-6 yr) with dampness and indoor mold in children's bedrooms in a tropical environment. A cross-sectional study adopting an expanded and modified ISAAC--International Study on Asthma and Allergies in Children--questionnaire for the evaluation of asthma and allergies was conducted on 6794 children (4759 responded--70%) attending 120 randomly selected daycare centers. Specific information on demographics, home dampness, and the visible presence of indoor molds were obtained. The prevalence ratios (PR) and 95% confidence interval (CI) were determined by Cox proportional hazard regression model with assumption of a constant risk period as recommended for cross-sectional studies. The calculated PRs were controlled for age, gender, ethnicity, socio-economic status, type of housing, maternal and paternal atopy, respiratory infections, environmental tobacco smoke (ETS) exposure, and food allergy. After adjusting for potential confounding effects, home dampness was observed to be significantly associated with current symptoms of rhinoconjunctivitis (adjusted PR 1.53, 95% CI: 1.00-2.33). The visible presence of mold was significantly associated with current symptoms of rhinitis (PR 1.55, 95% CI: 1.16-2.07) and rhinoconjunctivitis (PR 2.38, 95% CI: 1.51-3.75). Indoor dampness and mold in children's bedroom are important risk factors associated with allergic symptoms in young children in Singapore.

Salivary cotinine, doctor-diagnosed asthma and respiratory symptoms in primary schoolchildren

Due to impaired airway function, children are at risk for adverse respiratory symptoms if exposed to environmental tobacco smoke (ETS). A community-based, cross-sectional study of 425 children (5-11 years) attending 15 primary schools in a low socio-economic area of Merseyside/UK was undertaken to investigate the association of adverse respiratory symptoms and ETS exposure using a parent-completed questionnaire and children's salivary cotinine measurements. Overall, 28.9% of children had doctor-diagnosed asthma (DDA) and 11.3% a history of hospital admission for respiratory illnesses. The symptom triad of cough, wheeze and breathlessness (C+W+B+) occurred in 12.6% of children. The geometric mean cotinine level was 0.37 ng/ml (95% CI, 0.33-0.42 ng/ml) and it was estimated that 45.6% of children were ETS exposed. A history of asthma in the family was reported for 9.2% of fathers and 7.2% of mothers. Salivary cotinine level was significantly increased in children with DDA compared to those without (P = 0.002). Cotinine-validated levels [adjusted odds ratio (AOR), 1.8; 95% CI, 1.4-2.5), low socio-economic (disadvantaged) status (AOR, 1.4; 1.1-2.9), child's male gender (AOR, 1.6; 1.1-2.5) and maternal smoking (AOR, 2.2; 1.4-3.1) were significantly associated with DDA. The cotinine-validated level (AOR, 1.4; 1.1-2.9) as well as maternal smoking (AOR, 1.8; 1.1-2.5), were also independently associated with C+W+B+. The use of salivary cotinine as an indicator of ETS exposure could be used to inform parents of exposure risk to their asthmatic children and may help re-enforce deterrent efforts to reduce childhood parental smoking exposure.

Relationship between childhood atopy and wheeze: what mediates wheezing in atopic phenotypes?

BACKGROUND

The nature of the relationship between childhood wheeze and atopy remains uncertain.

OBJECTIVE

To characterize childhood wheeze among atopic phenotypes in a longitudinal birth cohort study.

METHODS

A whole population birth cohort (N = 1,456) was recruited in 1989. Children were seen at birth and at 1, 2, 4, and 10 years of age to obtain information on asthma and allergic disease development and relevant risk factors for these states. Skin prick testing at ages 4 (n = 980) and 10 (n = 1,036) years was used to define atopic phenotypes. Wheezing in these states was characterized, and logistic regression was used to identify independent risk factors for wheeze onset in different atopic phenotypes.

RESULTS

Wheeze ever occurred in 37% of never atopics, 38% of early childhood atopics, 65% of chronic childhood atopics, and 52% of delayed childhood atopics. Chronic childhood atopics had significant wheezing morbidity and bronchial hyperresponsiveness. Their wheezing was associated with male sex, early eczema, family history of eczema, and early tobacco exposure. Never atopic wheeze was related to maternal asthma, parental smoking, and respiratory tract infections. Exclusive breastfeeding protected against early childhood atopic wheeze. Maternal asthma, family history of urticaria, and dog ownership increased delayed childhood atopic wheeze.

CONCLUSIONS

In many respects, chronic childhood atopy is the atopic phenotype associated with the most significant forms of childhood wheezing. In such children, heritable drive, allergens, and synergy with other environmental triggers seem to be crucial determinants of wheeze onset. Where such sensitization is absent, numerous environmental factors plus genetic predisposition may assume importance for wheezing.

