Prevalence and risk factors of wheeze in Dutch infants in their first year of life

The impact of indoor pollution on asthma-related outcomes: A systematic review for the EAACI guidelines on environmental science for allergic diseases and asthma

Systematic review using GRADE of the impact of exposure to volatile organic compounds (VOCs), cleaning agents, mould/damp, pesticides on the risk of (i) new-onset asthma (incidence) and (ii) adverse asthma-related outcomes (impact). MEDLINE, EMBASE and Web of Science were searched for indoor pollutant exposure studies reporting on new-onset asthma and critical and important asthma-related outcomes. Ninety four studies were included: 11 for VOCs (7 for incidenceand 4 for impact), 25 for cleaning agents (7 for incidenceand 8 for impact), 48 for damp/mould (26 for incidence and 22 for impact) and 10 for pesticides (8 for incidence and 2 for impact). Exposure to damp/mould increases the risk of new-onset wheeze (moderate certainty evidence). Exposure to cleaning agents may be associated with a higher risk of new-onset asthma and with asthma severity (low level of certainty). Exposure to pesticides and VOCs may increase the risk of new-onset asthma (very low certainty evidence). The impact on asthma-related outcomes of all major indoor pollutants is uncertain. As the level of certainty is low or very low for most of the available evidence on the impact of indoor pollutants on asthma-related outcomes more rigorous research in the field is warranted.

Association between childhood asthma and history of assisted reproduction techniques: a systematic review and meta-analysis

Genetic and environmental factors during early development may influence lung growth and impact lung function. We performed a meta-analysis of epidemiological studies examining the association between conception history of assisted reproduction techniques (ART) and childhood asthma. We searched PubMed and Embase up to November 2020 for relevant observational studies and synthesized data data under a fixed or random effects model as appropriate. Heterogeneity was assessed using the I² metric. We identified 13 individual studies including 3,226,386 participants. We did not observe a statistically significant association between ART and physician-diagnosed asthma (n = 9, random OR 1.16; 95% CI 0.94-1.43; I² 61%). We observed a statistically significant association between ART and prescription of asthma medications (n = 6, fixed OR 1.27; 95% CI 1.23-1.32; I² 0%). Wheezing was also associated with ART (n = 4, fixed OR 1.71; 95% CI 1.08-2.72; I² 0%). When we combined studies using any asthma definition, a statistically significant association was observed (random OR 1.19; 95% CI 1.05-1.34; I² 80%).Conclusion: The available observational evidence suggests that the risk of asthma is higher among children born after ART. The mechanism and potential sources of bias behind this association are under scrutiny, and further work is needed to establish causality. What is Known: • "Positive" epidemiological signals for the association between assisted reproduction techniques and asthma stemming from large studies were not replicated by subsequent research. • Any available research synthesis effort so far bears no quantitative aspect. What is New: • The available observational evidence suggests that the risk of asthma is higher among children born after ART. • The mechanism and potential sources of bias behind this association are under scrutiny.

Preschool Wheezing and Gastro-Esophageal Reflux: --Causal or Casual Coincidence? Update from Literature

Gastroesophageal reflux (GER) and wheeze are two common conditions in children. GER has been advocated as a causative factor for explaining recurrent to persistent respiratory symptoms at any age. This association very often means that many children with cough, wheezing, or recurrent respiratory infections receive empirical anti-reflux medications. The causal relationship is still largely discussed. Compared to the large number of studies in infants and adolescents, literature on the relationship between GER and wheeze in preschool children is scarce and inconclusive. The aim of the present narrative review was to summarize what is known so far, and what the literature has proposed in the last 20 years, on the relationship between preschool wheezing and GER. In preschool children with respiratory symptoms there is a high rate of positivity of reflux testing, for this reason pH-MII testing and endoscopy are recommended. Flexible bronchoscopy may be useful to exclude anatomical abnormalities as the cause of wheezing in infancy and preschool years. Several biomarkers, as well as empirical anti-reflux therapy, have been proposed for the diagnosis of GER-related airway diseases, but the conclusions of these studies are controversial or even conflicting. There is a great need for future clinical trials to confirm or rule out the association.

The relation between serum vitamin D levels, viral infections and severity of attacks in children with recurrent wheezing

INTRODUCTION AND OBJECTIVES

Vitamin D deficiency is associated with increased susceptibility to infections and wheezing. We aimed to evaluate the relation between vitamin D levels, viral infections and severity of attacks in children with recurrent wheezing.

MATERIALS AND METHODS

A total of 52 patients who applied with wheezing, at the ages of 12-60 months with a history of three or more wheezing attacks in the last year and 54 healthy children were included. Sociodemographic data, risk factors for recurrent wheezing, and the severity of the wheezing attacks were recorded. 25(OH)D3, calcium, phosphor, alkaline phosphatase and parathormone levels of all children were measured. Nasopharyngeal samples of the patients for viruses were studied by multiplex polymerase chain reaction.

RESULTS

For the patient group, being breastfed for six months or less, history of cesarean section, cigarette exposure, humid home environment, and family history of allergic disease were significantly higher compared with the control group. Serum vitamin D levels in the patient group were significantly lower compared to the control group. There was no significant relationship between vitamin D levels and hospitalization, oxygen or steroid therapy. Virus was detected in 38 patients (73%). Rhinovirus (63.2%) was the most frequently detected virus. Coinfection was found in 14 (36.8%) patients. There was no statistically significant difference between detection of virus and vitamin D levels.

