Prevalence of respiratory symptoms in under 5s: 1993 to 2001

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.

Bacterial distribution in the lungs of children with protracted bacterial bronchitis

OBJECTIVES

Flexible bronchoscopy with bronchoalveolar lavage (FB-BAL) is increasingly used for the microbiological confirmation of protracted bacterial bronchitis (PBB) in children with a chronic wet cough. At our centre, when performing FB-BAL for microbiological diagnosis we sample 6 lobes (including lingula) as this is known to increase the rate of culture positive procedures in children with cystic fibrosis. We investigated if this is also the case in children with PBB.

METHODS

We undertook a retrospective case note review of 50 children investigated for suspected PBB between May 2011 and November 2013.

RESULTS

The median (IQR) age at bronchoscopy was 2.9 (1.7-4.4) years and the median (IQR) duration of cough was 11 (8.0-14) months. Positive cultures were obtained from 41/50 (82%) and 16 (39%) of these patients isolated ≥2 organisms. The commonest organisms isolated were Haemophilus influenzae (25 patients), Moraxella catarrhalis (14 patients), Staphylococcus aureus (11 patients) and Streptococcus pneumoniae (8 patients). If only one lobe had been sampled (as per the European Respiratory Society guidance) 17 different organisms would have been missed in 15 patients, 8 of whom would have had no organism cultured at all. The FB-BAL culture results led to an antibiotic other than co-amoxiclav being prescribed in 17/41 (41%) patients.

CONCLUSIONS

Bacterial distribution in the lungs of children with PBB is heterogeneous and organisms may therefore be missed if only one lobe is sampled at FB-BAL. Positive FB-BAL results are useful in children with PBB and can influence treatment.

Recurrent wheezing in the first three years of life: short-term prognosis and risk factors

OBJECTIVE

It is difficult to determine if preschool children with recurrent wheezing are suffering from asthma or will suffer from asthma in the future. The aim of this study was to investigate the prognosis and risk factors of recurrent wheezing in children, beginning in the first 3 years of life.

METHOD

Children who were referred because of recurrent wheezing episodes during the first 3 years of life were evaluated for the presence of asthma over a 4-year period. A child without any symptoms within the last 12 months was considered to be in remission.

RESULTS

The study included 529 (male/female: 2.17) children with a median (inter-quartile) age of 0.6 years (0.3-1.0) at symptom onset. The median follow-up and symptom durations were 2.93 years (1.74-4.76) and 4.30 years (2.91-5.97), respectively. Remission/recovery was achieved in 1.7%, 8.0%, and 14.4% of the children within 12, 24, and 36 months, respectively. A negative "stringent asthma predictive index" (API) significantly shortened the time to recovery of wheezing compared to the positive API (p = .036). Maternal smoking during pregnancy (OR = 4.35; 95% CI = 1.29-14.63); p = .018) and the number of emergency room admissions within the first 3 years of life (OR = 1.10; 95% CI = 1.01-1.19); p = .031) were found to be independent risk factors for the persistence of wheezing symptoms.

CONCLUSION

Most of the children who were referred with frequent wheezing remain symptomatic 3 years after the initial wheezing episodes. A negative API is related to a shorter wheezing duration. Maternal smoking during pregnancy and the severity of the wheezing episodes appeared to be significant risk factors for the persistence of wheezing symptoms.

Bronchial obstructive phenotypes in the first year of life among Paris birth cohort infants

As the natural history of respiratory and allergic manifestations is unclear, our ongoing Paris birth cohort study prospectively assesses the onset of these symptoms in early childhood. Data were collected by five questionnaires sent at regular intervals during the first year of life. Partitioning around medoids (PAM) was used to classify infants according to their bronchial obstructive symptoms. A polytomous logistic regression was performed to assess the eventual predictable power of various respiratory events and perinatal factors. Results are given for 2698 infants. Atopic dermatitis occurred in 17.9% of infants. The main respiratory symptoms in infancy were wheeze in the chest (22%), dyspnoea responsible for sleep disturbance (23.7%), nocturnal dry cough (14.5%) and shortness of breath (4.2%). The PAM method identified three groups of infants. Apart from the G0 group of infants mostly asymptomatic, two distinct clinical phenotypes (G1 and G2: 8.7% and 23.5% of total infants respectively) emerged. G2 was defined by severe bronchial obstructive disorders as all cases of dyspnoea with sleep disturbance were included in this group, while all infants assigned in G1 suffered from nocturnal dry cough. G2 group infants had significantly higher rates of respiratory events while a parental history of asthma, symptoms suggestive of rhino-conjunctivitis and birth season clearly differentiated the G1 group. Finally, G1 and G2 group infants should be closely followed up as they are expected to develop allergic and asthmatic phenotypes, possibly in relation to environmental and behavioural risk factors.