Airway inflammation in asymptomatic children with episodic wheeze

Airway pathologies have been comprehensively researched in adult asthma, but in children, the extent of airway inflammation associated with episodic wheeze, often diagnosed as asthma, has not been fully characterized. It is not clear whether persistent airway inflammation is present in the absence of wheezing symptoms, and there is controversy regarding the role of age and atopy. This study assessed cellular and cytokine markers of airway inflammation in asymptomatic children with a history of episodic wheeze. Children with a history of episodic wheeze and cough (study group) and nonasthmatic patients requiring elective surgery (control group) were recruited. All subjects in the study group had a history of significant episodic wheezing (>2 episodes per year), and used only as-needed beta-agonist treatment. Bronchoalveolar lavage (BAL) was obtained using bronchoscopic lavage (study group) and nonbronchoscopic lavage (control group). Differential cell counts of BAL and flow cytometry were performed to identify T-lymphocyte phenotypes, and intracellular cytokine profiles were measured after phorbol-12-myristate 13-acetate (PMA) stimulation of BAL fluid T-cells. Twenty-one children with a history of 2-12 episodes of wheeze per year and 21 nonasthmatic subjects without respiratory symptoms were recruited. Study and control subjects were matched for age (median age, 5 years) and demographic characteristics. Study subjects had higher IgE levels, but their measurements were still within normal range. No significant differences in BAL differential cell counts were noted, and in both groups, the majority of T-cells were CD3+ CD8+, with a median CD4:CD8 ratio of 0.6. There was no significant difference in T-cell expression of the activation markers HLA-DR and CD25 (IL-2 receptor), or in PMA-induced production of the intracellular cytokines IFN-gamma, IL-2, IL-4, IL-5, and IL-10. The results of this study suggest that significant T-cell-driven airway inflammation is absent in mild or nonatopic, asymptomatic children of this age group who have episodic wheeze. Our findings support asthma management guidelines that do not recommend long-term treatment of this group of patients with anti-inflammatory medications.

The relation of rhinitis to recurrent cough and wheezing: a longitudinal study

BACKGROUND

Recurrent cough can be a clinical manifestation of rhinitis. However, it remains unclear if the association between rhinitis and recurrent cough among children is independent of asthma.

OBJECTIVE

The aim of the present study was to determine, in a large longitudinal cohort, whether rhinitis is significantly associated with recurrent cough alone, wheezing alone, or the combination of both symptoms during childhood.

METHODS

We investigated determinants of recurrent cough, with or without wheezing, using longitudinal data from the Tucson Children's Respiratory Study. Among the 1246 subjects originally enrolled, 1024 children completed at least one questionnaire between the ages of 6 and 18 years and were included in the present study. In any survey, wheezing was defined as at least one wheezing episode during the past year and recurrent cough as two or more coughing episodes lasting at least 1 week without a cold during the past year. Generalized estimating equations were used to determine significant risk factors.

RESULTS

After adjusting for sex, skin test reactivity and parental asthma, both rhinitis (OR = 2.47 CI = 1.84, 3.30) and sinusitis (OR = 1.54 CI = 1.11, 2.14) were associated with an increased risk of recurrent cough plus wheezing. The OR associated with rhinitis were significantly reduced for subjects reporting only recurrent cough or only wheezing (OR = 1.43, CI = 1.03, 1.99; and OR = 1.30, CI = 1.07, 1.58, respectively). Recurrent cough and wheezing, when examined independently, showed different patterns of risk factors.

CONCLUSION

We found rhinitis to be an independent risk factor for both recurrent cough and wheezing during childhood. Different pathways may be involved in the association of rhinitis with recurrent cough and wheezing.

Cough and asthma

The relationship between cough and asthma is complex. Epidemiological studies now suggest that most children with recurrent cough who do not wheeze do not have asthma. These children are commonly described as having non-specific cough that appears to be due to increased cough receptor sensitivity during the coughing episode. Children with asthma who cough have also been shown to have increased cough receptor sensitivity during an acute exacerbation. Cough severity does not generally correlate with asthma severity. Apart from wheeze and dyspnoea, there are no clear distinguishing features to separate asthma from non-specific cough. To date, no specific treatment has clearly been shown to benefit children with non-specific cough. Although a trial of asthma treatment may be justified in these children, it is preferable to cease rather than escalate treatment if there is no response. In children with asthma who cough, cough should not be used as the predominant symptom to direct asthma therapy.

Guidelines for evaluating chronic cough in pediatrics: ACCP evidence-based clinical practice guidelines

OBJECTIVES

To review relevant literature and present evidence-based guidelines to assist general and specialist medical practitioners in the evaluation and management of children who present with chronic cough.

METHODOLOGY

The Cochrane, MEDLINE, and EMBASE databases, review articles, and reference lists of relevant articles were searched and reviewed by a single author. The date of the last comprehensive search was December 5, 2003, and that of the Cochrane database was November 7, 2004. The authors' own databases and expertise identified additional articles.

RESULTS/CONCLUSIONS

Pediatric chronic cough (ie, cough in children aged <15 years) is defined as a daily cough lasting for >4 weeks. This time frame was chosen based on the natural history of URTIs in children and differs from the definition of chronic cough in adults. In this guideline, only chronic cough will be discussed. Chronic cough is subdivided into specific cough (ie, cough associated with other symptoms and signs suggestive of an associated or underlying problem) and nonspecific cough (ie, dry cough in the absence of an identifiable respiratory disease of known etiology). The majority of this section focuses on nonspecific cough, as specific cough encompasses the entire spectrum of pediatric pulmonology. A review of the literature revealed few randomized controlled trials for treatment of nonspecific cough. Management guidelines are summarized in two pathways. Recommendations are derived from a systematic review of the literature and were integrated with expert opinion. They are a general guideline only, do not substitute for sound clinical judgment, and are not intended to be used as a protocol for the management of all children with a coughing illness. Children (aged <15 years) with cough should be managed according to child-specific guidelines, which differ from those for adults as the etiologic factors and treatments for children are sometimes different from those for adults. Cough in children should be treated based on etiology, and there is no evidence for using medications for the symptomatic relief of cough. If medications are used, it is imperative that the children are followed up and therapy with the medications stopped if there is no effect on the cough within an expected time frame. An evaluation of the time to response is important. Irrespective of diagnosis, environmental influences and parental expectations should be discussed and managed accordingly. Cough often impacts the quality of life of both children and parents, and the exploration of parental expectations and fears is often valuable in the management of cough in children.

Cough: are children really different to adults?