CONCLUSIONS

Cigarette exposure, being breastfed six months or less, humid home environment, history of cesarean section, family history of allergic disease and vitamin D deficiency might be risk factors for recurrent wheezing.

Meta-analysis of prevalence of wheezing and recurrent wheezing in infants

BACKGROUND

Wheezing affects children's quality of life, and is related with asthma in childhood. Although prevalence of wheezing has been previously studied in several countries, there is no reference of worldwide prevalence in infants. The aim of this meta-analysis is to estimate the prevalence of wheezing and recurrent wheezing in infants aged up to two years, and compare the prevalence across world regions.

METHODS

Literature search was conducted in MEDLINE and SCOPUS databases, looking for observational studies published up to June 2016, including as keywords "prevalence" or "epidemiology" combined with "wheeze", "wheezing" or "asthma symptoms" and "infant" or "preschool". Fast*Pro software and random effects Bayesian model were used. Heterogeneity was estimated using I² statistic, and sensitivity analyses were performed.

RESULTS

We identified 109 studies after duplicates were removed. After exclusions, 14 studies were included in the meta-analysis. Prevalence of wheezing and recurrent wheezing were 36.06% (95% CI 35.17-36.96), and 17.41% (95% CI 16.74-18.09), respectively. In European countries, prevalence of wheezing was 30.68% (95% CI 28.97-32.45), and 12.35% (95% CI 11.27-13.47) for recurrent wheezing. Prevalence of wheezing and recurrent wheezing in Latin America were higher, 40.55% (95% CI 39.40-41.71), and 19.27% (95% CI 18.44-20.11), respectively. In Africa, prevalence of wheezing was 15.97% (95% CI 14.05-18.00). Low or no heterogeneity was found in all cases.

CONCLUSIONS

More than one third of infants suffer from wheezing and almost one fifth from recurrent wheezing, being these illnesses especially prevalent in Latin American countries, pointing out an important public health problem.

The effect of early child care attendance on childhood asthma and wheezing: A meta-analysis

OBJECTIVE

Research evidence offers mixed results regarding the relationship between early child care attendance and childhood asthma and wheezing. A meta-analysis was conducted to synthesize the current research evidence of the association between early child care attendance and the risk of childhood asthma and wheezing.

METHOD

Peer reviewed studies published from 1964-January 2017 were identified in MEDLINE, CINAL, and EMBASE using MeSH headings relevant to child care and asthma. Two investigators independently reviewed the selected articles from this search. All relevant articles that met our inclusion criteria were selected for further analysis. Data were extracted from studies that had sufficient data to analyze the odds of asthma or wheezing among children who attended child care.

RESULTS

The meta-analysis of 32 studies found that (1) early child care attendance is protective against asthma in children 3-5 years of age but not for children with asthma 6 years of age or older. (2) Early child care attendance increases the risk of wheezing among children 2 years of age or younger, but not the risk of wheezing for children over 2 years of age.

CONCLUSIONS

This meta-analysis shows that early child care attendance is not significantly associated with the risk of asthma or wheeze in children 6 years of age or older.

Propranolol treatment for infantile hemangioma does not increase risk of childhood wheezing

OBJECTIVE

Propranolol is the treatment of choice for infantile hemangiomas requiring medical intervention. Although contraindicated in asthma, its bronchoconstrictive effect in infants and children has not been extensively studied. We aimed to assess the incidence of wheezing episodes in infants and children treated with propranolol for infantile hemangiomas.

STUDY DESIGN

A retrospective case-control study.

SETTING

a tertiary pediatric hospital.

PATIENTS

All Children followed for infantile hemangioma between 2009 and 2014. Children followed conservatively served as control group and were matched 1:1 for gender and month of birth by random matching to children treated with propranolol.

INTERVENTIONS

All respiratory episodes (asthma, wheezing, stridor, and pneumonia) and respiratory associated hospitalizations were recorded from hospital records, from the primary care physician visits records and pharmacy prescriptions. The main outcome measure was the incidence of respiratory episodes in the treatment and the control groups.

RESULTS

A total of 1828 clinic visits were reviewed for 683 children. In addition, primary care physician visits records were available in 80% of them. Two hundred and sixteen children were treated with propranolol. Incidence of respiratory episodes and recurrent respiratory episodes was similar in the propranolol and control groups (8.3% vs 12%, P = 0.265; 3.7% vs 6.5%, P = 0.274, respectively). Time to first episode was similar in the treatment and control groups (5.03 ± 3.32 vs 4.45 ± 3.21 months, respectively, P = 0.09). Respiratory hospital admission rate was similar in both groups.

CONCLUSIONS

Propranolol treatment does not exacerbate wheezing episodes in infants and children.

Duration of exclusive breastfeeding and wheezing in the first year of life: A longitudinal study

INTRODUCTION

Wheezing is the most common symptom associated with asthma in young children. There is a lack of well-designed prospective studies on the relationship of exclusive breastfeeding with wheezing in infants. This prospective cohort study investigated whether a relationship exists of exclusive breastfeeding with wheezing at 12 months of age.

MATERIALS AND METHODS

A series of 1632 mother-infant pairs were sequentially recruited. Mothers were trained at hospital on breastfeeding practices and how to recognise wheezing. At hospital discharge they received a calendar-diary to record the date at stopping breastfeeding and at onset of wheezing. Data were collected by telephone interviews through 12 months post-delivery. Breastfeeding was in accordance with the World Health Organisation and wheezing with the International Classification of Diseases (ICD-10-CM code R06.2).