Day-care attendance, position in sibship, and early childhood wheezing: a population-based birth cohort study

BACKGROUND

There are conflicting data on the effect of day-care attendance and position in sibship on the development of wheezing.

OBJECTIVE

To investigate the relationship between day-care attendance and position in sibship with early childhood wheeze.

METHODS

Prospective population-based birth cohort. At age 5 years, we collected information on parentally reported symptoms (n = 922); lung function was ascertained using plethysmography (n = 745) and allergic sensitization by skin testing (n = 815). Participants were assigned into categories according to the age of entry to day-care (0-6, 6-12, >12 mo) and number of older siblings (0, 1, 2, >2).

RESULTS

Current wheeze was reported by 203 participants (22%); 224 (28%) were sensitized. In the multivariate model, sensitization (odds ratio, 2.47; 95% CI, 1.66-3.67), male sex (1.49, 1.01-2.20), maternal asthma (1.72, 1.10-2.68), and maternal smoking during pregnancy (2.15, 1.26-3.66) significantly increased the risk of wheezing. Entering day-care between 6 and 12 or after 12 months of age was significantly and inversely associated with current wheeze (0.25, 0.11-0.60; and 0.65, 0.44-0.98, respectively). Entry into nursery between 6 and 12 months reduced the risk of persistent wheezing (P = .04). We found no association between day-care attendance and lung function. Entering nursery in the first 6 months of life was associated with increased risk of atopy (2.47, 1.23-4.95). Having older siblings was associated only with rhinoconjunctivitis (0.72, 0.54-0.97).

CONCLUSION

Day-care attendance was associated with a reduced risk of current wheezing in 5-year-old children. The protective effect appeared strongest for children who entered day-care between the ages of 6 and 12 months.

Long term prognosis in preschool children with wheeze: longitudinal postal questionnaire study 1993-2004

OBJECTIVES

To follow a population of preschool children with and without parent reported wheeze over a period of 6-11 years to determine prognosis and its important predictive factors.

DESIGN

Longitudinal series of five postal surveys based on the international study of asthma and allergies in childhood questionnaire carried out between 1993 and 2004.

SETTING

Two general practice populations, south Manchester.

PARTICIPANTS

628 children aged less than 5 years at recruitment and those with at least six years' follow-up data.

MAIN OUTCOME MEASURES

Parent completed questionnaire data for respiratory symptoms and associated features.

RESULTS

Of 628 children included in the study, 201 (32%) had parent reported wheeze at the first observation (baseline), of whom 27% also reported the symptom on the second occasion (persistent asthma). The only important baseline predictors of persistent asthma were exercise induced wheeze (odds ratio 3.94, 95% confidence interval 1.72 to 9.00) and a history of atopic disorders (4.44, 1.94 to 10.13). The presence of both predictors indicated a likelihood of 53.2% of developing asthma; if only one feature was present this decreased to 17.2%, whereas if neither was present the likelihood was 10.9%. Family history of asthma was not predictive of persistent asthma among children with preschool wheeze.

CONCLUSION

Using two simple predictive factors (baseline parent reported exercise induced wheeze and a history of atopic disorders), it is possible to estimate the likelihood of future asthma in children presenting with preschool wheeze. The absence of baseline exercise induced wheeze and a history of atopic disorders reduces the likelihood of subsequent asthma by a factor of five.

[Epidemiology of allergic respiratory disorders in infants]

INTRODUCTION

Allergic disorders of the respiratory tract have been the subject of many epidemiological studies, especially during infancy which is known to be a critical period for development of the immune system. This paper aims to describe the prevalence of allergic respiratory disorders in children below three years of age in the general population, despite the lack of shared definition of asthma and allergic rhinitis among studies.

STATE OF ART

Doctor-diagnosed asthma occurs in 5% of children below two years of age. One third of children below three years of age experience wheeze during a lower respiratory tract infection, but only 7% of children wheeze apart from a respiratory infection. Asthma-like cough and bronchial obstruction symptoms are reported in respectively 15% and 9% of children below two years of age. Depending on the definition of allergic rhinitis used, its prevalence varies from 1 to 30% among two years old children.