Worldwide paediatricians advocate that children should be managed differently from adults. In this article, similarities and differences between children and adults related to cough are presented. Physiologically, the cough pathway is closely linked to the control of breathing (the central respiratory pattern generator). As respiratory control and associated reflexes undergo a maturation process, it is expected that the cough would likewise undergo developmental stages as well. Clinically, the 'big three' causes of chronic cough in adults (asthma, post-nasal drip and gastroesophageal reflux) are far less common causes of chronic cough in children. This has been repeatedly shown by different groups in both clinical and epidemiological studies. Therapeutically, some medications used empirically for cough in adults have little role in paediatrics. For example, anti-histamines (in particular H1 antagonists) recommended as a front-line empirical treatment of chronic cough in adults have no effect in paediatric cough. Instead it is associated with adverse reactions and toxicity. Similarly, codeine and its derivatives used widely for cough in adults are not efficacious in children and are contraindicated in young children. Corticosteroids, the other front-line empirical therapy recommended for adults, are also minimally (if at all) efficacious for treating non-specific cough in children. In summary, current data support that management guidelines for paediatric cough should be different to those in adults as the aetiological factors and treatment in children significantly differ to those in adults.

Cough symptoms in children aged 5-14 years in Sydney, Australia: non-specific cough or unrecognized pertussis?

OBJECTIVE

The aim of this study was to estimate the community prevalence of coughing symptoms, consistent with surveillance definitions for pertussis, and doctor-diagnosed pertussis in children aged 5-14 years.

METHODOLOGY

A telephone survey of a cross-sectional community sample of parents regarding their child's cough symptoms in the previous 12 months was undertaken in a representative Australian urban region.

RESULTS

In 2020 interviews, parents reported that 22% of children had a cough lasting 2 weeks or longer in the preceding 12 months, and 14% (283) had additional symptoms meeting the Centers for Disease Control (CDC) case definition for pertussis. A cough meeting the case definition was significantly more commonly reported by parents of children aged 5-9 years (17%; P < 0.001) but reported exposure to diagnosed pertussis in such cases was significantly more common in children aged 10-14 years (4.3%; odds ratio 12.8; P < 0.01). Parents of 90% of children meeting the CDC case definition sought medical advice. A diagnosis of pertussis was reported in only 1.2% of cases, which extrapolates to an annual incidence of doctor-diagnosed pertussis of 347/100,000 (95% confidence interval, 140-714 per 100,000). This contrasts with 29/100,000 notified cases in the same age group, time period and geographic area.

CONCLUSION

Cough episodes meeting a clinical case definition for pertussis commonly used in surveillance are reported by a high proportion of carers of school-aged children in Australia. The majority of children who met the CDC and Australian case definitions for pertussis and sought medical attention were not identified as potentially having pertussis, suggesting underdiagnosis of pertussis. Even if less than half of this is true pertussis, the potential impact in terms of transmission of pertussis in the community is likely to be high. The reported incidence of doctor-diagnosed disease estimated from this survey was at least five and up to 20 times the official notification rate. More work needs to be done in raising awareness among medical practitioners of pertussis as a differential diagnosis in older children and adolescents with cough.

What plays a role in the choice of inhaler device for asthma therapy?

Inhalation is the preferred route of delivery for anti-asthma drugs. However, in reality inhalers are often prescribed on an empirical basis rather than on evidence-based awareness. Asthma management guidelines also guide inhaler choice, but they offer non-specific advice regarding inhaler choice, are very long and complicated and not conducive to rapid assimilation by a busy GP. In addition, device selection criteria differ according to who you are asking (i.e. the inhalation technologist, the physician or the patient). The ideal inhaler should be small and have a guided sequence of inhalation, leading patients in a logical sequence of events through the inhalation manoeuvre. It should be breath-activated, releasing medication only when all prerequisites for successful inhalation are met. Most importantly, there should be flow-independent deposition of drug in the lungs and feedback on the successfully performed inhalation manoeuvre to reassure the patient that the drug has been successfully released from the inhaler. The ideal inhaler should also have a low intrinsic airflow resistance, making it suitable for use by patients who have a low inspiratory airflow (e.g. children and elderly patients). In order to check for compliance, the ideal inhaler should have an accurate dose counter which is linked to correct inhalation rather than simply to dose release, and patients should be able to use an identical inhaler device to deliver each of their different medications. Finally, from an environmental and cost-effectiveness point of view, the ideal inhaler should be refillable. Among the currently available dry powder inhalers the Novolizer device fulfils several characteristics of an ideal inhaler for the treatment of asthma and chronic obstructive pulmonary disease (COPD).

Coughing in pre-school children in general practice: when are RAST's for inhalation allergy indicated?

To identify patterns of clinical history associated with extreme (high or low) probabilities of allergic sensitization in coughing children so as to restrict allergy testing to those with an intermediate probability of sensitization. A total of 752 children, aged 1-4, visiting their GPs for coughing (>or=5 days), were tested for IgE-antibodies to house dust mite, cat and dog [RadioAllergoSorbent Test (RAST)]. Parents completed a questionnaire on family history of atopy, breastfeeding, smoking, pets, and floor covering. Data of 640 children could be analyzed, 83 (13%) were IgE-positive. In a logistic regression analysis, a scoring formula for the prediction of being IgE-positive was constructed using variables from the patient's history. Significant contributors for sensitization were: age (3-4 yr), infantile eczema, positive family history of mite-allergy, sibling(s) with pollen-allergy, and smoking by parents. If only one of these characteristics is present, the probability of sensitization is < 25%. In such cases watchful waiting may be preferred over allergy testing. In other cases, a negative RAST may help to exclude sensitization, whereas a positive RAST helps to establish the diagnosis. Thus, acting on clinical history alone may save approximately 80% of RAST's. Patient history-derived information contributes to distinguishing children who are at low risk for sensitization to house dust mite, cat, and dog. The scoring formula may help GPs to identify children with a low probability of being sensitized. This may form the basis for watchful waiting. In others, allergy testing may be useful to gain more diagnostic certainty.