RESULTS

At 12 months 1522 mother-infant pairs were participating. Breastfeeding started in 95.9% of them and was exclusive in 86.1%. The incidence of wheezing ever and recurrent wheezing at 12 months of age was 33.7% and 10.0%, respectively. Duration of exclusive breastfeeding was shorter in wheezing than non-wheezing infants (median 2.6 months vs. 4.1 months, P<0.001). After adjustment for confounders each month of exclusive breastfeeding reduced the risk of wheezing ever by 11% and of recurrent wheezing by 15%, at 12 months of age.

CONCLUSION

Longer duration of exclusive breastfeeding reduces the risk of wheezing throughout the first 12 months of life. These findings would be relevant to all healthcare operators and mothers, also to improve their awareness about the best feeding practices for the infant's health.

Prevalence and risk factors for wheezing in infants in the region of Pamplona, Spain

BACKGROUND

Wheezing in the first year of life affects the baby's and family's quality of life. Risk factors such as male gender, nursery attending or a family history of asthma, and protective factors such as breastfeeding more than six months have been previously described. The aim of this study is to study the prevalence and risk factors for wheezing ever and recurrent wheezing in the first year of life in infants in the region of Pamplona, Spain.

MATERIAL AND METHODS

This cross-sectional study was part of the International Study of Wheezing in Infants (Estudio Internacional de Sibilancias en Lactantes, EISL). Between 2006 and 2008, participating families answered a standardised validated questionnaire on respiratory symptoms, environmental factors or family issues. An analysis with the chi square test (statistical significance p<0.05) identified the risk factors for wheezing ever and recurrent wheezing, which were assessed using logistic regression.

RESULTS

1065 questionnaires were answered. The prevalence of wheezing ever and recurrent wheezing were 31.2% and 12.3%, respectively. Male gender (p=<0.001), a history of pneumonia (p=<0.001) or nursery attendance (p=<0.001) were some of the risk factors found for wheezing ever. Infant eczema (p=<0.001), nursery attendance (p=<0.001) or prematurity (p=<0.001) were risk factors for recurrent wheezing. No associations with duration of breastfeeding (p=0.116 and p=0.851) or mould stains at home (p=0.153 and p=0.992) were found.

CONCLUSION

The study of prevalence and risk factors for wheezing shows the importance of this public health problem, and allows the development of control and treatment strategies against preventable factors.

Factors associated to recurrent wheezing in infants under one year of age in the province of Salamanca, Spain: Is intervention possible? A predictive model

OBJECTIVES

Wheezing is a very common problem in infants in the first months of life. The objective of this study is to identify risk factors that may be acted upon in order to modify the evolution of recurrent wheezing in the first months of life, and to develop a model based on certain factors associated to recurrent wheezing in nursing infants capable of predicting the probability of developing recurrent wheezing in the first year of life.

METHODS

The sample was drawn from a cross-sectional, multicentre, descriptive epidemiological study based on the general population. A total of 1164 children were studied, corresponding to a questionnaire response rate of 71%. The questionnaire of the Estudio Internacional de Sibilancias en Lactantes (EISL) was used. Multiple logistic regression analysis was used to estimate the probability of developing recurrent wheezing and to quantify the contribution of each individual variable in the presence of the rest.

RESULTS

Infants presenting eczema and attending nursery school, with a mother who has asthma, smoked during the third trimester of pregnancy, and did not consume a Mediterranean diet during pregnancy were found to have a probability of 79.7% of developing recurrent wheezing in the first year of life. In contrast, infants with none of these factors were seen to have a probability of only 4.1% of developing recurrent wheezing in the first year of life. These results in turn varied according to modifications in the risk or protective factors.

CONCLUSIONS

The mathematical model estimated the probability of developing recurrent wheezing in infants under one year of age in the province of Salamanca (Spain), according to the risk or protective factors associated to recurrent wheezing to which the infants are or have been exposed.

Establishing a birth cohort to investigate the course and aetiology of asthma and allergies across three generations - rationale, design, and methods of the ACROSSOLAR study

Background

Atopic diseases are a major burden of disease on a global scale. Regarding their aetiology, the early years of life are assumed to play a crucial role. In addition, there is growing evidence that elucidating the impact of cross-generational effects and epigenetic mechanisms such as DNA methylation can substantially widen the scientific knowledge of the occurrence and progression of these diseases. We are thus aiming at following the course of asthma, allergies, and potential risk factors for their occurrence across three generations by establishing a birth cohort in the offspring of an existing population-based cohort.

Methods/Design

2051 young adults who have been recruited in 1995 for Phase II of the International Study of Asthma and Allergies in Childhood (ISAAC) and who have subsequently been followed-up by the Study on Occupational Allergy Risks (SOLAR) are asked bi-annually since 2009 if they conceived a child in the meantime. If parenthood is reported, parents are invited to enrol along with their children in the ACROSSOLAR cohort. Participation involves completing a questionnaire assessing general and health-related information about the course of the pregnancy and the first year of life of their children. Subsequently, the children are followed up until primary school age when asthma and allergies can be diagnosed reliably. In addition, DNA for epigenetic analysis will be collected and analysed. Longitudinal data analysis techniques will then be used to assess potential associations between early-life exposures and onset of childhood asthma and allergies taking into account epigenetics.