PERSPECTIVES

Definitions of allergic respiratory tract disorders in infants become more elaborate involving parental and personal history of allergy and medication; epidemiological research now attempts to identify, using biological evidence of atopy, infants at risk of persistent allergic disorders.

CONCLUSIONS

A better definition of allergic respiratory disorders in infants may help epidemiological research and early care management.

Prospective health diary study for new onset chest symptoms in the Japanese general population

OBJECTIVES

Our aim was to analyze the incidence of new onset chest symptoms for the period of a month and to evaluate the possible association of these chest symptoms with demographic, socioeconomic or clinical characteristics.

DESIGN

Prospective observational cohort study using a self-reported health diary among subjects without baseline chest diseases.

SETTING

A nationally representative sample of households in Japan.

PARTICIPANTS

Of a total 3,568 subjects from the study recruitment sample, 3,477 participants completed the diary; of these, 127 participants with active chest diseases at baseline were excluded and the remaining 3,350 participants were analyzed.

MEASUREMENTS AND RESULTS

The mean number of episodes of chest symptoms was 1.19 with 95% confidence interval (CI) of 1.0-2.0 and the incidence was 21% (95% CI, 10-30%). Cough was the most frequent chest symptom with the mean number of episodes of 1.14 and the prevalence of 20%. Chest pain, dyspnea, palpitation, and wheezing were identified in less than 1%. Associated factors for cough were younger age, unemployment, and poor physical quality of life. Associated factors for chest pain included older age, living in smaller cities, unemployment, higher educational attainment, and poor physical and mental quality of life.

CONCLUSIONS

Chest symptoms are common in the Japanese general population. Cough is the most frequent symptom, followed by chest pain. Younger age, unemployment, and poor physical quality of life are significantly associated with cough.

Is the prevalence of wheeze in children altered by neonatal BCG vaccination?

BACKGROUND

The prevalence of asthma and atopic disease has increased in recent decades, but precise reasons for this increase are unknown. BCG vaccination is thought to be among a group of vaccines capable of manipulating the immune system toward T(H)1 dominance and therefore reducing the likelihood of atopic disease.

OBJECTIVE

The aim of this study was to determine the influence of neonatal BCG vaccination on the prevalence of wheeze in a large community population of children.

METHOD

In a historical cohort study, a parent-completed questionnaire was used to identify the prevalence of wheeze in BCG-vaccinated and nonvaccinated children in Manchester, England.

RESULTS

There were 2414 participants aged between 6 and 11 years. In a univariate analysis neonatal BCG vaccination was associated with a significantly lower prevalence of wheeze (odds ratio, 0.69; 95% CI, 0.55-0.86), and statistical significance was retained when the analysis was adjusted for potential confounders (odds ratio, 0.68; 95% CI, 0.53-0.87).

CONCLUSION

These results demonstrate an association between asthma symptom prevalence and neonatal BCG vaccination, relating to a possible 27% reduction in prevalence, and are therefore of considerable public health importance.

CLINICAL IMPLICATIONS

The capacity of neonatal BCG vaccination to reduce the prevalence of respiratory symptoms in children warrants further investigation.

Outcomes in children treated for persistent bacterial bronchitis

BACKGROUND

Persistent bacterial bronchitis (PBB) seems to be under-recognised and often misdiagnosed as asthma. In the absence of published data relating to the management and outcomes in this patient group, a review of the outcomes of patients with PBB attending a paediatric respiratory clinic was undertaken.

METHODS

A retrospective chart review was undertaken of 81 patients in whom a diagnosis of PBB had been made. Diagnosis was based on the standard criterion of a persistent, wet cough for >1 month that resolves with appropriate antibiotic treatment.

RESULTS

The most common reason for referral was a persistent cough or difficult asthma. In most of the patients, symptoms started before the age of 2 years, and had been present for >1 year in 59% of patients. At referral, 59% of patients were receiving asthma treatment and 11% antibiotics. Haemophilus influenzae and Streptococcus pneumoniae were the most commonly isolated organisms. Over half of the patients were completely symptom free after two courses of antibiotics. Only 13% of patients required > or =6 courses of antibiotics.

CONCLUSION

PBB is often misdiagnosed as asthma, although the two conditions may coexist. In addition to eliminating a persistent cough, treatment may also prevent progression to bronchiectasis. Further research relating to both diagnosis and treatment is urgently required.