Characterisation of atopic and non-atopic wheeze in 10 year old children

BACKGROUND

Wheezing occurs in both atopic and non-atopic children. The characteristics of atopic and non-atopic wheeze in children at 10 years of age were assessed and attempts made to identify whether different mechanisms underlie these states.

METHODS

Children were seen at birth and at 1, 2, 4 and 10 years of age in a whole population birth cohort study (n = 1456; 1373 seen at 10 years). Information was collected prospectively on inherited and early life environmental risk factors for wheezing. Skin prick testing, spirometry, and methacholine bronchial challenge were conducted at 10 years. Wheezing at 10 years of age was considered atopic or non-atopic depending on the results of the skin prick test. Independent significant risk factors for atopic and non-atopic wheeze were determined by logistic regression.

RESULTS

Atopic (10.9%) and non-atopic (9.7%) wheeze were equally common at 10 years of age. Greater bronchial hyperresponsiveness (p<0.001) and airways obstruction (p = 0.011) occurred in children with atopic wheeze than in those with non-atopic wheeze at 10 years. Children with atopic wheeze more often received treatment (p<0.001) or an asthma diagnosis for their disorder, although current morbidity at 10 years differed little for these states. Maternal asthma and recurrent chest infections at 2 years were independently significant factors for developing non-atopic wheeze. For atopic wheeze, sibling asthma, eczema at 1 year, rhinitis at 4 years, and male sex were independently significant.

CONCLUSIONS

Non-atopic wheeze is as common as atopic wheeze in children aged 10 years, but treatment is more frequent in those with atopic wheeze. Different risk factor profiles appear relevant to the presence of atopic and non-atopic wheeze at 10 years of age.

Bronchial hyper-responsiveness and atopy in urban, peri-urban and rural South African children

Twenty years ago, the prevalence of atopic sensitization and bronchial hyper-responsiveness (BHR) in Xhosa children in a rural location in South Africa was very low. The aim of this study was to document the current prevalence of these two indices by comparing traditional rural Xhosa children, recently urbanized Xhosa children and established city white children, and to consider factors that may account for the observed increase in all of these groups. One thousand four hundred and fifty-seven school children aged 10-14 years from the rural Transkei, from a recently urbanized peri-urban area and from urban Cape Town areas were studied using a questionnaire. Four hundred and eighteen children had histamine challenges, and 492 tests for atopy were also conducted. As determined by bronchial challenge with histamine, 17% of rural and 34.4% of recently urbanized Xhosa children had increased BHR, a marked increase from the 0.03% and 3.17% prevalence of increased BHR previously found using the exercise challenge. The prevalence of increased BHR in white urban children was 33%. Sensitization to one or more aero-allergens, as indicated by CAP RAST tests, was present in 36.6% of the rural Xhosa children with normal BHR and in 62.5% of those with increased BHR, a striking increase from that of previous studies. Atopic sensitization to one or more aero-allergens, as indicated by a skin prick test (SPT), was found in 42.3% of the recently urbanized Xhosa children and 45% of urbanized white children. We have also documented sensitization to house dust mites in the rural Xhosa children for the first time. Passive cigarette smoking was not identified as a risk factor for increased BHR or atopy. Wood smoke in the indoor environment did not play a role in the rural Xhosa children's BHR. Ascaris infection does not appear to play any modifying role in the development of increased BHR in the rural or urban children. We have found that increases in BHR in the rural and recently urbanized Xhosa children develop independently of increases in atopy. Our results challenge the 'hygiene' hypothesis as a complete explanation for the recent dramatic worldwide increases in allergic diseases.

Assessment of the diagnosis and prevalence of asthma in Australian indigenous children

BACKGROUND AND OBJECTIVE

Although the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire has been used in many countries and has been validated previously, it has not been used in Australian Indigenous communities. We endeavoured to assess its performance when administered in Aboriginal and Torres Strait Islander communities.

METHODS

In a cross-sectional study, we assessed the ISAAC's questionnaire when administered face-to-face in Indigenous communities in the Torres Strait region, Australia.

RESULTS

Comparing responses to the questionnaire with clinical assessment of 260 Indigenous children by a pediatric respiratory physician, sensitivity (87%) was high, but specificity (51%) and positive predictive value (33%) were low. Using a logistic regression model, we determined which questions were most useful in predicting a clinical diagnosis of asthma. Using a predictive equation, asthma was detected with 79% sensitivity and 77% specificity, and the calculated weighted estimate of asthma prevalence in the region was 16.3%.

CONCLUSION

Our findings reveal that although the ISAAC questionnaire is a reasonably sensitive tool for both epidemiologic and clinical studies of asthma in Indigenous communities, its value is enhanced when used in conjunction with a predictive model. We have also shown that asthma is prevalent in the Torres Strait region.

A parent completed questionnaire to describe the patterns of wheezing and other respiratory symptoms in infants and preschool children

AIM

To develop a standardised and validated respiratory symptom questionnaire for use in epidemiological or follow up studies in infants and preschool children.

METHODOLOGY

After initial design and development, the questionnaire was administered to two cohorts of subjects, one recruited from a respiratory clinic and the other from a postnatal ward. The two cohorts then repeated the questionnaire, two weeks apart. The qualities of the questionnaire were assessed.