Discussion

Birth cohorts are especially suited to elucidate the impact of genetic predisposition, epigenetics, exposures during the first years of life, and gene-environment interactions on the occurrence and progression of asthma and allergies. By building upon an existing cohort, ACROSSOLAR offers a unique and cost-effective opportunity to investigate the aetiology of atopic disease in a prospective and cross-generational way.

Wheezing and risk factors in the first year of life in Cantabria, Spain. The EISL study

OBJECTIVES

To determine the prevalence of wheezing during the first year of life in Cantabria, Spain and its associated risk factors.

METHODOLOGY

A cross-sectional, multicentre, descriptive epidemiological study was carried out in a representative sample of 958 infants in the first year of life, born in Cantabria. A previously validated and standardised written questionnaire was completed by the parents of infants seen between 12 and 15 months of age in the Primary Care Centres.

RESULTS

The prevalence of wheezing was 32.7%. A relationship was found with male gender (OR 1.38, 95%CI [1.05-1.81]), the presence of a sibling (OR 2.43 [1.38-3.98]), attending nursery school (OR 2.40 [1.71-3.35]), exclusive breastfeeding for <3 months (OR 1.47 [1.12-1.93]), a first cold at ≤3 months (OR 2.07 [1.56-2.74]), asthma in siblings (OR 2.17 [1.25-3.77]), parental allergic rhinitis (OR 1.62 [1.10-2.37]) and paracetamol use >1 a week (OR 2.49 [1.31-4.73]), and maternal smoking during pregnancy (OR 2.18 [1.51-3.15]). The prevalence of recurrent wheezing (≥3 episodes) was 14.3%. Significant associations were observed with the male gender (OR 1.79 [1.23-2.60]), attending nursery school (OR 2.92 [1.96-4.35]), first cold at ≤3 months (OR 2.11 [1.46-3.04]), eczema (OR 1.92 [1.21-3.04]), maternal asthma (OR 1.77 [1.00-3.14]), exclusive breastfeeding for <3 months (OR 1.53 [1.06-2.22]), and maternal smoking during pregnancy (OR 1.53 [1.05-2.22]).

CONCLUSIONS

One third of the infants experienced wheezing during the first year of life; those who were less exclusively breastfed, attended nursery school, presented eczema, family asthma or allergic rhinitis, and maternal smoking during pregnancy.

Epidemiological aspects of and risk factors for wheezing in the first year of life

OBJECTIVE:

To determine, in a sample of infants, the prevalence of and risk factors for occasional wheezing (OW) and recurrent wheezing-wheezy baby syndrome (WBS).

METHODS:

Parents of infants (12-15 months of age) completed the International Study of Wheezing in Infants questionnaire.

RESULTS:

We included 1,269 infants residing in the city of Blumenau, Brazil. Of those, 715 (56.34%) had a history of wheezing, which was more common among boys. The prevalences of OW and WBS were 27.03% (n = 343) and 29.31% (n = 372), respectively. On average, the first wheezing episode occurred at 5.55 ± 2.87 months of age. Among the 715 infants with a history of wheezing, the first episode occurred within the first six months of life in 479 (66.99%), and 372 (52.03%) had had three or more episodes. Factors associated with wheezing in general were pneumonia; oral corticosteroid use; a cold; attending daycare; having a parent with asthma or allergies; mother working outside the home; male gender; no breastfeeding; and mold. Factors associated with WBS were a cold; physician-diagnosed asthma; ER visits; corticosteroid use; pneumonia; bronchitis; dyspnea; attending daycare; bronchodilator use; having a parent with asthma; no breastfeeding; mother working outside the home; and a dog in the household.

CONCLUSIONS:

The prevalence of wheezing in the studied population was high (56.34%). The etiology was multifactorial, and the risk factors were intrinsic and extrinsic (respiratory tract infections, allergies, attending daycare, and early wheezing). The high prevalence and the intrinsic risk factors indicate the need and the opportunity for epidemiological and genetic studies in this population. In addition, mothers should be encouraged to prolong breastfeeding and to keep infants under six months of age out of daycare.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prevalence and risk factors for wheezing in Salvador, Brazil: a population-based study

BACKGROUND

Wheezing is one of the most frequent causes of visit to emergency rooms among children. However, data on wheezing burden are mostly provided at healthcare setting, and particularly only for infants.

AIMS

We sought to estimate the prevalence of wheezing in children under 4 years and to assess potential risk factors in the community.

DESIGN

This was a cross-sectional analysis of a population-based cohort study.

METHODS

The sample comprised children aged <4 years living in Salvador, Brazil. Data were collected via home visits when the parents/guardians were interviewed. Data were recorded on standardized forms.

RESULTS

Of 1534 children, mean age was 21 ± 14 months (minimum 3 days; maximum 47 months; 6% <2 months); 780 (51%) were males and 501 [33%; 95% confidence interval (95% CI): 30-35%] reported wheezing in the last 12 months. Among wheezers, 321 (64%) had occasional wheezing. Overall, 180 (12%; 95% CI: 10-14%) had recurrent wheezing and 157 (10%; 95% CI: 9-12%) had asthma. For children in the first, second, third and fourth year of life wheezing was reported in 23, 41, 34 and 37%, respectively. Mother atopic-related disease was independently associated with recurrent wheezing (AdjPR[95% CI]: 1.54 [1.12-2.11]) and asthma (AdjPR[95% CI]: 1.54 [1.10-2.16]). Smoker at home (AdjPR[95% CI]: 1.34 [1.07-1.67]) and low birth weight (AdjPR[95%CI]: 1.38 [1.05-1.81]) were independently associated with occasional wheezing.

CONCLUSIONS

One-third of under 4 years reported wheezing; history of mother's atopic-related disease was an independent risk factor for recurrent wheezing and asthma; smoker at home and low birth weight were independent risk factors for occasional wheezing.

Propranolol for infantile haemangiomas: single centre experience of 250 cases and proposed therapeutic protocol

OBJECTIVE

To assess the safety and efficacy of systemic propranolol for the treatment of complicated infantile haemangiomas.

DESIGN

Retrospective review of case notes of paediatric patients treated with propranolol for complicated infantile haemangiomas.

SETTING

Tertiary care children's hospital.

PATIENTS

All paediatric patients with complicated infantile haemangiomas who commenced treatment with propranolol from July 2008 to December 2011 and have completed treatment for at least 3 months.

RESULTS

250 patients were treated with propranolol; 34.4% were premature and 5.6% postmature. Indications for propranolol included: vision compromise (42.0%), bleeding and/or ulceration (30.4%) airway obstruction (8.8%), feeding difficulty (8.4%), risk of permanent disfigurement (4.4%) and other (6%) (nasal obstruction, auditory canal obstruction, large haemangioma, compression of neck structure and spinal cord). Median age at beginning of treatment was 4.5 months. Median age at end of treatment was 16.7 months. Median length of therapy was 11.8 months. Adverse effects (such as wheezing, worsening of ulceration, sleep disturbance, diarrhoea) occurred in 38 patients (15.2%), leading to modifications in management in 26 patients (10.4%). 240 patients (96%) had good to excellent response to treatment. 20 patients (8%) experienced regrowth of the haemangioma on cessation of propranolol and six patients (2.4%) required propranolol to be restarted.

CONCLUSIONS

In appropriately selected patients, propranolol is a safe and effective treatment for infantile haemangiomas.

Infant wheeze, comorbidities and school age asthma

BACKGROUND

Factors associated with early onset of wheeze have been described, but there is limited knowledge on which of these infant wheezers who will have developed asthma in school age. The aim was to identify clinical risk factors for asthma in the 8-yr-old children that wheezed during infancy in a population-based setting.

METHODS

Three thousand two hundred and fifty-one children from a population-based birth cohort followed prospectively from infancy until age 8 yr were included in the study. Data were analyzed using multivariate logistic regression analysis.

RESULTS

Parents reported any wheeze episode before age 2 yr in 823 subjects (25%). Infant wheezers had an almost fourfold risk of asthma at age 8 [adjusted odds ratio (aOR) 3.68, 95% CI 2.74-4.96], equivalent to an asthma prevalence of 14% compared with 4% among non-wheezers (p < 0.001). After adjustments for sex, exposure to tobacco smoke and indoor dampness/mould, allergic heredity (aOR 1.53, 95% CI 1.02-2.30), increased frequency of wheeze (aOR 3.41, 95% CI 2.09-5.56 for children with ≥3 episodes compared with ≤2 episodes during the first 2 yr of life), infant eczema (aOR 2.31, 95% CI 1.52-3.49), and recurrent abdominal pain (aOR 2.33, 95% CI 1.30-4.16) remained risk factors for school age asthma in the infant wheezing group.

CONCLUSIONS

Among infant wheezers, allergic heredity, increased severity of wheeze, infant eczema, and recurrent abdominal pain were independent risk factors for asthma at age 8 yr. Among children with three or four of these risk factors, 38% had asthma at school age.

Preterm birth and childhood wheezing disorders: a systematic review and meta-analysis

BACKGROUND

Accumulating evidence implicates early life factors in the aetiology of non-communicable diseases, including asthma/wheezing disorders. We undertook a systematic review investigating risks of asthma/wheezing disorders in children born preterm, including the increasing numbers who, as a result of advances in neonatal care, now survive very preterm birth.

METHODS AND FINDINGS

Two reviewers independently searched seven online databases for contemporaneous (1 January 1995-23 September 2013) epidemiological studies investigating the association between preterm birth and asthma/wheezing disorders. Additional studies were identified through reference and citation searches, and contacting international experts. Quality appraisal was undertaken using the Effective Public Health Practice Project instrument. We pooled unadjusted and adjusted effect estimates using random-effects meta-analysis, investigated "dose-response" associations, and undertook subgroup, sensitivity, and meta-regression analyses to assess the robustness of associations. We identified 42 eligible studies from six continents. Twelve were excluded for population overlap, leaving 30 unique studies involving 1,543,639 children. Preterm birth was associated with an increased risk of wheezing disorders in unadjusted (13.7% versus 8.3%; odds ratio [OR] 1.71, 95% CI 1.57-1.87; 26 studies including 1,500,916 children) and adjusted analyses (OR 1.46, 95% CI 1.29-1.65; 17 studies including 874,710 children). The risk was particularly high among children born very preterm (<32 wk gestation; unadjusted: OR 3.00, 95% CI 2.61-3.44; adjusted: OR 2.81, 95% CI 2.55-3.12). Findings were most pronounced for studies with low risk of bias and were consistent across sensitivity analyses. The estimated population-attributable risk of preterm birth for childhood wheezing disorders was ≥3.1%. Key limitations related to the paucity of data from low- and middle-income countries, and risk of residual confounding.