RESULTS

Response rate to the initial questionnaire was 100% for the clinic based cohort and 64% for postnatally recruited families (total number of subjects 114). Questions showed good to moderate short term reliability (weighted kappa scores 0.47-0.7; average correct classification rates 0.74-0.91). Four domain concept scores showed excellent internal consistency (Cronbach alpha scores 0.87-0.95). Using principal component factor analysis, four new domains were devised showing acceptable construct validity and internal consistency. Criterion validity was assessed using a respiratory physician based diagnosis of asthma (RPBDA) as the gold standard for comparison. All eight scales in the questionnaire could significantly distinguish between infants with RPBDA and well or mildly symptomatic subjects.

CONCLUSION

We have developed a practical, acceptable questionnaire with eight concept domains for use in infants and preschool children. The questionnaire has strong construct validity and internal consistency with good short term reliability of questions. More detailed study of criterion validity and the responsiveness of the questionnaire is required using a larger population and including children with the different phenotypes of wheezy illness.

More siblings, less hay fever: more evidence

The prevalence of allergic rhinitis is increasing. Many authors have noted the prevalence of hay fever is less in children from large families and the 'hygiene hypothesis' has been suggested as an explanation. We looked at the association of sibling number and other variables on the prevalence of hay fever and perennial rhinitis. From 26100 households selected at random, 34362 questionnaires were returned from individuals over 14 years of age; 19.3% had symptoms of hay fever and a further 6.0% had symptoms of perennial rhinitis. A logistic regression analysis showed that for individuals with two or more siblings, the odds of suffering from hay fever are less than the odds for people with no siblings and that these odds decrease as the number of siblings increases. This effect was not found in subjects with perennial rhinitis. This study adds weight to the 'hygiene hypothesis'.

Parents' accounts of wheeze and asthma related symptoms: a qualitative study

AIMS

To examine parents' accounts of how they recognise and judge respiratory symptoms in children, and to investigate their interpretations of respiratory survey questions about wheeze, shortness of breath, and cough.

METHODS

Qualitative study using semistructured interviews. Data were analysed using the constant comparative method. Nineteen parents of children aged under 6 years were recruited from a cohort of parents who had responded to an earlier respiratory symptom survey and from one general practice.

RESULTS

Parents judged respiratory symptoms using a range of cues, including changes in the sound of breathing and changes in appearance and behaviour. Experiential resources and contextual factors played an important role in parents' judgements. Interpretations of questions about respiratory symptoms were varied, particularly in relation to the terms "attacks of wheeze" and "shortness of breath". Parents' descriptions of wheeze differed from descriptions of the sound of wheeze used in some survey questionnaires. Parents drew fine distinctions between different "types" of cough and identified a distinct "asthma" cough.

CONCLUSIONS

Attention needs to be given to the complexity of reporting respiratory symptoms in children and to the importance of contextual factors in parents' judgements. We suggest that questions which require parents to report on children's internal feelings or states be avoided. Consideration should be given to providing parents with explicit direction on what cues to attend to or ignore in reporting symptoms, and to clarifying some questions that are currently used in clinical practice and in surveys.

The prevalence of asthma and wheezing illnesses amongst 10-year-old schoolchildren

Asthma and wheezing illnesses carry a significant burden of disease during childhood. Prevalence studies have the capacity to provide invaluable insights into the nature of these common conditions. As part of the Isle of Wight Whole Population Birth Cohort Study (n=1456) we have examined wheezing and asthma development amongst 10-year-old children. At this age 1373 children completed ISAAC written questionnaires whilst 1043 children performed further testing including skin-prick testing, serum inhalant IgE antibody screening, spirometry and bronchial challenge. At 10-years, prevalence of current wheeze was 18.9%, current asthma (symptomatic bronchial hyper-responsiveness--BHR) 14.4% and currently diagnosed asthma (current wheeze and asthma ever--CDA) 13.0%. Both wheezing and asthma at 10 years were associated with average symptom onset at 3 years of age indicating an early life origin for such conditions. Current wheeze (P=0.011) and CDA (P=0.008) showed significant male predominance. Considerable disease morbidity was identified for these states that tended to be greatest amongst children defined asthmatic rather than simply current wheezers. Wheezing and asthma were significantly associated with both atopy (P<0.001) and allergic co-morbidity Children with these states, particularly current asthma, also demonstrated impaired lung function (FEV1, P<0.001 and FEV1/FVC, P=0.010) and increased BHR (inverse slope, P<0.001). In conclusion, Asthma and wheezing showed substantial prevalence at 10 years of age. Strong associations to male gender, atopy, impaired lung function and BHR were seen for both wheeze and asthma. In regard to prevalence and morbidity characteristics, a questionnaire-based definition of currently diagnosed asthma gave similar results to the use of symptomatic BHR in defining current asthma.

Socioeconomic differences in children's health: how and why do these relationships change with age?

The effects of socioeconomic status (SES) on health are well documented in adulthood, but far less is known about its effects in childhood. The authors reviewed the literature and found support for a childhood SES effect, whereby each decrease in SES was associated with an increased health risk. The authors explored how this relationship changed as children underwent normal developmental changes and proposed 3 models to describe the temporal patterns. The authors found that a model's capacity to explain SES-health relationships varied across health outcomes. Childhood injury showed stronger relationships with SES at younger ages, whereas smoking showed stronger relationships with SES in adolescence. Finally, the authors proposed a developmental approach to exploring mechanisms that link SES and child health.