CONCLUSIONS

There is compelling evidence that preterm birth-particularly very preterm birth-increases the risk of asthma. Given the projected global increases in children surviving preterm births, research now needs to focus on understanding underlying mechanisms, and then to translate these insights into the development of preventive interventions.

REVIEW REGISTRATION

PROSPERO CRD42013004965.

What drives prescribing of asthma medication to preschool wheezing children? A primary care study

There is limited information on which data primary care pediatricians (PCPs) use to decide whether to prescribe or not asthma maintenance treatment, and what drives prescribing a specific therapy. The study aim was to investigate how prescribing anti-asthma maintenance treatment to preschool wheezing children is influenced by patient, family, environmental, and PCP characteristics. We conducted a cross-sectional study at 32 PCPs sites in Campania, Italy. Medical, family, and environmental information of 376 preschool wheezy children, and characteristics of the enrolled PCPs were collected. Main outcome measures of multilevel multivariate logistic regression analyses were the prescribing of maintenance treatment, and the prescription of a combined therapy as opposed to monotherapy. Variables significantly associated with long-term inhaled corticosteroids (ICS) and/or leukotriene modifiers prescription included frequent wheezing (OR = 7.19), emergency department (ED) visits (OR = 2.21), personal allergic diseases (OR = 8.49), day-care/kindergarten attendance (OR = 2.67), a high PCP prescribing volume (OR = 2.74), and a low proportion of 0- to 5-year-old patients with wheezing diagnosis (OR = 1.16). Leukotriene modifiers plus ICS were much more likely prescribed than ICS or leukotriene modifiers alone to older children (OR = 1.06) and to patients experiencing frequent wheezing (OR = 3.00), ED visits (OR = 3.12), or tobacco smoke exposure during the first 2 years of life (OR = 2.04). Finally, PCP's characteristics significantly associated with ICS plus leukotriene modifiers prescription were group practice (OR = 4.16) and a high prescribing volume (OR = 1.45). Our findings suggest that child characteristics alone are not sufficient to explain how PCPs decide to prescribe maintenance treatment and which therapy to assign, but variables associated to PCPs are crucial as well.

Evaluation of risk factors for recurrent wheezing episodes

Background

We aimed to evaluate the risk factors for recurrent wheezing in patients diagnosed with acute bronchiolitis.

Method

From 2009 to 2011, 500 patients from the pediatric clinics, with first attack of acute bronchiolitis were included in this prospective study. Each patient’s age, gender, birth weight, duration of breastfeeding, family history of atopy and asthma, smoking exposure, source of heating in the house, the presence of pets, any history of chronic disease have been questioned. The patients were followed for a duration of 12 - 24 months.

Results

In this study, 39% (n = 195) of the cases were female and 61% (n = 305) were male, with a median age of 3 months old. Male gender, low birth weight (< 2,500 g), low gestational age (< 37 weeks), breastfeeding of less than 6 months, congenital heart disease, family history of atopy, asthma, smoking exposure, stove warming, was found as significant risk factors for recurrent wheezing, however, presence of pets at home was found to be a protective factor.

Conclusions

Informing parents about the risk factors such as exposure to cigarette smoke, heating mode, duration of breastfeeding can significantly decrease recurrent episodes of wheezing.

The case of drug causation of childhood asthma: antibiotics and paracetamol

AIM

The rising prevalence of bronchial asthma has led to world-wide efforts to understand and stem this development. Cross-sectional studies appear to show that early childhood use of antibiotics may be an important contributory factor, with paracetamol as an additional suspected cause. However, mounting evidence, which is reviewed here, points to various confounding factors as the major reasons for these reported associations.

METHODS

PubMed and EMBASE were systematically searched for studies on associations between antibiotics and/or paracetamol with asthma and/or wheezing, published up to November 2012. A total of 64 pertinent studies were identified, 35 focusing on antibiotics, 19 on paracetamol, and ten addressing both antibiotics and paracetamol, bringing the number of relevant datasets to 74.

RESULTS

Numerous studies were cross-sectional and made no adjustment for the indication of antibiotics or paracetamol; consequently, they were unable to dismiss possible confounding by indication. Where such adjustments could be performed (mostly in longitudinal studies), they substantially weakened or entirely eliminated the association with asthma or asthma surrogates present in the unadjusted data.

CONCLUSION

The weight of evidence of the collected studies in our review strongly suggests that the association of antibiotics with childhood asthma reflects various forms of bias, the most prominent of which is confounding by indication. Recent studies and meta-analyses support the same conclusion for paracetamol. Truly indicated antibiotics should not be withheld from infants or young children for fears they might develop asthma. Likewise, there is no sound reason to replace paracetamol as the preferred pain relief and fever medication in this age group.

Risk factors and characteristics of respiratory and allergic phenotypes in early childhood

BACKGROUND

Unsupervised approaches can be used to analyze complex respiratory and allergic disorders.

OBJECTIVE

We investigated the respiratory and allergic phenotypes of children followed in the Pollution and Asthma Risk: An Infant Study (PARIS) birth cohort.

METHODS

Information on respiratory and allergic disorders, medical visits, and medications was collected during medical examinations of children at 18 months of age; biomarker data were also collected (total and allergen-specific IgE levels and eosinophilia). Phenotypes were determined by using latent class analysis. Associated risk factors were determined based on answers to questionnaires about environmental exposures.