Asthma, atopy and tuberculin responses in Chinese schoolchildren in Hong Kong

BACKGROUND

The prevalence rates of asthma and other atopic disorders have increased steadily in many developed countries over the past few decades. Recent epidemiological and animal studies have suggested that BCG vaccination might be beneficial in reducing the subsequent development of atopy. This study investigates the relationship between asthma, allergic symptoms, atopy, and tuberculin response in Chinese schoolchildren who received BCG vaccination at birth.

METHODS

A total of 3110 schoolchildren aged 10 years were recruited for the Hong Kong arm of the phase II International Study of Asthma and Allergies in Childhood. Of the 2599 children born in Hong Kong and vaccinated with BCG after birth, 2201 had tuberculin testing performed at a mean (SD) age of 8.4 (1.4) years. A random subsample of 980 children was also recruited for skin prick testing.

RESULTS

The prevalence rates of asthma ever, wheeze ever, current wheeze, current rhinoconjunctivitis, and current flexural eczema were not significantly different between tuberculin positive and negative subjects. The mean (SE) tuberculin response was 3.4 (0.2) mm in atopic subjects and 3.3 (0.2) mm in non-atopic subjects (difference not significant). Logistic regression analyses did not reveal any significant relationship between asthma ever, current wheeze, atopy, and positive tuberculin responses.

CONCLUSIONS

This study did not find any relationship between asthma, allergic symptoms, atopy, and positive tuberculin reactivity in Chinese schoolchildren vaccinated with BCG at birth.

Variação na prevalência de asma e atopia em um grupo de escolares de Porto Alegre, Rio Grande do Sul

Introdução: Considerável aumento na prevalência da asma e da atopia vem sendo mundialmente observado ao longo das últimas décadas, porém, em nosso país, os dados epidemiológicos ainda são insuficientes. Objetivo: Este estudo foi realizado a fim de determinar a prevalência de asma e atopia em um grupo de escolares e comparar tais dados com outros dois levantamentos previamente realizados em Porto Alegre, Rio Grande do Sul. Métodos: A prevalência de asma foi identificada através de um questionário aplicado a 855 alunos de cinco escolas de Porto Alegre. Foram considerados atópicos aqueles escolares que, submetidos a testes cutâneos, apresentaram pelo menos uma reação cutânea positiva. Assinatura do termo de consentimento pós-informação de um dos pais foi exigida para a realização dos testes cutâneos. Resultados: Foi identificada prevalência de 42,5% de asma cumulativa e 22% de asma ativa, com predominância nas meninas. Atopia foi identificada em 50,1% da amostra. Tais resultados foram significativamente superiores aos 6,7% (1980) e 16% (1989) de asma cumulativa, 10,9% (1989) de asma ativa e 15,8% (1980) de atopia encontrados nos dois estudos previamente realizados. Conclusões: Altas prevalências de asma e atopia foram identificadas em nossos estudantes. Futuros estudos deverão ser realizados a fim de elucidar o fenômeno aqui demonstrado.

A review of cough in children

Cough is a very common symptom of respiratory disease and reason for parents to seek medical attention. The article presents broad clinical guidelines on the approach to childhood cough and discusses current controversies of the management of cough in children.

Prevalence of asthma and other allergic diseases in an adolescent population: association with gender and race

OBJECTIVES

To estimate the prevalence and severity of asthma in an adolescent population by sex and race.

METHODS

Cross-sectional, population-based survey of school children.

SETTING

Midwestern city experiencing damage from the 1993 Mississippi River flood.

PARTICIPANTS

2,693 children attending grades 7 to 12.

MEASUREMENTS

Questions from the International Study of Asthma and Allergies in Childhood (ISAAC).

RESULTS

Two thousand six hundred ninety-three children were surveyed, for a response rate of 90%. In this population, 16.4% reported having ever been diagnosed with asthma; 25% reported wheezing in the last 12 months; 32% reported symptoms of rhinitis in the last 12 months; and 22% reported ever having hay fever. The prevalence rate for current asthma was 12.6%. Female students had significantly greater prevalence rates for current asthma (16.4% vs 9.0%, OR = 1.85); ever-diagnosed asthma (18.5% vs 14.3%, OR = 1.36); wheezing > or = 4 times in the last 12 months (12.0% vs 5.6%, OR = 1.95); current rhinitis (38.7% vs 25.4%, OR = 1.73); and hay fever (26.4% vs 18.4%, OR = 1.57). All associations with sex remained significant, except ever-diagnosed asthma, after controlling for other known risk factors in logistic regression. African-Americans had higher prevalence rates than other races with differences reaching statistical significance for ever-diagnosed asthma and current asthma; however, these relationships did not remain significant after controlling for other known risk factors in logistic regression.

CONCLUSIONS

Our prevalence rates were similar to those reported by other studies that used the ISAAC questionnaire. Female students reported significantly more asthma, wheezing, rhinitis, and hay fever than male students. Female students also reported more severe symptoms and a greater number of emergency room and hospital admissions.

What do parents of wheezy children understand by "wheeze"?

BACKGROUND

Reported wheeze is the cornerstone of asthma diagnosis.

AIMS

To determine what parents understand by wheeze.

METHODS

Two studies were undertaken: (1) Parents of clinic attendees with reported wheeze (n=160) were asked by questionnaire what they understood by "wheeze" and how they knew their child was wheezy. Responses were compared to definitions of wheeze in 12 epidemiology studies and their response options. (2) The extent of agreement of parents' reports (n=139) of acute wheezing in their children and clinicians' findings of "wheeze" and "asthma" was examined.

RESULTS

(1) "Sound" and "difficulty in breathing" were perceived central to "wheeze". "What you hear" was not selected by 23% (95% confidence interval (CI) 16-30%). "Whistling" was mentioned by 11% (CI 6-15%) but featured in 11 of 12 epidemiology questionnaires. (2) There was les than 50% agreement between parents' and clinicians' reports of wheeze and asthma.