RESULTS

Apart from a reference group, which had a low prevalence of respiratory symptoms or allergies (n=1271 [69.4%]), 3 phenotypes were identified. On the basis of clinical signs of severity and use of health care resources, we identified a mild phenotype (n=306 [16.7%]) characterized by occasional mild wheeze and 2 severe phenotypes separated by atopic status. The atopic severe phenotype (n=59 [3.2%]) included 49 (83%) children with wheezing and was characterized by a high prevalence of atopy (61% with allergenic sensitization) and atopic dermatitis (78%). In contrast, atopy was rare among children with the nonatopic severe phenotype (n=195 [11%]); this group included 88% of the children with recurrent wheezing. Risk factors for respiratory disease included parental history of asthma, male sex, siblings, day care attendance, exposure to tobacco smoke or molds, indoor renovations, and being overweight, although these factors did not have similar affects on risk for all phenotypes.

CONCLUSION

Atopy should be taken into account when assessing the risk of severe exacerbations (that require hospital-based care) in wheezing infants; precautions should be taken against respiratory irritants and molds and to prevent children from becoming overweight.

Respiratory tract illnesses during the first year of life: effect of dog and cat contacts

OBJECTIVES

To investigate the effect of dog and cat contacts on the frequency of respiratory symptoms and infections during the first year of life.

METHODS

In this birth cohort study, 397 children were followed up from pregnancy onward, and the frequency of respiratory symptoms and infections together with information about dog and cat contacts during the first year of life were reported by using weekly diaries and a questionnaire at the age of 1 year. All the children were born in eastern or middle Finland between September 2002 and May 2005.

RESULTS

In multivariate analysis, children having dogs at home were healthier (ie, had fewer respiratory tract symptoms or infections) than children with no dog contacts (adjusted odds ratio, [aOR]: 1.31; 95% confidence interval [CI]: 1.13-1.52). Furthermore, children having dog contacts at home had less frequent otitis (aOR: 0.56; 95% CI: 0.38-0.81) and tended to need fewer courses of antibiotics (aOR: 0.71; 95% CI: 0.52-0.96) than children without such contacts. In univariate analysis, both the weekly amount of contact with dogs and cats and the average yearly amount of contact were associated with decreased respiratory infectious disease morbidity.

CONCLUSIONS

These results suggest that dog contacts may have a protective effect on respiratory tract infections during the first year of life. Our findings support the theory that during the first year of life, animal contacts are important, possibly leading to better resistance to infectious respiratory illnesses during childhood.

Influence of host and environmental factors on wheezing severity in infants: findings from the PARIS birth cohort

BACKGROUND

Determinants of wheezing severity are poorly documented in infants.

OBJECTIVES

To study the determinants of wheezing severity in infants aged 18 months followed-up in the PARIS (« Pollution and Asthma Risk : an Infant Study ») birth cohort.

METHODS

Data on wheezing disorders, medical visits and medications, as well as biological markers of atopy, were collected during a medical examination at age 18 months. Severe wheeze was defined as wheeze that required inhaled corticosteroid and/or hospital-based care. Environmental exposures were assessed prospectively with regular questionnaires. Risk factors for wheeze in the first 18 months of life were assessed by multivariate regression models.

RESULTS

Participation in the medical examination concerned 48.2% of the original cohort. Prevalence of wheeze was 560/1879 (35.7%) and was influenced by male gender, parental history of asthma, siblings, daycare attendance, heavy parental smoking at home, and carpet covered floor in the child's bedroom. Being overweight increased the risk of wheeze by 62% (OR = 1.62, 95%CI 1.13-2.32). In addition, trends towards an increased risk of wheeze were found in infants exposed to daily use of cleaning sprays and to renovation activities. Conversely, the presence of a cat reduced the risk of wheeze (OR = 0.65, 95%CI 0.47-0.89), without any evidence of healthy-pet keeping effect. Severe wheeze concerned 286 of the wheezers (42.7%). The prevalence of severe wheeze was related to atopy, and risk of severe wheeze was in particular increased in infants having eosinophilia (OR = 1.76, 95%CI 1.21-2.55) or being sensitized to ≥ 2 allergens (OR = 1.88, 95%CI 1.13-3.14).

CONCLUSIONS AND CLINICAL RELEVANCE

Whilst risk factors for wheeze before 18 months of age are factors related to infections, indoor air pollution, and being overweight, the severity of wheeze is mainly due to the atopic status of the child. We suggest that atopy should be further considered in the assessment of wheezing severity in infants.

Study of wheezing and its risk factors in the first year of life in the Province of Salamanca, Spain. The EISL Study

OBJECTIVES

To determine the prevalence of wheezing and its associated risk factors in infants in the first year of life in the province of Salamanca, Spain.

METHODS

A multicentre, cross-sectional, descriptive epidemiological study was designed to evaluate a representative sample of 750 infants in the first year of life, born in the province of Salamanca between 1 June 2008 and 30 September 2009. The study was based on a previously validated and standardised written questionnaire administered among the parents of those children seen for control at 12 months of age in any of the Primary Care centres in the province of Salamanca.

RESULTS

The recorded wheezing rate was 32.3%. Feeding and sleep were seen to be affected in 46.3% and 80.9% of the wheezing children, respectively, and parent activity was also altered in 39.3% of the cases. A relationship was found between wheezing and nursery attendance (OR: 1.66, 95% confidence interval [1.19-2.31]); weight at birth >3500 g (OR: 1.45 [1.02-2.06]); the presence of eczema at this age (OR: 2.72 [1.75-4.24]); exclusive breastfeeding for <3 months (OR: 1.33 [0.98-1.81]); and maternal smoking during the last three months of pregnancy (OR: 1.60 [0.96-2.68]). The prevalence of recurrent wheezing (defined as three or more episodes) was 11.9%. Significant differences were observed with respect to nursery attendance (OR: 1.71 [1.08-2.72]), the presence of eczema at this age (OR: 2.55 [1.48-4.42]), a history of maternal asthma (OR: 2.19 [1.08-4.44]) and exclusive breastfeeding for <3 months (OR: 1.53 [0.98-2.38]).