CONCLUSIONS

Conceptual understandings of "wheeze" for parents of children with reported wheeze are different from epidemiology definitions. Parents' reports of acute wheeze and clinicians' findings also differ.

Outdoor air concentrations of nitrogen dioxide and sulfur dioxide and prevalence of wheezing in school children

We report analysis of data on outdoor air pollution and respiratory symptoms in children collected in the Czech part of the international Small Area Variations in Air pollution and Health (SAVIAH) Project, a methodological study designed to test the use of geographical information systems (GIS) in studies of environmental exposures and health at small area level. We collected the following data in two districts of Prague: (1) individual data on 3,680 children (response rate 88%) by questionnaires; (2) census-based socio-demographic data for small geographical units; (3) concentrations of nitrogen dioxide (NO2) and sulfur dioxide (SO2) measured by passive samplers in three 2-week surveys at 80 and 50 locations, respectively. We integrated all data into a geographical information system. Modeling of NO2 and SO2 allowed estimation of exposure to outdoor NO2 and SO2 at school and at home for each child. We examined the associations between air pollution and prevalence of wheezing or whistling in the chest in the last 12 months by logistic regression at individual level, weighted least squares regression at small area (ecological) level and multilevel modeling. The results varied by the level of analysis and method of exposure estimation. In multilevel analyses using individual data, odds ratios per 10 microg/m3 increase in concentrations were 1.16 (95% CI = 0.95-1.42) for NO2, and 1.08 (95% CI = 0.97-1.21) for SO2. While mapping of spatial distribution of NO2 and SO2 in the study area appeared valid, the interpolation from outdoor to personal exposures requires consideration.

Bronchial hyperresponsiveness in children and adolescents with Crohn's disease

Pulmonary manifestations have been described in Crohn's disease (CD). Bronchial responsiveness to methacholine (MCh) was evaluated in 14 children with CD with no evidence of airway disease, 10 asthmatics, and 10 healthy subjects. In patients with CD total blood eosinophils and serum IgE were 0.20 x 10(9) x L(-1) (95% CI -1.68 to 2.08) and 138.4 kU x L(-)(1) (95% CI 18.84 to 257.96), respectively. Three patients with CD had positive prick tests. Bronchial hyperresponsiveness (BHR) was demonstrated in 10 patients with CD (71%) and in the asthmatics, but not in control subjects. In patients with CD PD(20) appeared significantly greater than in asthmatics (699 microg [95% CI 238 to 1,115] versus 104 microg [95% CI 37.35 to 293]; p < 0.05), and was not related either to baseline FEV(1) or IgE or eosinophils (r = 0.32; r = -0.5; r = -0.15, p = NS, respectively). Neither activity nor treatment or duration of CD affected BHR. Five nonatopic CD patients underwent a second MCh challenge over a 25-mo period: the PD(20) appeared significantly greater than basal PD(20) (1,941 microg versus 575 microg, p < 0.05, respectively), in the absence of significant changes of disease activity. BHR might be the expression of subclinical airway inflammation, a phenomenon which can be responsible for the development of various pulmonary manifestations in CD.

Interaction between the growing lung and asthma: role of early intervention

Asthma is a syndrome where an imbalance exists between the forces that maintain airway patency and the forces that act to narrow, or close, airways. The child with asthma is a particular problem because of the rapid growth of the lung during growth that leaves it vulnerable. There is some evidence that asthma leads to impaired lung function in children because those children with untreated asthma show a loss of lung growth velocity. For unclear reasons, asthma is more frequent in boys. What drugs to use to treat childhood asthma is uncertain. Data show that glucocorticoids prevent the structure of the lung from fully developing. In children, the rationale for early intervention seems clear, but the exact means and criteria for initiation of the intervention are uncertain. Finally, childhood asthma raises fundamental issues and questions that are unique to the child with asthma and presents unique and many unresolved treatment dilemmas.

Choosing the right outcomes

Outcome measures are used to monitor the effects of interventions in clinical practice or in formal clinical trials. They may also be used to assess changes within populations either spontaneously or as a result of public-health measures. They are used to monitor the course of illness as part of a management plan or, for larger groups, to identify changes brought about, for instance, by migration or immunization. The choice of outcome measure depends on the age of the child, the complexity of the outcome (for instance, whether its application is to individuals or populations), and the time scale over which it is necessary to detect changes in outcome. The most commonly used outcome measures are clinical symptoms, which are often compiled into scoring systems. Surprisingly, these are often the least well-validated measures of outcome. Physiologic measures, although well validated, are difficult to apply to infants and pre-school children. The role of inflammatory markers is currently limited to research rather than clinical practice. Other outcome measures such as quality of life, impact-of-asthma instruments, and measures to determine the health-economic aspects of asthma are poorly developed in childhood. The right outcome depends on the question being asked, the age of the subjects, and the time scale and complexity over which measurement is required.

Effect of environmental tobacco smoke on peak flow variability

This study was undertaken to determine whether exposure to various indoor pollutants is associated with a higher prevalence of respiratory symptoms, a diagnosis of asthma, or more variable peak flow rates. Four hundred and twenty-six children aged 8-11 years in four junior schools at three locations recorded respiratory symptoms and diagnosis of asthma using the ISAAC questionnaire. Daily peak flow measurements were taken during two six-week periods (winter and summer). Symptoms in children with and without asthma were not related to gas fires, cookers, smokers, or pets in the home. However, the variability of lung function, expressed as the coefficient of variation, in all children was increased with a household smoker. Environmental tobacco smoke increases airways variability in children with and without asthma. Its effects were not apparent from a questionnaire completed by parents, and the coefficient of variation of serially measured peak flows was a more sensitive indicator of lung function.

Exposure and sensitization to cat dander: asthma and asthma-like symptoms among adults

BACKGROUND

Several pets, such as cats, dogs, and rodents, are known to produce allergens. Despite the clinical and laboratory evidence that exposure to pets can cause bronchoconstriction in sensitized subjects, the results of population studies have been contradictory.

OBJECTIVES

The purpose of this study was to investigate the relationship between cat ownership and the prevalence of asthma, asthma-like symptoms, and bronchitic symptoms among subjects 20 to 44 years of age in Vancouver, Canada and to determine whether sensitization is responsible for such an association.

METHODS

Two thousand nine hundred ninety-nine (88%) randomly selected subjects responded to a mail questionnaire. Of these, 504 participated in laboratory examination, including allergy skin testing.

RESULTS

One thousand nineteen study responders (34%) were pet owners at the time of the study (current owners). Current pet owners were found to have a higher prevalence of current asthma, asthma-like symptoms, and bronchitic symptoms compared with those without pets. Cat owners had significantly higher risk of having current asthma and asthma-like symptoms. In the subset who had allergic skin tests, we found that those who were allergic to cat dander had a significantly higher risk of current asthma than those not allergic to cat dander and not owning a cat.

CONCLUSION

This study provides evidence that sensitization to cat dander is a more important risk factor for current asthma and asthma-like symptoms than cat ownership itself.

Prevalence of asthma and 'probable' asthma in the Asian population in Blackburn, U.K

Local research had shown increased asthma admission rates in the Asian ethnic group in Blackburn, U.K. Patients also reported that asthma seemed to develop some years after first arrival in the U.K. A community prevalence survey of respiratory symptoms and asthma was undertaken in three practices with no special asthma interest. The questionnaire was administered by a Health Visitor and language link worker. Of the Asian patients in the practices, 96.6% were studied. The age distribution was similar to that of the local 1991 census. Of the patients, 181/1783 (10.2%) had diagnosed asthma but positive responses to individual questions suggested underdiagnosis of asthma. Asthma prevalence was higher in males up to age 20 (14.6% vs. 8.2%), and aged over 50 (16.5% vs. 10.5%), but higher in females aged 20-49 (5.6% vs. 9.2%). There were no correlations with social class or Jarman index, and no effect of country of origin or duration in the U.K. by multivariate analysis. The prevalence of diagnosed asthma at ages 5-9 and 10-14 was higher than in previous studies. Diagnosed asthma prevalence rates fell in the 20-49 age band but rose again in the over-50s. In all age groups the prevalence of asthma is probably underestimated. Asthma prevalence was not related to social factors. The data show that those born in the U.K. are more likely to describe regular symptoms and to be on regular treatment, but that for those born abroad there was an increasing rate of symptoms and medication use with increasing duration in the country. These observations confirm patient views but are explained by the age/sex distribution of those born in the U.K. compared to immigrants.

Respiratory symptoms and home environment in children: a national survey

BACKGROUND

Respiratory diseases are common in childhood and may lead to chronic disease in adult life; environmental factors probably play an important part in their causation.

METHODS

A survey of respiratory symptoms in children aged 12-14 years was conducted throughout Great Britain as part of the International Study of Asthma and Allergies in Childhood (ISAAC). Information was obtained on certain aspects of the home environment in order to assess their importance as risk factors.

RESULTS

The response rate was 79.3%, and 25,393 children in 93 schools participated. In a multiple regression analysis, wheeze was reported more often in nonmetropolitan areas and in association with active smoking, passive smoking, the presence of a furry pet, bottled gas, paraffin, and other unusual heating fuels; small regional differences persisted. Current smoking, previous smoking, and passive smoking accounted for 10.4%, 6.8%, and 6.5%, respectively, of wheezing in the past 12 months, and furry pets accounted for 5.0%. Cough and phlegm were associated with active and passive smoking and with the miscellaneous fuels; similar associations were found for rhinitis, but were less consistent for rhinitis occurring in spring and summer. Gas cooking showed little association with respiratory symptoms.

CONCLUSIONS

Passive as well as active smoking is an important cause of respiratory symptoms in adolescence. Pets seem to increase the risk of wheeze and rhinitis, and fumes from certain unusual heating fuels may have adverse effects. Home environment and geographical location have independent effects on the prevalence of respiratory symptoms.

The prevalence of allergic rhinitis and nasal symptoms in Nottingham

From 1200 households selected at random, 2114 questionnaires were returned from individuals over 14 years old. They reported that in the previous year the prevalence of 'symptoms of nasal obstruction every day for more than 14 consecutive days' was 16.9%; 19.8% had had a 'runny nose'; 7.1% reported sneezing bouts; and 19.6% had hay fever during the same period. Also, 13.7% had had rhinosinusitis in the previous year using the criterion of 'two out of three symptoms of congestion, rhinorrhoea and sneezing for more than 1 h per day for a period in excess of 2 weeks'. The prevalence of perennial symptoms in individuals who did not have hay fever was 8.6%. Over the previous 2 years 18.2% of all respondents had visited their General Practitioner and 0.2% had visited a hospital as a result of their hay fever. Individuals who responded as having hay fever were significantly more likely to have worked in an environment with a lot of dust in the last 2 years than asymptomatic respondents (chi 2, P = 0.002), although fume exposure was not found to be a significant risk factor (P = 0.0681). Individuals with perennial symptoms were no more likely to have been working in a dusty or smoky environment. In those with either seasonal or perennial symptoms there was no significant effect of either social class or manual/non-manual occupation.