CONCLUSIONS

In the province of Salamanca, one third of the infants studied suffered wheezing in the first year of life. Infants exclusively breastfed for less than three months; attending a nursery; having suffered eczema; or with an asthmatic mother showed significantly more wheezing than the rest. Wheezing proved recurrent in 11.9% of the cases.

Recurrent wheeze in children with Down syndrome: is it asthma?

AIM

To compare the prevalence of current wheeze in children with Down syndrome (DS), their siblings, and nonrelated population controls.

METHODS

This was a case-control study in which the International Study of Asthma and Allergy in Childhood questionnaire for respiratory symptoms was completed by parents for 130 children with DS, 167 of their siblings, and for 119 age- and sex-matched control subjects from the general population.

RESULTS

Both wheeze ever and wheeze during the last 12 months was more commonly reported in DS than in their siblings or controls. The relative risk (RR) of current wheeze in DS was 2.8 (95% CI, 1.42-5.51) compared with siblings, and 2.75 (95% CI, 1.28-5.88) compared with controls. A doctor's diagnosis of asthma was found in 3.1% in children with DS, in 4.2% in siblings and in 6.7% in controls. During 4-years follow-up, the diagnosis of asthma could not be confirmed in the 24 DS children with current wheeze, and atopy was found in none of them.

CONCLUSION

Wheeze is common in children with DS. This is likely to be related to the factors specific for DS and probably unrelated to asthma.

Episodic viral wheeze and multiple trigger wheeze in preschool children: a useful distinction for clinicians?

Accumulating evidence suggest that splitting preschool recurrent wheezing disorders into Episodic (Viral) Wheeze (EVW) and Multiple Trigger Wheeze (MTW) is an oversimplification. There is little evidence that the EVW and MTW phenotypes are related to the longitudinal patterns of wheeze, or to different underlying pathological processes. As the clinical response to inhaled corticosteroids and montelukast varies considerably between individual children with EVW, and between individual patients with MTW, the clinical usefulness of the EVW-MTW approach is doubtful. Based on the currently available evidence, we propose to describe preschool wheeze symptoms not only in terms of temporal pattern, but also in terms of frequency and severity, and age of onset. Relevant associated clinical parameters like atopy and eczema should be described with recognition of age of onset, pattern, and severity. Comparing these data to biomarkers and histopathology may help to improve our understanding of preschool wheezing disorders in the future. Until phenotypes can be described that are associated with different pathobiological process, are related to different longitudinal outcomes, or are clearly different in terms of response to therapy, clinicians are encouraged to take a trial and error approach of different therapeutic agents in preschool children with troublesome recurrent wheeze.

The influence of environment, as represented by diet and air pollution, upon incidence and prevalence of wheezing illnesses in young children

PURPOSE OF REVIEW

The purpose of this review is to consider the collective influence of factors affecting recurrent wheezing in young children.

RECENT FINDINGS

Specific allergen sensitization, upper respiratory infections, genetic polymorphisms and environmental factors have collectively been reported in the prevalence of and induction of recurrent wheezing in young children. Two examples of environmental factors are diet and exposure to air pollution, both of which are potentially modifiable. Recent investigations provide evidence that a 'Mediterranean diet' and a diet that emphasizes polyunsaturated fatty acids during pregnancy and early infancy, as well as breastfeeding, may be protective for wheezing, and that exposure to traffic-related pollution may be an independent factor in the incidence of wheezing in young children.

SUMMARY

Recent studies of early childhood wheezing demonstrate a potentially protective effect of diet and exposure to air pollution as a significant risk factor. An evaluation of collective factors influencing the presence of disease may help to broaden the clinical assessment and give parents and physicians the opportunity to potentially modify circumstances that promote the incidence of recurrent wheezing in infants and preschool aged children.

Vaccination coverage and risk factors for incomplete vaccination in children with recurrent wheeze

AIM

To determine the possible impact of recurrent wheeze on immunisation status in the first three years of life.

METHOD

A cross-sectional case control study of 288 children less than three years of age with a history of recurrent wheezing, hospitalised at a single centre for wheeze; and a control group of 190 children with no prior history of wheezing. Vaccination charts of all children were analysed according to the National Immunisation Schedule. Additionally, some associated data were collected through a questionnaire to the parents.

RESULTS

Children with recurrent wheezing during the first three years of life were less likely to be vaccinated against BCG (Bacillus-Calmette-Guerin), hepatitis B, Hib (Haemophilus influenza type B), and MMR (Measles, Mumps, Rubella) (p < 0.001). A significant inverse association was also found between the number of wheezy episodes and the number of vaccine doses received. The odds ratio of incomplete vaccination in children with recurrent wheeze was 10.6 (95% CI, 2.96 to 38.1).

CONCLUSION

Children under three years of age with recurrent wheeze run a high risk of incomplete immunisation. Efforts should be therefore made to insure that such children receive adequate vaccination.

Prevalence and severity of wheezing in the first year of life

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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